path: root/libavformat/oggparsevp8.c (plain)
blob: c534ab117d94e2aee590f03641681d5031aa83c4

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) {
49	av_log(s, AV_LOG_WARNING,
50	"Unknown OggVP8 version %d.%d\n", p[6], p[7]);
51	return AVERROR_INVALIDDATA;
52	}
53
54	st->codecpar->width = AV_RB16(p + 8);
55	st->codecpar->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);
62	st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
63	st->codecpar->codec_id = AV_CODEC_ID_VP8;
64	st->need_parsing = AVSTREAM_PARSE_HEADERS;
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	int invcnt = !((granule >> 30) & 3);
86	// If page granule is that of an invisible vp8 frame, its pts will be
87	// that of the end of the next visible frame. We subtract 1 for those
88	// to prevent messing up pts calculations.
89	uint64_t pts = (granule >> 32) - invcnt;
90	uint32_t dist = (granule >> 3) & 0x07ffffff;
91
92	if (!dist)
93	os->pflags |= AV_PKT_FLAG_KEY;
94
95	if (dts)
96	*dts = pts;
97
98	return pts;
99	}
100
101	static int vp8_packet(AVFormatContext *s, int idx)
102	{
103	struct ogg *ogg = s->priv_data;
104	struct ogg_stream *os = ogg->streams + idx;
105	uint8_t *p = os->buf + os->pstart;
106
107	if ((!os->lastpts || os->lastpts == AV_NOPTS_VALUE) &&
108	!(os->flags & OGG_FLAG_EOS)) {
109	int seg;
110	int duration;
111	uint8_t *last_pkt = p;
112	uint8_t *next_pkt;
113
114	seg = os->segp;
115	duration = (last_pkt[0] >> 4) & 1;
116	next_pkt = last_pkt += os->psize;
117	for (; seg < os->nsegs; seg++) {
118	if (os->segments[seg] < 255) {
119	duration += (last_pkt[0] >> 4) & 1;
120	last_pkt = next_pkt + os->segments[seg];
121	}
122	next_pkt += os->segments[seg];
123	}
124	os->lastpts =
125	os->lastdts = vp8_gptopts(s, idx, os->granule, NULL) - duration;
126	if(s->streams[idx]->start_time == AV_NOPTS_VALUE) {
127	s->streams[idx]->start_time = os->lastpts;
128	if (s->streams[idx]->duration)
129	s->streams[idx]->duration -= s->streams[idx]->start_time;
130	}
131	}
132
133	if (os->psize > 0)
134	os->pduration = (p[0] >> 4) & 1;
135
136	return 0;
137	}
138
139	const struct ogg_codec ff_vp8_codec = {
140	.magic = "OVP80",
141	.magicsize = 5,
142	.header = vp8_header,
143	.packet = vp8_packet,
144	.gptopts = vp8_gptopts,
145	.nb_header = 1,
146	};
147