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
  23 static 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
  76 const AVCodecParser ff_vp8_parser = {
  77     .codec_ids    = { AV_CODEC_ID_VP8 },
  78     .parser_parse = parse,
  79 };