Libav
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 <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  if (length_size == 3)
73  return AVERROR(EINVAL);
74 
75  /* retrieve sps and pps unit(s) */
76  unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
77  if (!unit_nb) {
78  unit_nb = *extradata++; /* number of pps unit(s) */
79  sps_done++;
80 
81  if (unit_nb)
82  pps_seen = 1;
83  } else {
84  sps_seen = 1;
85  }
86 
87  while (unit_nb--) {
88  int err;
89 
90  unit_size = AV_RB16(extradata);
91  total_size += unit_size + 4;
92  if (total_size > INT_MAX - padding ||
93  extradata + 2 + unit_size > avctx->extradata +
94  avctx->extradata_size) {
95  av_free(out);
96  return AVERROR(EINVAL);
97  }
98  if ((err = av_reallocp(&out, total_size + padding)) < 0)
99  return err;
100  memcpy(out + total_size - unit_size - 4, nalu_header, 4);
101  memcpy(out + total_size - unit_size, extradata + 2, unit_size);
102  extradata += 2 + unit_size;
103 
104  if (!unit_nb && !sps_done++) {
105  unit_nb = *extradata++; /* number of pps unit(s) */
106  if (unit_nb)
107  pps_seen = 1;
108  }
109  }
110 
111  if (out)
112  memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
113 
114  if (!sps_seen)
115  av_log(avctx, AV_LOG_WARNING,
116  "Warning: SPS NALU missing or invalid. "
117  "The resulting stream may not play.\n");
118 
119  if (!pps_seen)
120  av_log(avctx, AV_LOG_WARNING,
121  "Warning: PPS NALU missing or invalid. "
122  "The resulting stream may not play.\n");
123 
124  av_free(avctx->extradata);
125  avctx->extradata = out;
126  avctx->extradata_size = total_size;
127 
128  return length_size;
129 }
130 
132  AVCodecContext *avctx, const char *args,
133  uint8_t **poutbuf, int *poutbuf_size,
134  const uint8_t *buf, int buf_size,
135  int keyframe)
136 {
137  H264BSFContext *ctx = bsfc->priv_data;
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  if (buf + ctx->length_size > buf_end)
165  goto fail;
166 
167  if (ctx->length_size == 1) {
168  nal_size = buf[0];
169  } else if (ctx->length_size == 2) {
170  nal_size = AV_RB16(buf);
171  } else
172  nal_size = AV_RB32(buf);
173 
174  buf += ctx->length_size;
175  unit_type = *buf & 0x1f;
176 
177  if (buf + nal_size > buf_end || nal_size < 0)
178  goto fail;
179 
180  /* prepend only to the first type 5 NAL unit of an IDR picture */
181  if (ctx->first_idr && unit_type == 5) {
182  if (alloc_and_copy(poutbuf, poutbuf_size,
183  avctx->extradata, avctx->extradata_size,
184  buf, nal_size) < 0)
185  goto fail;
186  ctx->first_idr = 0;
187  } else {
188  if (alloc_and_copy(poutbuf, poutbuf_size,
189  NULL, 0, buf, nal_size) < 0)
190  goto fail;
191  if (!ctx->first_idr && unit_type == 1)
192  ctx->first_idr = 1;
193  }
194 
195  buf += nal_size;
196  cumul_size += nal_size + ctx->length_size;
197  } while (cumul_size < buf_size);
198 
199  return 1;
200 
201 fail:
202  av_freep(poutbuf);
203  *poutbuf_size = 0;
204  return AVERROR(EINVAL);
205 }
206 
208  "h264_mp4toannexb",
209  sizeof(H264BSFContext),
211 };