libavcodec/vp9_parser.c

   1 /*
   2  * VP9 compatible video decoder
   3  *
   4  * Copyright (C) 2013 Ronald S. Bultje <rsbultje gmail com>
   5  * Copyright (C) 2013 Clément Bœsch <u pkh me>
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include "libavutil/intreadwrite.h"
  25 #include "libavcodec/get_bits.h"
  26 #include "parser.h"
  27
  28 static int parse(AVCodecParserContext *ctx,
  29                  AVCodecContext *avctx,
  30                  const uint8_t **out_data, int *out_size,
  31                  const uint8_t *data, int size)
  32 {
  33     GetBitContext gb;
  34     int res, profile, keyframe;
  35
  36     *out_data = data;
  37     *out_size = size;
  38
  39     if (!size || (res = init_get_bits8(&gb, data, size)) < 0)
  40         return size; // parsers can't return errors
  41     get_bits(&gb, 2); // frame marker
  42     profile  = get_bits1(&gb);
  43     profile |= get_bits1(&gb) << 1;
  44     if (profile == 3) profile += get_bits1(&gb);
  45     if (profile > 3)
  46         return size;
  47
  48     avctx->profile = profile;
  49
  50     if (get_bits1(&gb)) {
  51         keyframe = 0;
  52     } else {
  53         keyframe  = !get_bits1(&gb);
  54     }
  55
  56     if (!keyframe) {
  57         ctx->pict_type = AV_PICTURE_TYPE_P;
  58         ctx->key_frame = 0;
  59     } else {
  60         ctx->pict_type = AV_PICTURE_TYPE_I;
  61         ctx->key_frame = 1;
  62     }
  63
  64     return size;
  65 }
  66
  67 const AVCodecParser ff_vp9_parser = {
  68     .codec_ids      = { AV_CODEC_ID_VP9 },
  69     .parser_parse   = parse,
  70 };