libavcodec/sipr_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  * Sipr audio parser
  22  */
  23
  24 #include "parser.h"
  25
  26 typedef struct SiprParserContext{
  27     ParseContext pc;
  28 } SiprParserContext;
  29
  30 static int sipr_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
  31 {
  32     int next;
  33
  34     switch (avctx->block_align) {
  35     case 20:
  36     case 19:
  37     case 29:
  38     case 37: next = avctx->block_align; break;
  39     default:
  40         if      (avctx->bit_rate > 12200) next = 20;
  41         else if (avctx->bit_rate > 7500 ) next = 19;
  42         else if (avctx->bit_rate > 5750 ) next = 29;
  43         else                              next = 37;
  44     }
  45
  46     return FFMIN(next, buf_size);
  47 }
  48
  49 static int sipr_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
  50                       const uint8_t **poutbuf, int *poutbuf_size,
  51                       const uint8_t *buf, int buf_size)
  52 {
  53     SiprParserContext *s = s1->priv_data;
  54     ParseContext *pc = &s->pc;
  55     int next;
  56
  57     next = sipr_split(avctx, buf, buf_size);
  58     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
  59         *poutbuf = NULL;
  60         *poutbuf_size = 0;
  61         return buf_size;
  62     }
  63
  64     *poutbuf      = buf;
  65     *poutbuf_size = buf_size;
  66     return next;
  67 }
  68
  69 const AVCodecParser ff_sipr_parser = {
  70     .codec_ids      = { AV_CODEC_ID_SIPR },
  71     .priv_data_size = sizeof(SiprParserContext),
  72     .parser_parse   = sipr_parse,
  73     .parser_close   = ff_parse_close,
  74 };