2 * This file is part of FFmpeg.
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 #include "libavutil/avassert.h"
22 #include "cbs_internal.h"
23 #include "cbs_mpeg2.h"
27 #define HEADER(name) do { \
28 ff_cbs_trace_header(ctx, name); \
31 #define CHECK(call) do { \
37 #define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
38 #define FUNC_MPEG2(rw, name) FUNC_NAME(rw, mpeg2, name)
39 #define FUNC(name) FUNC_MPEG2(READWRITE, name)
41 #define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
43 #define ui(width, name) \
44 xui(width, name, current->name, 0, MAX_UINT_BITS(width), 0)
45 #define uir(width, name) \
46 xui(width, name, current->name, 1, MAX_UINT_BITS(width), 0)
47 #define uis(width, name, subs, ...) \
48 xui(width, name, current->name, 0, MAX_UINT_BITS(width), subs, __VA_ARGS__)
49 #define uirs(width, name, subs, ...) \
50 xui(width, name, current->name, 1, MAX_UINT_BITS(width), subs, __VA_ARGS__)
51 #define xui(width, name, var, range_min, range_max, subs, ...) \
52 xuia(width, #name, var, range_min, range_max, subs, __VA_ARGS__)
53 #define sis(width, name, subs, ...) \
54 xsi(width, name, current->name, subs, __VA_ARGS__)
56 #define marker_bit() \
58 #define bit(string, value) do { \
59 av_unused uint32_t bit = value; \
60 xuia(1, string, bit, value, value, 0); \
65 #define READWRITE read
66 #define RWContext GetBitContext
68 #define xuia(width, string, var, range_min, range_max, subs, ...) do { \
70 CHECK(ff_cbs_read_unsigned(ctx, rw, width, string, \
71 SUBSCRIPTS(subs, __VA_ARGS__), \
72 &value, range_min, range_max)); \
76 #define xsi(width, name, var, subs, ...) do { \
78 CHECK(ff_cbs_read_signed(ctx, rw, width, #name, \
79 SUBSCRIPTS(subs, __VA_ARGS__), &value, \
80 MIN_INT_BITS(width), \
81 MAX_INT_BITS(width))); \
85 #define nextbits(width, compare, var) \
86 (get_bits_left(rw) >= width && \
87 (var = show_bits(rw, width)) == (compare))
89 #define infer(name, value) do { \
90 current->name = value; \
93 #include "cbs_mpeg2_syntax_template.c"
105 #define READWRITE write
106 #define RWContext PutBitContext
108 #define xuia(width, string, var, range_min, range_max, subs, ...) do { \
109 CHECK(ff_cbs_write_unsigned(ctx, rw, width, string, \
110 SUBSCRIPTS(subs, __VA_ARGS__), \
111 var, range_min, range_max)); \
114 #define xsi(width, name, var, subs, ...) do { \
115 CHECK(ff_cbs_write_signed(ctx, rw, width, #name, \
116 SUBSCRIPTS(subs, __VA_ARGS__), var, \
117 MIN_INT_BITS(width), \
118 MAX_INT_BITS(width))); \
121 #define nextbits(width, compare, var) (var)
123 #define infer(name, value) do { \
124 if (current->name != (value)) { \
125 av_log(ctx->log_ctx, AV_LOG_WARNING, "Warning: " \
126 "%s does not match inferred value: " \
127 "%"PRId64", but should be %"PRId64".\n", \
128 #name, (int64_t)current->name, (int64_t)(value)); \
132 #include "cbs_mpeg2_syntax_template.c"
143 static void cbs_mpeg2_free_picture_header(void *opaque, uint8_t *content)
145 MPEG2RawPictureHeader *picture = (MPEG2RawPictureHeader*)content;
146 av_buffer_unref(&picture->extra_information_picture.extra_information_ref);
150 static void cbs_mpeg2_free_user_data(void *opaque, uint8_t *content)
152 MPEG2RawUserData *user = (MPEG2RawUserData*)content;
153 av_buffer_unref(&user->user_data_ref);
157 static void cbs_mpeg2_free_slice(void *opaque, uint8_t *content)
159 MPEG2RawSlice *slice = (MPEG2RawSlice*)content;
160 av_buffer_unref(&slice->header.extra_information_slice.extra_information_ref);
161 av_buffer_unref(&slice->data_ref);
165 static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx,
166 CodedBitstreamFragment *frag,
169 const uint8_t *start, *end;
170 CodedBitstreamUnitType unit_type;
171 uint32_t start_code = -1;
173 int err, i, final = 0;
175 start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
177 if (start_code >> 8 != 0x000001) {
178 // No start code found.
179 return AVERROR_INVALIDDATA;
183 unit_type = start_code & 0xff;
185 if (start == frag->data + frag->data_size) {
186 // The last four bytes form a start code which constitutes
187 // a unit of its own. In this situation avpriv_find_start_code
188 // won't modify start_code at all so modify start_code so that
189 // the next unit will be treated as the last unit.
193 end = avpriv_find_start_code(start--, frag->data + frag->data_size,
196 // start points to the byte containing the start_code_identifier
197 // (may be the last byte of fragment->data); end points to the byte
198 // following the byte containing the start code identifier (or to
199 // the end of fragment->data).
200 if (start_code >> 8 == 0x000001) {
201 // Unit runs from start to the beginning of the start code
202 // pointed to by end (including any padding zeroes).
203 unit_size = (end - 4) - start;
205 // We didn't find a start code, so this is the final unit.
206 unit_size = end - start;
210 err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type, (uint8_t*)start,
211 unit_size, frag->data_ref);
224 static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx,
225 CodedBitstreamUnit *unit)
230 err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
234 if (MPEG2_START_IS_SLICE(unit->type)) {
235 MPEG2RawSlice *slice;
238 err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*slice),
239 &cbs_mpeg2_free_slice);
242 slice = unit->content;
244 err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
248 pos = get_bits_count(&gbc);
249 len = unit->data_size;
251 slice->data_size = len - pos / 8;
252 slice->data_ref = av_buffer_ref(unit->data_ref);
253 if (!slice->data_ref)
254 return AVERROR(ENOMEM);
255 slice->data = unit->data + pos / 8;
257 slice->data_bit_start = pos % 8;
260 switch (unit->type) {
261 #define START(start_code, type, read_func, free_func) \
265 err = ff_cbs_alloc_unit_content(ctx, unit, \
266 sizeof(*header), free_func); \
269 header = unit->content; \
270 err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \
275 START(MPEG2_START_PICTURE, MPEG2RawPictureHeader,
276 picture_header, &cbs_mpeg2_free_picture_header);
277 START(MPEG2_START_USER_DATA, MPEG2RawUserData,
278 user_data, &cbs_mpeg2_free_user_data);
279 START(MPEG2_START_SEQUENCE_HEADER, MPEG2RawSequenceHeader,
280 sequence_header, NULL);
281 START(MPEG2_START_EXTENSION, MPEG2RawExtensionData,
282 extension_data, NULL);
283 START(MPEG2_START_GROUP, MPEG2RawGroupOfPicturesHeader,
284 group_of_pictures_header, NULL);
285 START(MPEG2_START_SEQUENCE_END, MPEG2RawSequenceEnd,
289 return AVERROR(ENOSYS);
296 static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx,
297 CodedBitstreamUnit *unit,
302 switch (unit->type) {
303 #define START(start_code, type, func) \
305 err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
307 START(MPEG2_START_PICTURE, MPEG2RawPictureHeader, picture_header);
308 START(MPEG2_START_USER_DATA, MPEG2RawUserData, user_data);
309 START(MPEG2_START_SEQUENCE_HEADER, MPEG2RawSequenceHeader, sequence_header);
310 START(MPEG2_START_EXTENSION, MPEG2RawExtensionData, extension_data);
311 START(MPEG2_START_GROUP, MPEG2RawGroupOfPicturesHeader,
312 group_of_pictures_header);
313 START(MPEG2_START_SEQUENCE_END, MPEG2RawSequenceEnd, sequence_end);
316 av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
317 "code %02"PRIx32".\n", unit->type);
318 return AVERROR_PATCHWELCOME;
324 static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx,
325 CodedBitstreamUnit *unit,
328 MPEG2RawSlice *slice = unit->content;
331 err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
336 size_t rest = slice->data_size - (slice->data_bit_start + 7) / 8;
337 uint8_t *pos = slice->data + slice->data_bit_start / 8;
339 av_assert0(slice->data_bit_start >= 0 &&
340 8 * slice->data_size > slice->data_bit_start);
342 if (slice->data_size * 8 + 8 > put_bits_left(pbc))
343 return AVERROR(ENOSPC);
345 // First copy the remaining bits of the first byte
346 if (slice->data_bit_start % 8)
347 put_bits(pbc, 8 - slice->data_bit_start % 8,
348 *pos++ & MAX_UINT_BITS(8 - slice->data_bit_start % 8));
350 if (put_bits_count(pbc) % 8 == 0) {
351 // If the writer is aligned at this point,
352 // memcpy can be used to improve performance.
353 // This is the normal case.
355 memcpy(put_bits_ptr(pbc), pos, rest);
356 skip_put_bytes(pbc, rest);
358 // If not, we have to copy manually:
359 for (; rest > 3; rest -= 4, pos += 4)
360 put_bits32(pbc, AV_RB32(pos));
362 for (; rest; rest--, pos++)
363 put_bits(pbc, 8, *pos);
366 put_bits(pbc, 8 - put_bits_count(pbc) % 8, 0);
373 static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx,
374 CodedBitstreamUnit *unit)
376 CodedBitstreamMPEG2Context *priv = ctx->priv_data;
380 if (!priv->write_buffer) {
381 // Initial write buffer size is 1MB.
382 priv->write_buffer_size = 1024 * 1024;
384 reallocate_and_try_again:
385 err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
387 av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
388 "sufficiently large write buffer (last attempt "
389 "%"SIZE_SPECIFIER" bytes).\n", priv->write_buffer_size);
394 init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
396 if (MPEG2_START_IS_SLICE(unit->type))
397 err = cbs_mpeg2_write_slice(ctx, unit, &pbc);
399 err = cbs_mpeg2_write_header(ctx, unit, &pbc);
401 if (err == AVERROR(ENOSPC)) {
403 priv->write_buffer_size *= 2;
404 goto reallocate_and_try_again;
407 // Write failed for some other reason.
411 if (put_bits_count(&pbc) % 8)
412 unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
414 unit->data_bit_padding = 0;
416 unit->data_size = (put_bits_count(&pbc) + 7) / 8;
417 flush_put_bits(&pbc);
419 err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
423 memcpy(unit->data, priv->write_buffer, unit->data_size);
428 static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
429 CodedBitstreamFragment *frag)
436 for (i = 0; i < frag->nb_units; i++)
437 size += 3 + frag->units[i].data_size;
439 frag->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
441 return AVERROR(ENOMEM);
442 data = frag->data_ref->data;
445 for (i = 0; i < frag->nb_units; i++) {
446 CodedBitstreamUnit *unit = &frag->units[i];
452 memcpy(data + dp, unit->data, unit->data_size);
453 dp += unit->data_size;
456 av_assert0(dp == size);
458 memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
460 frag->data_size = size;
465 static void cbs_mpeg2_close(CodedBitstreamContext *ctx)
467 CodedBitstreamMPEG2Context *priv = ctx->priv_data;
469 av_freep(&priv->write_buffer);
472 const CodedBitstreamType ff_cbs_type_mpeg2 = {
473 .codec_id = AV_CODEC_ID_MPEG2VIDEO,
475 .priv_data_size = sizeof(CodedBitstreamMPEG2Context),
477 .split_fragment = &cbs_mpeg2_split_fragment,
478 .read_unit = &cbs_mpeg2_read_unit,
479 .write_unit = &cbs_mpeg2_write_unit,
480 .assemble_fragment = &cbs_mpeg2_assemble_fragment,
482 .close = &cbs_mpeg2_close,