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oggparsevp8.c
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1 /*
2  * On2 VP8 parser for Ogg
3  * Copyright (C) 2013 James Almer
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 "libavutil/intreadwrite.h"
23 
24 #include "avformat.h"
25 #include "internal.h"
26 #include "oggdec.h"
27 
28 #define VP8_HEADER_SIZE 26
29 
30 static int vp8_header(AVFormatContext *s, int idx)
31 {
32  struct ogg *ogg = s->priv_data;
33  struct ogg_stream *os = ogg->streams + idx;
34  uint8_t *p = os->buf + os->pstart;
35  AVStream *st = s->streams[idx];
36  AVRational framerate;
37 
38  if (os->psize < 7 || p[0] != 0x4f)
39  return 0;
40 
41  switch (p[5]){
42  case 0x01:
43  if (os->psize < VP8_HEADER_SIZE) {
44  av_log(s, AV_LOG_ERROR, "Invalid OggVP8 header packet");
45  return AVERROR_INVALIDDATA;
46  }
47 
48  if (p[6] != 1) {
50  "Unknown OggVP8 version %d.%d\n", p[6], p[7]);
51  return AVERROR_INVALIDDATA;
52  }
53 
54  st->codec->width = AV_RB16(p + 8);
55  st->codec->height = AV_RB16(p + 10);
56  st->sample_aspect_ratio.num = AV_RB24(p + 12);
57  st->sample_aspect_ratio.den = AV_RB24(p + 15);
58  framerate.num = AV_RB32(p + 18);
59  framerate.den = AV_RB32(p + 22);
60 
61  avpriv_set_pts_info(st, 64, framerate.den, framerate.num);
65  break;
66  case 0x02:
67  if (p[6] != 0x20)
68  return AVERROR_INVALIDDATA;
69  ff_vorbis_stream_comment(s, st, p + 7, os->psize - 7);
70  break;
71  default:
72  av_log(s, AV_LOG_ERROR, "Unknown VP8 header type 0x%02X\n", p[5]);
73  return AVERROR_INVALIDDATA;
74  }
75 
76  return 1;
77 }
78 
79 static uint64_t vp8_gptopts(AVFormatContext *s, int idx,
80  uint64_t granule, int64_t *dts)
81 {
82  struct ogg *ogg = s->priv_data;
83  struct ogg_stream *os = ogg->streams + idx;
84 
85  uint64_t pts = (granule >> 32);
86  uint32_t dist = (granule >> 3) & 0x07ffffff;
87 
88  if (!dist)
89  os->pflags |= AV_PKT_FLAG_KEY;
90 
91  if (dts)
92  *dts = pts;
93 
94  return pts;
95 }
96 
97 static int vp8_packet(AVFormatContext *s, int idx)
98 {
99  struct ogg *ogg = s->priv_data;
100  struct ogg_stream *os = ogg->streams + idx;
101  uint8_t *p = os->buf + os->pstart;
102 
103  if ((!os->lastpts || os->lastpts == AV_NOPTS_VALUE) &&
104  !(os->flags & OGG_FLAG_EOS)) {
105  int seg;
106  int duration;
107  uint8_t *last_pkt = p;
108  uint8_t *next_pkt;
109 
110  seg = os->segp;
111  duration = (last_pkt[0] >> 4) & 1;
112  next_pkt = last_pkt += os->psize;
113  for (; seg < os->nsegs; seg++) {
114  if (os->segments[seg] < 255) {
115  duration += (last_pkt[0] >> 4) & 1;
116  last_pkt = next_pkt + os->segments[seg];
117  }
118  next_pkt += os->segments[seg];
119  }
120  os->lastpts =
121  os->lastdts = vp8_gptopts(s, idx, os->granule, NULL) - duration;
122  if(s->streams[idx]->start_time == AV_NOPTS_VALUE) {
123  s->streams[idx]->start_time = os->lastpts;
124  if (s->streams[idx]->duration)
125  s->streams[idx]->duration -= s->streams[idx]->start_time;
126  }
127  }
128 
129  if (os->psize > 0)
130  os->pduration = (p[0] >> 4) & 1;
131 
132  return 0;
133 }
134 
135 const struct ogg_codec ff_vp8_codec = {
136  .magic = "OVP80",
137  .magicsize = 5,
138  .header = vp8_header,
139  .packet = vp8_packet,
140  .gptopts = vp8_gptopts,
141  .nb_header = 1,
142 };