apps/codecs/libpcm/qt_ima_adpcm.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2010 Yoshihisa Uchida
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include "codeclib.h"
  22 #include "pcm_common.h"
  23 #include "ima_adpcm_common.h"
  24
  25 /*
  26  * Apple QuickTime IMA ADPCM
  27  *
  28  * References
  29  * [1] Multimedia Wiki, Apple QuickTime IMA ADPCM
  30  *     URL:http://wiki.multimedia.cx/index.php?title=Apple_QuickTime_IMA_ADPCM
  31  * [2] Apple Inc., Technical Note TN1081 Understanding the Differences Between
  32  *     Apple and Windows IMA-ADPCM Compressed Sound Files, 1996
  33  * [3] ffmpeg source code, libavcodec/adpcm.c
  34  */
  35
  36 static struct pcm_format *fmt;
  37
  38 static bool set_format(struct pcm_format *format)
  39 {
  40     fmt = format;
  41
  42     if (fmt->bitspersample != 4)
  43     {
  44         DEBUGF("CODEC_ERROR: quicktime ima adpcm must be 4 bitspersample: %d\n",
  45                              fmt->bitspersample);
  46         return false;
  47     }
  48
  49     fmt->blockalign = 34 * fmt->channels;
  50     fmt->samplesperblock = 64;
  51
  52     /* chunksize = about 1/50[s] data */
  53     fmt->chunksize = (ci->id3->frequency / (50 * fmt->samplesperblock))
  54                                          * fmt->blockalign;
  55
  56     init_ima_adpcm_decoder(4, NULL);
  57     return true;
  58 }
  59
  60 static struct pcm_pos *get_seek_pos(long seek_time,
  61                                     uint8_t *(*read_buffer)(size_t *realsize))
  62 {
  63     static struct pcm_pos newpos;
  64     uint32_t newblock = ((uint64_t)seek_time * ci->id3->frequency)
  65                                              / (1000LL * fmt->samplesperblock);
  66
  67     (void)read_buffer;
  68     newpos.pos     = newblock * fmt->blockalign;
  69     newpos.samples = newblock * fmt->samplesperblock;
  70     return &newpos;
  71 }
  72
  73 static int decode(const uint8_t *inbuf, size_t inbufsize,
  74                   int32_t *outbuf, int *outbufcount)
  75 {
  76     int ch;
  77     size_t nsamples = 0;
  78     int block_size;
  79     int32_t *pcmbuf;
  80     int32_t init_pcmdata;
  81     int8_t init_index;
  82
  83     while (inbufsize > 0)
  84     {
  85         for (ch = 0; ch < fmt->channels; ch++)
  86         {
  87             /* read block header */
  88             init_pcmdata = (inbuf[0] << 8)|(inbuf[1] & 0x80);
  89             if (init_pcmdata > 32767)
  90                 init_pcmdata -= 65536;
  91
  92             init_index = inbuf[1] & 0x7f;
  93             if (init_index > 88)
  94             {
  95                 DEBUGF("CODEC_ERROR: quicktime ima adpcm illegal step index=%d > 88\n",
  96                                      init_index);
  97                 return CODEC_ERROR;
  98             }
  99
 100             inbuf += 2;
 101             inbufsize -= 2;
 102
 103             set_decode_parameters(1, &init_pcmdata, &init_index);
 104
 105             /* read block data */
 106             pcmbuf = outbuf + ch;
 107             for (block_size = 32; block_size > 0 && inbufsize > 0; block_size--, inbufsize--)
 108             {
 109                 *pcmbuf = create_pcmdata_size4(ch, *inbuf     ) << 13;
 110                 pcmbuf += fmt->channels;
 111                 *pcmbuf = create_pcmdata_size4(ch, *inbuf >> 4) << 13;
 112                 pcmbuf += fmt->channels;
 113                 nsamples += 2;
 114                 inbuf++;
 115             }
 116         }
 117         outbuf += 64 * fmt->channels;
 118     }
 119
 120     if (fmt->channels == 2)
 121         nsamples >>= 1;
 122     *outbufcount = nsamples;
 123
 124     return CODEC_OK;
 125 }
 126
 127 static const struct pcm_codec codec = {
 128                                           set_format,
 129                                           get_seek_pos,
 130                                           decode,
 131                                       };
 132
 133 const struct pcm_codec *get_qt_ima_adpcm_codec(void)
 134 {
 135     return &codec;
 136 }