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1 @chapter Format Options
2 @c man begin FORMAT OPTIONS
3
4 The libavformat library provides some generic global options, which
5 can be set on all the muxers and demuxers. In addition each muxer or
6 demuxer may support so-called private options, which are specific for
7 that component.
8
9 Options may be set by specifying -@var{option} @var{value} in the
10 FFmpeg tools, or by setting the value explicitly in the
11 @code{AVFormatContext} options or using the @file{libavutil/opt.h} API
12 for programmatic use.
13
14 The list of supported options follows:
15
16 @table @option
17 @item avioflags @var{flags} (@emph{input/output})
18 Possible values:
19 @table @samp
20 @item direct
21 Reduce buffering.
22 @end table
23
24 @item probesize @var{integer} (@emph{input})
25 Set probing size in bytes, i.e. the size of the data to analyze to get
26 stream information. A higher value will enable detecting more
27 information in case it is dispersed into the stream, but will increase
28 latency. Must be an integer not lesser than 32. It is 5000000 by default.
29
30 @item packetsize @var{integer} (@emph{output})
31 Set packet size.
32
33 @item fflags @var{flags} (@emph{input/output})
34 Set format flags.
35
36 Possible values:
37 @table @samp
38 @item ignidx
39 Ignore index.
40 @item fastseek
41 Enable fast, but inaccurate seeks for some formats.
42 @item genpts
43 Generate PTS.
44 @item nofillin
45 Do not fill in missing values that can be exactly calculated.
46 @item noparse
47 Disable AVParsers, this needs @code{+nofillin} too.
48 @item igndts
49 Ignore DTS.
50 @item discardcorrupt
51 Discard corrupted frames.
52 @item sortdts
53 Try to interleave output packets by DTS.
54 @item keepside
55 Do not merge side data.
56 @item latm
57 Enable RTP MP4A-LATM payload.
58 @item nobuffer
59 Reduce the latency introduced by optional buffering
60 @item bitexact
61 Only write platform-, build- and time-independent data.
62 This ensures that file and data checksums are reproducible and match between
63 platforms. Its primary use is for regression testing.
64 @item shortest
65 Stop muxing at the end of the shortest stream.
66 It may be needed to increase max_interleave_delta to avoid flushing the longer
67 streams before EOF.
68 @end table
69
70 @item seek2any @var{integer} (@emph{input})
71 Allow seeking to non-keyframes on demuxer level when supported if set to 1.
72 Default is 0.
73
74 @item analyzeduration @var{integer} (@emph{input})
75 Specify how many microseconds are analyzed to probe the input. A
76 higher value will enable detecting more accurate information, but will
77 increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
78
79 @item cryptokey @var{hexadecimal string} (@emph{input})
80 Set decryption key.
81
82 @item indexmem @var{integer} (@emph{input})
83 Set max memory used for timestamp index (per stream).
84
85 @item rtbufsize @var{integer} (@emph{input})
86 Set max memory used for buffering real-time frames.
87
88 @item fdebug @var{flags} (@emph{input/output})
89 Print specific debug info.
90
91 Possible values:
92 @table @samp
93 @item ts
94 @end table
95
96 @item max_delay @var{integer} (@emph{input/output})
97 Set maximum muxing or demuxing delay in microseconds.
98
99 @item fpsprobesize @var{integer} (@emph{input})
100 Set number of frames used to probe fps.
101
102 @item audio_preload @var{integer} (@emph{output})
103 Set microseconds by which audio packets should be interleaved earlier.
104
105 @item chunk_duration @var{integer} (@emph{output})
106 Set microseconds for each chunk.
107
108 @item chunk_size @var{integer} (@emph{output})
109 Set size in bytes for each chunk.
110
111 @item err_detect, f_err_detect @var{flags} (@emph{input})
112 Set error detection flags. @code{f_err_detect} is deprecated and
113 should be used only via the @command{ffmpeg} tool.
114
115 Possible values:
116 @table @samp
117 @item crccheck
118 Verify embedded CRCs.
119 @item bitstream
120 Detect bitstream specification deviations.
121 @item buffer
122 Detect improper bitstream length.
123 @item explode
124 Abort decoding on minor error detection.
125 @item careful
126 Consider things that violate the spec and have not been seen in the
127 wild as errors.
128 @item compliant
129 Consider all spec non compliancies as errors.
130 @item aggressive
131 Consider things that a sane encoder should not do as an error.
132 @end table
133
134 @item max_interleave_delta @var{integer} (@emph{output})
135 Set maximum buffering duration for interleaving. The duration is
136 expressed in microseconds, and defaults to 1000000 (1 second).
137
138 To ensure all the streams are interleaved correctly, libavformat will
139 wait until it has at least one packet for each stream before actually
140 writing any packets to the output file. When some streams are
141 "sparse" (i.e. there are large gaps between successive packets), this
142 can result in excessive buffering.
143
144 This field specifies the maximum difference between the timestamps of the
145 first and the last packet in the muxing queue, above which libavformat
146 will output a packet regardless of whether it has queued a packet for all
147 the streams.
148
149 If set to 0, libavformat will continue buffering packets until it has
150 a packet for each stream, regardless of the maximum timestamp
151 difference between the buffered packets.
152
153 @item use_wallclock_as_timestamps @var{integer} (@emph{input})
154 Use wallclock as timestamps if set to 1. Default is 0.
155
156 @item avoid_negative_ts @var{integer} (@emph{output})
157
158 Possible values:
159 @table @samp
160 @item make_non_negative
161 Shift timestamps to make them non-negative.
162 Also note that this affects only leading negative timestamps, and not
163 non-monotonic negative timestamps.
164 @item make_zero
165 Shift timestamps so that the first timestamp is 0.
166 @item auto (default)
167 Enables shifting when required by the target format.
168 @item disabled
169 Disables shifting of timestamp.
170 @end table
171
172 When shifting is enabled, all output timestamps are shifted by the
173 same amount. Audio, video, and subtitles desynching and relative
174 timestamp differences are preserved compared to how they would have
175 been without shifting.
176
177 @item skip_initial_bytes @var{integer} (@emph{input})
178 Set number of bytes to skip before reading header and frames if set to 1.
179 Default is 0.
180
181 @item correct_ts_overflow @var{integer} (@emph{input})
182 Correct single timestamp overflows if set to 1. Default is 1.
183
184 @item flush_packets @var{integer} (@emph{output})
185 Flush the underlying I/O stream after each packet. Default 1 enables it, and
186 has the effect of reducing the latency; 0 disables it and may slightly
187 increase performance in some cases.
188
189 @item output_ts_offset @var{offset} (@emph{output})
190 Set the output time offset.
191
192 @var{offset} must be a time duration specification,
193 see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
194
195 The offset is added by the muxer to the output timestamps.
196
197 Specifying a positive offset means that the corresponding streams are
198 delayed bt the time duration specified in @var{offset}. Default value
199 is @code{0} (meaning that no offset is applied).
200
201 @item format_whitelist @var{list} (@emph{input})
202 "," separated list of allowed demuxers. By default all are allowed.
203
204 @item dump_separator @var{string} (@emph{input})
205 Separator used to separate the fields printed on the command line about the
206 Stream parameters.
207 For example to separate the fields with newlines and indention:
208 @example
209 ffprobe -dump_separator "
210                           "  -i ~/videos/matrixbench_mpeg2.mpg
211 @end example
212
213 @item max_streams @var{integer} (@emph{input})
214 Specifies the maximum number of streams. This can be used to reject files that
215 would require too many resources due to a large number of streams.
216 @end table
217
218 @c man end FORMAT OPTIONS
219
220 @anchor{Format stream specifiers}
221 @section Format stream specifiers
222
223 Format stream specifiers allow selection of one or more streams that
224 match specific properties.
225
226 Possible forms of stream specifiers are:
227 @table @option
228 @item @var{stream_index}
229 Matches the stream with this index.
230
231 @item @var{stream_type}[:@var{stream_index}]
232 @var{stream_type} is one of following: 'v' for video, 'a' for audio,
233 's' for subtitle, 'd' for data, and 't' for attachments. If
234 @var{stream_index} is given, then it matches the stream number
235 @var{stream_index} of this type. Otherwise, it matches all streams of
236 this type.
237
238 @item p:@var{program_id}[:@var{stream_index}]
239 If @var{stream_index} is given, then it matches the stream with number
240 @var{stream_index} in the program with the id
241 @var{program_id}. Otherwise, it matches all streams in the program.
242
243 @item #@var{stream_id}
244 Matches the stream by a format-specific ID.
245 @end table
246
247 The exact semantics of stream specifiers is defined by the
248 @code{avformat_match_stream_specifier()} function declared in the
249 @file{libavformat/avformat.h} header.
250
251 @ifclear config-writeonly
252 @include demuxers.texi
253 @end ifclear
254 @ifclear config-readonly
255 @include muxers.texi
256 @end ifclear
257 @include metadata.texi
258
1	@chapter Format Options
2	@c man begin FORMAT OPTIONS
3
4	The libavformat library provides some generic global options, which
5	can be set on all the muxers and demuxers. In addition each muxer or
6	demuxer may support so-called private options, which are specific for
7	that component.
8
9	Options may be set by specifying -@var{option} @var{value} in the
10	FFmpeg tools, or by setting the value explicitly in the
11	@code{AVFormatContext} options or using the @file{libavutil/opt.h} API
12	for programmatic use.
13
14	The list of supported options follows:
15
16	@table @option
17	@item avioflags @var{flags} (@emph{input/output})
18	Possible values:
19	@table @samp
20	@item direct
21	Reduce buffering.
22	@end table
23
24	@item probesize @var{integer} (@emph{input})
25	Set probing size in bytes, i.e. the size of the data to analyze to get
26	stream information. A higher value will enable detecting more
27	information in case it is dispersed into the stream, but will increase
28	latency. Must be an integer not lesser than 32. It is 5000000 by default.
29
30	@item packetsize @var{integer} (@emph{output})
31	Set packet size.
32
33	@item fflags @var{flags} (@emph{input/output})
34	Set format flags.
35
36	Possible values:
37	@table @samp
38	@item ignidx
39	Ignore index.
40	@item fastseek
41	Enable fast, but inaccurate seeks for some formats.
42	@item genpts
43	Generate PTS.
44	@item nofillin
45	Do not fill in missing values that can be exactly calculated.
46	@item noparse
47	Disable AVParsers, this needs @code{+nofillin} too.
48	@item igndts
49	Ignore DTS.
50	@item discardcorrupt
51	Discard corrupted frames.
52	@item sortdts
53	Try to interleave output packets by DTS.
54	@item keepside
55	Do not merge side data.
56	@item latm
57	Enable RTP MP4A-LATM payload.
58	@item nobuffer
59	Reduce the latency introduced by optional buffering
60	@item bitexact
61	Only write platform-, build- and time-independent data.
62	This ensures that file and data checksums are reproducible and match between
63	platforms. Its primary use is for regression testing.
64	@item shortest
65	Stop muxing at the end of the shortest stream.
66	It may be needed to increase max_interleave_delta to avoid flushing the longer
67	streams before EOF.
68	@end table
69
70	@item seek2any @var{integer} (@emph{input})
71	Allow seeking to non-keyframes on demuxer level when supported if set to 1.
72	Default is 0.
73
74	@item analyzeduration @var{integer} (@emph{input})
75	Specify how many microseconds are analyzed to probe the input. A
76	higher value will enable detecting more accurate information, but will
77	increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
78
79	@item cryptokey @var{hexadecimal string} (@emph{input})
80	Set decryption key.
81
82	@item indexmem @var{integer} (@emph{input})
83	Set max memory used for timestamp index (per stream).
84
85	@item rtbufsize @var{integer} (@emph{input})
86	Set max memory used for buffering real-time frames.
87
88	@item fdebug @var{flags} (@emph{input/output})
89	Print specific debug info.
90
91	Possible values:
92	@table @samp
93	@item ts
94	@end table
95
96	@item max_delay @var{integer} (@emph{input/output})
97	Set maximum muxing or demuxing delay in microseconds.
98
99	@item fpsprobesize @var{integer} (@emph{input})
100	Set number of frames used to probe fps.
101
102	@item audio_preload @var{integer} (@emph{output})
103	Set microseconds by which audio packets should be interleaved earlier.
104
105	@item chunk_duration @var{integer} (@emph{output})
106	Set microseconds for each chunk.
107
108	@item chunk_size @var{integer} (@emph{output})
109	Set size in bytes for each chunk.
110
111	@item err_detect, f_err_detect @var{flags} (@emph{input})
112	Set error detection flags. @code{f_err_detect} is deprecated and
113	should be used only via the @command{ffmpeg} tool.
114
115	Possible values:
116	@table @samp
117	@item crccheck
118	Verify embedded CRCs.
119	@item bitstream
120	Detect bitstream specification deviations.
121	@item buffer
122	Detect improper bitstream length.
123	@item explode
124	Abort decoding on minor error detection.
125	@item careful
126	Consider things that violate the spec and have not been seen in the
127	wild as errors.
128	@item compliant
129	Consider all spec non compliancies as errors.
130	@item aggressive
131	Consider things that a sane encoder should not do as an error.
132	@end table
133
134	@item max_interleave_delta @var{integer} (@emph{output})
135	Set maximum buffering duration for interleaving. The duration is
136	expressed in microseconds, and defaults to 1000000 (1 second).
137
138	To ensure all the streams are interleaved correctly, libavformat will
139	wait until it has at least one packet for each stream before actually
140	writing any packets to the output file. When some streams are
141	"sparse" (i.e. there are large gaps between successive packets), this
142	can result in excessive buffering.
143
144	This field specifies the maximum difference between the timestamps of the
145	first and the last packet in the muxing queue, above which libavformat
146	will output a packet regardless of whether it has queued a packet for all
147	the streams.
148
149	If set to 0, libavformat will continue buffering packets until it has
150	a packet for each stream, regardless of the maximum timestamp
151	difference between the buffered packets.
152
153	@item use_wallclock_as_timestamps @var{integer} (@emph{input})
154	Use wallclock as timestamps if set to 1. Default is 0.
155
156	@item avoid_negative_ts @var{integer} (@emph{output})
157
158	Possible values:
159	@table @samp
160	@item make_non_negative
161	Shift timestamps to make them non-negative.
162	Also note that this affects only leading negative timestamps, and not
163	non-monotonic negative timestamps.
164	@item make_zero
165	Shift timestamps so that the first timestamp is 0.
166	@item auto (default)
167	Enables shifting when required by the target format.
168	@item disabled
169	Disables shifting of timestamp.
170	@end table
171
172	When shifting is enabled, all output timestamps are shifted by the
173	same amount. Audio, video, and subtitles desynching and relative
174	timestamp differences are preserved compared to how they would have
175	been without shifting.
176
177	@item skip_initial_bytes @var{integer} (@emph{input})
178	Set number of bytes to skip before reading header and frames if set to 1.
179	Default is 0.
180
181	@item correct_ts_overflow @var{integer} (@emph{input})
182	Correct single timestamp overflows if set to 1. Default is 1.
183
184	@item flush_packets @var{integer} (@emph{output})
185	Flush the underlying I/O stream after each packet. Default 1 enables it, and
186	has the effect of reducing the latency; 0 disables it and may slightly
187	increase performance in some cases.
188
189	@item output_ts_offset @var{offset} (@emph{output})
190	Set the output time offset.
191
192	@var{offset} must be a time duration specification,
193	see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
194
195	The offset is added by the muxer to the output timestamps.
196
197	Specifying a positive offset means that the corresponding streams are
198	delayed bt the time duration specified in @var{offset}. Default value
199	is @code{0} (meaning that no offset is applied).
200
201	@item format_whitelist @var{list} (@emph{input})
202	"," separated list of allowed demuxers. By default all are allowed.
203
204	@item dump_separator @var{string} (@emph{input})
205	Separator used to separate the fields printed on the command line about the
206	Stream parameters.
207	For example to separate the fields with newlines and indention:
208	@example
209	ffprobe -dump_separator "
210	" -i ~/videos/matrixbench_mpeg2.mpg
211	@end example
212
213	@item max_streams @var{integer} (@emph{input})
214	Specifies the maximum number of streams. This can be used to reject files that
215	would require too many resources due to a large number of streams.
216	@end table
217
218	@c man end FORMAT OPTIONS
219
220	@anchor{Format stream specifiers}
221	@section Format stream specifiers
222
223	Format stream specifiers allow selection of one or more streams that
224	match specific properties.
225
226	Possible forms of stream specifiers are:
227	@table @option
228	@item @var{stream_index}
229	Matches the stream with this index.
230
231	@item @var{stream_type}[:@var{stream_index}]
232	@var{stream_type} is one of following: 'v' for video, 'a' for audio,
233	's' for subtitle, 'd' for data, and 't' for attachments. If
234	@var{stream_index} is given, then it matches the stream number
235	@var{stream_index} of this type. Otherwise, it matches all streams of
236	this type.
237
238	@item p:@var{program_id}[:@var{stream_index}]
239	If @var{stream_index} is given, then it matches the stream with number
240	@var{stream_index} in the program with the id
241	@var{program_id}. Otherwise, it matches all streams in the program.
242
243	@item #@var{stream_id}
244	Matches the stream by a format-specific ID.
245	@end table
246
247	The exact semantics of stream specifiers is defined by the
248	@code{avformat_match_stream_specifier()} function declared in the
249	@file{libavformat/avformat.h} header.
250
251	@ifclear config-writeonly
252	@include demuxers.texi
253	@end ifclear
254	@ifclear config-readonly
255	@include muxers.texi
256	@end ifclear
257	@include metadata.texi
258