3716abba92
- wav(RIFF) supports Microsoft ADPCM, Dialogic OKI ADPCM, YAMAHA ADPCM, Adobe SWF ADPCM. - AIFF supports QuickTime IMA ADPCM. - DVI ADPCM(IMA ADPCM) reworks. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24782 a1c6a512-1295-4272-9138-f99709370657
101 lines
3 KiB
C
101 lines
3 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 "adpcm_seek.h"
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#include "codeclib.h"
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/*
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* The helper functions in order to seek for the adpcm codec
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* which does not include the header each the data block.
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*/
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#define MAX_STORE_COUNT 1000
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static struct adpcm_data seek_table[MAX_STORE_COUNT];
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static int seek_count;
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static int cur_count;
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static int max_ratio;
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static int cur_ratio;
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void init_seek_table(uint32_t max_count)
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{
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int i = 0;
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for ( ; i < MAX_STORE_COUNT; i++)
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{
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seek_table[i].is_valid = false;
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}
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seek_count = max_count / MAX_STORE_COUNT + 1;
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max_ratio = max_count / seek_count + 1;
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cur_count = 0;
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cur_ratio = -1;
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}
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void add_adpcm_data(struct adpcm_data *data)
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{
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if (--cur_count <= 0)
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{
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cur_count = seek_count;
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if (++cur_ratio >= max_ratio)
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cur_ratio = max_ratio - 1;
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if (!seek_table[cur_ratio].is_valid)
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{
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seek_table[cur_ratio].pcmdata[0] = data->pcmdata[0];
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seek_table[cur_ratio].pcmdata[1] = data->pcmdata[1];
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seek_table[cur_ratio].step[0] = data->step[0];
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seek_table[cur_ratio].step[1] = data->step[1];
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seek_table[cur_ratio].is_valid = true;
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}
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}
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}
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uint32_t seek(uint32_t count, struct adpcm_data *seek_data,
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uint8_t *(*read_buffer)(size_t *realsize),
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int (*decode)(const uint8_t *inbuf, size_t inbufsize))
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{
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int new_ratio = count / seek_count;
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if (new_ratio >= max_ratio)
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new_ratio = max_ratio - 1;
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if (!seek_table[new_ratio].is_valid)
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{
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uint8_t *buffer;
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size_t n;
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do
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{
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buffer = read_buffer(&n);
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if (n == 0)
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break;
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decode(buffer, n);
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} while (cur_ratio < new_ratio);
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}
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seek_data->pcmdata[0] = seek_table[new_ratio].pcmdata[0];
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seek_data->pcmdata[1] = seek_table[new_ratio].pcmdata[1];
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seek_data->step[0] = seek_table[new_ratio].step[0];
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seek_data->step[1] = seek_table[new_ratio].step[1];
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cur_ratio = new_ratio;
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cur_count = seek_count;
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return cur_ratio * seek_count;
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}
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