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h2645_parse.c
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1 /*
2  * H.264/HEVC common parsing code
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <string.h>
22 
23 #include "config.h"
24 
25 #include "libavutil/intmath.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/mem.h"
28 
29 #include "bytestream.h"
30 #include "hevc.h"
31 #include "h2645_parse.h"
32 
34  H2645RBSP *rbsp, H2645NAL *nal, int small_padding)
35 {
36  int i, si, di;
37  uint8_t *dst;
38 
39  nal->skipped_bytes = 0;
40 #define STARTCODE_TEST \
41  if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) { \
42  if (src[i + 2] != 3 && src[i + 2] != 0) { \
43  /* startcode, so we must be past the end */ \
44  length = i; \
45  } \
46  break; \
47  }
48 #if HAVE_FAST_UNALIGNED
49 #define FIND_FIRST_ZERO \
50  if (i > 0 && !src[i]) \
51  i--; \
52  while (src[i]) \
53  i++
54 #if HAVE_FAST_64BIT
55  for (i = 0; i + 1 < length; i += 9) {
56  if (!((~AV_RN64A(src + i) &
57  (AV_RN64A(src + i) - 0x0100010001000101ULL)) &
58  0x8000800080008080ULL))
59  continue;
60  FIND_FIRST_ZERO;
62  i -= 7;
63  }
64 #else
65  for (i = 0; i + 1 < length; i += 5) {
66  if (!((~AV_RN32A(src + i) &
67  (AV_RN32A(src + i) - 0x01000101U)) &
68  0x80008080U))
69  continue;
70  FIND_FIRST_ZERO;
72  i -= 3;
73  }
74 #endif /* HAVE_FAST_64BIT */
75 #else
76  for (i = 0; i + 1 < length; i += 2) {
77  if (src[i])
78  continue;
79  if (i > 0 && src[i - 1] == 0)
80  i--;
82  }
83 #endif /* HAVE_FAST_UNALIGNED */
84 
85  if (i >= length - 1 && small_padding) { // no escaped 0
86  nal->data =
87  nal->raw_data = src;
88  nal->size =
89  nal->raw_size = length;
90  return length;
91  } else if (i > length)
92  i = length;
93 
94  nal->rbsp_buffer = &rbsp->rbsp_buffer[rbsp->rbsp_buffer_size];
95  dst = nal->rbsp_buffer;
96 
97  memcpy(dst, src, i);
98  si = di = i;
99  while (si + 2 < length) {
100  // remove escapes (very rare 1:2^22)
101  if (src[si + 2] > 3) {
102  dst[di++] = src[si++];
103  dst[di++] = src[si++];
104  } else if (src[si] == 0 && src[si + 1] == 0 && src[si + 2] != 0) {
105  if (src[si + 2] == 3) { // escape
106  dst[di++] = 0;
107  dst[di++] = 0;
108  si += 3;
109 
110  if (nal->skipped_bytes_pos) {
111  nal->skipped_bytes++;
112  if (nal->skipped_bytes_pos_size < nal->skipped_bytes) {
113  nal->skipped_bytes_pos_size *= 2;
117  sizeof(*nal->skipped_bytes_pos));
118  if (!nal->skipped_bytes_pos) {
119  nal->skipped_bytes_pos_size = 0;
120  return AVERROR(ENOMEM);
121  }
122  }
123  if (nal->skipped_bytes_pos)
124  nal->skipped_bytes_pos[nal->skipped_bytes-1] = di - 1;
125  }
126  continue;
127  } else // next start code
128  goto nsc;
129  }
130 
131  dst[di++] = src[si++];
132  }
133  while (si < length)
134  dst[di++] = src[si++];
135 
136 nsc:
137  memset(dst + di, 0, AV_INPUT_BUFFER_PADDING_SIZE);
138 
139  nal->data = dst;
140  nal->size = di;
141  nal->raw_data = src;
142  nal->raw_size = si;
143  rbsp->rbsp_buffer_size += si;
144 
145  return si;
146 }
147 
148 static const char *nal_unit_name(int nal_type)
149 {
150  switch(nal_type) {
151  case HEVC_NAL_TRAIL_N : return "TRAIL_N";
152  case HEVC_NAL_TRAIL_R : return "TRAIL_R";
153  case HEVC_NAL_TSA_N : return "TSA_N";
154  case HEVC_NAL_TSA_R : return "TSA_R";
155  case HEVC_NAL_STSA_N : return "STSA_N";
156  case HEVC_NAL_STSA_R : return "STSA_R";
157  case HEVC_NAL_RADL_N : return "RADL_N";
158  case HEVC_NAL_RADL_R : return "RADL_R";
159  case HEVC_NAL_RASL_N : return "RASL_N";
160  case HEVC_NAL_RASL_R : return "RASL_R";
161  case HEVC_NAL_BLA_W_LP : return "BLA_W_LP";
162  case HEVC_NAL_BLA_W_RADL : return "BLA_W_RADL";
163  case HEVC_NAL_BLA_N_LP : return "BLA_N_LP";
164  case HEVC_NAL_IDR_W_RADL : return "IDR_W_RADL";
165  case HEVC_NAL_IDR_N_LP : return "IDR_N_LP";
166  case HEVC_NAL_CRA_NUT : return "CRA_NUT";
167  case HEVC_NAL_VPS : return "VPS";
168  case HEVC_NAL_SPS : return "SPS";
169  case HEVC_NAL_PPS : return "PPS";
170  case HEVC_NAL_AUD : return "AUD";
171  case HEVC_NAL_EOS_NUT : return "EOS_NUT";
172  case HEVC_NAL_EOB_NUT : return "EOB_NUT";
173  case HEVC_NAL_FD_NUT : return "FD_NUT";
174  case HEVC_NAL_SEI_PREFIX : return "SEI_PREFIX";
175  case HEVC_NAL_SEI_SUFFIX : return "SEI_SUFFIX";
176  default : return "?";
177  }
178 }
179 
180 static int get_bit_length(H2645NAL *nal, int skip_trailing_zeros)
181 {
182  int size = nal->size;
183  int v;
184 
185  while (skip_trailing_zeros && size > 0 && nal->data[size - 1] == 0)
186  size--;
187 
188  if (!size)
189  return 0;
190 
191  v = nal->data[size - 1];
192 
193  if (size > INT_MAX / 8)
194  return AVERROR(ERANGE);
195  size *= 8;
196 
197  /* remove the stop bit and following trailing zeros,
198  * or nothing for damaged bitstreams */
199  if (v)
200  size -= ff_ctz(v) + 1;
201 
202  return size;
203 }
204 
205 /**
206  * @return AVERROR_INVALIDDATA if the packet is not a valid NAL unit,
207  * 0 if the unit should be skipped, 1 otherwise
208  */
209 static int hevc_parse_nal_header(H2645NAL *nal, void *logctx)
210 {
211  GetBitContext *gb = &nal->gb;
212  int nuh_layer_id;
213 
214  if (get_bits1(gb) != 0)
215  return AVERROR_INVALIDDATA;
216 
217  nal->type = get_bits(gb, 6);
218 
219  nuh_layer_id = get_bits(gb, 6);
220  nal->temporal_id = get_bits(gb, 3) - 1;
221  if (nal->temporal_id < 0)
222  return AVERROR_INVALIDDATA;
223 
224  av_log(logctx, AV_LOG_DEBUG,
225  "nal_unit_type: %d(%s), nuh_layer_id: %d, temporal_id: %d\n",
226  nal->type, nal_unit_name(nal->type), nuh_layer_id, nal->temporal_id);
227 
228  return nuh_layer_id == 0;
229 }
230 
231 static int h264_parse_nal_header(H2645NAL *nal, void *logctx)
232 {
233  GetBitContext *gb = &nal->gb;
234 
235  if (get_bits1(gb) != 0)
236  return AVERROR_INVALIDDATA;
237 
238  nal->ref_idc = get_bits(gb, 2);
239  nal->type = get_bits(gb, 5);
240 
241  av_log(logctx, AV_LOG_DEBUG,
242  "nal_unit_type: %d, nal_ref_idc: %d\n",
243  nal->type, nal->ref_idc);
244 
245  return 1;
246 }
247 
248 static int find_next_start_code(const uint8_t *buf, const uint8_t *next_avc)
249 {
250  int i = 0;
251 
252  if (buf + 3 >= next_avc)
253  return next_avc - buf;
254 
255  while (buf + i + 3 < next_avc) {
256  if (buf[i] == 0 && buf[i + 1] == 0 && buf[i + 2] == 1)
257  break;
258  i++;
259  }
260  return i + 3;
261 }
262 
264  void *logctx, int is_nalff, int nal_length_size,
265  enum AVCodecID codec_id, int small_padding)
266 {
267  GetByteContext bc;
268  int consumed, ret = 0;
269  int next_avc = is_nalff ? 0 : length;
270  int64_t padding = small_padding ? 0 : MAX_MBPAIR_SIZE;
271 
272  bytestream2_init(&bc, buf, length);
273  av_fast_padded_malloc(&pkt->rbsp.rbsp_buffer, &pkt->rbsp.rbsp_buffer_alloc_size, length + padding);
274  if (!pkt->rbsp.rbsp_buffer)
275  return AVERROR(ENOMEM);
276 
277  pkt->rbsp.rbsp_buffer_size = 0;
278  pkt->nb_nals = 0;
279  while (bytestream2_get_bytes_left(&bc) >= 4) {
280  H2645NAL *nal;
281  int extract_length = 0;
282  int skip_trailing_zeros = 1;
283 
284  if (bytestream2_tell(&bc) == next_avc) {
285  int i = 0;
286  extract_length = get_nalsize(nal_length_size,
287  bc.buffer, bytestream2_get_bytes_left(&bc), &i, logctx);
288  if (extract_length < 0)
289  return extract_length;
290 
291  bytestream2_skip(&bc, nal_length_size);
292 
293  next_avc = bytestream2_tell(&bc) + extract_length;
294  } else {
295  int buf_index;
296 
297  if (bytestream2_tell(&bc) > next_avc)
298  av_log(logctx, AV_LOG_WARNING, "Exceeded next NALFF position, re-syncing.\n");
299 
300  /* search start code */
301  buf_index = find_next_start_code(bc.buffer, buf + next_avc);
302 
303  bytestream2_skip(&bc, buf_index);
304 
305  if (!bytestream2_get_bytes_left(&bc)) {
306  if (pkt->nb_nals > 0) {
307  // No more start codes: we discarded some irrelevant
308  // bytes at the end of the packet.
309  return 0;
310  } else {
311  av_log(logctx, AV_LOG_ERROR, "No start code is found.\n");
312  return AVERROR_INVALIDDATA;
313  }
314  }
315 
316  extract_length = FFMIN(bytestream2_get_bytes_left(&bc), next_avc - bytestream2_tell(&bc));
317 
318  if (bytestream2_tell(&bc) >= next_avc) {
319  /* skip to the start of the next NAL */
320  bytestream2_skip(&bc, next_avc - bytestream2_tell(&bc));
321  continue;
322  }
323  }
324 
325  if (pkt->nals_allocated < pkt->nb_nals + 1) {
326  int new_size = pkt->nals_allocated + 1;
327  void *tmp = av_realloc_array(pkt->nals, new_size, sizeof(*pkt->nals));
328 
329  if (!tmp)
330  return AVERROR(ENOMEM);
331 
332  pkt->nals = tmp;
333  memset(pkt->nals + pkt->nals_allocated, 0,
334  (new_size - pkt->nals_allocated) * sizeof(*pkt->nals));
335 
336  nal = &pkt->nals[pkt->nb_nals];
337  nal->skipped_bytes_pos_size = 1024; // initial buffer size
339  if (!nal->skipped_bytes_pos)
340  return AVERROR(ENOMEM);
341 
342  pkt->nals_allocated = new_size;
343  }
344  nal = &pkt->nals[pkt->nb_nals];
345 
346  consumed = ff_h2645_extract_rbsp(bc.buffer, extract_length, &pkt->rbsp, nal, small_padding);
347  if (consumed < 0)
348  return consumed;
349 
350  if (is_nalff && (extract_length != consumed) && extract_length)
351  av_log(logctx, AV_LOG_DEBUG,
352  "NALFF: Consumed only %d bytes instead of %d\n",
353  consumed, extract_length);
354 
355  pkt->nb_nals++;
356 
357  bytestream2_skip(&bc, consumed);
358 
359  /* see commit 3566042a0 */
360  if (bytestream2_get_bytes_left(&bc) >= 4 &&
361  bytestream2_peek_be32(&bc) == 0x000001E0)
362  skip_trailing_zeros = 0;
363 
364  nal->size_bits = get_bit_length(nal, skip_trailing_zeros);
365 
366  ret = init_get_bits(&nal->gb, nal->data, nal->size_bits);
367  if (ret < 0)
368  return ret;
369 
370  if (codec_id == AV_CODEC_ID_HEVC)
371  ret = hevc_parse_nal_header(nal, logctx);
372  else
373  ret = h264_parse_nal_header(nal, logctx);
374  if (ret <= 0 || nal->size <= 0) {
375  if (ret < 0) {
376  av_log(logctx, AV_LOG_ERROR, "Invalid NAL unit %d, skipping.\n",
377  nal->type);
378  }
379  pkt->nb_nals--;
380  }
381  }
382 
383  return 0;
384 }
385 
387 {
388  int i;
389  for (i = 0; i < pkt->nals_allocated; i++) {
390  av_freep(&pkt->nals[i].skipped_bytes_pos);
391  }
392  av_freep(&pkt->nals);
393  pkt->nals_allocated = 0;
394  av_freep(&pkt->rbsp.rbsp_buffer);
396 }
int ff_h2645_packet_split(H2645Packet *pkt, const uint8_t *buf, int length, void *logctx, int is_nalff, int nal_length_size, enum AVCodecID codec_id, int small_padding)
Split an input packet into NAL units.
Definition: h2645_parse.c:263
#define ff_ctz
Definition: intmath.h:106
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
int size
Definition: h2645_parse.h:34
static int get_bit_length(H2645NAL *nal, int skip_trailing_zeros)
Definition: h2645_parse.c:180
static unsigned int get_bits(GetBitContext *s, int n)
Read 1-25 bits.
Definition: get_bits.h:261
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
Memory handling functions.
static const char * nal_unit_name(int nal_type)
Definition: h2645_parse.c:148
static av_always_inline void bytestream2_init(GetByteContext *g, const uint8_t *buf, int buf_size)
Definition: bytestream.h:133
void av_fast_padded_malloc(void *ptr, unsigned int *size, size_t min_size)
Same behaviour av_fast_malloc but the buffer has additional AV_INPUT_BUFFER_PADDING_SIZE at the end w...
Definition: utils.c:123
static AVPacket pkt
#define src
Definition: vp8dsp.c:254
int size_bits
Size, in bits, of just the data, excluding the stop bit and any trailing padding. ...
Definition: h2645_parse.h:41
int skipped_bytes_pos_size
Definition: h2645_parse.h:59
#define AV_RN32A(p)
Definition: intreadwrite.h:526
#define STARTCODE_TEST
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
uint8_t
void ff_h2645_packet_uninit(H2645Packet *pkt)
Free all the allocated memory in the packet.
Definition: h2645_parse.c:386
const uint8_t * buffer
Definition: bytestream.h:34
ptrdiff_t size
Definition: opengl_enc.c:101
void * av_realloc_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:198
#define av_log(a,...)
AVCodecID
Identify the syntax and semantics of the bitstream.
Definition: avcodec.h:215
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int * skipped_bytes_pos
Definition: h2645_parse.h:60
#define AVERROR(e)
Definition: error.h:43
static av_always_inline void bytestream2_skip(GetByteContext *g, unsigned int size)
Definition: bytestream.h:164
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
Definition: bytestream.h:154
GLsizei GLsizei * length
Definition: opengl_enc.c:115
int raw_size
Definition: h2645_parse.h:43
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:205
#define MAX_MBPAIR_SIZE
Definition: h2645_parse.h:29
#define FFMIN(a, b)
Definition: common.h:96
static int get_nalsize(int nal_length_size, const uint8_t *buf, int buf_size, int *buf_index, void *logctx)
Definition: h2645_parse.h:99
enum AVCodecID codec_id
Definition: vaapi_decode.c:236
int ref_idc
H.264 only, nal_ref_idc.
Definition: h2645_parse.h:64
int type
NAL unit type.
Definition: h2645_parse.h:51
static av_always_inline int bytestream2_tell(GetByteContext *g)
Definition: bytestream.h:188
int nals_allocated
Definition: h2645_parse.h:78
static int hevc_parse_nal_header(H2645NAL *nal, void *logctx)
Definition: h2645_parse.c:209
static int h264_parse_nal_header(H2645NAL *nal, void *logctx)
Definition: h2645_parse.c:231
const uint8_t * data
Definition: h2645_parse.h:35
void * buf
Definition: avisynth_c.h:690
int rbsp_buffer_size
Definition: h2645_parse.h:70
int rbsp_buffer_alloc_size
Definition: h2645_parse.h:69
static unsigned int get_bits1(GetBitContext *s)
Definition: get_bits.h:313
uint8_t * rbsp_buffer
Definition: h2645_parse.h:68
static int init_get_bits(GetBitContext *s, const uint8_t *buffer, int bit_size)
Initialize GetBitContext.
Definition: get_bits.h:425
H2645RBSP rbsp
Definition: h2645_parse.h:76
int skipped_bytes
Definition: h2645_parse.h:58
GetBitContext gb
Definition: h2645_parse.h:46
#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
const uint8_t * raw_data
Definition: h2645_parse.h:44
H2645NAL * nals
Definition: h2645_parse.h:75
int temporal_id
HEVC only, nuh_temporal_id_plus_1 - 1.
Definition: h2645_parse.h:56
uint8_t * rbsp_buffer
Definition: h2645_parse.h:32
#define av_freep(p)
#define av_malloc_array(a, b)
#define AV_RN64A(p)
Definition: intreadwrite.h:530
int ff_h2645_extract_rbsp(const uint8_t *src, int length, H2645RBSP *rbsp, H2645NAL *nal, int small_padding)
Extract the raw (unescaped) bitstream.
Definition: h2645_parse.c:33
static int find_next_start_code(const uint8_t *buf, const uint8_t *next_avc)
Definition: h2645_parse.c:248
static uint8_t tmp[11]
Definition: aes_ctr.c:26