path: root/libavcodec/qtrleenc.c (plain)
blob: cdd864bf820953cf22e6b389583ee9d95c0829a7

1	/*
2	* Quicktime Animation (RLE) Video Encoder
3	* Copyright (C) 2007 Clemens Fruhwirth
4	* Copyright (C) 2007 Alexis Ballier
5	*
6	* This file is based on flashsvenc.c.
7	*
8	* This file is part of FFmpeg.
9	*
10	* FFmpeg is free software; you can redistribute it and/or
11	* modify it under the terms of the GNU Lesser General Public
12	* License as published by the Free Software Foundation; either
13	* version 2.1 of the License, or (at your option) any later version.
14	*
15	* FFmpeg is distributed in the hope that it will be useful,
16	* but WITHOUT ANY WARRANTY; without even the implied warranty of
17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18	* Lesser General Public License for more details.
19	*
20	* You should have received a copy of the GNU Lesser General Public
21	* License along with FFmpeg; if not, write to the Free Software
22	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23	*/
24
25	#include "libavutil/imgutils.h"
26	#include "avcodec.h"
27	#include "bytestream.h"
28	#include "internal.h"
29
30	/** Maximum RLE code for bulk copy */
31	#define MAX_RLE_BULK 127
32	/** Maximum RLE code for repeat */
33	#define MAX_RLE_REPEAT 128
34	/** Maximum RLE code for skip */
35	#define MAX_RLE_SKIP 254
36
37	typedef struct QtrleEncContext {
38	AVCodecContext *avctx;
39	int pixel_size;
40	AVFrame *previous_frame;
41	unsigned int max_buf_size;
42	int logical_width;
43	/**
44	* This array will contain at ith position the value of the best RLE code
45	* if the line started at pixel i
46	* There can be 3 values :
47	* skip (0) : skip as much as possible pixels because they are equal to the
48	* previous frame ones
49	* repeat (<-1) : repeat that pixel -rle_code times, still as much as
50	* possible
51	* copy (>0) : copy the raw next rle_code pixels */
52	signed char *rlecode_table;
53	/**
54	* This array will contain the length of the best rle encoding of the line
55	* starting at ith pixel */
56	int *length_table;
57	/**
58	* Will contain at ith position the number of consecutive pixels equal to the previous
59	* frame starting from pixel i */
60	uint8_t* skip_table;
61
62	/** Encoded frame is a key frame */
63	int key_frame;
64	} QtrleEncContext;
65
66	static av_cold int qtrle_encode_end(AVCodecContext *avctx)
67	{
68	QtrleEncContext *s = avctx->priv_data;
69
70	av_frame_free(&s->previous_frame);
71	av_free(s->rlecode_table);
72	av_free(s->length_table);
73	av_free(s->skip_table);
74	return 0;
75	}
76
77	static av_cold int qtrle_encode_init(AVCodecContext *avctx)
78	{
79	QtrleEncContext *s = avctx->priv_data;
80
81	if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
82	return AVERROR(EINVAL);
83	}
84	s->avctx=avctx;
85	s->logical_width=avctx->width;
86
87	switch (avctx->pix_fmt) {
88	case AV_PIX_FMT_GRAY8:
89	if (avctx->width % 4) {
90	av_log(avctx, AV_LOG_ERROR, "Width not being a multiple of 4 is not supported\n");
91	return AVERROR(EINVAL);
92	}
93	s->logical_width = avctx->width / 4;
94	s->pixel_size = 4;
95	break;
96	case AV_PIX_FMT_RGB555BE:
97	s->pixel_size = 2;
98	break;
99	case AV_PIX_FMT_RGB24:
100	s->pixel_size = 3;
101	break;
102	case AV_PIX_FMT_ARGB:
103	s->pixel_size = 4;
104	break;
105	default:
106	av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
107	break;
108	}
109	avctx->bits_per_coded_sample = avctx->pix_fmt == AV_PIX_FMT_GRAY8 ? 40 : s->pixel_size*8;
110
111	s->rlecode_table = av_mallocz(s->logical_width);
112	s->skip_table = av_mallocz(s->logical_width);
113	s->length_table = av_mallocz_array(s->logical_width + 1, sizeof(int));
114	if (!s->skip_table || !s->length_table || !s->rlecode_table) {
115	av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
116	return AVERROR(ENOMEM);
117	}
118	s->previous_frame = av_frame_alloc();
119	if (!s->previous_frame) {
120	av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
121	return AVERROR(ENOMEM);
122	}
123
124	s->max_buf_size = s->logical_width*s->avctx->height*s->pixel_size*2 /* image base material */
125	+ 15 /* header + footer */
126	+ s->avctx->height*2 /* skip code+rle end */
127	+ s->logical_width/MAX_RLE_BULK + 1 /* rle codes */;
128
129	return 0;
130	}
131
132	/**
133	* Compute the best RLE sequence for a line
134	*/
135	static void qtrle_encode_line(QtrleEncContext *s, const AVFrame *p, int line, uint8_t **buf)
136	{
137	int width=s->logical_width;
138	int i;
139	signed char rlecode;
140
141	/* This will be the number of pixels equal to the previous frame one's
142	* starting from the ith pixel */
143	unsigned int skipcount;
144	/* This will be the number of consecutive equal pixels in the current
145	* frame, starting from the ith one also */
146	unsigned int av_uninit(repeatcount);
147
148	/* The cost of the three different possibilities */
149	int total_skip_cost;
150	int total_repeat_cost;
151
152	int base_bulk_cost;
153	int lowest_bulk_cost;
154	int lowest_bulk_cost_index;
155	int sec_lowest_bulk_cost;
156	int sec_lowest_bulk_cost_index;
157
158	uint8_t *this_line = p-> data[0] + line*p-> linesize[0] +
159	(width - 1)*s->pixel_size;
160	uint8_t *prev_line = s->previous_frame->data[0] + line * s->previous_frame->linesize[0] +
161	(width - 1)*s->pixel_size;
162
163	s->length_table[width] = 0;
164	skipcount = 0;
165
166	/* Initial values */
167	lowest_bulk_cost = INT_MAX / 2;
168	lowest_bulk_cost_index = width;
169	sec_lowest_bulk_cost = INT_MAX / 2;
170	sec_lowest_bulk_cost_index = width;
171
172	base_bulk_cost = 1 + s->pixel_size;
173
174	for (i = width - 1; i >= 0; i--) {
175
176	int prev_bulk_cost;
177
178	/* If our lowest bulk cost index is too far away, replace it
179	* with the next lowest bulk cost */
180	if (FFMIN(width, i + MAX_RLE_BULK) < lowest_bulk_cost_index) {
181	lowest_bulk_cost = sec_lowest_bulk_cost;
182	lowest_bulk_cost_index = sec_lowest_bulk_cost_index;
183
184	sec_lowest_bulk_cost = INT_MAX / 2;
185	sec_lowest_bulk_cost_index = width;
186	}
187
188	/* Deal with the first pixel's bulk cost */
189	if (!i) {
190	base_bulk_cost++;
191	lowest_bulk_cost++;
192	sec_lowest_bulk_cost++;
193	}
194
195	/* Look at the bulk cost of the previous loop and see if it is
196	* a new lower bulk cost */
197	prev_bulk_cost = s->length_table[i + 1] + base_bulk_cost;
198	if (prev_bulk_cost <= sec_lowest_bulk_cost) {
199	/* If it's lower than the 2nd lowest, then it may be lower
200	* than the lowest */
201	if (prev_bulk_cost <= lowest_bulk_cost) {
202
203	/* If we have found a new lowest bulk cost,
204	* then the 2nd lowest bulk cost is now farther than the
205	* lowest bulk cost, and will never be used */
206	sec_lowest_bulk_cost = INT_MAX / 2;
207
208	lowest_bulk_cost = prev_bulk_cost;
209	lowest_bulk_cost_index = i + 1;
210	} else {
211	/* Then it must be the 2nd lowest bulk cost */
212	sec_lowest_bulk_cost = prev_bulk_cost;
213	sec_lowest_bulk_cost_index = i + 1;
214	}
215	}
216
217	if (!s->key_frame && !memcmp(this_line, prev_line, s->pixel_size))
218	skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
219	else
220	skipcount = 0;
221
222	total_skip_cost = s->length_table[i + skipcount] + 2;
223	s->skip_table[i] = skipcount;
224
225
226	if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
227	repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
228	else
229	repeatcount = 1;
230
231	total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
232
233	/* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
234	* so let's make it aware */
235	if (i == 0) {
236	total_skip_cost--;
237	total_repeat_cost++;
238	}
239
240	if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
241	/* repeat is the best */
242	s->length_table[i] = total_repeat_cost;
243	s->rlecode_table[i] = -repeatcount;
244	}
245	else if (skipcount > 0) {
246	/* skip is the best choice here */
247	s->length_table[i] = total_skip_cost;
248	s->rlecode_table[i] = 0;
249	}
250	else {
251	/* We cannot do neither skip nor repeat
252	* thus we use the best bulk copy */
253
254	s->length_table[i] = lowest_bulk_cost;
255	s->rlecode_table[i] = lowest_bulk_cost_index - i;
256
257	}
258
259	/* These bulk costs increase every iteration */
260	lowest_bulk_cost += s->pixel_size;
261	sec_lowest_bulk_cost += s->pixel_size;
262
263	this_line -= s->pixel_size;
264	prev_line -= s->pixel_size;
265	}
266
267	/* Good! Now we have the best sequence for this line, let's output it. */
268
269	/* We do a special case for the first pixel so that we avoid testing it in
270	* the whole loop */
271
272	i=0;
273	this_line = p-> data[0] + line*p->linesize[0];
274
275	if (s->rlecode_table[0] == 0) {
276	bytestream_put_byte(buf, s->skip_table[0] + 1);
277	i += s->skip_table[0];
278	}
279	else bytestream_put_byte(buf, 1);
280
281
282	while (i < width) {
283	rlecode = s->rlecode_table[i];
284	bytestream_put_byte(buf, rlecode);
285	if (rlecode == 0) {
286	/* Write a skip sequence */
287	bytestream_put_byte(buf, s->skip_table[i] + 1);
288	i += s->skip_table[i];
289	}
290	else if (rlecode > 0) {
291	/* bulk copy */
292	if (s->avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
293	int j;
294	// QT grayscale colorspace has 0=white and 255=black, we will
295	// ignore the palette that is included in the AVFrame because
296	// AV_PIX_FMT_GRAY8 has defined color mapping
297	for (j = 0; j < rlecode*s->pixel_size; ++j)
298	bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
299	} else {
300	bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
301	}
302	i += rlecode;
303	}
304	else {
305	/* repeat the bits */
306	if (s->avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
307	int j;
308	// QT grayscale colorspace has 0=white and 255=black, ...
309	for (j = 0; j < s->pixel_size; ++j)
310	bytestream_put_byte(buf, *(this_line + i*s->pixel_size + j) ^ 0xff);
311	} else {
312	bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
313	}
314	i -= rlecode;
315	}
316	}
317	bytestream_put_byte(buf, -1); // end RLE line
318	}
319
320	/** Encode frame including header */
321	static int encode_frame(QtrleEncContext *s, const AVFrame *p, uint8_t *buf)
322	{
323	int i;
324	int start_line = 0;
325	int end_line = s->avctx->height;
326	uint8_t *orig_buf = buf;
327
328	if (!s->key_frame) {
329	unsigned line_size = s->logical_width * s->pixel_size;
330	for (start_line = 0; start_line < s->avctx->height; start_line++)
331	if (memcmp(p->data[0] + start_line*p->linesize[0],
332	s->previous_frame->data[0] + start_line * s->previous_frame->linesize[0],
333	line_size))
334	break;
335
336	for (end_line=s->avctx->height; end_line > start_line; end_line--)
337	if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
338	s->previous_frame->data[0] + (end_line - 1) * s->previous_frame->linesize[0],
339	line_size))
340	break;
341	}
342
343	bytestream_put_be32(&buf, 0); // CHUNK SIZE, patched later
344
345	if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
346	bytestream_put_be16(&buf, 0); // header
347	else {
348	bytestream_put_be16(&buf, 8); // header
349	bytestream_put_be16(&buf, start_line); // starting line
350	bytestream_put_be16(&buf, 0); // unknown
351	bytestream_put_be16(&buf, end_line - start_line); // lines to update
352	bytestream_put_be16(&buf, 0); // unknown
353	}
354	for (i = start_line; i < end_line; i++)
355	qtrle_encode_line(s, p, i, &buf);
356
357	bytestream_put_byte(&buf, 0); // zero skip code = frame finished
358	AV_WB32(orig_buf, buf - orig_buf); // patch the chunk size
359	return buf - orig_buf;
360	}
361
362	static int qtrle_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
363	const AVFrame *pict, int *got_packet)
364	{
365	QtrleEncContext * const s = avctx->priv_data;
366	int ret;
367
368	if ((ret = ff_alloc_packet2(avctx, pkt, s->max_buf_size, 0)) < 0)
369	return ret;
370
371	if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
372	/* I-Frame */
373	s->key_frame = 1;
374	} else {
375	/* P-Frame */
376	s->key_frame = 0;
377	}
378
379	pkt->size = encode_frame(s, pict, pkt->data);
380
381	/* save the current frame */
382	av_frame_unref(s->previous_frame);
383	ret = av_frame_ref(s->previous_frame, pict);
384	if (ret < 0) {
385	av_log(avctx, AV_LOG_ERROR, "cannot add reference\n");
386	return ret;
387	}
388
389	#if FF_API_CODED_FRAME
390	FF_DISABLE_DEPRECATION_WARNINGS
391	avctx->coded_frame->key_frame = s->key_frame;
392	avctx->coded_frame->pict_type = s->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
393	FF_ENABLE_DEPRECATION_WARNINGS
394	#endif
395
396	if (s->key_frame)
397	pkt->flags |= AV_PKT_FLAG_KEY;
398	*got_packet = 1;
399
400	return 0;
401	}
402
403	AVCodec ff_qtrle_encoder = {
404	.name = "qtrle",
405	.long_name = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
406	.type = AVMEDIA_TYPE_VIDEO,
407	.id = AV_CODEC_ID_QTRLE,
408	.priv_data_size = sizeof(QtrleEncContext),
409	.init = qtrle_encode_init,
410	.encode2 = qtrle_encode_frame,
411	.close = qtrle_encode_end,
412	.pix_fmts = (const enum AVPixelFormat[]){
413	AV_PIX_FMT_RGB24, AV_PIX_FMT_RGB555BE, AV_PIX_FMT_ARGB, AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
414	},
415	};
416