FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/bsf/h264_mp4toannexb.c
Date: 2025-06-01 09:29:47
Exec Total Coverage
Lines: 184 228 80.7%
Functions: 7 8 87.5%
Branches: 107 152 70.4%

Line Branch Exec Source
1 /*
2 * H.264 MP4 to Annex B byte stream format filter
3 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include <string.h>
23
24 #include "libavutil/avassert.h"
25 #include "libavutil/intreadwrite.h"
26 #include "libavutil/mem.h"
27
28 #include "bsf.h"
29 #include "bsf_internal.h"
30 #include "bytestream.h"
31 #include "defs.h"
32 #include "h264.h"
33 #include "sei.h"
34
35 typedef struct H264BSFContext {
36 uint8_t *sps;
37 uint8_t *pps;
38 int sps_size;
39 int pps_size;
40 unsigned sps_buf_size;
41 unsigned pps_buf_size;
42 uint8_t length_size;
43 uint8_t new_idr;
44 uint8_t idr_sps_seen;
45 uint8_t idr_pps_seen;
46 int extradata_parsed;
47 } H264BSFContext;
48
49 enum PsSource {
50 PS_OUT_OF_BAND = -1,
51 PS_NONE = 0,
52 PS_IN_BAND = 1,
53 };
54
55 3618 static void count_or_copy(uint8_t **out, uint64_t *out_size,
56 const uint8_t *in, int in_size, enum PsSource ps, int copy)
57 {
58 uint8_t start_code_size;
59
60
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3618 if (ps == PS_OUT_OF_BAND)
61 /* start code already present in out-of-band ps data, so don't need to
62 * add it manually again
63 */
64 108 start_code_size = 0;
65
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3510 else if (ps == PS_IN_BAND || *out_size == 0)
66 824 start_code_size = 4;
67 else
68 2686 start_code_size = 3;
69
70
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3618 if (copy) {
71 1809 memcpy(*out + start_code_size, in, in_size);
72
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1809 if (start_code_size == 4) {
73 412 AV_WB32(*out, 1);
74
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1397 } else if (start_code_size) {
75 1343 (*out)[0] =
76 1343 (*out)[1] = 0;
77 1343 (*out)[2] = 1;
78 }
79 1809 *out += start_code_size + in_size;
80 }
81 3618 *out_size += start_code_size + in_size;
82 3618 }
83
84 10 static int h264_extradata_to_annexb(AVBSFContext *ctx,
85 uint8_t *extradata, int extradata_size)
86 {
87 10 H264BSFContext *s = ctx->priv_data;
88 10 GetByteContext ogb, *gb = &ogb;
89 uint16_t unit_size;
90 10 uint32_t total_size = 0;
91 10 uint8_t *out = NULL, unit_nb, sps_done = 0;
92 static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
93 10 const int padding = AV_INPUT_BUFFER_PADDING_SIZE;
94 10 int length_size, pps_offset = 0;
95
96
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10 if (extradata_size < 7) {
97 av_log(ctx, AV_LOG_ERROR, "Invalid extradata size: %d\n", extradata_size);
98 return AVERROR_INVALIDDATA;
99 }
100
101 10 bytestream2_init(gb, extradata, extradata_size);
102
103 10 bytestream2_skipu(gb, 4);
104
105 /* retrieve length coded size */
106 10 length_size = (bytestream2_get_byteu(gb) & 0x3) + 1;
107
108 /* retrieve sps and pps unit(s) */
109 10 unit_nb = bytestream2_get_byteu(gb) & 0x1f; /* number of sps unit(s) */
110
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10 if (!unit_nb) {
111 goto pps;
112 }
113
114
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30 while (unit_nb--) {
115 int err;
116
117 /* possible overread ok due to padding */
118 20 unit_size = bytestream2_get_be16u(gb);
119 20 total_size += unit_size + 4;
120 av_assert1(total_size <= INT_MAX - padding);
121
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20 if (bytestream2_get_bytes_left(gb) < unit_size + !sps_done) {
122 av_log(ctx, AV_LOG_ERROR, "Global extradata truncated, "
123 "corrupted stream or invalid MP4/AVCC bitstream\n");
124 av_free(out);
125 return AVERROR_INVALIDDATA;
126 }
127
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20 if ((err = av_reallocp(&out, total_size + padding)) < 0)
128 return err;
129 20 memcpy(out + total_size - unit_size - 4, nalu_header, 4);
130 20 bytestream2_get_bufferu(gb, out + total_size - unit_size, unit_size);
131 20 pps:
132
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20 if (!unit_nb && !sps_done++) {
133 10 unit_nb = bytestream2_get_byteu(gb); /* number of pps unit(s) */
134 10 pps_offset = total_size;
135 }
136 }
137
138
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10 if (out)
139 10 memset(out + total_size, 0, padding);
140
141
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10 if (pps_offset) {
142 uint8_t *sps;
143
144 10 s->sps_size = pps_offset;
145 10 sps = av_fast_realloc(s->sps, &s->sps_buf_size, s->sps_size);
146
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10 if (!sps) {
147 av_free(out);
148 return AVERROR(ENOMEM);
149 }
150 10 s->sps = sps;
151 10 memcpy(s->sps, out, s->sps_size);
152 } else {
153 av_log(ctx, AV_LOG_WARNING,
154 "Warning: SPS NALU missing or invalid. "
155 "The resulting stream may not play.\n");
156 }
157
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10 if (pps_offset < total_size) {
158 uint8_t *pps;
159
160 10 s->pps_size = total_size - pps_offset;
161 10 pps = av_fast_realloc(s->pps, &s->pps_buf_size, s->pps_size);
162
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10 if (!pps) {
163 av_freep(&s->sps);
164 av_free(out);
165 return AVERROR(ENOMEM);
166 }
167 10 s->pps = pps;
168 10 memcpy(s->pps, out + pps_offset, s->pps_size);
169 } else {
170 av_log(ctx, AV_LOG_WARNING,
171 "Warning: PPS NALU missing or invalid. "
172 "The resulting stream may not play.\n");
173 }
174
175 10 av_freep(&ctx->par_out->extradata);
176 10 ctx->par_out->extradata = out;
177 10 ctx->par_out->extradata_size = total_size;
178
179 10 s->length_size = length_size;
180 10 s->new_idr = 1;
181 10 s->idr_sps_seen = 0;
182 10 s->idr_pps_seen = 0;
183 10 s->extradata_parsed = 1;
184
185 10 return 0;
186 }
187
188 2 static int h264_mp4toannexb_save_ps(uint8_t **dst, int *dst_size,
189 unsigned *dst_buf_size,
190 const uint8_t *nal, uint32_t nal_size,
191 int first)
192 {
193 static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
194 2 const int start_code_size = sizeof(nalu_header);
195 uint8_t *ptr;
196 uint32_t size;
197
198
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2 if (first)
199 2 size = 0;
200 else
201 size = *dst_size;
202
203 2 ptr = av_fast_realloc(*dst, dst_buf_size, size + nal_size + start_code_size);
204
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2 if (!ptr)
205 return AVERROR(ENOMEM);
206
207 2 memcpy(ptr + size, nalu_header, start_code_size);
208 2 size += start_code_size;
209 2 memcpy(ptr + size, nal, nal_size);
210 2 size += nal_size;
211
212 2 *dst = ptr;
213 2 *dst_size = size;
214 2 return 0;
215 }
216
217 412 static int h264_mp4toannexb_filter_ps(H264BSFContext *s,
218 const uint8_t *buf,
219 const uint8_t *buf_end)
220 {
221 412 int sps_count = 0;
222 412 int pps_count = 0;
223 uint8_t unit_type;
224
225 do {
226 1760 uint32_t nal_size = 0;
227
228 /* possible overread ok due to padding */
229
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8800 for (int i = 0; i < s->length_size; i++)
230 7040 nal_size = (nal_size << 8) | buf[i];
231
232 1760 buf += s->length_size;
233
234 /* This check requires the cast as the right side might
235 * otherwise be promoted to an unsigned value. */
236
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1760 if ((int64_t)nal_size > buf_end - buf)
237 1 return AVERROR_INVALIDDATA;
238
239
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1759 if (!nal_size)
240 continue;
241
242 1759 unit_type = *buf & 0x1f;
243
244
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1759 if (unit_type == H264_NAL_SPS) {
245 1 h264_mp4toannexb_save_ps(&s->sps, &s->sps_size, &s->sps_buf_size, buf,
246 nal_size, !sps_count);
247 1 sps_count++;
248
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1758 } else if (unit_type == H264_NAL_PPS) {
249 1 h264_mp4toannexb_save_ps(&s->pps, &s->pps_size, &s->pps_buf_size, buf,
250 nal_size, !pps_count);
251 1 pps_count++;
252 }
253
254 1759 buf += nal_size;
255
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1759 } while (buf < buf_end);
256
257 411 return 0;
258 }
259
260 7 static int h264_mp4toannexb_init(AVBSFContext *ctx)
261 {
262 7 int extra_size = ctx->par_in->extradata_size;
263
264 /* retrieve sps and pps NAL units from extradata */
265
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7 if (!extra_size ||
266
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7 (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) ||
267
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7 (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) {
268 av_log(ctx, AV_LOG_VERBOSE,
269 "The input looks like it is Annex B already\n");
270 return 0;
271 }
272 7 return h264_extradata_to_annexb(ctx,
273 7 ctx->par_in->extradata,
274 7 ctx->par_in->extradata_size);
275 }
276
277 831 static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
278 {
279 831 H264BSFContext *s = ctx->priv_data;
280 AVPacket *in;
281 uint8_t unit_type, new_idr, sps_seen, pps_seen;
282 const uint8_t *buf;
283 const uint8_t *buf_end;
284 uint8_t *out;
285 uint64_t out_size;
286 int ret;
287 size_t extradata_size;
288 uint8_t *extradata;
289
290 831 ret = ff_bsf_get_packet(ctx, &in);
291
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831 if (ret < 0)
292 419 return ret;
293
294 412 extradata = av_packet_get_side_data(in, AV_PKT_DATA_NEW_EXTRADATA,
295 &extradata_size);
296
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412 if (extradata && extradata[0] == 1) {
297 3 ret = h264_extradata_to_annexb(ctx, extradata, extradata_size);
298
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3 if (ret < 0)
299 goto fail;
300 3 av_packet_side_data_remove(in->side_data, &in->side_data_elems,
301 AV_PKT_DATA_NEW_EXTRADATA);
302 }
303
304 /* nothing to filter */
305
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412 if (!s->extradata_parsed) {
306 av_packet_move_ref(opkt, in);
307 av_packet_free(&in);
308 return 0;
309 }
310
311 412 buf_end = in->data + in->size;
312 412 ret = h264_mp4toannexb_filter_ps(s, in->data, buf_end);
313
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412 if (ret < 0)
314 1 goto fail;
315
316 #define LOG_ONCE(...) \
317 if (j) \
318 av_log(__VA_ARGS__)
319
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1233 for (int j = 0; j < 2; j++) {
320 822 buf = in->data;
321 822 new_idr = s->new_idr;
322 822 sps_seen = s->idr_sps_seen;
323 822 pps_seen = s->idr_pps_seen;
324 822 out_size = 0;
325
326 do {
327 3510 uint32_t nal_size = 0;
328 enum PsSource ps;
329
330 /* possible overread ok due to padding */
331
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17550 for (int i = 0; i < s->length_size; i++)
332 14040 nal_size = (nal_size << 8) | buf[i];
333
334 3510 buf += s->length_size;
335
336 /* This check requires the cast as the right side might
337 * otherwise be promoted to an unsigned value. */
338
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3510 if ((int64_t)nal_size > buf_end - buf) {
339 ret = AVERROR_INVALIDDATA;
340 goto fail;
341 }
342
343
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3510 if (!nal_size)
344 continue;
345
346 3510 unit_type = *buf & 0x1f;
347
348
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3510 if (unit_type == H264_NAL_SPS) {
349 2 sps_seen = new_idr = 1;
350
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3508 } else if (unit_type == H264_NAL_PPS) {
351 2 pps_seen = new_idr = 1;
352 /* if SPS has not been seen yet, prepend the AVCC one to PPS */
353
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2 if (!sps_seen) {
354 if (!s->sps_size) {
355 LOG_ONCE(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
356 } else {
357 count_or_copy(&out, &out_size, s->sps, s->sps_size, PS_OUT_OF_BAND, j);
358 sps_seen = 1;
359 }
360 }
361 }
362
363 /* If this is a new IDR picture following an IDR picture, reset the idr flag.
364 * Just check first_mb_in_slice to be 0 as this is the simplest solution.
365 * This could be checking idr_pic_id instead, but would complexify the parsing. */
366
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3510 if (!new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
367 new_idr = 1;
368
369 /* If this is a buffering period SEI without a corresponding sps/pps
370 * then prepend any existing sps/pps before the SEI */
371
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3510 if (unit_type == H264_NAL_SEI && buf[1] == SEI_TYPE_BUFFERING_PERIOD &&
372
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40 !sps_seen && !pps_seen) {
373
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40 if (s->sps_size) {
374 40 count_or_copy(&out, &out_size, s->sps, s->sps_size, PS_OUT_OF_BAND, j);
375 40 sps_seen = 1;
376 }
377
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40 if (s->pps_size) {
378 40 count_or_copy(&out, &out_size, s->pps, s->pps_size, PS_OUT_OF_BAND, j);
379 40 pps_seen = 1;
380 }
381 }
382
383 /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
384
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3510 if (new_idr && unit_type == H264_NAL_IDR_SLICE && !sps_seen && !pps_seen) {
385
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14 if (s->sps_size)
386 14 count_or_copy(&out, &out_size, s->sps, s->sps_size, PS_OUT_OF_BAND, j);
387
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14 if (s->pps_size)
388 14 count_or_copy(&out, &out_size, s->pps, s->pps_size, PS_OUT_OF_BAND, j);
389 14 new_idr = 0;
390 /* if only SPS has been seen, also insert PPS */
391
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3496 } else if (new_idr && unit_type == H264_NAL_IDR_SLICE && sps_seen && !pps_seen) {
392 if (!s->pps_size) {
393 LOG_ONCE(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
394 } else {
395 count_or_copy(&out, &out_size, s->pps, s->pps_size, PS_OUT_OF_BAND, j);
396 }
397 }
398
399
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3510 if (unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS)
400 4 ps = PS_IN_BAND;
401 else
402 3506 ps = PS_NONE;
403 3510 count_or_copy(&out, &out_size, buf, nal_size, ps, j);
404
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3510 if (unit_type == H264_NAL_SLICE) {
405 1760 new_idr = 1;
406 1760 sps_seen = 0;
407 1760 pps_seen = 0;
408 }
409
410 3510 buf += nal_size;
411
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3510 } while (buf < buf_end);
412
413
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822 if (!j) {
414
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411 if (out_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
415 ret = AVERROR_INVALIDDATA;
416 goto fail;
417 }
418 411 ret = av_new_packet(opkt, out_size);
419
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411 if (ret < 0)
420 goto fail;
421 411 out = opkt->data;
422 }
423 }
424 #undef LOG_ONCE
425
426 av_assert1(out_size == opkt->size);
427
428 411 s->new_idr = new_idr;
429 411 s->idr_sps_seen = sps_seen;
430 411 s->idr_pps_seen = pps_seen;
431
432 411 ret = av_packet_copy_props(opkt, in);
433
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411 if (ret < 0)
434 goto fail;
435
436 411 fail:
437
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412 if (ret < 0)
438 1 av_packet_unref(opkt);
439 412 av_packet_free(&in);
440
441 412 return ret;
442 }
443
444 7 static void h264_mp4toannexb_close(AVBSFContext *ctx)
445 {
446 7 H264BSFContext *s = ctx->priv_data;
447
448 7 av_freep(&s->sps);
449 7 av_freep(&s->pps);
450 7 }
451
452 static void h264_mp4toannexb_flush(AVBSFContext *ctx)
453 {
454 H264BSFContext *s = ctx->priv_data;
455
456 s->idr_sps_seen = 0;
457 s->idr_pps_seen = 0;
458 s->new_idr = s->extradata_parsed;
459 }
460
461 static const enum AVCodecID codec_ids[] = {
462 AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
463 };
464
465 const FFBitStreamFilter ff_h264_mp4toannexb_bsf = {
466 .p.name = "h264_mp4toannexb",
467 .p.codec_ids = codec_ids,
468 .priv_data_size = sizeof(H264BSFContext),
469 .init = h264_mp4toannexb_init,
470 .filter = h264_mp4toannexb_filter,
471 .close = h264_mp4toannexb_close,
472 .flush = h264_mp4toannexb_flush,
473 };
474