FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/cbs_mpeg2.c
Date: 2021-09-22 23:55:11
Exec Total Coverage
Lines: 95 115 82.6%
Branches: 52 80 65.0%

Line Branch Exec Source
1 /*
2 * This file is part of FFmpeg.
3 *
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.
8 *
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.
13 *
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
17 */
18
19 #include "libavutil/avassert.h"
20
21 #include "cbs.h"
22 #include "cbs_internal.h"
23 #include "cbs_mpeg2.h"
24 #include "internal.h"
25
26
27 #define HEADER(name) do { \
28 ff_cbs_trace_header(ctx, name); \
29 } while (0)
30
31 #define CHECK(call) do { \
32 err = (call); \
33 if (err < 0) \
34 return err; \
35 } while (0)
36
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)
40
41 #define SUBSCRIPTS(subs, ...) (subs > 0 ? ((int[subs + 1]){ subs, __VA_ARGS__ }) : NULL)
42
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__)
55
56 #define marker_bit() \
57 bit("marker_bit", 1)
58 #define bit(string, value) do { \
59 av_unused uint32_t bit = value; \
60 xuia(1, string, bit, value, value, 0, ); \
61 } while (0)
62
63
64 #define READ
65 #define READWRITE read
66 #define RWContext GetBitContext
67
68 #define xuia(width, string, var, range_min, range_max, subs, ...) do { \
69 uint32_t value; \
70 CHECK(ff_cbs_read_unsigned(ctx, rw, width, string, \
71 SUBSCRIPTS(subs, __VA_ARGS__), \
72 &value, range_min, range_max)); \
73 var = value; \
74 } while (0)
75
76 #define xsi(width, name, var, subs, ...) do { \
77 int32_t value; \
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))); \
82 var = value; \
83 } while (0)
84
85 #define nextbits(width, compare, var) \
86 (get_bits_left(rw) >= width && \
87 (var = show_bits(rw, width)) == (compare))
88
89 #define infer(name, value) do { \
90 current->name = value; \
91 } while (0)
92
93 #include "cbs_mpeg2_syntax_template.c"
94
95 #undef READ
96 #undef READWRITE
97 #undef RWContext
98 #undef xuia
99 #undef xsi
100 #undef nextbits
101 #undef infer
102
103
104 #define WRITE
105 #define READWRITE write
106 #define RWContext PutBitContext
107
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)); \
112 } while (0)
113
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))); \
119 } while (0)
120
121 #define nextbits(width, compare, var) (var)
122
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)); \
129 } \
130 } while (0)
131
132 #include "cbs_mpeg2_syntax_template.c"
133
134 #undef WRITE
135 #undef READWRITE
136 #undef RWContext
137 #undef xuia
138 #undef xsi
139 #undef nextbits
140 #undef infer
141
142
143 18 static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx,
144 CodedBitstreamFragment *frag,
145 int header)
146 {
147 const uint8_t *start, *end;
148 CodedBitstreamUnitType unit_type;
149 18 uint32_t start_code = -1;
150 size_t unit_size;
151 18 int err, i, final = 0;
152
153 18 start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
154 &start_code);
155
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18 if (start_code >> 8 != 0x000001) {
156 // No start code found.
157 return AVERROR_INVALIDDATA;
158 }
159
160 18 for (i = 0;; i++) {
161 8843 unit_type = start_code & 0xff;
162
163
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8843 if (start == frag->data + frag->data_size) {
164 // The last four bytes form a start code which constitutes
165 // a unit of its own. In this situation avpriv_find_start_code
166 // won't modify start_code at all so modify start_code so that
167 // the next unit will be treated as the last unit.
168 3 start_code = 0;
169 }
170
171 8843 end = avpriv_find_start_code(start--, frag->data + frag->data_size,
172 &start_code);
173
174 // start points to the byte containing the start_code_identifier
175 // (may be the last byte of fragment->data); end points to the byte
176 // following the byte containing the start code identifier (or to
177 // the end of fragment->data).
178
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8843 if (start_code >> 8 == 0x000001) {
179 // Unit runs from start to the beginning of the start code
180 // pointed to by end (including any padding zeroes).
181 8825 unit_size = (end - 4) - start;
182 } else {
183 // We didn't find a start code, so this is the final unit.
184 18 unit_size = end - start;
185 18 final = 1;
186 }
187
188 8843 err = ff_cbs_insert_unit_data(frag, i, unit_type, (uint8_t*)start,
189 unit_size, frag->data_ref);
190
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8843 if (err < 0)
191 return err;
192
193
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8843 if (final)
194 18 break;
195
196 8825 start = end;
197 }
198
199 18 return 0;
200 }
201
202 8843 static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx,
203 CodedBitstreamUnit *unit)
204 {
205 GetBitContext gbc;
206 int err;
207
208 8843 err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
209
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8843 if (err < 0)
210 return err;
211
212 8843 err = ff_cbs_alloc_unit_content2(ctx, unit);
213
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8843 if (err < 0)
214 return err;
215
216
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8843 if (MPEG2_START_IS_SLICE(unit->type)) {
217 8746 MPEG2RawSlice *slice = unit->content;
218 int pos, len;
219
220 8746 err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
221
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8746 if (err < 0)
222 return err;
223
224
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8746 if (!get_bits_left(&gbc))
225 return AVERROR_INVALIDDATA;
226
227 8746 pos = get_bits_count(&gbc);
228 8746 len = unit->data_size;
229
230 8746 slice->data_size = len - pos / 8;
231 8746 slice->data_ref = av_buffer_ref(unit->data_ref);
232
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8746 if (!slice->data_ref)
233 return AVERROR(ENOMEM);
234 8746 slice->data = unit->data + pos / 8;
235
236 8746 slice->data_bit_start = pos % 8;
237
238 } else {
239
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97 switch (unit->type) {
240 #define START(start_code, type, read_func, free_func) \
241 case start_code: \
242 { \
243 type *header = unit->content; \
244 err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \
245 if (err < 0) \
246 return err; \
247 } \
248 break;
249
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19 START(MPEG2_START_PICTURE, MPEG2RawPictureHeader,
250 picture_header, &cbs_mpeg2_free_picture_header);
251
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14 START(MPEG2_START_USER_DATA, MPEG2RawUserData,
252 user_data, &cbs_mpeg2_free_user_data);
253
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6 START(MPEG2_START_SEQUENCE_HEADER, MPEG2RawSequenceHeader,
254 sequence_header, NULL);
255
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53 START(MPEG2_START_EXTENSION, MPEG2RawExtensionData,
256 extension_data, NULL);
257
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2 START(MPEG2_START_GROUP, MPEG2RawGroupOfPicturesHeader,
258 group_of_pictures_header, NULL);
259
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3 START(MPEG2_START_SEQUENCE_END, MPEG2RawSequenceEnd,
260 sequence_end, NULL);
261 #undef START
262 default:
263 return AVERROR(ENOSYS);
264 }
265 }
266
267 8843 return 0;
268 }
269
270 97 static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx,
271 CodedBitstreamUnit *unit,
272 PutBitContext *pbc)
273 {
274 int err;
275
276
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97 switch (unit->type) {
277 #define START(start_code, type, func) \
278 case start_code: \
279 err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
280 break;
281 19 START(MPEG2_START_PICTURE, MPEG2RawPictureHeader, picture_header);
282 14 START(MPEG2_START_USER_DATA, MPEG2RawUserData, user_data);
283 6 START(MPEG2_START_SEQUENCE_HEADER, MPEG2RawSequenceHeader, sequence_header);
284 53 START(MPEG2_START_EXTENSION, MPEG2RawExtensionData, extension_data);
285 2 START(MPEG2_START_GROUP, MPEG2RawGroupOfPicturesHeader,
286 group_of_pictures_header);
287 3 START(MPEG2_START_SEQUENCE_END, MPEG2RawSequenceEnd, sequence_end);
288 #undef START
289 default:
290 av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
291 "code %02"PRIx32".\n", unit->type);
292 return AVERROR_PATCHWELCOME;
293 }
294
295 97 return err;
296 }
297
298 8746 static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx,
299 CodedBitstreamUnit *unit,
300 PutBitContext *pbc)
301 {
302 8746 MPEG2RawSlice *slice = unit->content;
303 int err;
304
305 8746 err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
306
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8746 if (err < 0)
307 return err;
308
309
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8746 if (slice->data) {
310 8746 size_t rest = slice->data_size - (slice->data_bit_start + 7) / 8;
311 8746 uint8_t *pos = slice->data + slice->data_bit_start / 8;
312
313
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8746 av_assert0(slice->data_bit_start >= 0 &&
314 slice->data_size > slice->data_bit_start / 8);
315
316
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8746 if (slice->data_size * 8 + 8 > put_bits_left(pbc))
317 return AVERROR(ENOSPC);
318
319 // First copy the remaining bits of the first byte
320
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8746 if (slice->data_bit_start % 8)
321 8746 put_bits(pbc, 8 - slice->data_bit_start % 8,
322 8746 *pos++ & MAX_UINT_BITS(8 - slice->data_bit_start % 8));
323
324
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8746 if (put_bits_count(pbc) % 8 == 0) {
325 // If the writer is aligned at this point,
326 // memcpy can be used to improve performance.
327 // This is the normal case.
328 8746 flush_put_bits(pbc);
329 8746 memcpy(put_bits_ptr(pbc), pos, rest);
330 8746 skip_put_bytes(pbc, rest);
331 } else {
332 // If not, we have to copy manually:
333 for (; rest > 3; rest -= 4, pos += 4)
334 put_bits32(pbc, AV_RB32(pos));
335
336 for (; rest; rest--, pos++)
337 put_bits(pbc, 8, *pos);
338
339 // Align with zeros
340 put_bits(pbc, 8 - put_bits_count(pbc) % 8, 0);
341 }
342 }
343
344 8746 return 0;
345 }
346
347 8843 static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx,
348 CodedBitstreamUnit *unit,
349 PutBitContext *pbc)
350 {
351
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8843 if (MPEG2_START_IS_SLICE(unit->type))
352 8746 return cbs_mpeg2_write_slice (ctx, unit, pbc);
353 else
354 97 return cbs_mpeg2_write_header(ctx, unit, pbc);
355 }
356
357 18 static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx,
358 CodedBitstreamFragment *frag)
359 {
360 uint8_t *data;
361 size_t size, dp;
362 int i;
363
364 18 size = 0;
365
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8861 for (i = 0; i < frag->nb_units; i++)
366 8843 size += 3 + frag->units[i].data_size;
367
368 18 frag->data_ref = av_buffer_alloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
369
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18 if (!frag->data_ref)
370 return AVERROR(ENOMEM);
371 18 data = frag->data_ref->data;
372
373 18 dp = 0;
374
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8861 for (i = 0; i < frag->nb_units; i++) {
375 8843 CodedBitstreamUnit *unit = &frag->units[i];
376
377 8843 data[dp++] = 0;
378 8843 data[dp++] = 0;
379 8843 data[dp++] = 1;
380
381 8843 memcpy(data + dp, unit->data, unit->data_size);
382 8843 dp += unit->data_size;
383 }
384
385
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18 av_assert0(dp == size);
386
387 18 memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
388 18 frag->data = data;
389 18 frag->data_size = size;
390
391 18 return 0;
392 }
393
394 static const CodedBitstreamUnitTypeDescriptor cbs_mpeg2_unit_types[] = {
395 CBS_UNIT_TYPE_INTERNAL_REF(MPEG2_START_PICTURE, MPEG2RawPictureHeader,
396 extra_information_picture.extra_information),
397
398 {
399 .nb_unit_types = CBS_UNIT_TYPE_RANGE,
400 .unit_type_range_start = 0x01,
401 .unit_type_range_end = 0xaf,
402
403 .content_type = CBS_CONTENT_TYPE_INTERNAL_REFS,
404 .content_size = sizeof(MPEG2RawSlice),
405 .nb_ref_offsets = 2,
406 .ref_offsets = { offsetof(MPEG2RawSlice, header.extra_information_slice.extra_information),
407 offsetof(MPEG2RawSlice, data) },
408 },
409
410 CBS_UNIT_TYPE_INTERNAL_REF(MPEG2_START_USER_DATA, MPEG2RawUserData,
411 user_data),
412
413 CBS_UNIT_TYPE_POD(MPEG2_START_SEQUENCE_HEADER, MPEG2RawSequenceHeader),
414 CBS_UNIT_TYPE_POD(MPEG2_START_EXTENSION, MPEG2RawExtensionData),
415 CBS_UNIT_TYPE_POD(MPEG2_START_SEQUENCE_END, MPEG2RawSequenceEnd),
416 CBS_UNIT_TYPE_POD(MPEG2_START_GROUP, MPEG2RawGroupOfPicturesHeader),
417
418 CBS_UNIT_TYPE_END_OF_LIST
419 };
420
421 const CodedBitstreamType ff_cbs_type_mpeg2 = {
422 .codec_id = AV_CODEC_ID_MPEG2VIDEO,
423
424 .priv_data_size = sizeof(CodedBitstreamMPEG2Context),
425
426 .unit_types = cbs_mpeg2_unit_types,
427
428 .split_fragment = &cbs_mpeg2_split_fragment,
429 .read_unit = &cbs_mpeg2_read_unit,
430 .write_unit = &cbs_mpeg2_write_unit,
431 .assemble_fragment = &cbs_mpeg2_assemble_fragment,
432 };
433