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1	@chapter Encoders
2	@c man begin ENCODERS
3
4	Encoders are configured elements in FFmpeg which allow the encoding of
5	multimedia streams.
6
7	When you configure your FFmpeg build, all the supported native encoders
8	are enabled by default. Encoders requiring an external library must be enabled
9	manually via the corresponding @code{--enable-lib} option. You can list all
10	available encoders using the configure option @code{--list-encoders}.
11
12	You can disable all the encoders with the configure option
13	@code{--disable-encoders} and selectively enable / disable single encoders
14	with the options @code{--enable-encoder=@var{ENCODER}} /
15	@code{--disable-encoder=@var{ENCODER}}.
16
17	The option @code{-encoders} of the ff* tools will display the list of
18	enabled encoders.
19
20	@c man end ENCODERS
21
22	@chapter Audio Encoders
23	@c man begin AUDIO ENCODERS
24
25	A description of some of the currently available audio encoders
26	follows.
27
28	@anchor{aacenc}
29	@section aac
30
31	Advanced Audio Coding (AAC) encoder.
32
33	This encoder is the default AAC encoder, natively implemented into FFmpeg. Its
34	quality is on par or better than libfdk_aac at the default bitrate of 128kbps.
35	This encoder also implements more options, profiles and samplerates than
36	other encoders (with only the AAC-HE profile pending to be implemented) so this
37	encoder has become the default and is the recommended choice.
38
39	@subsection Options
40
41	@table @option
42	@item b
43	Set bit rate in bits/s. Setting this automatically activates constant bit rate
44	(CBR) mode. If this option is unspecified it is set to 128kbps.
45
46	@item q
47	Set quality for variable bit rate (VBR) mode. This option is valid only using
48	the @command{ffmpeg} command-line tool. For library interface users, use
49	@option{global_quality}.
50
51	@item cutoff
52	Set cutoff frequency. If unspecified will allow the encoder to dynamically
53	adjust the cutoff to improve clarity on low bitrates.
54
55	@item aac_coder
56	Set AAC encoder coding method. Possible values:
57
58	@table @samp
59	@item twoloop
60	Two loop searching (TLS) method.
61
62	This method first sets quantizers depending on band thresholds and then tries
63	to find an optimal combination by adding or subtracting a specific value from
64	all quantizers and adjusting some individual quantizer a little. Will tune
65	itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns}
66	are enabled.
67	This is the default choice for a coder.
68
69	@item anmr
70	Average noise to mask ratio (ANMR) trellis-based solution.
71
72	This is an experimental coder which currently produces a lower quality, is more
73	unstable and is slower than the default twoloop coder but has potential.
74	Currently has no support for the @option{aac_is} or @option{aac_pns} options.
75	Not currently recommended.
76
77	@item fast
78	Constant quantizer method.
79
80	This method sets a constant quantizer for all bands. This is the fastest of all
81	the methods and has no rate control or support for @option{aac_is} or
82	@option{aac_pns}.
83	Not recommended.
84
85	@end table
86
87	@item aac_ms
88	Sets mid/side coding mode. The default value of "auto" will automatically use
89	M/S with bands which will benefit from such coding. Can be forced for all bands
90	using the value "enable", which is mainly useful for debugging or disabled using
91	"disable".
92
93	@item aac_is
94	Sets intensity stereo coding tool usage. By default, it's enabled and will
95	automatically toggle IS for similar pairs of stereo bands if it's benefitial.
96	Can be disabled for debugging by setting the value to "disable".
97
98	@item aac_pns
99	Uses perceptual noise substitution to replace low entropy high frequency bands
100	with imperceivable white noise during the decoding process. By default, it's
101	enabled, but can be disabled for debugging purposes by using "disable".
102
103	@item aac_tns
104	Enables the use of a multitap FIR filter which spans through the high frequency
105	bands to hide quantization noise during the encoding process and is reverted
106	by the decoder. As well as decreasing unpleasant artifacts in the high range
107	this also reduces the entropy in the high bands and allows for more bits to
108	be used by the mid-low bands. By default it's enabled but can be disabled for
109	debugging by setting the option to "disable".
110
111	@item aac_ltp
112	Enables the use of the long term prediction extension which increases coding
113	efficiency in very low bandwidth situations such as encoding of voice or
114	solo piano music by extending constant harmonic peaks in bands throughout
115	frames. This option is implied by profile:a aac_low and is incompatible with
116	aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
117
118	@item aac_pred
119	Enables the use of a more traditional style of prediction where the spectral
120	coefficients transmitted are replaced by the difference of the current
121	coefficients minus the previous "predicted" coefficients. In theory and sometimes
122	in practice this can improve quality for low to mid bitrate audio.
123	This option implies the aac_main profile and is incompatible with aac_ltp.
124
125	@item profile
126	Sets the encoding profile, possible values:
127
128	@table @samp
129	@item aac_low
130	The default, AAC "Low-complexity" profile. Is the most compatible and produces
131	decent quality.
132
133	@item mpeg2_aac_low
134	Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
135	MPEG4 specifications.
136
137	@item aac_ltp
138	Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
139	option. Introduced in MPEG4.
140
141	@item aac_main
142	Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
143	option. Introduced in MPEG2.
144
145	@end table
146	If this option is unspecified it is set to @samp{aac_low}.
147	@end table
148
149	@section ac3 and ac3_fixed
150
151	AC-3 audio encoders.
152
153	These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
154	the undocumented RealAudio 3 (a.k.a. dnet).
155
156	The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
157	encoder only uses fixed-point integer math. This does not mean that one is
158	always faster, just that one or the other may be better suited to a
159	particular system. The floating-point encoder will generally produce better
160	quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
161	default codec for any of the output formats, so it must be specified explicitly
162	using the option @code{-acodec ac3_fixed} in order to use it.
163
164	@subsection AC-3 Metadata
165
166	The AC-3 metadata options are used to set parameters that describe the audio,
167	but in most cases do not affect the audio encoding itself. Some of the options
168	do directly affect or influence the decoding and playback of the resulting
169	bitstream, while others are just for informational purposes. A few of the
170	options will add bits to the output stream that could otherwise be used for
171	audio data, and will thus affect the quality of the output. Those will be
172	indicated accordingly with a note in the option list below.
173
174	These parameters are described in detail in several publicly-available
175	documents.
176	@itemize
177	@item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
178	@item @uref{http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf,A/54 - Guide to the Use of the ATSC Digital Television Standard}
179	@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
180	@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
181	@end itemize
182
183	@subsubsection Metadata Control Options
184
185	@table @option
186
187	@item -per_frame_metadata @var{boolean}
188	Allow Per-Frame Metadata. Specifies if the encoder should check for changing
189	metadata for each frame.
190	@table @option
191	@item 0
192	The metadata values set at initialization will be used for every frame in the
193	stream. (default)
194	@item 1
195	Metadata values can be changed before encoding each frame.
196	@end table
197
198	@end table
199
200	@subsubsection Downmix Levels
201
202	@table @option
203
204	@item -center_mixlev @var{level}
205	Center Mix Level. The amount of gain the decoder should apply to the center
206	channel when downmixing to stereo. This field will only be written to the
207	bitstream if a center channel is present. The value is specified as a scale
208	factor. There are 3 valid values:
209	@table @option
210	@item 0.707
211	Apply -3dB gain
212	@item 0.595
213	Apply -4.5dB gain (default)
214	@item 0.500
215	Apply -6dB gain
216	@end table
217
218	@item -surround_mixlev @var{level}
219	Surround Mix Level. The amount of gain the decoder should apply to the surround
220	channel(s) when downmixing to stereo. This field will only be written to the
221	bitstream if one or more surround channels are present. The value is specified
222	as a scale factor. There are 3 valid values:
223	@table @option
224	@item 0.707
225	Apply -3dB gain
226	@item 0.500
227	Apply -6dB gain (default)
228	@item 0.000
229	Silence Surround Channel(s)
230	@end table
231
232	@end table
233
234	@subsubsection Audio Production Information
235	Audio Production Information is optional information describing the mixing
236	environment. Either none or both of the fields are written to the bitstream.
237
238	@table @option
239
240	@item -mixing_level @var{number}
241	Mixing Level. Specifies peak sound pressure level (SPL) in the production
242	environment when the mix was mastered. Valid values are 80 to 111, or -1 for
243	unknown or not indicated. The default value is -1, but that value cannot be
244	used if the Audio Production Information is written to the bitstream. Therefore,
245	if the @code{room_type} option is not the default value, the @code{mixing_level}
246	option must not be -1.
247
248	@item -room_type @var{type}
249	Room Type. Describes the equalization used during the final mixing session at
250	the studio or on the dubbing stage. A large room is a dubbing stage with the
251	industry standard X-curve equalization; a small room has flat equalization.
252	This field will not be written to the bitstream if both the @code{mixing_level}
253	option and the @code{room_type} option have the default values.
254	@table @option
255	@item 0
256	@itemx notindicated
257	Not Indicated (default)
258	@item 1
259	@itemx large
260	Large Room
261	@item 2
262	@itemx small
263	Small Room
264	@end table
265
266	@end table
267
268	@subsubsection Other Metadata Options
269
270	@table @option
271
272	@item -copyright @var{boolean}
273	Copyright Indicator. Specifies whether a copyright exists for this audio.
274	@table @option
275	@item 0
276	@itemx off
277	No Copyright Exists (default)
278	@item 1
279	@itemx on
280	Copyright Exists
281	@end table
282
283	@item -dialnorm @var{value}
284	Dialogue Normalization. Indicates how far the average dialogue level of the
285	program is below digital 100% full scale (0 dBFS). This parameter determines a
286	level shift during audio reproduction that sets the average volume of the
287	dialogue to a preset level. The goal is to match volume level between program
288	sources. A value of -31dB will result in no volume level change, relative to
289	the source volume, during audio reproduction. Valid values are whole numbers in
290	the range -31 to -1, with -31 being the default.
291
292	@item -dsur_mode @var{mode}
293	Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
294	(Pro Logic). This field will only be written to the bitstream if the audio
295	stream is stereo. Using this option does @b{NOT} mean the encoder will actually
296	apply Dolby Surround processing.
297	@table @option
298	@item 0
299	@itemx notindicated
300	Not Indicated (default)
301	@item 1
302	@itemx off
303	Not Dolby Surround Encoded
304	@item 2
305	@itemx on
306	Dolby Surround Encoded
307	@end table
308
309	@item -original @var{boolean}
310	Original Bit Stream Indicator. Specifies whether this audio is from the
311	original source and not a copy.
312	@table @option
313	@item 0
314	@itemx off
315	Not Original Source
316	@item 1
317	@itemx on
318	Original Source (default)
319	@end table
320
321	@end table
322
323	@subsection Extended Bitstream Information
324	The extended bitstream options are part of the Alternate Bit Stream Syntax as
325	specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
326	If any one parameter in a group is specified, all values in that group will be
327	written to the bitstream. Default values are used for those that are written
328	but have not been specified. If the mixing levels are written, the decoder
329	will use these values instead of the ones specified in the @code{center_mixlev}
330	and @code{surround_mixlev} options if it supports the Alternate Bit Stream
331	Syntax.
332
333	@subsubsection Extended Bitstream Information - Part 1
334
335	@table @option
336
337	@item -dmix_mode @var{mode}
338	Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
339	(Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
340	@table @option
341	@item 0
342	@itemx notindicated
343	Not Indicated (default)
344	@item 1
345	@itemx ltrt
346	Lt/Rt Downmix Preferred
347	@item 2
348	@itemx loro
349	Lo/Ro Downmix Preferred
350	@end table
351
352	@item -ltrt_cmixlev @var{level}
353	Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
354	center channel when downmixing to stereo in Lt/Rt mode.
355	@table @option
356	@item 1.414
357	Apply +3dB gain
358	@item 1.189
359	Apply +1.5dB gain
360	@item 1.000
361	Apply 0dB gain
362	@item 0.841
363	Apply -1.5dB gain
364	@item 0.707
365	Apply -3.0dB gain
366	@item 0.595
367	Apply -4.5dB gain (default)
368	@item 0.500
369	Apply -6.0dB gain
370	@item 0.000
371	Silence Center Channel
372	@end table
373
374	@item -ltrt_surmixlev @var{level}
375	Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
376	surround channel(s) when downmixing to stereo in Lt/Rt mode.
377	@table @option
378	@item 0.841
379	Apply -1.5dB gain
380	@item 0.707
381	Apply -3.0dB gain
382	@item 0.595
383	Apply -4.5dB gain
384	@item 0.500
385	Apply -6.0dB gain (default)
386	@item 0.000
387	Silence Surround Channel(s)
388	@end table
389
390	@item -loro_cmixlev @var{level}
391	Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
392	center channel when downmixing to stereo in Lo/Ro mode.
393	@table @option
394	@item 1.414
395	Apply +3dB gain
396	@item 1.189
397	Apply +1.5dB gain
398	@item 1.000
399	Apply 0dB gain
400	@item 0.841
401	Apply -1.5dB gain
402	@item 0.707
403	Apply -3.0dB gain
404	@item 0.595
405	Apply -4.5dB gain (default)
406	@item 0.500
407	Apply -6.0dB gain
408	@item 0.000
409	Silence Center Channel
410	@end table
411
412	@item -loro_surmixlev @var{level}
413	Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
414	surround channel(s) when downmixing to stereo in Lo/Ro mode.
415	@table @option
416	@item 0.841
417	Apply -1.5dB gain
418	@item 0.707
419	Apply -3.0dB gain
420	@item 0.595
421	Apply -4.5dB gain
422	@item 0.500
423	Apply -6.0dB gain (default)
424	@item 0.000
425	Silence Surround Channel(s)
426	@end table
427
428	@end table
429
430	@subsubsection Extended Bitstream Information - Part 2
431
432	@table @option
433
434	@item -dsurex_mode @var{mode}
435	Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
436	(7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
437	apply Dolby Surround EX processing.
438	@table @option
439	@item 0
440	@itemx notindicated
441	Not Indicated (default)
442	@item 1
443	@itemx on
444	Dolby Surround EX Off
445	@item 2
446	@itemx off
447	Dolby Surround EX On
448	@end table
449
450	@item -dheadphone_mode @var{mode}
451	Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
452	encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
453	option does @b{NOT} mean the encoder will actually apply Dolby Headphone
454	processing.
455	@table @option
456	@item 0
457	@itemx notindicated
458	Not Indicated (default)
459	@item 1
460	@itemx on
461	Dolby Headphone Off
462	@item 2
463	@itemx off
464	Dolby Headphone On
465	@end table
466
467	@item -ad_conv_type @var{type}
468	A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
469	conversion.
470	@table @option
471	@item 0
472	@itemx standard
473	Standard A/D Converter (default)
474	@item 1
475	@itemx hdcd
476	HDCD A/D Converter
477	@end table
478
479	@end table
480
481	@subsection Other AC-3 Encoding Options
482
483	@table @option
484
485	@item -stereo_rematrixing @var{boolean}
486	Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
487	is an optional AC-3 feature that increases quality by selectively encoding
488	the left/right channels as mid/side. This option is enabled by default, and it
489	is highly recommended that it be left as enabled except for testing purposes.
490
491	@item cutoff @var{frequency}
492	Set lowpass cutoff frequency. If unspecified, the encoder selects a default
493	determined by various other encoding parameters.
494
495	@end table
496
497	@subsection Floating-Point-Only AC-3 Encoding Options
498
499	These options are only valid for the floating-point encoder and do not exist
500	for the fixed-point encoder due to the corresponding features not being
501	implemented in fixed-point.
502
503	@table @option
504
505	@item -channel_coupling @var{boolean}
506	Enables/Disables use of channel coupling, which is an optional AC-3 feature
507	that increases quality by combining high frequency information from multiple
508	channels into a single channel. The per-channel high frequency information is
509	sent with less accuracy in both the frequency and time domains. This allows
510	more bits to be used for lower frequencies while preserving enough information
511	to reconstruct the high frequencies. This option is enabled by default for the
512	floating-point encoder and should generally be left as enabled except for
513	testing purposes or to increase encoding speed.
514	@table @option
515	@item -1
516	@itemx auto
517	Selected by Encoder (default)
518	@item 0
519	@itemx off
520	Disable Channel Coupling
521	@item 1
522	@itemx on
523	Enable Channel Coupling
524	@end table
525
526	@item -cpl_start_band @var{number}
527	Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
528	value higher than the bandwidth is used, it will be reduced to 1 less than the
529	coupling end band. If @var{auto} is used, the start band will be determined by
530	the encoder based on the bit rate, sample rate, and channel layout. This option
531	has no effect if channel coupling is disabled.
532	@table @option
533	@item -1
534	@itemx auto
535	Selected by Encoder (default)
536	@end table
537
538	@end table
539
540	@anchor{flac}
541	@section flac
542
543	FLAC (Free Lossless Audio Codec) Encoder
544
545	@subsection Options
546
547	The following options are supported by FFmpeg's flac encoder.
548
549	@table @option
550	@item compression_level
551	Sets the compression level, which chooses defaults for many other options
552	if they are not set explicitly. Valid values are from 0 to 12, 5 is the
553	default.
554
555	@item frame_size
556	Sets the size of the frames in samples per channel.
557
558	@item lpc_coeff_precision
559	Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
560	default.
561
562	@item lpc_type
563	Sets the first stage LPC algorithm
564	@table @samp
565	@item none
566	LPC is not used
567
568	@item fixed
569	fixed LPC coefficients
570
571	@item levinson
572
573	@item cholesky
574	@end table
575
576	@item lpc_passes
577	Number of passes to use for Cholesky factorization during LPC analysis
578
579	@item min_partition_order
580	The minimum partition order
581
582	@item max_partition_order
583	The maximum partition order
584
585	@item prediction_order_method
586	@table @samp
587	@item estimation
588	@item 2level
589	@item 4level
590	@item 8level
591	@item search
592	Bruteforce search
593	@item log
594	@end table
595
596	@item ch_mode
597	Channel mode
598	@table @samp
599	@item auto
600	The mode is chosen automatically for each frame
601	@item indep
602	Chanels are independently coded
603	@item left_side
604	@item right_side
605	@item mid_side
606	@end table
607
608	@item exact_rice_parameters
609	Chooses if rice parameters are calculated exactly or approximately.
610	if set to 1 then they are chosen exactly, which slows the code down slightly and
611	improves compression slightly.
612
613	@item multi_dim_quant
614	Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
615	applied after the first stage to finetune the coefficients. This is quite slow
616	and slightly improves compression.
617
618	@end table
619
620	@anchor{opusenc}
621	@section opus
622
623	Opus encoder.
624
625	This is a native FFmpeg encoder for the Opus format. Currently its in development and
626	only implements the CELT part of the codec. Its quality is usually worse and at best
627	is equal to the libopus encoder.
628
629	@subsection Options
630
631	@table @option
632	@item b
633	Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
634	to make a good guess.
635
636	@item opus_delay
637	Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
638	decrease quality.
639	@end table
640
641	@anchor{libfdk-aac-enc}
642	@section libfdk_aac
643
644	libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
645
646	The libfdk-aac library is based on the Fraunhofer FDK AAC code from
647	the Android project.
648
649	Requires the presence of the libfdk-aac headers and library during
650	configuration. You need to explicitly configure the build with
651	@code{--enable-libfdk-aac}. The library is also incompatible with GPL,
652	so if you allow the use of GPL, you should configure with
653	@code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
654
655	This encoder is considered to produce output on par or worse at 128kbps to the
656	@ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
657	sounding audio at identical or lower bitrates and has support for the
658	AAC-HE profiles.
659
660	VBR encoding, enabled through the @option{vbr} or @option{flags
661	+qscale} options, is experimental and only works with some
662	combinations of parameters.
663
664	Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
665	higher.
666
667	For more information see the fdk-aac project at
668	@url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
669
670	@subsection Options
671
672	The following options are mapped on the shared FFmpeg codec options.
673
674	@table @option
675	@item b
676	Set bit rate in bits/s. If the bitrate is not explicitly specified, it
677	is automatically set to a suitable value depending on the selected
678	profile.
679
680	In case VBR mode is enabled the option is ignored.
681
682	@item ar
683	Set audio sampling rate (in Hz).
684
685	@item channels
686	Set the number of audio channels.
687
688	@item flags +qscale
689	Enable fixed quality, VBR (Variable Bit Rate) mode.
690	Note that VBR is implicitly enabled when the @option{vbr} value is
691	positive.
692
693	@item cutoff
694	Set cutoff frequency. If not specified (or explicitly set to 0) it
695	will use a value automatically computed by the library. Default value
696	is 0.
697
698	@item profile
699	Set audio profile.
700
701	The following profiles are recognized:
702	@table @samp
703	@item aac_low
704	Low Complexity AAC (LC)
705
706	@item aac_he
707	High Efficiency AAC (HE-AAC)
708
709	@item aac_he_v2
710	High Efficiency AAC version 2 (HE-AACv2)
711
712	@item aac_ld
713	Low Delay AAC (LD)
714
715	@item aac_eld
716	Enhanced Low Delay AAC (ELD)
717	@end table
718
719	If not specified it is set to @samp{aac_low}.
720	@end table
721
722	The following are private options of the libfdk_aac encoder.
723
724	@table @option
725	@item afterburner
726	Enable afterburner feature if set to 1, disabled if set to 0. This
727	improves the quality but also the required processing power.
728
729	Default value is 1.
730
731	@item eld_sbr
732	Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
733	if set to 0.
734
735	Default value is 0.
736
737	@item signaling
738	Set SBR/PS signaling style.
739
740	It can assume one of the following values:
741	@table @samp
742	@item default
743	choose signaling implicitly (explicit hierarchical by default,
744	implicit if global header is disabled)
745
746	@item implicit
747	implicit backwards compatible signaling
748
749	@item explicit_sbr
750	explicit SBR, implicit PS signaling
751
752	@item explicit_hierarchical
753	explicit hierarchical signaling
754	@end table
755
756	Default value is @samp{default}.
757
758	@item latm
759	Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
760
761	Default value is 0.
762
763	@item header_period
764	Set StreamMuxConfig and PCE repetition period (in frames) for sending
765	in-band configuration buffers within LATM/LOAS transport layer.
766
767	Must be a 16-bits non-negative integer.
768
769	Default value is 0.
770
771	@item vbr
772	Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
773	good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
774	(Constant Bit Rate) is enabled.
775
776	Currently only the @samp{aac_low} profile supports VBR encoding.
777
778	VBR modes 1-5 correspond to roughly the following average bit rates:
779
780	@table @samp
781	@item 1
782	32 kbps/channel
783	@item 2
784	40 kbps/channel
785	@item 3
786	48-56 kbps/channel
787	@item 4
788	64 kbps/channel
789	@item 5
790	about 80-96 kbps/channel
791	@end table
792
793	Default value is 0.
794	@end table
795
796	@subsection Examples
797
798	@itemize
799	@item
800	Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
801	container:
802	@example
803	ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
804	@end example
805
806	@item
807	Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
808	High-Efficiency AAC profile:
809	@example
810	ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
811	@end example
812	@end itemize
813
814	@anchor{libmp3lame}
815	@section libmp3lame
816
817	LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
818
819	Requires the presence of the libmp3lame headers and library during
820	configuration. You need to explicitly configure the build with
821	@code{--enable-libmp3lame}.
822
823	See @ref{libshine} for a fixed-point MP3 encoder, although with a
824	lower quality.
825
826	@subsection Options
827
828	The following options are supported by the libmp3lame wrapper. The
829	@command{lame}-equivalent of the options are listed in parentheses.
830
831	@table @option
832	@item b (@emph{-b})
833	Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
834	expressed in kilobits/s.
835
836	@item q (@emph{-V})
837	Set constant quality setting for VBR. This option is valid only
838	using the @command{ffmpeg} command-line tool. For library interface
839	users, use @option{global_quality}.
840
841	@item compression_level (@emph{-q})
842	Set algorithm quality. Valid arguments are integers in the 0-9 range,
843	with 0 meaning highest quality but slowest, and 9 meaning fastest
844	while producing the worst quality.
845
846	@item cutoff (@emph{--lowpass})
847	Set lowpass cutoff frequency. If unspecified, the encoder dynamically
848	adjusts the cutoff.
849
850	@item reservoir
851	Enable use of bit reservoir when set to 1. Default value is 1. LAME
852	has this enabled by default, but can be overridden by use
853	@option{--nores} option.
854
855	@item joint_stereo (@emph{-m j})
856	Enable the encoder to use (on a frame by frame basis) either L/R
857	stereo or mid/side stereo. Default value is 1.
858
859	@item abr (@emph{--abr})
860	Enable the encoder to use ABR when set to 1. The @command{lame}
861	@option{--abr} sets the target bitrate, while this options only
862	tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
863
864	@end table
865
866	@section libopencore-amrnb
867
868	OpenCORE Adaptive Multi-Rate Narrowband encoder.
869
870	Requires the presence of the libopencore-amrnb headers and library during
871	configuration. You need to explicitly configure the build with
872	@code{--enable-libopencore-amrnb --enable-version3}.
873
874	This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
875	but you can override it by setting @option{strict} to @samp{unofficial} or
876	lower.
877
878	@subsection Options
879
880	@table @option
881
882	@item b
883	Set bitrate in bits per second. Only the following bitrates are supported,
884	otherwise libavcodec will round to the nearest valid bitrate.
885
886	@table @option
887	@item 4750
888	@item 5150
889	@item 5900
890	@item 6700
891	@item 7400
892	@item 7950
893	@item 10200
894	@item 12200
895	@end table
896
897	@item dtx
898	Allow discontinuous transmission (generate comfort noise) when set to 1. The
899	default value is 0 (disabled).
900
901	@end table
902
903	@section libopus
904
905	libopus Opus Interactive Audio Codec encoder wrapper.
906
907	Requires the presence of the libopus headers and library during
908	configuration. You need to explicitly configure the build with
909	@code{--enable-libopus}.
910
911	@subsection Option Mapping
912
913	Most libopus options are modelled after the @command{opusenc} utility from
914	opus-tools. The following is an option mapping chart describing options
915	supported by the libopus wrapper, and their @command{opusenc}-equivalent
916	in parentheses.
917
918	@table @option
919
920	@item b (@emph{bitrate})
921	Set the bit rate in bits/s. FFmpeg's @option{b} option is
922	expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
923	kilobits/s.
924
925	@item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
926	Set VBR mode. The FFmpeg @option{vbr} option has the following
927	valid arguments, with the @command{opusenc} equivalent options
928	in parentheses:
929
930	@table @samp
931	@item off (@emph{hard-cbr})
932	Use constant bit rate encoding.
933
934	@item on (@emph{vbr})
935	Use variable bit rate encoding (the default).
936
937	@item constrained (@emph{cvbr})
938	Use constrained variable bit rate encoding.
939	@end table
940
941	@item compression_level (@emph{comp})
942	Set encoding algorithm complexity. Valid options are integers in
943	the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
944	gives the highest quality but slowest encoding. The default is 10.
945
946	@item frame_duration (@emph{framesize})
947	Set maximum frame size, or duration of a frame in milliseconds. The
948	argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
949	frame sizes achieve lower latency but less quality at a given bitrate.
950	Sizes greater than 20ms are only interesting at fairly low bitrates.
951	The default is 20ms.
952
953	@item packet_loss (@emph{expect-loss})
954	Set expected packet loss percentage. The default is 0.
955
956	@item application (N.A.)
957	Set intended application type. Valid options are listed below:
958
959	@table @samp
960	@item voip
961	Favor improved speech intelligibility.
962	@item audio
963	Favor faithfulness to the input (the default).
964	@item lowdelay
965	Restrict to only the lowest delay modes.
966	@end table
967
968	@item cutoff (N.A.)
969	Set cutoff bandwidth in Hz. The argument must be exactly one of the
970	following: 4000, 6000, 8000, 12000, or 20000, corresponding to
971	narrowband, mediumband, wideband, super wideband, and fullband
972	respectively. The default is 0 (cutoff disabled).
973
974	@item mapping_family (@emph{mapping_family})
975	Set channel mapping family to be used by the encoder. The default value of -1
976	uses mapping family 0 for mono and stereo inputs, and mapping family 1
977	otherwise. The default also disables the surround masking and LFE bandwidth
978	optimzations in libopus, and requires that the input contains 8 channels or
979	fewer.
980
981	Other values include 0 for mono and stereo, 1 for surround sound with masking
982	and LFE bandwidth optimizations, and 255 for independent streams with an
983	unspecified channel layout.
984
985	@end table
986
987	@anchor{libshine}
988	@section libshine
989
990	Shine Fixed-Point MP3 encoder wrapper.
991
992	Shine is a fixed-point MP3 encoder. It has a far better performance on
993	platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
994	However, as it is more targeted on performance than quality, it is not on par
995	with LAME and other production-grade encoders quality-wise. Also, according to
996	the project's homepage, this encoder may not be free of bugs as the code was
997	written a long time ago and the project was dead for at least 5 years.
998
999	This encoder only supports stereo and mono input. This is also CBR-only.
1000
1001	The original project (last updated in early 2007) is at
1002	@url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1003	updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1004
1005	Requires the presence of the libshine headers and library during
1006	configuration. You need to explicitly configure the build with
1007	@code{--enable-libshine}.
1008
1009	See also @ref{libmp3lame}.
1010
1011	@subsection Options
1012
1013	The following options are supported by the libshine wrapper. The
1014	@command{shineenc}-equivalent of the options are listed in parentheses.
1015
1016	@table @option
1017	@item b (@emph{-b})
1018	Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1019	is expressed in kilobits/s.
1020
1021	@end table
1022
1023	@section libtwolame
1024
1025	TwoLAME MP2 encoder wrapper.
1026
1027	Requires the presence of the libtwolame headers and library during
1028	configuration. You need to explicitly configure the build with
1029	@code{--enable-libtwolame}.
1030
1031	@subsection Options
1032
1033	The following options are supported by the libtwolame wrapper. The
1034	@command{twolame}-equivalent options follow the FFmpeg ones and are in
1035	parentheses.
1036
1037	@table @option
1038	@item b (@emph{-b})
1039	Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1040	option is expressed in kilobits/s. Default value is 128k.
1041
1042	@item q (@emph{-V})
1043	Set quality for experimental VBR support. Maximum value range is
1044	from -50 to 50, useful range is from -10 to 10. The higher the
1045	value, the better the quality. This option is valid only using the
1046	@command{ffmpeg} command-line tool. For library interface users,
1047	use @option{global_quality}.
1048
1049	@item mode (@emph{--mode})
1050	Set the mode of the resulting audio. Possible values:
1051
1052	@table @samp
1053	@item auto
1054	Choose mode automatically based on the input. This is the default.
1055	@item stereo
1056	Stereo
1057	@item joint_stereo
1058	Joint stereo
1059	@item dual_channel
1060	Dual channel
1061	@item mono
1062	Mono
1063	@end table
1064
1065	@item psymodel (@emph{--psyc-mode})
1066	Set psychoacoustic model to use in encoding. The argument must be
1067	an integer between -1 and 4, inclusive. The higher the value, the
1068	better the quality. The default value is 3.
1069
1070	@item energy_levels (@emph{--energy})
1071	Enable energy levels extensions when set to 1. The default value is
1072	0 (disabled).
1073
1074	@item error_protection (@emph{--protect})
1075	Enable CRC error protection when set to 1. The default value is 0
1076	(disabled).
1077
1078	@item copyright (@emph{--copyright})
1079	Set MPEG audio copyright flag when set to 1. The default value is 0
1080	(disabled).
1081
1082	@item original (@emph{--original})
1083	Set MPEG audio original flag when set to 1. The default value is 0
1084	(disabled).
1085
1086	@end table
1087
1088	@section libvo-amrwbenc
1089
1090	VisualOn Adaptive Multi-Rate Wideband encoder.
1091
1092	Requires the presence of the libvo-amrwbenc headers and library during
1093	configuration. You need to explicitly configure the build with
1094	@code{--enable-libvo-amrwbenc --enable-version3}.
1095
1096	This is a mono-only encoder. Officially it only supports 16000Hz sample
1097	rate, but you can override it by setting @option{strict} to
1098	@samp{unofficial} or lower.
1099
1100	@subsection Options
1101
1102	@table @option
1103
1104	@item b
1105	Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1106	libavcodec will round to the nearest valid bitrate.
1107
1108	@table @samp
1109	@item 6600
1110	@item 8850
1111	@item 12650
1112	@item 14250
1113	@item 15850
1114	@item 18250
1115	@item 19850
1116	@item 23050
1117	@item 23850
1118	@end table
1119
1120	@item dtx
1121	Allow discontinuous transmission (generate comfort noise) when set to 1. The
1122	default value is 0 (disabled).
1123
1124	@end table
1125
1126	@section libvorbis
1127
1128	libvorbis encoder wrapper.
1129
1130	Requires the presence of the libvorbisenc headers and library during
1131	configuration. You need to explicitly configure the build with
1132	@code{--enable-libvorbis}.
1133
1134	@subsection Options
1135
1136	The following options are supported by the libvorbis wrapper. The
1137	@command{oggenc}-equivalent of the options are listed in parentheses.
1138
1139	To get a more accurate and extensive documentation of the libvorbis
1140	options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1141	See @url{http://xiph.org/vorbis/},
1142	@url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1143
1144	@table @option
1145	@item b (@emph{-b})
1146	Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1147	expressed in kilobits/s.
1148
1149	@item q (@emph{-q})
1150	Set constant quality setting for VBR. The value should be a float
1151	number in the range of -1.0 to 10.0. The higher the value, the better
1152	the quality. The default value is @samp{3.0}.
1153
1154	This option is valid only using the @command{ffmpeg} command-line tool.
1155	For library interface users, use @option{global_quality}.
1156
1157	@item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1158	Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1159	related option is expressed in kHz. The default value is @samp{0} (cutoff
1160	disabled).
1161
1162	@item minrate (@emph{-m})
1163	Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1164	expressed in kilobits/s.
1165
1166	@item maxrate (@emph{-M})
1167	Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1168	expressed in kilobits/s. This only has effect on ABR mode.
1169
1170	@item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1171	Set noise floor bias for impulse blocks. The value is a float number from
1172	-15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1173	to the crispness of transients in the encoded audio. The tradeoff for better
1174	transient response is a higher bitrate.
1175
1176	@end table
1177
1178	@anchor{libwavpack}
1179	@section libwavpack
1180
1181	A wrapper providing WavPack encoding through libwavpack.
1182
1183	Only lossless mode using 32-bit integer samples is supported currently.
1184
1185	Requires the presence of the libwavpack headers and library during
1186	configuration. You need to explicitly configure the build with
1187	@code{--enable-libwavpack}.
1188
1189	Note that a libavcodec-native encoder for the WavPack codec exists so users can
1190	encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1191
1192	@subsection Options
1193
1194	@command{wavpack} command line utility's corresponding options are listed in
1195	parentheses, if any.
1196
1197	@table @option
1198	@item frame_size (@emph{--blocksize})
1199	Default is 32768.
1200
1201	@item compression_level
1202	Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1203
1204	@table @samp
1205	@item 0 (@emph{-f})
1206	Fast mode.
1207
1208	@item 1
1209	Normal (default) settings.
1210
1211	@item 2 (@emph{-h})
1212	High quality.
1213
1214	@item 3 (@emph{-hh})
1215	Very high quality.
1216
1217	@item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1218	Same as @samp{3}, but with extra processing enabled.
1219
1220	@samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1221
1222	@end table
1223	@end table
1224
1225	@anchor{mjpegenc}
1226	@section mjpeg
1227
1228	Motion JPEG encoder.
1229
1230	@subsection Options
1231
1232	@table @option
1233	@item huffman
1234	Set the huffman encoding strategy. Possible values:
1235
1236	@table @samp
1237	@item default
1238	Use the default huffman tables. This is the default strategy.
1239
1240	@item optimal
1241	Compute and use optimal huffman tables.
1242
1243	@end table
1244	@end table
1245
1246	@anchor{wavpackenc}
1247	@section wavpack
1248
1249	WavPack lossless audio encoder.
1250
1251	This is a libavcodec-native WavPack encoder. There is also an encoder based on
1252	libwavpack, but there is virtually no reason to use that encoder.
1253
1254	See also @ref{libwavpack}.
1255
1256	@subsection Options
1257
1258	The equivalent options for @command{wavpack} command line utility are listed in
1259	parentheses.
1260
1261	@subsubsection Shared options
1262
1263	The following shared options are effective for this encoder. Only special notes
1264	about this particular encoder will be documented here. For the general meaning
1265	of the options, see @ref{codec-options,,the Codec Options chapter}.
1266
1267	@table @option
1268	@item frame_size (@emph{--blocksize})
1269	For this encoder, the range for this option is between 128 and 131072. Default
1270	is automatically decided based on sample rate and number of channel.
1271
1272	For the complete formula of calculating default, see
1273	@file{libavcodec/wavpackenc.c}.
1274
1275	@item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1276	This option's syntax is consistent with @ref{libwavpack}'s.
1277	@end table
1278
1279	@subsubsection Private options
1280
1281	@table @option
1282	@item joint_stereo (@emph{-j})
1283	Set whether to enable joint stereo. Valid values are:
1284
1285	@table @samp
1286	@item on (@emph{1})
1287	Force mid/side audio encoding.
1288	@item off (@emph{0})
1289	Force left/right audio encoding.
1290	@item auto
1291	Let the encoder decide automatically.
1292	@end table
1293
1294	@item optimize_mono
1295	Set whether to enable optimization for mono. This option is only effective for
1296	non-mono streams. Available values:
1297
1298	@table @samp
1299	@item on
1300	enabled
1301	@item off
1302	disabled
1303	@end table
1304
1305	@end table
1306
1307	@c man end AUDIO ENCODERS
1308
1309	@chapter Video Encoders
1310	@c man begin VIDEO ENCODERS
1311
1312	A description of some of the currently available video encoders
1313	follows.
1314
1315	@section Hap
1316
1317	Vidvox Hap video encoder.
1318
1319	@subsection Options
1320
1321	@table @option
1322	@item format @var{integer}
1323	Specifies the Hap format to encode.
1324
1325	@table @option
1326	@item hap
1327	@item hap_alpha
1328	@item hap_q
1329	@end table
1330
1331	Default value is @option{hap}.
1332
1333	@item chunks @var{integer}
1334	Specifies the number of chunks to split frames into, between 1 and 64. This
1335	permits multithreaded decoding of large frames, potentially at the cost of
1336	data-rate. The encoder may modify this value to divide frames evenly.
1337
1338	Default value is @var{1}.
1339
1340	@item compressor @var{integer}
1341	Specifies the second-stage compressor to use. If set to @option{none},
1342	@option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1343	benefit.
1344
1345	@table @option
1346	@item none
1347	@item snappy
1348	@end table
1349
1350	Default value is @option{snappy}.
1351
1352	@end table
1353
1354	@section jpeg2000
1355
1356	The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1357	option can be used to set the encoding quality. Lossless encoding
1358	can be selected with @code{-pred 1}.
1359
1360	@subsection Options
1361
1362	@table @option
1363	@item format
1364	Can be set to either @code{j2k} or @code{jp2} (the default) that
1365	makes it possible to store non-rgb pix_fmts.
1366
1367	@end table
1368
1369	@section libkvazaar
1370
1371	Kvazaar H.265/HEVC encoder.
1372
1373	Requires the presence of the libkvazaar headers and library during
1374	configuration. You need to explicitly configure the build with
1375	@option{--enable-libkvazaar}.
1376
1377	@subsection Options
1378
1379	@table @option
1380
1381	@item b
1382	Set target video bitrate in bit/s and enable rate control.
1383
1384	@item kvazaar-params
1385	Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1386	by commas (,). See kvazaar documentation for a list of options.
1387
1388	@end table
1389
1390	@section libopenh264
1391
1392	Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1393
1394	This encoder requires the presence of the libopenh264 headers and
1395	library during configuration. You need to explicitly configure the
1396	build with @code{--enable-libopenh264}. The library is detected using
1397	@command{pkg-config}.
1398
1399	For more information about the library see
1400	@url{http://www.openh264.org}.
1401
1402	@subsection Options
1403
1404	The following FFmpeg global options affect the configurations of the
1405	libopenh264 encoder.
1406
1407	@table @option
1408	@item b
1409	Set the bitrate (as a number of bits per second).
1410
1411	@item g
1412	Set the GOP size.
1413
1414	@item maxrate
1415	Set the max bitrate (as a number of bits per second).
1416
1417	@item flags +global_header
1418	Set global header in the bitstream.
1419
1420	@item slices
1421	Set the number of slices, used in parallelized encoding. Default value
1422	is 0. This is only used when @option{slice_mode} is set to
1423	@samp{fixed}.
1424
1425	@item slice_mode
1426	Set slice mode. Can assume one of the following possible values:
1427
1428	@table @samp
1429	@item fixed
1430	a fixed number of slices
1431	@item rowmb
1432	one slice per row of macroblocks
1433	@item auto
1434	automatic number of slices according to number of threads
1435	@item dyn
1436	dynamic slicing
1437	@end table
1438
1439	Default value is @samp{auto}.
1440
1441	@item loopfilter
1442	Enable loop filter, if set to 1 (automatically enabled). To disable
1443	set a value of 0.
1444
1445	@item profile
1446	Set profile restrictions. If set to the value of @samp{main} enable
1447	CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1448
1449	@item max_nal_size
1450	Set maximum NAL size in bytes.
1451
1452	@item allow_skip_frames
1453	Allow skipping frames to hit the target bitrate if set to 1.
1454	@end table
1455
1456	@section libtheora
1457
1458	libtheora Theora encoder wrapper.
1459
1460	Requires the presence of the libtheora headers and library during
1461	configuration. You need to explicitly configure the build with
1462	@code{--enable-libtheora}.
1463
1464	For more information about the libtheora project see
1465	@url{http://www.theora.org/}.
1466
1467	@subsection Options
1468
1469	The following global options are mapped to internal libtheora options
1470	which affect the quality and the bitrate of the encoded stream.
1471
1472	@table @option
1473	@item b
1474	Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1475	case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1476
1477	@item flags
1478	Used to enable constant quality mode (VBR) encoding through the
1479	@option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1480	modes.
1481
1482	@item g
1483	Set the GOP size.
1484
1485	@item global_quality
1486	Set the global quality as an integer in lambda units.
1487
1488	Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1489	value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1490	clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1491	value in the native libtheora range [0-63]. A higher value corresponds
1492	to a higher quality.
1493
1494	@item q
1495	Enable VBR mode when set to a non-negative value, and set constant
1496	quality value as a double floating point value in QP units.
1497
1498	The value is clipped in the [0-10] range, and then multiplied by 6.3
1499	to get a value in the native libtheora range [0-63].
1500
1501	This option is valid only using the @command{ffmpeg} command-line
1502	tool. For library interface users, use @option{global_quality}.
1503	@end table
1504
1505	@subsection Examples
1506
1507	@itemize
1508	@item
1509	Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1510	@example
1511	ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1512	@end example
1513
1514	@item
1515	Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1516	@example
1517	ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1518	@end example
1519	@end itemize
1520
1521	@section libvpx
1522
1523	VP8/VP9 format supported through libvpx.
1524
1525	Requires the presence of the libvpx headers and library during configuration.
1526	You need to explicitly configure the build with @code{--enable-libvpx}.
1527
1528	@subsection Options
1529
1530	The following options are supported by the libvpx wrapper. The
1531	@command{vpxenc}-equivalent options or values are listed in parentheses
1532	for easy migration.
1533
1534	To reduce the duplication of documentation, only the private options
1535	and some others requiring special attention are documented here. For
1536	the documentation of the undocumented generic options, see
1537	@ref{codec-options,,the Codec Options chapter}.
1538
1539	To get more documentation of the libvpx options, invoke the command
1540	@command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1541	@command{vpxenc --help}. Further information is available in the libvpx API
1542	documentation.
1543
1544	@table @option
1545
1546	@item b (@emph{target-bitrate})
1547	Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1548	expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1549	kilobits/s.
1550
1551	@item g (@emph{kf-max-dist})
1552
1553	@item keyint_min (@emph{kf-min-dist})
1554
1555	@item qmin (@emph{min-q})
1556
1557	@item qmax (@emph{max-q})
1558
1559	@item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1560	Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1561	specified in milliseconds, the libvpx wrapper converts this value as follows:
1562	@code{buf-sz = bufsize * 1000 / bitrate},
1563	@code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1564
1565	@item rc_init_occupancy (@emph{buf-initial-sz})
1566	Set number of bits which should be loaded into the rc buffer before decoding
1567	starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1568	wrapper converts this value as follows:
1569	@code{rc_init_occupancy * 1000 / bitrate}.
1570
1571	@item undershoot-pct
1572	Set datarate undershoot (min) percentage of the target bitrate.
1573
1574	@item overshoot-pct
1575	Set datarate overshoot (max) percentage of the target bitrate.
1576
1577	@item skip_threshold (@emph{drop-frame})
1578
1579	@item qcomp (@emph{bias-pct})
1580
1581	@item maxrate (@emph{maxsection-pct})
1582	Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1583	percentage of the target bitrate, the libvpx wrapper converts this value as
1584	follows: @code{(maxrate * 100 / bitrate)}.
1585
1586	@item minrate (@emph{minsection-pct})
1587	Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1588	percentage of the target bitrate, the libvpx wrapper converts this value as
1589	follows: @code{(minrate * 100 / bitrate)}.
1590
1591	@item minrate, maxrate, b @emph{end-usage=cbr}
1592	@code{(minrate == maxrate == bitrate)}.
1593
1594	@item crf (@emph{end-usage=cq}, @emph{cq-level})
1595
1596	@item tune (@emph{tune})
1597	@table @samp
1598	@item psnr (@emph{psnr})
1599	@item ssim (@emph{ssim})
1600	@end table
1601
1602	@item quality, deadline (@emph{deadline})
1603	@table @samp
1604	@item best
1605	Use best quality deadline. Poorly named and quite slow, this option should be
1606	avoided as it may give worse quality output than good.
1607	@item good
1608	Use good quality deadline. This is a good trade-off between speed and quality
1609	when used with the @option{cpu-used} option.
1610	@item realtime
1611	Use realtime quality deadline.
1612	@end table
1613
1614	@item speed, cpu-used (@emph{cpu-used})
1615	Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1616	of quality.
1617
1618	@item nr (@emph{noise-sensitivity})
1619
1620	@item static-thresh
1621	Set a change threshold on blocks below which they will be skipped by the
1622	encoder.
1623
1624	@item slices (@emph{token-parts})
1625	Note that FFmpeg's @option{slices} option gives the total number of partitions,
1626	while @command{vpxenc}'s @option{token-parts} is given as
1627	@code{log2(partitions)}.
1628
1629	@item max-intra-rate
1630	Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1631	means unlimited.
1632
1633	@item force_key_frames
1634	@code{VPX_EFLAG_FORCE_KF}
1635
1636	@item Alternate reference frame related
1637	@table @option
1638	@item auto-alt-ref
1639	Enable use of alternate reference frames (2-pass only).
1640	@item arnr-max-frames
1641	Set altref noise reduction max frame count.
1642	@item arnr-type
1643	Set altref noise reduction filter type: backward, forward, centered.
1644	@item arnr-strength
1645	Set altref noise reduction filter strength.
1646	@item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1647	Set number of frames to look ahead for frametype and ratecontrol.
1648	@end table
1649
1650	@item error-resilient
1651	Enable error resiliency features.
1652
1653	@item VP9-specific options
1654	@table @option
1655	@item lossless
1656	Enable lossless mode.
1657	@item tile-columns
1658	Set number of tile columns to use. Note this is given as
1659	@code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1660	setting the @option{tile-columns} option to 3.
1661	@item tile-rows
1662	Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1663	For example, 4 tile rows would be requested by setting the @option{tile-rows}
1664	option to 2.
1665	@item frame-parallel
1666	Enable frame parallel decodability features.
1667	@item aq-mode
1668	Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1669	cyclic refresh).
1670	@item colorspace @emph{color-space}
1671	Set input color space. The VP9 bitstream supports signaling the following
1672	colorspaces:
1673	@table @option
1674	@item @samp{rgb} @emph{sRGB}
1675	@item @samp{bt709} @emph{bt709}
1676	@item @samp{unspecified} @emph{unknown}
1677	@item @samp{bt470bg} @emph{bt601}
1678	@item @samp{smpte170m} @emph{smpte170}
1679	@item @samp{smpte240m} @emph{smpte240}
1680	@item @samp{bt2020_ncl} @emph{bt2020}
1681	@end table
1682	@end table
1683
1684	@end table
1685
1686	For more information about libvpx see:
1687	@url{http://www.webmproject.org/}
1688
1689	@section libwebp
1690
1691	libwebp WebP Image encoder wrapper
1692
1693	libwebp is Google's official encoder for WebP images. It can encode in either
1694	lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1695	frame. Lossless images are a separate codec developed by Google.
1696
1697	@subsection Pixel Format
1698
1699	Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1700	to limitations of the format and libwebp. Alpha is supported for either mode.
1701	Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1702	passed in for encoding lossless, the pixel format will automatically be
1703	converted using functions from libwebp. This is not ideal and is done only for
1704	convenience.
1705
1706	@subsection Options
1707
1708	@table @option
1709
1710	@item -lossless @var{boolean}
1711	Enables/Disables use of lossless mode. Default is 0.
1712
1713	@item -compression_level @var{integer}
1714	For lossy, this is a quality/speed tradeoff. Higher values give better quality
1715	for a given size at the cost of increased encoding time. For lossless, this is
1716	a size/speed tradeoff. Higher values give smaller size at the cost of increased
1717	encoding time. More specifically, it controls the number of extra algorithms
1718	and compression tools used, and varies the combination of these tools. This
1719	maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1720	Default is 4.
1721
1722	@item -qscale @var{float}
1723	For lossy encoding, this controls image quality, 0 to 100. For lossless
1724	encoding, this controls the effort and time spent at compressing more. The
1725	default value is 75. Note that for usage via libavcodec, this option is called
1726	@var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1727
1728	@item -preset @var{type}
1729	Configuration preset. This does some automatic settings based on the general
1730	type of the image.
1731	@table @option
1732	@item none
1733	Do not use a preset.
1734	@item default
1735	Use the encoder default.
1736	@item picture
1737	Digital picture, like portrait, inner shot
1738	@item photo
1739	Outdoor photograph, with natural lighting
1740	@item drawing
1741	Hand or line drawing, with high-contrast details
1742	@item icon
1743	Small-sized colorful images
1744	@item text
1745	Text-like
1746	@end table
1747
1748	@end table
1749
1750	@section libx264, libx264rgb
1751
1752	x264 H.264/MPEG-4 AVC encoder wrapper.
1753
1754	This encoder requires the presence of the libx264 headers and library
1755	during configuration. You need to explicitly configure the build with
1756	@code{--enable-libx264}.
1757
1758	libx264 supports an impressive number of features, including 8x8 and
1759	4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1760	entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1761	for detail retention (adaptive quantization, psy-RD, psy-trellis).
1762
1763	Many libx264 encoder options are mapped to FFmpeg global codec
1764	options, while unique encoder options are provided through private
1765	options. Additionally the @option{x264opts} and @option{x264-params}
1766	private options allows one to pass a list of key=value tuples as accepted
1767	by the libx264 @code{x264_param_parse} function.
1768
1769	The x264 project website is at
1770	@url{http://www.videolan.org/developers/x264.html}.
1771
1772	The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1773	pixel formats as input instead of YUV.
1774
1775	@subsection Supported Pixel Formats
1776
1777	x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1778	x264's configure time. FFmpeg only supports one bit depth in one particular
1779	build. In other words, it is not possible to build one FFmpeg with multiple
1780	versions of x264 with different bit depths.
1781
1782	@subsection Options
1783
1784	The following options are supported by the libx264 wrapper. The
1785	@command{x264}-equivalent options or values are listed in parentheses
1786	for easy migration.
1787
1788	To reduce the duplication of documentation, only the private options
1789	and some others requiring special attention are documented here. For
1790	the documentation of the undocumented generic options, see
1791	@ref{codec-options,,the Codec Options chapter}.
1792
1793	To get a more accurate and extensive documentation of the libx264
1794	options, invoke the command @command{x264 --full-help} or consult
1795	the libx264 documentation.
1796
1797	@table @option
1798	@item b (@emph{bitrate})
1799	Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1800	expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1801	kilobits/s.
1802
1803	@item bf (@emph{bframes})
1804
1805	@item g (@emph{keyint})
1806
1807	@item qmin (@emph{qpmin})
1808	Minimum quantizer scale.
1809
1810	@item qmax (@emph{qpmax})
1811	Maximum quantizer scale.
1812
1813	@item qdiff (@emph{qpstep})
1814	Maximum difference between quantizer scales.
1815
1816	@item qblur (@emph{qblur})
1817	Quantizer curve blur
1818
1819	@item qcomp (@emph{qcomp})
1820	Quantizer curve compression factor
1821
1822	@item refs (@emph{ref})
1823	Number of reference frames each P-frame can use. The range is from @var{0-16}.
1824
1825	@item sc_threshold (@emph{scenecut})
1826	Sets the threshold for the scene change detection.
1827
1828	@item trellis (@emph{trellis})
1829	Performs Trellis quantization to increase efficiency. Enabled by default.
1830
1831	@item nr (@emph{nr})
1832
1833	@item me_range (@emph{merange})
1834	Maximum range of the motion search in pixels.
1835
1836	@item me_method (@emph{me})
1837	Set motion estimation method. Possible values in the decreasing order
1838	of speed:
1839
1840	@table @samp
1841	@item dia (@emph{dia})
1842	@item epzs (@emph{dia})
1843	Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1844	@samp{dia}.
1845	@item hex (@emph{hex})
1846	Hexagonal search with radius 2.
1847	@item umh (@emph{umh})
1848	Uneven multi-hexagon search.
1849	@item esa (@emph{esa})
1850	Exhaustive search.
1851	@item tesa (@emph{tesa})
1852	Hadamard exhaustive search (slowest).
1853	@end table
1854
1855	@item forced-idr
1856	Normally, when forcing a I-frame type, the encoder can select any type
1857	of I-frame. This option forces it to choose an IDR-frame.
1858
1859	@item subq (@emph{subme})
1860	Sub-pixel motion estimation method.
1861
1862	@item b_strategy (@emph{b-adapt})
1863	Adaptive B-frame placement decision algorithm. Use only on first-pass.
1864
1865	@item keyint_min (@emph{min-keyint})
1866	Minimum GOP size.
1867
1868	@item coder
1869	Set entropy encoder. Possible values:
1870
1871	@table @samp
1872	@item ac
1873	Enable CABAC.
1874
1875	@item vlc
1876	Enable CAVLC and disable CABAC. It generates the same effect as
1877	@command{x264}'s @option{--no-cabac} option.
1878	@end table
1879
1880	@item cmp
1881	Set full pixel motion estimation comparison algorithm. Possible values:
1882
1883	@table @samp
1884	@item chroma
1885	Enable chroma in motion estimation.
1886
1887	@item sad
1888	Ignore chroma in motion estimation. It generates the same effect as
1889	@command{x264}'s @option{--no-chroma-me} option.
1890	@end table
1891
1892	@item threads (@emph{threads})
1893	Number of encoding threads.
1894
1895	@item thread_type
1896	Set multithreading technique. Possible values:
1897
1898	@table @samp
1899	@item slice
1900	Slice-based multithreading. It generates the same effect as
1901	@command{x264}'s @option{--sliced-threads} option.
1902	@item frame
1903	Frame-based multithreading.
1904	@end table
1905
1906	@item flags
1907	Set encoding flags. It can be used to disable closed GOP and enable
1908	open GOP by setting it to @code{-cgop}. The result is similar to
1909	the behavior of @command{x264}'s @option{--open-gop} option.
1910
1911	@item rc_init_occupancy (@emph{vbv-init})
1912
1913	@item preset (@emph{preset})
1914	Set the encoding preset.
1915
1916	@item tune (@emph{tune})
1917	Set tuning of the encoding params.
1918
1919	@item profile (@emph{profile})
1920	Set profile restrictions.
1921
1922	@item fastfirstpass
1923	Enable fast settings when encoding first pass, when set to 1. When set
1924	to 0, it has the same effect of @command{x264}'s
1925	@option{--slow-firstpass} option.
1926
1927	@item crf (@emph{crf})
1928	Set the quality for constant quality mode.
1929
1930	@item crf_max (@emph{crf-max})
1931	In CRF mode, prevents VBV from lowering quality beyond this point.
1932
1933	@item qp (@emph{qp})
1934	Set constant quantization rate control method parameter.
1935
1936	@item aq-mode (@emph{aq-mode})
1937	Set AQ method. Possible values:
1938
1939	@table @samp
1940	@item none (@emph{0})
1941	Disabled.
1942
1943	@item variance (@emph{1})
1944	Variance AQ (complexity mask).
1945
1946	@item autovariance (@emph{2})
1947	Auto-variance AQ (experimental).
1948	@end table
1949
1950	@item aq-strength (@emph{aq-strength})
1951	Set AQ strength, reduce blocking and blurring in flat and textured areas.
1952
1953	@item psy
1954	Use psychovisual optimizations when set to 1. When set to 0, it has the
1955	same effect as @command{x264}'s @option{--no-psy} option.
1956
1957	@item psy-rd (@emph{psy-rd})
1958	Set strength of psychovisual optimization, in
1959	@var{psy-rd}:@var{psy-trellis} format.
1960
1961	@item rc-lookahead (@emph{rc-lookahead})
1962	Set number of frames to look ahead for frametype and ratecontrol.
1963
1964	@item weightb
1965	Enable weighted prediction for B-frames when set to 1. When set to 0,
1966	it has the same effect as @command{x264}'s @option{--no-weightb} option.
1967
1968	@item weightp (@emph{weightp})
1969	Set weighted prediction method for P-frames. Possible values:
1970
1971	@table @samp
1972	@item none (@emph{0})
1973	Disabled
1974	@item simple (@emph{1})
1975	Enable only weighted refs
1976	@item smart (@emph{2})
1977	Enable both weighted refs and duplicates
1978	@end table
1979
1980	@item ssim (@emph{ssim})
1981	Enable calculation and printing SSIM stats after the encoding.
1982
1983	@item intra-refresh (@emph{intra-refresh})
1984	Enable the use of Periodic Intra Refresh instead of IDR frames when set
1985	to 1.
1986
1987	@item avcintra-class (@emph{class})
1988	Configure the encoder to generate AVC-Intra.
1989	Valid values are 50,100 and 200
1990
1991	@item bluray-compat (@emph{bluray-compat})
1992	Configure the encoder to be compatible with the bluray standard.
1993	It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1994
1995	@item b-bias (@emph{b-bias})
1996	Set the influence on how often B-frames are used.
1997
1998	@item b-pyramid (@emph{b-pyramid})
1999	Set method for keeping of some B-frames as references. Possible values:
2000
2001	@table @samp
2002	@item none (@emph{none})
2003	Disabled.
2004	@item strict (@emph{strict})
2005	Strictly hierarchical pyramid.
2006	@item normal (@emph{normal})
2007	Non-strict (not Blu-ray compatible).
2008	@end table
2009
2010	@item mixed-refs
2011	Enable the use of one reference per partition, as opposed to one
2012	reference per macroblock when set to 1. When set to 0, it has the
2013	same effect as @command{x264}'s @option{--no-mixed-refs} option.
2014
2015	@item 8x8dct
2016	Enable adaptive spatial transform (high profile 8x8 transform)
2017	when set to 1. When set to 0, it has the same effect as
2018	@command{x264}'s @option{--no-8x8dct} option.
2019
2020	@item fast-pskip
2021	Enable early SKIP detection on P-frames when set to 1. When set
2022	to 0, it has the same effect as @command{x264}'s
2023	@option{--no-fast-pskip} option.
2024
2025	@item aud (@emph{aud})
2026	Enable use of access unit delimiters when set to 1.
2027
2028	@item mbtree
2029	Enable use macroblock tree ratecontrol when set to 1. When set
2030	to 0, it has the same effect as @command{x264}'s
2031	@option{--no-mbtree} option.
2032
2033	@item deblock (@emph{deblock})
2034	Set loop filter parameters, in @var{alpha}:@var{beta} form.
2035
2036	@item cplxblur (@emph{cplxblur})
2037	Set fluctuations reduction in QP (before curve compression).
2038
2039	@item partitions (@emph{partitions})
2040	Set partitions to consider as a comma-separated list of. Possible
2041	values in the list:
2042
2043	@table @samp
2044	@item p8x8
2045	8x8 P-frame partition.
2046	@item p4x4
2047	4x4 P-frame partition.
2048	@item b8x8
2049	4x4 B-frame partition.
2050	@item i8x8
2051	8x8 I-frame partition.
2052	@item i4x4
2053	4x4 I-frame partition.
2054	(Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2055	@samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2056	option) to be enabled.)
2057	@item none (@emph{none})
2058	Do not consider any partitions.
2059	@item all (@emph{all})
2060	Consider every partition.
2061	@end table
2062
2063	@item direct-pred (@emph{direct})
2064	Set direct MV prediction mode. Possible values:
2065
2066	@table @samp
2067	@item none (@emph{none})
2068	Disable MV prediction.
2069	@item spatial (@emph{spatial})
2070	Enable spatial predicting.
2071	@item temporal (@emph{temporal})
2072	Enable temporal predicting.
2073	@item auto (@emph{auto})
2074	Automatically decided.
2075	@end table
2076
2077	@item slice-max-size (@emph{slice-max-size})
2078	Set the limit of the size of each slice in bytes. If not specified
2079	but RTP payload size (@option{ps}) is specified, that is used.
2080
2081	@item stats (@emph{stats})
2082	Set the file name for multi-pass stats.
2083
2084	@item nal-hrd (@emph{nal-hrd})
2085	Set signal HRD information (requires @option{vbv-bufsize} to be set).
2086	Possible values:
2087
2088	@table @samp
2089	@item none (@emph{none})
2090	Disable HRD information signaling.
2091	@item vbr (@emph{vbr})
2092	Variable bit rate.
2093	@item cbr (@emph{cbr})
2094	Constant bit rate (not allowed in MP4 container).
2095	@end table
2096
2097	@item x264opts (N.A.)
2098	Set any x264 option, see @command{x264 --fullhelp} for a list.
2099
2100	Argument is a list of @var{key}=@var{value} couples separated by
2101	":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2102	themselves, use "," instead. They accept it as well since long ago but this
2103	is kept undocumented for some reason.
2104
2105	For example to specify libx264 encoding options with @command{ffmpeg}:
2106	@example
2107	ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2108	@end example
2109
2110	@item a53cc @var{boolean}
2111	Import closed captions (which must be ATSC compatible format) into output.
2112	Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2113
2114	@item x264-params (N.A.)
2115	Override the x264 configuration using a :-separated list of key=value
2116	parameters.
2117
2118	This option is functionally the same as the @option{x264opts}, but is
2119	duplicated for compatibility with the Libav fork.
2120
2121	For example to specify libx264 encoding options with @command{ffmpeg}:
2122	@example
2123	ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2124	cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2125	no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2126	@end example
2127	@end table
2128
2129	Encoding ffpresets for common usages are provided so they can be used with the
2130	general presets system (e.g. passing the @option{pre} option).
2131
2132	@section libx265
2133
2134	x265 H.265/HEVC encoder wrapper.
2135
2136	This encoder requires the presence of the libx265 headers and library
2137	during configuration. You need to explicitly configure the build with
2138	@option{--enable-libx265}.
2139
2140	@subsection Options
2141
2142	@table @option
2143	@item preset
2144	Set the x265 preset.
2145
2146	@item tune
2147	Set the x265 tune parameter.
2148
2149	@item forced-idr
2150	Normally, when forcing a I-frame type, the encoder can select any type
2151	of I-frame. This option forces it to choose an IDR-frame.
2152
2153	@item x265-params
2154	Set x265 options using a list of @var{key}=@var{value} couples separated
2155	by ":". See @command{x265 --help} for a list of options.
2156
2157	For example to specify libx265 encoding options with @option{-x265-params}:
2158
2159	@example
2160	ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2161	@end example
2162	@end table
2163
2164	@section libxvid
2165
2166	Xvid MPEG-4 Part 2 encoder wrapper.
2167
2168	This encoder requires the presence of the libxvidcore headers and library
2169	during configuration. You need to explicitly configure the build with
2170	@code{--enable-libxvid --enable-gpl}.
2171
2172	The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2173	users can encode to this format without this library.
2174
2175	@subsection Options
2176
2177	The following options are supported by the libxvid wrapper. Some of
2178	the following options are listed but are not documented, and
2179	correspond to shared codec options. See @ref{codec-options,,the Codec
2180	Options chapter} for their documentation. The other shared options
2181	which are not listed have no effect for the libxvid encoder.
2182
2183	@table @option
2184	@item b
2185
2186	@item g
2187
2188	@item qmin
2189
2190	@item qmax
2191
2192	@item mpeg_quant
2193
2194	@item threads
2195
2196	@item bf
2197
2198	@item b_qfactor
2199
2200	@item b_qoffset
2201
2202	@item flags
2203	Set specific encoding flags. Possible values:
2204
2205	@table @samp
2206
2207	@item mv4
2208	Use four motion vector by macroblock.
2209
2210	@item aic
2211	Enable high quality AC prediction.
2212
2213	@item gray
2214	Only encode grayscale.
2215
2216	@item gmc
2217	Enable the use of global motion compensation (GMC).
2218
2219	@item qpel
2220	Enable quarter-pixel motion compensation.
2221
2222	@item cgop
2223	Enable closed GOP.
2224
2225	@item global_header
2226	Place global headers in extradata instead of every keyframe.
2227
2228	@end table
2229
2230	@item trellis
2231
2232	@item me_method
2233	Set motion estimation method. Possible values in decreasing order of
2234	speed and increasing order of quality:
2235
2236	@table @samp
2237	@item zero
2238	Use no motion estimation (default).
2239
2240	@item phods
2241	@item x1
2242	@item log
2243	Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2244	refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2245	@samp{phods}.
2246
2247	@item epzs
2248	Enable all of the things described above, plus advanced diamond zonal
2249	search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2250	estimation on chroma planes.
2251
2252	@item full
2253	Enable all of the things described above, plus extended 16x16 and 8x8
2254	blocks search.
2255	@end table
2256
2257	@item mbd
2258	Set macroblock decision algorithm. Possible values in the increasing
2259	order of quality:
2260
2261	@table @samp
2262	@item simple
2263	Use macroblock comparing function algorithm (default).
2264
2265	@item bits
2266	Enable rate distortion-based half pixel and quarter pixel refinement for
2267	16x16 blocks.
2268
2269	@item rd
2270	Enable all of the things described above, plus rate distortion-based
2271	half pixel and quarter pixel refinement for 8x8 blocks, and rate
2272	distortion-based search using square pattern.
2273	@end table
2274
2275	@item lumi_aq
2276	Enable lumi masking adaptive quantization when set to 1. Default is 0
2277	(disabled).
2278
2279	@item variance_aq
2280	Enable variance adaptive quantization when set to 1. Default is 0
2281	(disabled).
2282
2283	When combined with @option{lumi_aq}, the resulting quality will not
2284	be better than any of the two specified individually. In other
2285	words, the resulting quality will be the worse one of the two
2286	effects.
2287
2288	@item ssim
2289	Set structural similarity (SSIM) displaying method. Possible values:
2290
2291	@table @samp
2292	@item off
2293	Disable displaying of SSIM information.
2294
2295	@item avg
2296	Output average SSIM at the end of encoding to stdout. The format of
2297	showing the average SSIM is:
2298
2299	@example
2300	Average SSIM: %f
2301	@end example
2302
2303	For users who are not familiar with C, %f means a float number, or
2304	a decimal (e.g. 0.939232).
2305
2306	@item frame
2307	Output both per-frame SSIM data during encoding and average SSIM at
2308	the end of encoding to stdout. The format of per-frame information
2309	is:
2310
2311	@example
2312	SSIM: avg: %1.3f min: %1.3f max: %1.3f
2313	@end example
2314
2315	For users who are not familiar with C, %1.3f means a float number
2316	rounded to 3 digits after the dot (e.g. 0.932).
2317
2318	@end table
2319
2320	@item ssim_acc
2321	Set SSIM accuracy. Valid options are integers within the range of
2322	0-4, while 0 gives the most accurate result and 4 computes the
2323	fastest.
2324
2325	@end table
2326
2327	@section mpeg2
2328
2329	MPEG-2 video encoder.
2330
2331	@subsection Options
2332
2333	@table @option
2334	@item seq_disp_ext @var{integer}
2335	Specifies if the encoder should write a sequence_display_extension to the
2336	output.
2337	@table @option
2338	@item -1
2339	@itemx auto
2340	Decide automatically to write it or not (this is the default) by checking if
2341	the data to be written is different from the default or unspecified values.
2342	@item 0
2343	@itemx never
2344	Never write it.
2345	@item 1
2346	@itemx always
2347	Always write it.
2348	@end table
2349	@end table
2350
2351	@section png
2352
2353	PNG image encoder.
2354
2355	@subsection Private options
2356
2357	@table @option
2358	@item dpi @var{integer}
2359	Set physical density of pixels, in dots per inch, unset by default
2360	@item dpm @var{integer}
2361	Set physical density of pixels, in dots per meter, unset by default
2362	@end table
2363
2364	@section ProRes
2365
2366	Apple ProRes encoder.
2367
2368	FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2369	The used encoder can be chosen with the @code{-vcodec} option.
2370
2371	@subsection Private Options for prores-ks
2372
2373	@table @option
2374	@item profile @var{integer}
2375	Select the ProRes profile to encode
2376	@table @samp
2377	@item proxy
2378	@item lt
2379	@item standard
2380	@item hq
2381	@item 4444
2382	@end table
2383
2384	@item quant_mat @var{integer}
2385	Select quantization matrix.
2386	@table @samp
2387	@item auto
2388	@item default
2389	@item proxy
2390	@item lt
2391	@item standard
2392	@item hq
2393	@end table
2394	If set to @var{auto}, the matrix matching the profile will be picked.
2395	If not set, the matrix providing the highest quality, @var{default}, will be
2396	picked.
2397
2398	@item bits_per_mb @var{integer}
2399	How many bits to allot for coding one macroblock. Different profiles use
2400	between 200 and 2400 bits per macroblock, the maximum is 8000.
2401
2402	@item mbs_per_slice @var{integer}
2403	Number of macroblocks in each slice (1-8); the default value (8)
2404	should be good in almost all situations.
2405
2406	@item vendor @var{string}
2407	Override the 4-byte vendor ID.
2408	A custom vendor ID like @var{apl0} would claim the stream was produced by
2409	the Apple encoder.
2410
2411	@item alpha_bits @var{integer}
2412	Specify number of bits for alpha component.
2413	Possible values are @var{0}, @var{8} and @var{16}.
2414	Use @var{0} to disable alpha plane coding.
2415
2416	@end table
2417
2418	@subsection Speed considerations
2419
2420	In the default mode of operation the encoder has to honor frame constraints
2421	(i.e. not produce frames with size bigger than requested) while still making
2422	output picture as good as possible.
2423	A frame containing a lot of small details is harder to compress and the encoder
2424	would spend more time searching for appropriate quantizers for each slice.
2425
2426	Setting a higher @option{bits_per_mb} limit will improve the speed.
2427
2428	For the fastest encoding speed set the @option{qscale} parameter (4 is the
2429	recommended value) and do not set a size constraint.
2430
2431	@section QSV encoders
2432
2433	The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2434
2435	The ratecontrol method is selected as follows:
2436
2437	@itemize @bullet
2438	@item
2439	When @option{global_quality} is specified, a quality-based mode is used.
2440	Specifically this means either
2441	@itemize @minus
2442	@item
2443	@var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2444	also set (the @option{-qscale} ffmpeg option).
2445
2446	@item
2447	@var{LA_ICQ} - intelligent constant quality with lookahead, when the
2448	@option{look_ahead} option is also set.
2449
2450	@item
2451	@var{ICQ} -- intelligent constant quality otherwise.
2452	@end itemize
2453
2454	@item
2455	Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2456	least the desired average bitrate with the @option{b} option.
2457	@itemize @minus
2458	@item
2459	@var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2460
2461	@item
2462	@var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2463
2464	@item
2465	@var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2466	the average bitrate.
2467
2468	@item
2469	@var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2470	than the average bitrate.
2471
2472	@item
2473	@var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2474	is further configured by the @option{avbr_accuracy} and
2475	@option{avbr_convergence} options.
2476	@end itemize
2477	@end itemize
2478
2479	Note that depending on your system, a different mode than the one you specified
2480	may be selected by the encoder. Set the verbosity level to @var{verbose} or
2481	higher to see the actual settings used by the QSV runtime.
2482
2483	Additional libavcodec global options are mapped to MSDK options as follows:
2484
2485	@itemize
2486	@item
2487	@option{g/gop_size} -> @option{GopPicSize}
2488
2489	@item
2490	@option{bf/max_b_frames}+1 -> @option{GopRefDist}
2491
2492	@item
2493	@option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2494	@option{InitialDelayInKB}
2495
2496	@item
2497	@option{slices} -> @option{NumSlice}
2498
2499	@item
2500	@option{refs} -> @option{NumRefFrame}
2501
2502	@item
2503	@option{b_strategy/b_frame_strategy} -> @option{BRefType}
2504
2505	@item
2506	@option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2507
2508	@item
2509	For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2510	@option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2511	and @var{QPP} and @var{QPB} respectively.
2512
2513	@item
2514	Setting the @option{coder} option to the value @var{vlc} will make the H.264
2515	encoder use CAVLC instead of CABAC.
2516
2517	@end itemize
2518
2519	@section snow
2520
2521	@subsection Options
2522
2523	@table @option
2524	@item iterative_dia_size
2525	dia size for the iterative motion estimation
2526	@end table
2527
2528	@section vc2
2529
2530	SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2531	professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2532	8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2533	other tasks which require low overhead and low compression (like screen
2534	recording).
2535
2536	@subsection Options
2537
2538	@table @option
2539
2540	@item b
2541	Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2542	video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2543	values (close to the uncompressed bitrate) turn on lossless compression mode.
2544
2545	@item field_order
2546	Enables field coding when set (e.g. to tt - top field first) for interlaced
2547	inputs. Should increase compression with interlaced content as it splits the
2548	fields and encodes each separately.
2549
2550	@item wavelet_depth
2551	Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2552	Lower values reduce compression and quality. Less capable decoders may not be
2553	able to handle values of @option{wavelet_depth} over 3.
2554
2555	@item wavelet_type
2556	Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2557	(Deslauriers-Dubuc)
2558	are implemented, with 9_7 being the one with better compression and thus
2559	is the default.
2560
2561	@item slice_width
2562	@item slice_height
2563	Sets the slice size for each slice. Larger values result in better compression.
2564	For compatibility with other more limited decoders use @option{slice_width} of
2565	32 and @option{slice_height} of 8.
2566
2567	@item tolerance
2568	Sets the undershoot tolerance of the rate control system in percent. This is
2569	to prevent an expensive search from being run.
2570
2571	@item qm
2572	Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2573	is set to 5
2574	@itemize @minus
2575	@item
2576	@var{default}
2577	Uses the default quantization matrix from the specifications, extended with
2578	values for the fifth level. This provides a good balance between keeping detail
2579	and omitting artifacts.
2580
2581	@item
2582	@var{flat}
2583	Use a completely zeroed out quantization matrix. This increases PSNR but might
2584	reduce perception. Use in bogus benchmarks.
2585
2586	@item
2587	@var{color}
2588	Reduces detail but attempts to preserve color at extremely low bitrates.
2589	@end itemize
2590
2591	@end table
2592
2593	@c man end VIDEO ENCODERS
2594
2595	@chapter Subtitles Encoders
2596	@c man begin SUBTITLES ENCODERS
2597
2598	@section dvdsub
2599
2600	This codec encodes the bitmap subtitle format that is used in DVDs.
2601	Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2602	and they can also be used in Matroska files.
2603
2604	@subsection Options
2605
2606	@table @option
2607	@item even_rows_fix
2608	When set to 1, enable a work-around that makes the number of pixel rows
2609	even in all subtitles. This fixes a problem with some players that
2610	cut off the bottom row if the number is odd. The work-around just adds
2611	a fully transparent row if needed. The overhead is low, typically
2612	one byte per subtitle on average.
2613
2614	By default, this work-around is disabled.
2615	@end table
2616
2617	@c man end SUBTITLES ENCODERS
2618