libavcodec/rv34_parser.c

   1 /*
   2  * RV30/40 parser
   3  * Copyright (c) 2011 Konstantin Shishkov
   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 /**
  23  * @file
  24  * RV30/40 parser
  25  */
  26
  27 #include "avcodec.h"
  28 #include "libavutil/intreadwrite.h"
  29
  30 typedef struct RV34ParseContext {
  31     int64_t key_dts;
  32     int key_pts;
  33 } RV34ParseContext;
  34
  35 static const int rv_to_av_frame_type[4] = {
  36     AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_I, AV_PICTURE_TYPE_P, AV_PICTURE_TYPE_B,
  37 };
  38
  39 static int rv34_parse(AVCodecParserContext *s,
  40                       AVCodecContext *avctx,
  41                       const uint8_t **poutbuf, int *poutbuf_size,
  42                       const uint8_t *buf, int buf_size)
  43 {
  44     RV34ParseContext *pc = s->priv_data;
  45     int type, pts, hdr;
  46
  47     if (buf_size < 13 + *buf * 8) {
  48         *poutbuf = buf;
  49         *poutbuf_size = buf_size;
  50         return buf_size;
  51     }
  52
  53     hdr = AV_RB32(buf + 9 + *buf * 8);
  54     if (avctx->codec_id == AV_CODEC_ID_RV30) {
  55         type = (hdr >> 27) & 3;
  56         pts  = (hdr >>  7) & 0x1FFF;
  57     } else {
  58         type = (hdr >> 29) & 3;
  59         pts  = (hdr >>  6) & 0x1FFF;
  60     }
  61
  62     if (type != 3 && s->pts != AV_NOPTS_VALUE) {
  63         pc->key_dts = s->pts;
  64         pc->key_pts = pts;
  65     } else {
  66         if (type != 3)
  67             s->pts = pc->key_dts + ((pts - pc->key_pts) & 0x1FFF);
  68         else
  69             s->pts = pc->key_dts - ((pc->key_pts - pts) & 0x1FFF);
  70     }
  71     s->pict_type = rv_to_av_frame_type[type];
  72
  73     *poutbuf = buf;
  74     *poutbuf_size = buf_size;
  75     return buf_size;
  76 }
  77
  78 const AVCodecParser ff_rv34_parser = {
  79     .codec_ids      = { AV_CODEC_ID_RV30, AV_CODEC_ID_RV40 },
  80     .priv_data_size = sizeof(RV34ParseContext),
  81     .parser_parse   = rv34_parse,
  82 };