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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2010 Yoshihisa Uchida
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "codeclib.h"
#include "ima_adpcm_common.h"
#include "support_formats.h"
/*
* Apple QuickTime IMA ADPCM
*
* References
* [1] Multimedia Wiki, Apple QuickTime IMA ADPCM
* URL:http://wiki.multimedia.cx/index.php?title=Apple_QuickTime_IMA_ADPCM
* [2] Apple Inc., Technical Note TN1081 Understanding the Differences Between
* Apple and Windows IMA-ADPCM Compressed Sound Files, 1996
* [3] ffmpeg source code, libavcodec/adpcm.c
*/
static struct libpcm_pcm_format *fmt;
static bool set_format(struct libpcm_pcm_format *format)
{
fmt = format;
if (fmt->bitspersample != 4)
{
DEBUGF("CODEC_ERROR: quicktime ima adpcm must be 4 bitspersample: %d\n",
fmt->bitspersample);
return false;
}
fmt->blockalign = 34 * fmt->channels;
fmt->samplesperblock = 64;
/* chunksize = about 1/50[s] data */
fmt->chunksize = (ci->id3->frequency / (50 * fmt->samplesperblock))
* fmt->blockalign;
init_ima_adpcm_decoder(4, NULL);
return true;
}
static struct pcm_pos *get_seek_pos(uint32_t seek_val, int seek_mode,
uint8_t *(*read_buffer)(size_t *realsize))
{
static struct pcm_pos newpos;
uint32_t newblock = (seek_mode == PCM_SEEK_TIME) ?
((uint64_t)seek_val * ci->id3->frequency / 1000LL)
/ fmt->samplesperblock :
seek_val / fmt->blockalign;
(void)read_buffer;
newpos.pos = newblock * fmt->blockalign;
newpos.samples = newblock * fmt->samplesperblock;
return &newpos;
}
static int decode(const uint8_t *inbuf, size_t inbufsize,
int32_t *outbuf, int *outbufcount)
{
int ch;
size_t nsamples = 0;
int block_size;
int32_t *pcmbuf;
int32_t init_pcmdata;
int8_t init_index;
while (inbufsize > 0)
{
for (ch = 0; ch < fmt->channels; ch++)
{
/* read block header */
init_pcmdata = (inbuf[0] << 8)|(inbuf[1] & 0x80);
if (init_pcmdata > 32767)
init_pcmdata -= 65536;
init_index = inbuf[1] & 0x7f;
if (init_index > 88)
{
DEBUGF("CODEC_ERROR: quicktime ima adpcm illegal step index=%d > 88\n",
init_index);
return CODEC_ERROR;
}
inbuf += 2;
inbufsize -= 2;
set_decode_parameters(1, &init_pcmdata, &init_index);
/* read block data */
pcmbuf = outbuf + ch;
for (block_size = 32; block_size > 0 && inbufsize > 0; block_size--, inbufsize--)
{
*pcmbuf = create_pcmdata_size4(ch, *inbuf ) << IMA_ADPCM_INC_DEPTH;
pcmbuf += fmt->channels;
*pcmbuf = create_pcmdata_size4(ch, *inbuf >> 4) << IMA_ADPCM_INC_DEPTH;
pcmbuf += fmt->channels;
nsamples += 2;
inbuf++;
}
}
outbuf += 64 * fmt->channels;
}
if (fmt->channels == 2)
nsamples >>= 1;
*outbufcount = nsamples;
return CODEC_OK;
}
static const struct pcm_codec codec = {
set_format,
get_seek_pos,
decode,
};
const struct pcm_codec *get_qt_ima_adpcm_codec(void)
{
return &codec;
}
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