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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  int err;
41 
42  *poutbuf_size += sps_pps_size + in_size + nal_header_size;
43  if ((err = av_reallocp(poutbuf,
44  *poutbuf_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0) {
45  *poutbuf_size = 0;
46  return err;
47  }
48  if (sps_pps)
49  memcpy(*poutbuf + offset, sps_pps, sps_pps_size);
50  memcpy(*poutbuf + sps_pps_size + nal_header_size + offset, in, in_size);
51  if (!offset) {
52  AV_WB32(*poutbuf + sps_pps_size, 1);
53  } else {
54  (*poutbuf + offset + sps_pps_size)[0] =
55  (*poutbuf + offset + sps_pps_size)[1] = 0;
56  (*poutbuf + offset + sps_pps_size)[2] = 1;
57  }
58 
59  return 0;
60 }
61 
62 static int h264_extradata_to_annexb(AVCodecContext *avctx, const int padding)
63 {
64  uint16_t unit_size;
65  uint64_t total_size = 0;
66  uint8_t *out = NULL, unit_nb, sps_done = 0,
67  sps_seen = 0, pps_seen = 0;
68  const uint8_t *extradata = avctx->extradata + 4;
69  static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
70  int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size
71 
72  /* retrieve sps and pps unit(s) */
73  unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
74  if (!unit_nb) {
75  goto pps;
76  } else {
77  sps_seen = 1;
78  }
79 
80  while (unit_nb--) {
81  int err;
82 
83  unit_size = AV_RB16(extradata);
84  total_size += unit_size + 4;
85  if (total_size > INT_MAX - padding) {
86  av_log(avctx, AV_LOG_ERROR,
87  "Too big extradata size, corrupted stream or invalid MP4/AVCC bitstream\n");
88  av_free(out);
89  return AVERROR(EINVAL);
90  }
91  if (extradata + 2 + unit_size > avctx->extradata + avctx->extradata_size) {
92  av_log(avctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, "
93  "corrupted stream or invalid MP4/AVCC bitstream\n");
94  av_free(out);
95  return AVERROR(EINVAL);
96  }
97  if ((err = av_reallocp(&out, total_size + padding)) < 0)
98  return err;
99  memcpy(out + total_size - unit_size - 4, nalu_header, 4);
100  memcpy(out + total_size - unit_size, extradata + 2, unit_size);
101  extradata += 2 + unit_size;
102 pps:
103  if (!unit_nb && !sps_done++) {
104  unit_nb = *extradata++; /* number of pps unit(s) */
105  if (unit_nb)
106  pps_seen = 1;
107  }
108  }
109 
110  if (out)
111  memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
112 
113  if (!sps_seen)
114  av_log(avctx, AV_LOG_WARNING,
115  "Warning: SPS NALU missing or invalid. "
116  "The resulting stream may not play.\n");
117 
118  if (!pps_seen)
119  av_log(avctx, AV_LOG_WARNING,
120  "Warning: PPS NALU missing or invalid. "
121  "The resulting stream may not play.\n");
122 
123  av_free(avctx->extradata);
124  avctx->extradata = out;
125  avctx->extradata_size = total_size;
126 
127  return length_size;
128 }
129 
131  AVCodecContext *avctx, const char *args,
132  uint8_t **poutbuf, int *poutbuf_size,
133  const uint8_t *buf, int buf_size,
134  int keyframe)
135 {
136  H264BSFContext *ctx = bsfc->priv_data;
137  int i;
138  uint8_t unit_type;
139  int32_t nal_size;
140  uint32_t cumul_size = 0;
141  const uint8_t *buf_end = buf + buf_size;
142  int ret = 0;
143 
144  /* nothing to filter */
145  if (!avctx->extradata || avctx->extradata_size < 6) {
146  *poutbuf = (uint8_t *)buf;
147  *poutbuf_size = buf_size;
148  return 0;
149  }
150 
151  /* retrieve sps and pps NAL units from extradata */
152  if (!ctx->extradata_parsed) {
154  if (ret < 0)
155  return ret;
156  ctx->length_size = ret;
157  ctx->first_idr = 1;
158  ctx->extradata_parsed = 1;
159  }
160 
161  *poutbuf_size = 0;
162  *poutbuf = NULL;
163  do {
164  ret= AVERROR(EINVAL);
165  if (buf + ctx->length_size > buf_end)
166  goto fail;
167 
168  for (nal_size = 0, i = 0; i<ctx->length_size; i++)
169  nal_size = (nal_size << 8) | buf[i];
170 
171  buf += ctx->length_size;
172  unit_type = *buf & 0x1f;
173 
174  if (buf + nal_size > buf_end || nal_size < 0)
175  goto fail;
176 
177  /* prepend only to the first type 5 NAL unit of an IDR picture */
178  if (ctx->first_idr && (unit_type == 5 || unit_type == 7 || unit_type == 8)) {
179  if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
180  avctx->extradata, avctx->extradata_size,
181  buf, nal_size)) < 0)
182  goto fail;
183  ctx->first_idr = 0;
184  } else {
185  if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
186  NULL, 0, buf, nal_size)) < 0)
187  goto fail;
188  if (!ctx->first_idr && unit_type == 1)
189  ctx->first_idr = 1;
190  }
191 
192  buf += nal_size;
193  cumul_size += nal_size + ctx->length_size;
194  } while (cumul_size < buf_size);
195 
196  return 1;
197 
198 fail:
199  av_freep(poutbuf);
200  *poutbuf_size = 0;
201  return ret;
202 }
203 
205  .name = "h264_mp4toannexb",
206  .priv_data_size = sizeof(H264BSFContext),
208 };