/libavcodec/vp8_parser.c

 1/*
 2 * This file is part of FFmpeg.
 3 *
 4 * FFmpeg is free software; you can redistribute it and/or
 5 * modify it under the terms of the GNU Lesser General Public
 6 * License as published by the Free Software Foundation; either
 7 * version 2.1 of the License, or (at your option) any later version.
 8 *
 9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#include "libavutil/intreadwrite.h"
20
21#include "avcodec.h"
22
23static int parse(AVCodecParserContext *s,
24                 AVCodecContext *avctx,
25                 const uint8_t **poutbuf, int *poutbuf_size,
26                 const uint8_t *buf, int buf_size)
27{
28    unsigned int frame_type;
29    unsigned int profile;
30
31    *poutbuf      = buf;
32    *poutbuf_size = buf_size;
33
34    if (buf_size < 3)
35        return buf_size;
36
37    frame_type = buf[0] & 1;
38    profile    = (buf[0] >> 1) & 7;
39    if (profile > 3) {
40        av_log(avctx, AV_LOG_ERROR, "Invalid profile %u.\n", profile);
41        return buf_size;
42    }
43
44    avctx->profile = profile;
45    s->key_frame   = frame_type == 0;
46    s->pict_type   = frame_type ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;
47    s->format      = AV_PIX_FMT_YUV420P;
48    s->field_order = AV_FIELD_PROGRESSIVE;
49    s->picture_structure = AV_PICTURE_STRUCTURE_FRAME;
50
51    if (frame_type == 0) {
52        unsigned int sync_code;
53        unsigned int width, height;
54
55        if (buf_size < 10)
56            return buf_size;
57
58        sync_code = AV_RL24(buf + 3);
59        if (sync_code != 0x2a019d) {
60            av_log(avctx, AV_LOG_ERROR, "Invalid sync code %06x.\n", sync_code);
61            return buf_size;
62        }
63
64        width  = AV_RL16(buf + 6) & 0x3fff;
65        height = AV_RL16(buf + 8) & 0x3fff;
66
67        s->width        = width;
68        s->height       = height;
69        s->coded_width  = FFALIGN(width,  16);
70        s->coded_height = FFALIGN(height, 16);
71    }
72
73    return buf_size;
74}
75
76AVCodecParser ff_vp8_parser = {
77    .codec_ids    = { AV_CODEC_ID_VP8 },
78    .parser_parse = parse,
79};