FFmpeg  4.4.6
cbs_mpeg2.c
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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 
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 
133 
134 #undef WRITE
135 #undef READWRITE
136 #undef RWContext
137 #undef xuia
138 #undef xsi
139 #undef nextbits
140 #undef infer
141 
142 
145  int header)
146 {
147  const uint8_t *start, *end;
148  CodedBitstreamUnitType unit_type;
149  uint32_t start_code = -1;
150  size_t unit_size;
151  int err, i, final = 0;
152 
153  start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
154  &start_code);
155  if (start_code >> 8 != 0x000001) {
156  // No start code found.
157  return AVERROR_INVALIDDATA;
158  }
159 
160  for (i = 0;; i++) {
161  unit_type = start_code & 0xff;
162 
163  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  start_code = 0;
169  }
170 
171  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  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  unit_size = (end - 4) - start;
182  } else {
183  // We didn't find a start code, so this is the final unit.
184  unit_size = end - start;
185  final = 1;
186  }
187 
188  err = ff_cbs_insert_unit_data(frag, i, unit_type, (uint8_t*)start,
189  unit_size, frag->data_ref);
190  if (err < 0)
191  return err;
192 
193  if (final)
194  break;
195 
196  start = end;
197  }
198 
199  return 0;
200 }
201 
203  CodedBitstreamUnit *unit)
204 {
205  GetBitContext gbc;
206  int err;
207 
208  err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
209  if (err < 0)
210  return err;
211 
212  err = ff_cbs_alloc_unit_content2(ctx, unit);
213  if (err < 0)
214  return err;
215 
216  if (MPEG2_START_IS_SLICE(unit->type)) {
217  MPEG2RawSlice *slice = unit->content;
218  int pos, len;
219 
220  err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
221  if (err < 0)
222  return err;
223 
224  if (!get_bits_left(&gbc))
225  return AVERROR_INVALIDDATA;
226 
227  pos = get_bits_count(&gbc);
228  len = unit->data_size;
229 
230  slice->data_size = len - pos / 8;
231  slice->data_ref = av_buffer_ref(unit->data_ref);
232  if (!slice->data_ref)
233  return AVERROR(ENOMEM);
234  slice->data = unit->data + pos / 8;
235 
236  slice->data_bit_start = pos % 8;
237 
238  } else {
239  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;
250  picture_header, &cbs_mpeg2_free_picture_header);
252  user_data, &cbs_mpeg2_free_user_data);
260  sequence_end, NULL);
261 #undef START
262  default:
263  return AVERROR(ENOSYS);
264  }
265  }
266 
267  return 0;
268 }
269 
271  CodedBitstreamUnit *unit,
272  PutBitContext *pbc)
273 {
274  int err;
275 
276  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;
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  return err;
296 }
297 
299  CodedBitstreamUnit *unit,
300  PutBitContext *pbc)
301 {
302  MPEG2RawSlice *slice = unit->content;
303  int err;
304 
305  err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
306  if (err < 0)
307  return err;
308 
309  if (slice->data) {
310  size_t rest = slice->data_size - (slice->data_bit_start + 7) / 8;
311  uint8_t *pos = slice->data + slice->data_bit_start / 8;
312 
313  av_assert0(slice->data_bit_start >= 0 &&
314  slice->data_size > slice->data_bit_start / 8);
315 
316  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  if (slice->data_bit_start % 8)
321  put_bits(pbc, 8 - slice->data_bit_start % 8,
322  *pos++ & MAX_UINT_BITS(8 - slice->data_bit_start % 8));
323 
324  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  flush_put_bits(pbc);
329  memcpy(put_bits_ptr(pbc), pos, rest);
330  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  return 0;
345 }
346 
348  CodedBitstreamUnit *unit,
349  PutBitContext *pbc)
350 {
351  if (MPEG2_START_IS_SLICE(unit->type))
352  return cbs_mpeg2_write_slice (ctx, unit, pbc);
353  else
354  return cbs_mpeg2_write_header(ctx, unit, pbc);
355 }
356 
359 {
360  uint8_t *data;
361  size_t size, dp;
362  int i;
363 
364  size = 0;
365  for (i = 0; i < frag->nb_units; i++)
366  size += 3 + frag->units[i].data_size;
367 
369  if (!frag->data_ref)
370  return AVERROR(ENOMEM);
371  data = frag->data_ref->data;
372 
373  dp = 0;
374  for (i = 0; i < frag->nb_units; i++) {
375  CodedBitstreamUnit *unit = &frag->units[i];
376 
377  data[dp++] = 0;
378  data[dp++] = 0;
379  data[dp++] = 1;
380 
381  memcpy(data + dp, unit->data, unit->data_size);
382  dp += unit->data_size;
383  }
384 
385  av_assert0(dp == size);
386 
387  memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
388  frag->data = data;
389  frag->data_size = size;
390 
391  return 0;
392 }
393 
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 
411  user_data),
412 
417 
419 };
420 
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 };
uint8_t
simple assert() macros that are a bit more flexible than ISO C assert().
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
#define AV_RB32
Definition: intreadwrite.h:130
int ff_cbs_insert_unit_data(CodedBitstreamFragment *frag, int position, CodedBitstreamUnitType type, uint8_t *data, size_t data_size, AVBufferRef *data_buf)
Insert a new unit into a fragment with the given data bitstream.
Definition: cbs.c:773
int ff_cbs_alloc_unit_content2(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Allocate a new internal content buffer matching the type of the unit.
Definition: cbs.c:869
uint32_t CodedBitstreamUnitType
The codec-specific type of a bitstream unit.
Definition: cbs.h:43
static int FUNC() extension_data(CodedBitstreamContext *ctx, RWContext *rw, H265RawExtensionData *current)
@ CBS_UNIT_TYPE_RANGE
Definition: cbs_internal.h:49
#define CBS_UNIT_TYPE_END_OF_LIST
Definition: cbs_internal.h:201
#define CBS_UNIT_TYPE_INTERNAL_REF(type, structure, ref_field)
Definition: cbs_internal.h:186
@ CBS_CONTENT_TYPE_INTERNAL_REFS
Definition: cbs_internal.h:34
#define CBS_UNIT_TYPE_POD(type, structure)
Definition: cbs_internal.h:180
#define MAX_UINT_BITS(length)
Definition: cbs_internal.h:169
static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag)
Definition: cbs_mpeg2.c:357
const CodedBitstreamType ff_cbs_type_mpeg2
Definition: cbs_mpeg2.c:421
#define START(start_code, type, read_func, free_func)
static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:298
static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:347
static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:270
static const CodedBitstreamUnitTypeDescriptor cbs_mpeg2_unit_types[]
Definition: cbs_mpeg2.c:394
static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, int header)
Definition: cbs_mpeg2.c:143
static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:202
#define MPEG2_START_IS_SLICE(type)
Definition: cbs_mpeg2.h:40
@ MPEG2_START_PICTURE
Definition: cbs_mpeg2.h:29
@ MPEG2_START_SEQUENCE_HEADER
Definition: cbs_mpeg2.h:33
@ MPEG2_START_SEQUENCE_END
Definition: cbs_mpeg2.h:36
@ MPEG2_START_EXTENSION
Definition: cbs_mpeg2.h:35
@ MPEG2_START_GROUP
Definition: cbs_mpeg2.h:37
@ MPEG2_START_USER_DATA
Definition: cbs_mpeg2.h:32
static int FUNC() picture_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawPictureHeader *current)
static int FUNC() user_data(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawUserData *current)
static int FUNC() group_of_pictures_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawGroupOfPicturesHeader *current)
static int FUNC() sequence_end(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawSequenceEnd *current)
static int FUNC() sequence_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawSequenceHeader *current)
#define NULL
Definition: coverity.c:32
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:849
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:219
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:659
@ AV_CODEC_ID_MPEG2VIDEO
preferred ID for MPEG-1/2 video decoding
Definition: codec_id.h:51
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding.
Definition: avcodec.h:215
AVBufferRef * av_buffer_alloc(buffer_size_t size)
Allocate an AVBuffer of the given size using av_malloc().
Definition: buffer.c:67
AVBufferRef * av_buffer_ref(AVBufferRef *buf)
Create a new reference to an AVBuffer.
Definition: buffer.c:93
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
int i
Definition: input.c:407
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:218
const uint8_t * avpriv_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state)
common internal API header
const char data[16]
Definition: mxf.c:142
static void av_unused put_bits32(PutBitContext *s, uint32_t value)
Write exactly 32 bits into a bitstream.
Definition: put_bits.h:263
static uint8_t * put_bits_ptr(PutBitContext *s)
Return the pointer to the byte where the bitstream writer will put the next bit.
Definition: put_bits.h:342
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:76
static int put_bits_left(PutBitContext *s)
Definition: put_bits.h:102
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:110
static void skip_put_bytes(PutBitContext *s, int n)
Skip the given number of bytes.
Definition: put_bits.h:351
static const uint8_t header[24]
Definition: sdr2.c:67
unsigned int pos
Definition: spdifenc.c:412
uint8_t * data
The data buffer.
Definition: buffer.h:92
Context structure for coded bitstream operations.
Definition: cbs.h:170
Coded bitstream fragment structure, combining one or more units.
Definition: cbs.h:118
CodedBitstreamUnit * units
Pointer to an array of units of length nb_units_allocated.
Definition: cbs.h:164
int nb_units
Number of units in this fragment.
Definition: cbs.h:149
size_t data_size
The number of bytes in the bitstream.
Definition: cbs.h:131
uint8_t * data
Pointer to the bitstream form of this fragment.
Definition: cbs.h:124
AVBufferRef * data_ref
A reference to the buffer containing data.
Definition: cbs.h:141
enum AVCodecID codec_id
Definition: cbs_internal.h:87
Coded bitstream unit structure.
Definition: cbs.h:66
void * content
Pointer to the decomposed form of this unit.
Definition: cbs.h:103
uint8_t * data
Pointer to the directly-parsable bitstream form of this unit.
Definition: cbs.h:77
CodedBitstreamUnitType type
Codec-specific type of this unit.
Definition: cbs.h:70
size_t data_size
The number of bytes in the bitstream (including any padding bits in the final byte).
Definition: cbs.h:82
AVBufferRef * data_ref
A reference to the buffer containing data.
Definition: cbs.h:94
AVBufferRef * data_ref
Definition: cbs_mpeg2.h:210
uint8_t * data
Definition: cbs_mpeg2.h:209
int data_bit_start
Definition: cbs_mpeg2.h:212
MPEG2RawSliceHeader header
Definition: cbs_mpeg2.h:207
size_t data_size
Definition: cbs_mpeg2.h:211
#define av_log(a,...)
AVFormatContext * ctx
Definition: movenc.c:48
int size
static const uint8_t start_code[]
int len