libavcodec/xma_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 /**
  20  * @file
  21  * XMA2 audio parser
  22  */
  23
  24 #include "parser.h"
  25
  26 typedef struct XMAParserContext{
  27     int skip_packets;
  28 } XMAParserContext;
  29
  30 static int xma_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
  31                      const uint8_t **poutbuf, int *poutbuf_size,
  32                      const uint8_t *buf, int buf_size)
  33 {
  34     XMAParserContext *s = s1->priv_data;
  35
  36     if (buf_size % 2048 == 0) {
  37         int duration = 0, packet, nb_packets = buf_size / 2048;
  38
  39         for (packet = 0; packet < nb_packets; packet++) {
  40             if (s->skip_packets == 0) {
  41                 duration += buf[packet * 2048] * 128;
  42                 s->skip_packets = buf[packet * 2048 + 3] + 1;
  43             }
  44             s->skip_packets--;
  45         }
  46
  47         s1->duration = duration;
  48         s1->key_frame = !!duration;
  49     }
  50
  51     /* always return the full packet. this parser isn't doing any splitting or
  52        combining, only packet analysis */
  53     *poutbuf      = buf;
  54     *poutbuf_size = buf_size;
  55     return buf_size;
  56 }
  57
  58 const AVCodecParser ff_xma_parser = {
  59     .codec_ids      = { AV_CODEC_ID_XMA2 },
  60     .priv_data_size = sizeof(XMAParserContext),
  61     .parser_parse   = xma_parse,
  62 };