h264_mp4toannexb_bsf.c
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1 /*
2  * H.264 MP4 to Annex B byte stream format filter
3  * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
4  *
5  * This file is part of Libav.
6  *
7  * Libav is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * Libav is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/intreadwrite.h"
23 #include "avcodec.h"
24 
25 typedef struct H264BSFContext {
26  uint8_t length_size;
27  uint8_t first_idr;
30 
31 static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size,
32  const uint8_t *sps_pps, uint32_t sps_pps_size,
33  const uint8_t *in, uint32_t in_size) {
34  uint32_t offset = *poutbuf_size;
35  uint8_t nal_header_size = offset ? 3 : 4;
36  void *tmp;
37 
38  *poutbuf_size += sps_pps_size+in_size+nal_header_size;
39  tmp = av_realloc(*poutbuf, *poutbuf_size);
40  if (!tmp)
41  return AVERROR(ENOMEM);
42  *poutbuf = tmp;
43  if (sps_pps)
44  memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
45  memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
46  if (!offset) {
47  AV_WB32(*poutbuf+sps_pps_size, 1);
48  } else {
49  (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
50  (*poutbuf+offset+sps_pps_size)[2] = 1;
51  }
52 
53  return 0;
54 }
55 
57  AVCodecContext *avctx, const char *args,
58  uint8_t **poutbuf, int *poutbuf_size,
59  const uint8_t *buf, int buf_size,
60  int keyframe) {
61  H264BSFContext *ctx = bsfc->priv_data;
62  uint8_t unit_type;
63  int32_t nal_size;
64  uint32_t cumul_size = 0;
65  const uint8_t *buf_end = buf + buf_size;
66 
67  /* nothing to filter */
68  if (!avctx->extradata || avctx->extradata_size < 6) {
69  *poutbuf = (uint8_t*) buf;
70  *poutbuf_size = buf_size;
71  return 0;
72  }
73 
74  /* retrieve sps and pps NAL units from extradata */
75  if (!ctx->extradata_parsed) {
76  uint16_t unit_size;
77  uint64_t total_size = 0;
78  uint8_t *out = NULL, unit_nb, sps_done = 0, sps_seen = 0, pps_seen = 0;
79  const uint8_t *extradata = avctx->extradata+4;
80  static const uint8_t nalu_header[4] = {0, 0, 0, 1};
81 
82  /* retrieve length coded size */
83  ctx->length_size = (*extradata++ & 0x3) + 1;
84  if (ctx->length_size == 3)
85  return AVERROR(EINVAL);
86 
87  /* retrieve sps and pps unit(s) */
88  unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
89  if (!unit_nb) {
90  unit_nb = *extradata++; /* number of pps unit(s) */
91  sps_done++;
92 
93  if (unit_nb)
94  pps_seen = 1;
95  } else {
96  sps_seen = 1;
97  }
98 
99  while (unit_nb--) {
100  void *tmp;
101 
102  unit_size = AV_RB16(extradata);
103  total_size += unit_size+4;
104  if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE ||
105  extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
106  av_free(out);
107  return AVERROR(EINVAL);
108  }
109  tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE);
110  if (!tmp) {
111  av_free(out);
112  return AVERROR(ENOMEM);
113  }
114  out = tmp;
115  memcpy(out+total_size-unit_size-4, nalu_header, 4);
116  memcpy(out+total_size-unit_size, extradata+2, unit_size);
117  extradata += 2+unit_size;
118 
119  if (!unit_nb && !sps_done++) {
120  unit_nb = *extradata++; /* number of pps unit(s) */
121  if (unit_nb)
122  pps_seen = 1;
123  }
124  }
125 
126  if(out)
127  memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
128 
129  if (!sps_seen)
130  av_log(avctx, AV_LOG_WARNING, "Warning: SPS NALU missing or invalid. The resulting stream may not play.\n");
131  if (!pps_seen)
132  av_log(avctx, AV_LOG_WARNING, "Warning: PPS NALU missing or invalid. The resulting stream may not play.\n");
133 
134  av_free(avctx->extradata);
135  avctx->extradata = out;
136  avctx->extradata_size = total_size;
137  ctx->first_idr = 1;
138  ctx->extradata_parsed = 1;
139  }
140 
141  *poutbuf_size = 0;
142  *poutbuf = NULL;
143  do {
144  if (buf + ctx->length_size > buf_end)
145  goto fail;
146 
147  if (ctx->length_size == 1) {
148  nal_size = buf[0];
149  } else if (ctx->length_size == 2) {
150  nal_size = AV_RB16(buf);
151  } else
152  nal_size = AV_RB32(buf);
153 
154  buf += ctx->length_size;
155  unit_type = *buf & 0x1f;
156 
157  if (buf + nal_size > buf_end || nal_size < 0)
158  goto fail;
159 
160  /* prepend only to the first type 5 NAL unit of an IDR picture */
161  if (ctx->first_idr && unit_type == 5) {
162  if (alloc_and_copy(poutbuf, poutbuf_size,
163  avctx->extradata, avctx->extradata_size,
164  buf, nal_size) < 0)
165  goto fail;
166  ctx->first_idr = 0;
167  } else {
168  if (alloc_and_copy(poutbuf, poutbuf_size,
169  NULL, 0,
170  buf, nal_size) < 0)
171  goto fail;
172  if (!ctx->first_idr && unit_type == 1)
173  ctx->first_idr = 1;
174  }
175 
176  buf += nal_size;
177  cumul_size += nal_size + ctx->length_size;
178  } while (cumul_size < buf_size);
179 
180  return 1;
181 
182 fail:
183  av_freep(poutbuf);
184  *poutbuf_size = 0;
185  return AVERROR(EINVAL);
186 }
187 
189  "h264_mp4toannexb",
190  sizeof(H264BSFContext),
192 };
193