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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 
42 #define READ
43 #define READWRITE read
44 #define RWContext GetBitContext
45 
46 #define xui(width, name, var) do { \
47  uint32_t value = 0; \
48  CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, \
49  &value, 0, (1 << width) - 1)); \
50  var = value; \
51  } while (0)
52 
53 #define ui(width, name) \
54  xui(width, name, current->name)
55 
56 #define marker_bit() do { \
57  av_unused uint32_t one; \
58  CHECK(ff_cbs_read_unsigned(ctx, rw, 1, "marker_bit", &one, 1, 1)); \
59  } while (0)
60 
61 #define nextbits(width, compare, var) \
62  (get_bits_left(rw) >= width && \
63  (var = show_bits(rw, width)) == (compare))
64 
66 
67 #undef READ
68 #undef READWRITE
69 #undef RWContext
70 #undef xui
71 #undef ui
72 #undef marker_bit
73 #undef nextbits
74 
75 
76 #define WRITE
77 #define READWRITE write
78 #define RWContext PutBitContext
79 
80 #define xui(width, name, var) do { \
81  CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, \
82  var, 0, (1 << width) - 1)); \
83  } while (0)
84 
85 #define ui(width, name) \
86  xui(width, name, current->name)
87 
88 #define marker_bit() do { \
89  CHECK(ff_cbs_write_unsigned(ctx, rw, 1, "marker_bit", 1, 1, 1)); \
90  } while (0)
91 
92 #define nextbits(width, compare, var) (var)
93 
95 
96 #undef READ
97 #undef READWRITE
98 #undef RWContext
99 #undef xui
100 #undef ui
101 #undef marker_bit
102 #undef nextbits
103 
104 
107  int header)
108 {
109  const uint8_t *start, *end;
110  uint8_t *unit_data;
111  uint32_t start_code = -1, next_start_code = -1;
112  size_t unit_size;
113  int err, i, unit_type;
114 
115  start = avpriv_find_start_code(frag->data, frag->data + frag->data_size,
116  &start_code);
117  for (i = 0;; i++) {
118  end = avpriv_find_start_code(start, frag->data + frag->data_size,
119  &next_start_code);
120 
121  unit_type = start_code & 0xff;
122 
123  // The start and end pointers point at to the byte following the
124  // start_code_identifier in the start code that they found.
125  if (end == frag->data + frag->data_size) {
126  // We didn't find a start code, so this is the final unit.
127  unit_size = end - (start - 1);
128  } else {
129  // Unit runs from start to the beginning of the start code
130  // pointed to by end (including any padding zeroes).
131  unit_size = (end - 4) - (start - 1);
132  }
133 
134  unit_data = av_malloc(unit_size + AV_INPUT_BUFFER_PADDING_SIZE);
135  if (!unit_data)
136  return AVERROR(ENOMEM);
137  memcpy(unit_data, start - 1, unit_size);
138  memset(unit_data + unit_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
139 
140  err = ff_cbs_insert_unit_data(ctx, frag, i, unit_type,
141  unit_data, unit_size);
142  if (err < 0) {
143  av_freep(&unit_data);
144  return err;
145  }
146 
147  if (end == frag->data + frag->data_size)
148  break;
149 
150  start_code = next_start_code;
151  start = end;
152  }
153 
154  return 0;
155 }
156 
158  CodedBitstreamUnit *unit)
159 {
160  GetBitContext gbc;
161  int err;
162 
163  err = init_get_bits(&gbc, unit->data, 8 * unit->data_size);
164  if (err < 0)
165  return err;
166 
167  if (MPEG2_START_IS_SLICE(unit->type)) {
168  MPEG2RawSlice *slice;
169  int pos, len;
170 
171  slice = av_mallocz(sizeof(*slice));
172  if (!slice)
173  return AVERROR(ENOMEM);
174  err = cbs_mpeg2_read_slice_header(ctx, &gbc, &slice->header);
175  if (err < 0) {
176  av_free(slice);
177  return err;
178  }
179 
180  pos = get_bits_count(&gbc);
181  len = unit->data_size;
182 
183  slice->data_size = len - pos / 8;
184  slice->data = av_malloc(slice->data_size +
186  if (!slice->data) {
187  av_free(slice);
188  return AVERROR(ENOMEM);
189  }
190 
191  memcpy(slice->data,
192  unit->data + pos / 8, slice->data_size);
193  memset(slice->data + slice->data_size, 0,
195  slice->data_bit_start = pos % 8;
196 
197  unit->content = slice;
198 
199  } else {
200  switch (unit->type) {
201 #define START(start_code, type, func) \
202  case start_code: \
203  { \
204  type *header; \
205  header = av_mallocz(sizeof(*header)); \
206  if (!header) \
207  return AVERROR(ENOMEM); \
208  err = cbs_mpeg2_read_ ## func(ctx, &gbc, header); \
209  if (err < 0) { \
210  av_free(header); \
211  return err; \
212  } \
213  unit->content = header; \
214  } \
215  break;
221 #undef START
222  default:
223  av_log(ctx->log_ctx, AV_LOG_ERROR, "Unknown start code %"PRIx32".\n",
224  unit->type);
225  return AVERROR_INVALIDDATA;
226  }
227  }
228 
229  return 0;
230 }
231 
233  CodedBitstreamUnit *unit,
234  PutBitContext *pbc)
235 {
236  int err;
237 
238  switch (unit->type) {
239 #define START(start_code, type, func) \
240  case start_code: \
241  err = cbs_mpeg2_write_ ## func(ctx, pbc, unit->content); \
242  break;
248 #undef START
249  default:
250  av_log(ctx->log_ctx, AV_LOG_ERROR, "Write unimplemented for start "
251  "code %02"PRIu32".\n", unit->type);
252  return AVERROR_PATCHWELCOME;
253  }
254 
255  return err;
256 }
257 
259  CodedBitstreamUnit *unit,
260  PutBitContext *pbc)
261 {
262  MPEG2RawSlice *slice = unit->content;
263  GetBitContext gbc;
264  size_t bits_left;
265  int err;
266 
267  err = cbs_mpeg2_write_slice_header(ctx, pbc, &slice->header);
268  if (err < 0)
269  return err;
270 
271  if (slice->data) {
272  if (slice->data_size * 8 + 8 > put_bits_left(pbc))
273  return AVERROR(ENOSPC);
274 
275  init_get_bits(&gbc, slice->data, slice->data_size * 8);
276  skip_bits_long(&gbc, slice->data_bit_start);
277 
278  while (get_bits_left(&gbc) > 15)
279  put_bits(pbc, 16, get_bits(&gbc, 16));
280 
281  bits_left = get_bits_left(&gbc);
282  put_bits(pbc, bits_left, get_bits(&gbc, bits_left));
283 
284  // Align with zeroes.
285  while (put_bits_count(pbc) % 8 != 0)
286  put_bits(pbc, 1, 0);
287  }
288 
289  return 0;
290 }
291 
293  CodedBitstreamUnit *unit)
294 {
296  PutBitContext pbc;
297  int err;
298 
299  if (!priv->write_buffer) {
300  // Initial write buffer size is 1MB.
301  priv->write_buffer_size = 1024 * 1024;
302 
303  reallocate_and_try_again:
304  err = av_reallocp(&priv->write_buffer, priv->write_buffer_size);
305  if (err < 0) {
306  av_log(ctx->log_ctx, AV_LOG_ERROR, "Unable to allocate a "
307  "sufficiently large write buffer (last attempt "
308  "%zu bytes).\n", priv->write_buffer_size);
309  return err;
310  }
311  }
312 
313  init_put_bits(&pbc, priv->write_buffer, priv->write_buffer_size);
314 
315  if (unit->type >= 0x01 && unit->type <= 0xaf)
316  err = cbs_mpeg2_write_slice(ctx, unit, &pbc);
317  else
318  err = cbs_mpeg2_write_header(ctx, unit, &pbc);
319 
320  if (err == AVERROR(ENOSPC)) {
321  // Overflow.
322  priv->write_buffer_size *= 2;
323  goto reallocate_and_try_again;
324  }
325  if (err < 0) {
326  // Write failed for some other reason.
327  return err;
328  }
329 
330  if (put_bits_count(&pbc) % 8)
331  unit->data_bit_padding = 8 - put_bits_count(&pbc) % 8;
332  else
333  unit->data_bit_padding = 0;
334 
335  unit->data_size = (put_bits_count(&pbc) + 7) / 8;
336  flush_put_bits(&pbc);
337 
338  err = av_reallocp(&unit->data, unit->data_size);
339  if (err < 0)
340  return err;
341 
342  memcpy(unit->data, priv->write_buffer, unit->data_size);
343 
344  return 0;
345 }
346 
349 {
350  uint8_t *data;
351  size_t size, dp, sp;
352  int i;
353 
354  size = 0;
355  for (i = 0; i < frag->nb_units; i++)
356  size += 3 + frag->units[i].data_size;
357 
358  data = av_malloc(size);
359  if (!data)
360  return AVERROR(ENOMEM);
361 
362  dp = 0;
363  for (i = 0; i < frag->nb_units; i++) {
364  CodedBitstreamUnit *unit = &frag->units[i];
365 
366  data[dp++] = 0;
367  data[dp++] = 0;
368  data[dp++] = 1;
369 
370  for (sp = 0; sp < unit->data_size; sp++)
371  data[dp++] = unit->data[sp];
372  }
373 
374  av_assert0(dp == size);
375 
376  frag->data = data;
377  frag->data_size = size;
378 
379  return 0;
380 }
381 
383 {
384  if (MPEG2_START_IS_SLICE(unit->type)) {
385  MPEG2RawSlice *slice = unit->content;
386  av_freep(&slice->data);
388  } else if (unit->type == MPEG2_START_USER_DATA) {
389  MPEG2RawUserData *user = unit->content;
390  av_freep(&user->user_data);
391  }
392  av_freep(&unit->content);
393 }
394 
396 {
398 
399  av_freep(&priv->write_buffer);
400 }
401 
404 
405  .priv_data_size = sizeof(CodedBitstreamMPEG2Context),
406 
407  .split_fragment = &cbs_mpeg2_split_fragment,
408  .read_unit = &cbs_mpeg2_read_unit,
409  .write_unit = &cbs_mpeg2_write_unit,
410  .assemble_fragment = &cbs_mpeg2_assemble_fragment,
411 
412  .free_unit = &cbs_mpeg2_free_unit,
413  .close = &cbs_mpeg2_close,
414 };
int nb_units
Number of units in this fragment.
Definition: cbs.h:133
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
ptrdiff_t const GLvoid * data
Definition: opengl_enc.c:101
uint8_t * data
Definition: cbs_mpeg2.h:203
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:207
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:261
static void skip_bits_long(GetBitContext *s, int n)
Definition: get_bits.h:204
CodedBitstreamUnitType type
Codec-specific type of this unit.
Definition: cbs.h:65
static void cbs_mpeg2_free_unit(CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:382
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:236
static int cbs_mpeg2_write_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:292
static int cbs_mpeg2_read_unit(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit)
Definition: cbs_mpeg2.c:157
int ff_cbs_insert_unit_data(CodedBitstreamContext *ctx, CodedBitstreamFragment *frag, int position, CodedBitstreamUnitType type, uint8_t *data, size_t data_size)
Insert a new unit into a fragment with the given data bitstream.
Definition: cbs.c:445
#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:347
static int FUNC() extension_data(CodedBitstreamContext *ctx, RWContext *rw, H265RawPSExtensionData *current)
uint8_t
#define av_malloc(s)
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
size_t data_bit_padding
The number of bits which should be ignored in the final byte.
Definition: cbs.h:83
static int get_bits_count(const GetBitContext *s)
Definition: get_bits.h:199
#define sp
Definition: regdef.h:63
Coded bitstream unit structure.
Definition: cbs.h:61
ptrdiff_t size
Definition: opengl_enc.c:101
void * content
Pointer to the decomposed form of this unit.
Definition: cbs.h:92
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:139
uint8_t * data
Pointer to the directly-parsable bitstream form of this unit.
Definition: cbs.h:72
#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:121
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:587
#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
AVS_Value void * user_data
Definition: avisynth_c.h:699
simple assert() macros that are a bit more flexible than ISO C assert().
uint8_t * extra_information
Definition: cbs_mpeg2.h:197
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:105
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:150
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:114
uint8_t * user_data
Definition: cbs_mpeg2.h:77
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
Definition: error.h:62
const CodedBitstreamType ff_cbs_type_mpeg2
Definition: cbs_mpeg2.c:402
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:205
static int FUNC() sequence_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawSequenceHeader *current)
#define START(start_code, type, func)
Coded bitstream fragment structure, combining one or more units.
Definition: cbs.h:108
#define MPEG2_START_IS_SLICE(type)
Definition: cbs_mpeg2.h:38
Context structure for coded bitstream operations.
Definition: cbs.h:145
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:425
enum AVCodecID codec_id
Definition: cbs_internal.h:29
static int cbs_mpeg2_write_slice(CodedBitstreamContext *ctx, CodedBitstreamUnit *unit, PutBitContext *pbc)
Definition: cbs_mpeg2.c:258
MPEG2RawSliceHeader header
Definition: cbs_mpeg2.h:201
void * priv_data
Internal codec-specific data.
Definition: cbs.h:166
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:395
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:770
#define av_free(p)
int len
size_t data_size
Definition: cbs_mpeg2.h:204
#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:232
size_t data_size
The number of bytes in the bitstream (including any padding bits in the final byte).
Definition: cbs.h:77