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  1. /*
  2.  * Copyright (c) 2011  Justin Ruggles
  3.  *
  4.  * This file is part of FFmpeg.
  5.  *
  6.  * FFmpeg is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU Lesser General Public
  8.  * License as published by the Free Software Foundation; either
  9.  * version 2.1 of the License, or (at your option) any later version.
  10.  *
  11.  * FFmpeg is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14.  * Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public
  17.  * License along with FFmpeg; if not, write to the Free Software
  18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19.  */
  20.  
  21. /**
  22.  * @file
  23.  * ADX audio parser
  24.  *
  25.  * Splits packets into individual blocks.
  26.  */
  27.  
  28. #include "libavutil/intreadwrite.h"
  29. #include "parser.h"
  30. #include "adx.h"
  31.  
  32. typedef struct ADXParseContext {
  33.     ParseContext pc;
  34.     int header_size;
  35.     int block_size;
  36.     int remaining;
  37. } ADXParseContext;
  38.  
  39. static int adx_parse(AVCodecParserContext *s1,
  40.                            AVCodecContext *avctx,
  41.                            const uint8_t **poutbuf, int *poutbuf_size,
  42.                            const uint8_t *buf, int buf_size)
  43. {
  44.     ADXParseContext *s = s1->priv_data;
  45.     ParseContext *pc = &s->pc;
  46.     int next = END_NOT_FOUND;
  47.     int i;
  48.     uint64_t state = pc->state64;
  49.  
  50.     if (!s->header_size) {
  51.         for (i = 0; i < buf_size; i++) {
  52.             state = (state << 8) | buf[i];
  53.             /* check for fixed fields in ADX header for possible match */
  54.             if ((state & 0xFFFF0000FFFFFF00) == 0x8000000003120400ULL) {
  55.                 int channels    = state & 0xFF;
  56.                 int header_size = ((state >> 32) & 0xFFFF) + 4;
  57.                 if (channels > 0 && header_size >= 8) {
  58.                     s->header_size = header_size;
  59.                     s->block_size  = BLOCK_SIZE * channels;
  60.                     s->remaining   = i - 7 + s->header_size + s->block_size;
  61.                     break;
  62.                 }
  63.             }
  64.         }
  65.         pc->state64 = state;
  66.     }
  67.  
  68.     if (s->header_size) {
  69.         if (!s->remaining)
  70.             s->remaining = s->block_size;
  71.         if (s->remaining <= buf_size) {
  72.             next = s->remaining;
  73.             s->remaining = 0;
  74.         } else
  75.             s->remaining -= buf_size;
  76.     }
  77.  
  78.     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
  79.         *poutbuf      = NULL;
  80.         *poutbuf_size = 0;
  81.         return buf_size;
  82.     }
  83.  
  84.     s1->duration = BLOCK_SAMPLES;
  85.  
  86.     *poutbuf = buf;
  87.     *poutbuf_size = buf_size;
  88.     return next;
  89. }
  90.  
  91. AVCodecParser ff_adx_parser = {
  92.     .codec_ids      = { AV_CODEC_ID_ADPCM_ADX },
  93.     .priv_data_size = sizeof(ADXParseContext),
  94.     .parser_parse   = adx_parse,
  95.     .parser_close   = ff_parse_close,
  96. };
  97.