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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 "pcm_common.h"
#include "ima_adpcm_common.h"
/*
* Adobe SWF ADPCM
*
* References
* [1] Adobe, SWF File Format Specification Version 10, 2008
* [2] Jack Jansen, adpcm.c in adpcm.zip
* [3] ffmpeg source code, libavcodec/adpcm.c
*/
/* step index table when bitspersample is 3.
* (when bitspersample is 2, 4, 5, step index table uses the table
* which is defined ima_adpcm_common.c.)
*/
static const int index_table[4] ICONST_ATTR = {
-1, -1, 2, 4,
};
static int validity_bits = 8;
static bool first_block = true;
static int blockbits = 0;
static int lastbytebits = 0;
static bool after_seek = false;
static struct pcm_format *fmt;
static bool set_format(struct pcm_format *format)
{
fmt = format;
if (fmt->bitspersample < 2 || fmt->bitspersample > 5)
{
DEBUGF("CODEC_ERROR: swf adpcm must be 2, 3, 4 or 5 bitspersample: %d\n",
fmt->bitspersample);
return false;
}
if (fmt->samplesperblock == 0)
fmt->samplesperblock = (((fmt->blockalign << 3) - 2) / fmt->channels - 22)
/ fmt->bitspersample + 1;
blockbits = ((fmt->samplesperblock - 1) * fmt->bitspersample + 22) * fmt->channels;
/*
* chunksize = about 93 [ms] data (frequency:44.1kHz, 4096 [sample/block])
* chunksize changes depending upon the position of block.
*/
fmt->chunksize = (blockbits + 9) >> 3;
/* initialize for ima adpcm common functions */
if (fmt->bitspersample == 3)
init_ima_adpcm_decoder(fmt->bitspersample, index_table);
else
init_ima_adpcm_decoder(fmt->bitspersample, NULL);
return true;
}
static struct pcm_pos *get_seek_pos(long seek_time,
uint8_t *(*read_buffer)(size_t *realsize))
{
static struct pcm_pos newpos;
uint32_t chunkbits = blockbits;
uint32_t seekbits = (((uint64_t)seek_time * ci->id3->frequency)
/ (1000LL * fmt->samplesperblock)) * blockbits + 2;
(void)read_buffer;
newpos.pos = seekbits >> 3;
newpos.samples = (((uint64_t)seek_time * ci->id3->frequency)
/ (1000LL * fmt->samplesperblock))
* fmt->samplesperblock;
if (newpos.pos == 0)
{
first_block = true;
lastbytebits = 0;
}
else
{
first_block = false;
lastbytebits = seekbits & 0x07;
if (lastbytebits != 0)
chunkbits -= (8 - lastbytebits);
}
/* calculates next read bytes */
fmt->chunksize = (chunkbits >> 3) + (((chunkbits & 0x07) > 0)?1:0)
+ ((lastbytebits > 0)?1:0);
after_seek = true;
return &newpos;
}
static uint8_t get_data(const uint8_t **buf, int bit)
{
uint8_t res = 0;
uint8_t mask = (1 << bit) - 1;
if (validity_bits >= bit)
{
validity_bits -= bit;
return (**buf >> validity_bits) & mask;
}
if (validity_bits > 0)
res = **buf << (bit - validity_bits);
validity_bits += 8 - bit;
res = (res | (*(++(*buf)) >> validity_bits)) & mask;
return res;
}
static int decode(const uint8_t *inbuf, size_t inbufsize,
int32_t *outbuf, int *outbufcount)
{
int ch;
int adpcm_code_size;
int count = fmt->samplesperblock;
int32_t init_pcmdata[2];
int8_t init_index[2];
static uint8_t lastbyte = 0;
(void)inbufsize;
validity_bits = 8;
/* read block header */
ch = fmt->channels - 1;
if (first_block)
{
adpcm_code_size = get_data(&inbuf, 2) + 2;
if (fmt->bitspersample != adpcm_code_size)
{
DEBUGF("CODEC_ERROR: swf adpcm different adpcm code size=%d != %d\n",
adpcm_code_size, fmt->bitspersample);
return CODEC_ERROR;
}
init_pcmdata[0] = (get_data(&inbuf, 8) << 8) | get_data(&inbuf, 8);
lastbytebits = 0;
first_block = false;
}
else
{
if (after_seek && lastbytebits > 0)
{
lastbyte = *inbuf++;
after_seek = false;
}
if (lastbytebits > 0)
init_pcmdata[0] = ((lastbyte << (8 + lastbytebits)) |
(get_data(&inbuf, 8) << lastbytebits) |
get_data(&inbuf, lastbytebits)) & 65535;
else
init_pcmdata[0] = (get_data(&inbuf, 8) << 8) | get_data(&inbuf, 8);
}
after_seek = false;
init_index[0] = get_data(&inbuf, 6);
if (init_pcmdata[0] > 32767)
init_pcmdata[0] -= 65536;
if (ch > 0)
{
init_pcmdata[1] = (get_data(&inbuf, 8) << 8) | get_data(&inbuf, 8);
init_index[1] = get_data(&inbuf, 6);
if (init_pcmdata[1] > 32767)
init_pcmdata[1] -= 65536;
}
*outbuf++ = init_pcmdata[0] << 13;
if (ch > 0)
*outbuf++ = init_pcmdata[1] << 13;
set_decode_parameters(fmt->channels, init_pcmdata, init_index);
/* read block data */
while (--count > 0)
{
*outbuf++ = create_pcmdata(0, get_data(&inbuf, fmt->bitspersample)) << 13;
if (ch > 0)
*outbuf++ = create_pcmdata(ch, get_data(&inbuf, fmt->bitspersample)) << 13;
}
*outbufcount = fmt->samplesperblock;
lastbyte = *inbuf;
lastbytebits = (8 - validity_bits) & 0x07;
/* calculates next read bytes */
fmt->chunksize = (blockbits - validity_bits + 7) >> 3;
return CODEC_OK;
}
static const struct pcm_codec codec = {
set_format,
get_seek_pos,
decode,
};
const struct pcm_codec *get_swf_adpcm_codec(void)
{
first_block = true;
lastbytebits = 0;
after_seek = false;
return &codec;
}
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