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