FFmpeg  4.1.5
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 sis(width, name, subs, ...) \
52  xsi(width, name, current->name, subs, __VA_ARGS__)
53 
54 
55 #define READ
56 #define READWRITE read
57 #define RWContext GetBitContext
58 
59 #define xui(width, name, var, range_min, range_max, subs, ...) do { \
60  uint32_t value = 0; \
61  CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
62  SUBSCRIPTS(subs, __VA_ARGS__), \
63  &value, range_min, range_max)); \
64  var = value; \
65  } while (0)
66 
67 #define xsi(width, name, var, subs, ...) do { \
68  int32_t value; \
69  CHECK(ff_cbs_read_signed(ctx, rw, width, #name, \
70  SUBSCRIPTS(subs, __VA_ARGS__), &value, \
71  MIN_INT_BITS(width), \
72  MAX_INT_BITS(width))); \
73  var = value; \
74  } while (0)
75 
76 #define marker_bit() do { \
77  av_unused uint32_t one; \
78  CHECK(ff_cbs_read_unsigned(ctx, rw, 1, "marker_bit", NULL, &one, 1, 1)); \
79  } while (0)
80 
81 #define nextbits(width, compare, var) \
82  (get_bits_left(rw) >= width && \
83  (var = show_bits(rw, width)) == (compare))
84 
86 
87 #undef READ
88 #undef READWRITE
89 #undef RWContext
90 #undef xui
91 #undef xsi
92 #undef marker_bit
93 #undef nextbits
94 
95 
96 #define WRITE
97 #define READWRITE write
98 #define RWContext PutBitContext
99 
100 #define xui(width, name, var, range_min, range_max, subs, ...) do { \
101  CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
102  SUBSCRIPTS(subs, __VA_ARGS__), \
103  var, range_min, range_max)); \
104  } while (0)
105 
106 #define xsi(width, name, var, subs, ...) do { \
107  CHECK(ff_cbs_write_signed(ctx, rw, width, #name, \
108  SUBSCRIPTS(subs, __VA_ARGS__), var, \
109  MIN_INT_BITS(width), \
110  MAX_INT_BITS(width))); \
111  } while (0)
112 
113 #define marker_bit() do { \
114  CHECK(ff_cbs_write_unsigned(ctx, rw, 1, "marker_bit", NULL, 1, 1, 1)); \
115  } while (0)
116 
117 #define nextbits(width, compare, var) (var)
118 
120 
121 #undef READ
122 #undef READWRITE
123 #undef RWContext
124 #undef xui
125 #undef xsi
126 #undef marker_bit
127 #undef nextbits
128 
129 
130 static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content)
131 {
132  MPEG2RawUserData *user = (MPEG2RawUserData*)content;
134  av_freep(&content);
135 }
136 
137 static void cbs_mpeg2_free_slice(void *unit, uint8_t *content)
138 {
139  MPEG2RawSlice *slice = (MPEG2RawSlice*)content;
141  av_buffer_unref(&slice->data_ref);
142  av_freep(&content);
143 }
144 
147  int header)
148 {
149  const uint8_t *start, *end;
150  uint8_t *unit_data;
151  uint32_t start_code = -1, next_start_code = -1;
152  size_t unit_size;
153  int err, i, unit_type;
154 
155  start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
156  &start_code);
157  for (i = 0;; i++) {
158  end = avpriv_find_start_code(start, frag->data + frag->data_size,
159  &next_start_code);
160 
161  unit_type = start_code & 0xff;
162 
163  // The start and end pointers point at to the byte following the
164  // start_code_identifier in the start code that they found.
165  if (end == frag->data + frag->data_size) {
166  // We didn't find a start code, so this is the final unit.
167  unit_size = end - (start - 1);
168  } else {
169  // Unit runs from start to the beginning of the start code
170  // pointed to by end (including any padding zeroes).
171  unit_size = (end - 4) - (start - 1);
172  }
173 
174  unit_data = (uint8_t *)start - 1;
175 
176  err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type,
177  unit_data, unit_size, frag->data_ref);
178  if (err < 0)
179  return err;
180 
181  if (end == frag->data + frag->data_size)
182  break;
183 
184  start_code = next_start_code;
185  start = end;
186  }
187 
188  return 0;
189 }
190 
192  CodedBitstreamUnit *unit)
193 {
194  GetBitContext gbc;
195  int err;
196 
197  err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
198  if (err < 0)
199  return err;
200 
201  if (MPEG2_START_IS_SLICE(unit->type)) {
202  MPEG2RawSlice *slice;
203  int pos, len;
204 
205  err = ff_cbs_alloc_unit_content(ctx, unit, sizeof(*slice),
207  if (err < 0)
208  return err;
209  slice = unit->content;
210 
211  err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
212  if (err < 0)
213  return err;
214 
215  pos = get_bits_count(&gbc);
216  len = unit->data_size;
217 
218  slice->data_size = len - pos / 8;
219  slice->data_ref = av_buffer_ref(unit->data_ref);
220  if (!slice->data_ref)
221  return AVERROR(ENOMEM);
222  slice->data = unit->data + pos / 8;
223 
224  slice->data_bit_start = pos % 8;
225 
226  } else {
227  switch (unit->type) {
228 #define START(start_code, type, read_func, free_func) \
229  case start_code: \
230  { \
231  type *header; \
232  err = ff_cbs_alloc_unit_content(ctx, unit, \
233  sizeof(*header), free_func); \
234  if (err < 0) \
235  return err; \
236  header = unit->content; \
237  err = cbs_mpeg2_read_ ## read_func(ctx, &gbc, header); \
238  if (err < 0) \
239  return err; \
240  } \
241  break;
249 #undef START
250  default:
251  av_log(ctx->log_ctx, AV_LOG_ERROR, "Unknown start code %02"PRIx32".\n",
252  unit->type);
253  return AVERROR_INVALIDDATA;
254  }
255  }
256 
257  return 0;
258 }
259 
261  CodedBitstreamUnit *unit,
262  PutBitContext *pbc)
263 {
264  int err;
265 
266  switch (unit->type) {
267 #define START(start_code, type, func) \
268  case start_code: \
269  err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
270  break;
276 #undef START
277  default:
278  av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
279  "code %02"PRIx32".\n", unit->type);
280  return AVERROR_PATCHWELCOME;
281  }
282 
283  return err;
284 }
285 
287  CodedBitstreamUnit *unit,
288  PutBitContext *pbc)
289 {
290  MPEG2RawSlice *slice = unit->content;
291  GetBitContext gbc;
292  size_t bits_left;
293  int err;
294 
295  err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
296  if (err < 0)
297  return err;
298 
299  if (slice->data) {
300  if (slice->data_size * 8 + 8 > put_bits_left(pbc))
301  return AVERROR(ENOSPC);
302 
303  init_get_bits(&gbc, slice->data, slice->data_size * 8);
304  skip_bits_long(&gbc, slice->data_bit_start);
305 
306  while (get_bits_left(&gbc) > 15)
307  put_bits(pbc, 16, get_bits(&gbc, 16));
308 
309  bits_left = get_bits_left(&gbc);
310  put_bits(pbc, bits_left, get_bits(&gbc, bits_left));
311 
312  // Align with zeroes.
313  while (put_bits_count(pbc) % 8 != 0)
314  put_bits(pbc, 1, 0);
315  }
316 
317  return 0;
318 }
319 
321  CodedBitstreamUnit *unit)
322 {
324  PutBitContext pbc;
325  int err;
326 
327  if (!priv->write_buffer) {
328  // Initial write buffer size is 1MB.
329  priv->write_buffer_size = 1024 * 1024;
330 
331  reallocate_and_try_again:
332  err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
333  if (err < 0) {
334  av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
335  "sufficiently large write buffer (last attempt "
336  "%"SIZE_SPECIFIER" bytes).\n", priv->write_buffer_size);
337  return err;
338  }
339  }
340 
341  init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
342 
343  if (unit->type >= 0x01 && unit->type <= 0xaf)
344  err = cbs_mpeg2_write_slice(ctx, unit, &pbc);
345  else
346  err = cbs_mpeg2_write_header(ctx, unit, &pbc);
347 
348  if (err == AVERROR(ENOSPC)) {
349  // Overflow.
350  priv->write_buffer_size *= 2;
351  goto reallocate_and_try_again;
352  }
353  if (err < 0) {
354  // Write failed for some other reason.
355  return err;
356  }
357 
358  if (put_bits_count(&pbc) % 8)
359  unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
360  else
361  unit->data_bit_padding = 0;
362 
363  unit->data_size = (put_bits_count(&pbc) + 7) / 8;
364  flush_put_bits(&pbc);
365 
366  err = ff_cbs_alloc_unit_data(ctx, unit, unit->data_size);
367  if (err < 0)
368  return err;
369 
370  memcpy(unit->data, priv->write_buffer, unit->data_size);
371 
372  return 0;
373 }
374 
377 {
378  uint8_t *data;
379  size_t size, dp;
380  int i;
381 
382  size = 0;
383  for (i = 0; i < frag->nb_units; i++)
384  size += 3 + frag->units[i].data_size;
385 
387  if (!frag->data_ref)
388  return AVERROR(ENOMEM);
389  data = frag->data_ref->data;
390 
391  dp = 0;
392  for (i = 0; i < frag->nb_units; i++) {
393  CodedBitstreamUnit *unit = &frag->units[i];
394 
395  data[dp++] = 0;
396  data[dp++] = 0;
397  data[dp++] = 1;
398 
399  memcpy(data + dp, unit->data, unit->data_size);
400  dp += unit->data_size;
401  }
402 
403  av_assert0(dp == size);
404 
405  memset(data + size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
406  frag->data = data;
407  frag->data_size = size;
408 
409  return 0;
410 }
411 
413 {
415 
416  av_freep(&priv->write_buffer);
417 }
418 
421 
422  .priv_data_size = sizeof(CodedBitstreamMPEG2Context),
423 
424  .split_fragment = &cbs_mpeg2_split_fragment,
425  .read_unit = &cbs_mpeg2_read_unit,
426  .write_unit = &cbs_mpeg2_write_unit,
427  .assemble_fragment = &cbs_mpeg2_assemble_fragment,
428 
429  .close = &cbs_mpeg2_close,
430 };
#define NULL
Definition: coverity.c:32
int nb_units
Number of units in this fragment.
Definition: cbs.h:147
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
void av_buffer_unref(AVBufferRef **buf)
Free a given reference and automatically free the buffer if there are no more references to it...
Definition: buffer.c:125
int size
uint8_t * data
Definition: cbs_mpeg2.h:207
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:208
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:381
static void skip_bits_long(GetBitContext *s, int n)
Skips the specified number of bits.
Definition: get_bits.h:293
CodedBitstreamUnitType type
Codec-specific type of this unit.
Definition: cbs.h:68
int ff_cbs_alloc_unit_content(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, size_t size, void(*free)(void *opaque, uint8_t *data))
Definition: cbs.c:585
static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:320
static void cbs_mpeg2_free_user_data(void *unit, uint8_t *content)
Definition: cbs_mpeg2.c:130
static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:191
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
static int cbs_mpeg2_assemble_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag)
Definition: cbs_mpeg2.c:375
static int FUNC() extension_data(CodedBitstreamContext *ctx, RWContext *rw, H265RawPSExtensionData *current)
uint8_t
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
AVBufferRef * extra_information_ref
Definition: cbs_mpeg2.h:201
size_t data_bit_padding
The number of bits which should be ignored in the final byte.
Definition: cbs.h:86
const char data[16]
Definition: mxf.c:91
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:219
int ff_cbs_alloc_unit_data(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, size_t size)
Allocate a new internal data buffer of the given size in the unit.
Definition: cbs.c:606
Coded bitstream unit structure.
Definition: cbs.h:64
void * content
Pointer to the decomposed form of this unit.
Definition: cbs.h:101
static const uint8_t header[24]
Definition: sdr2.c:67
CodedBitstreamUnit * units
Pointer to an array of units of length nb_units.
Definition: cbs.h:153
uint8_t * data
Pointer to the directly-parsable bitstream form of this unit.
Definition: cbs.h:75
int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx, 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:686
#define av_log(a,...)
const uint8_t * avpriv_find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state)
size_t data_size
The number of bytes in the bitstream.
Definition: cbs.h:129
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:814
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:258
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
static int put_bits_left(PutBitContext *s)
Definition: put_bits.h:93
#define AVERROR(e)
Definition: error.h:43
const char const char AVS_ApplyFunc void * user_data
Definition: avisynth_c.h:775
AVBufferRef * user_data_ref
Definition: cbs_mpeg2.h:81
simple assert() macros that are a bit more flexible than ISO C assert().
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:85
static int cbs_mpeg2_split_fragment(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, int header)
Definition: cbs_mpeg2.c:145
static int FUNC() picture_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawPictureHeader *current)
void * log_ctx
Logging context to be passed to all av_log() calls associated with this context.
Definition: cbs.h:164
#define START(start_code, type, read_func, free_func)
AVFormatContext * ctx
Definition: movenc.c:48
preferred ID for MPEG-1/2 video decoding
Definition: avcodec.h:220
uint8_t * data
Pointer to the bitstream form of this fragment.
Definition: cbs.h:122
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
const CodedBitstreamType ff_cbs_type_mpeg2
Definition: cbs_mpeg2.c:419
int av_reallocp(void *ptr, size_t size)
Allocate, reallocate, or free a block of memory through a pointer to a pointer.
Definition: mem.c:163
int data_bit_start
Definition: cbs_mpeg2.h:209
static int FUNC() sequence_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawSequenceHeader *current)
AVBufferRef * av_buffer_alloc(int size)
Allocate an AVBuffer of the given size using av_malloc().
Definition: buffer.c:67
Coded bitstream fragment structure, combining one or more units.
Definition: cbs.h:116
#define MPEG2_START_IS_SLICE(type)
Definition: cbs_mpeg2.h:40
uint8_t * data
The data buffer.
Definition: buffer.h:89
Context structure for coded bitstream operations.
Definition: cbs.h:159
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:615
enum AVCodecID codec_id
Definition: cbs_internal.h:29
#define SIZE_SPECIFIER
Definition: internal.h:262
static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:286
MPEG2RawSliceHeader header
Definition: cbs_mpeg2.h:205
void * priv_data
Internal codec-specific data.
Definition: cbs.h:180
common internal api header.
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:101
static void cbs_mpeg2_close(CodedBitstreamContext *ctx)
Definition: cbs_mpeg2.c:412
AVBufferRef * data_ref
A reference to the buffer containing data.
Definition: cbs.h:92
AVBufferRef * av_buffer_ref(AVBufferRef *buf)
Create a new reference to an AVBuffer.
Definition: buffer.c:93
static int FUNC() group_of_pictures_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawGroupOfPicturesHeader *current)
static void init_put_bits(PutBitContext *s, uint8_t *buffer, int buffer_size)
Initialize the PutBitContext s.
Definition: put_bits.h:48
#define AV_INPUT_BUFFER_PADDING_SIZE
Required number of additionally allocated bytes at the end of the input bitstream for decoding...
Definition: avcodec.h:782
int len
static void cbs_mpeg2_free_slice(void *unit, uint8_t *content)
Definition: cbs_mpeg2.c:137
AVBufferRef * data_ref
Definition: cbs_mpeg2.h:210
size_t data_size
Definition: cbs_mpeg2.h:208
#define av_freep(p)
void INT64 start
Definition: avisynth_c.h:690
static const uint8_t start_code[]
static int cbs_mpeg2_write_header(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:260
AVBufferRef * data_ref
A reference to the buffer containing data.
Definition: cbs.h:139
size_t data_size
The number of bytes in the bitstream (including any padding bits in the final byte).
Definition: cbs.h:80