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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 FFmpeg.
6  *
7  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <string.h>
23 
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26 #include "avcodec.h"
27 
28 typedef struct H264BSFContext {
33 
34 static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size,
35  const uint8_t *sps_pps, uint32_t sps_pps_size,
36  const uint8_t *in, uint32_t in_size)
37 {
38  uint32_t offset = *poutbuf_size;
39  uint8_t nal_header_size = offset ? 3 : 4;
40  void *tmp;
41 
42  *poutbuf_size += sps_pps_size + in_size + nal_header_size;
43  tmp = av_realloc(*poutbuf, *poutbuf_size + FF_INPUT_BUFFER_PADDING_SIZE);
44  if (!tmp)
45  return AVERROR(ENOMEM);
46  *poutbuf = tmp;
47  if (sps_pps)
48  memcpy(*poutbuf + offset, sps_pps, sps_pps_size);
49  memcpy(*poutbuf + sps_pps_size + nal_header_size + offset, in, in_size);
50  if (!offset) {
51  AV_WB32(*poutbuf + sps_pps_size, 1);
52  } else {
53  (*poutbuf + offset + sps_pps_size)[0] =
54  (*poutbuf + offset + sps_pps_size)[1] = 0;
55  (*poutbuf + offset + sps_pps_size)[2] = 1;
56  }
57 
58  return 0;
59 }
60 
61 static int h264_extradata_to_annexb(AVCodecContext *avctx, const int padding)
62 {
63  uint16_t unit_size;
64  uint64_t total_size = 0;
65  uint8_t *out = NULL, unit_nb, sps_done = 0,
66  sps_seen = 0, pps_seen = 0;
67  const uint8_t *extradata = avctx->extradata + 4;
68  static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
69  int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size
70 
71  /* retrieve sps and pps unit(s) */
72  unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
73  if (!unit_nb) {
74  goto pps;
75  } else {
76  sps_seen = 1;
77  }
78 
79  while (unit_nb--) {
80  void *tmp;
81 
82  unit_size = AV_RB16(extradata);
83  total_size += unit_size + 4;
84  if (total_size > INT_MAX - padding ||
85  extradata + 2 + unit_size > avctx->extradata +
86  avctx->extradata_size) {
87  av_free(out);
88  return AVERROR(EINVAL);
89  }
90  tmp = av_realloc(out, total_size + padding);
91  if (!tmp) {
92  av_free(out);
93  return AVERROR(ENOMEM);
94  }
95  out = tmp;
96  memcpy(out + total_size - unit_size - 4, nalu_header, 4);
97  memcpy(out + total_size - unit_size, extradata + 2, unit_size);
98  extradata += 2 + unit_size;
99 pps:
100  if (!unit_nb && !sps_done++) {
101  unit_nb = *extradata++; /* number of pps unit(s) */
102  if (unit_nb)
103  pps_seen = 1;
104  }
105  }
106 
107  if (out)
108  memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
109 
110  if (!sps_seen)
111  av_log(avctx, AV_LOG_WARNING,
112  "Warning: SPS NALU missing or invalid. "
113  "The resulting stream may not play.\n");
114 
115  if (!pps_seen)
116  av_log(avctx, AV_LOG_WARNING,
117  "Warning: PPS NALU missing or invalid. "
118  "The resulting stream may not play.\n");
119 
120  av_free(avctx->extradata);
121  avctx->extradata = out;
122  avctx->extradata_size = total_size;
123 
124  return length_size;
125 }
126 
128  AVCodecContext *avctx, const char *args,
129  uint8_t **poutbuf, int *poutbuf_size,
130  const uint8_t *buf, int buf_size,
131  int keyframe)
132 {
133  H264BSFContext *ctx = bsfc->priv_data;
134  int i;
135  uint8_t unit_type;
136  int32_t nal_size;
137  uint32_t cumul_size = 0;
138  const uint8_t *buf_end = buf + buf_size;
139  int ret = 0;
140 
141  /* nothing to filter */
142  if (!avctx->extradata || avctx->extradata_size < 6) {
143  *poutbuf = (uint8_t *)buf;
144  *poutbuf_size = buf_size;
145  return 0;
146  }
147 
148  /* retrieve sps and pps NAL units from extradata */
149  if (!ctx->extradata_parsed) {
151  if (ret < 0)
152  return ret;
153  ctx->length_size = ret;
154  ctx->first_idr = 1;
155  ctx->extradata_parsed = 1;
156  }
157 
158  *poutbuf_size = 0;
159  *poutbuf = NULL;
160  do {
161  ret= AVERROR(EINVAL);
162  if (buf + ctx->length_size > buf_end)
163  goto fail;
164 
165  for (nal_size = 0, i = 0; i<ctx->length_size; i++)
166  nal_size = (nal_size << 8) | buf[i];
167 
168  buf += ctx->length_size;
169  unit_type = *buf & 0x1f;
170 
171  if (buf + nal_size > buf_end || nal_size < 0)
172  goto fail;
173 
174  /* prepend only to the first type 5 NAL unit of an IDR picture */
175  if (ctx->first_idr && unit_type == 5) {
176  if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
177  avctx->extradata, avctx->extradata_size,
178  buf, nal_size)) < 0)
179  goto fail;
180  ctx->first_idr = 0;
181  } else {
182  if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
183  NULL, 0, buf, nal_size)) < 0)
184  goto fail;
185  if (!ctx->first_idr && unit_type == 1)
186  ctx->first_idr = 1;
187  }
188 
189  buf += nal_size;
190  cumul_size += nal_size + ctx->length_size;
191  } while (cumul_size < buf_size);
192 
193  return 1;
194 
195 fail:
196  av_freep(poutbuf);
197  *poutbuf_size = 0;
198  return ret;
199 }
200 
202  "h264_mp4toannexb",
203  sizeof(H264BSFContext),
205 };