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/*
* ADX ADPCM codecs
* Copyright (c) 2001,2003 BERO
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "adx.h"
#include "get_bits.h"
/**
* @file
* SEGA CRI adx codecs.
*
* Reference documents:
* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
*/
static av_cold int adx_decode_init(AVCodecContext *avctx)
{
ADXContext *c = avctx->priv_data;
int ret, header_size;
if (avctx->extradata_size < 24)
return AVERROR_INVALIDDATA;
if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
avctx->extradata_size, &header_size,
c->coeff)) < 0) {
av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
return AVERROR_INVALIDDATA;
}
c->channels = avctx->channels;
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
return 0;
}
/**
* Decode 32 samples from 18 bytes.
*
* A 16-bit scalar value is applied to 32 residuals, which then have a
* 2nd-order LPC filter applied to it to form the output signal for a single
* channel.
*/
static int adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch)
{
ADXChannelState *prev = &c->prev[ch];
GetBitContext gb;
int scale = AV_RB16(in);
int i;
int s0, s1, s2, d;
/* check if this is an EOF packet */
if (scale & 0x8000)
return -1;
init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
s1 = prev->s1;
s2 = prev->s2;
for (i = 0; i < BLOCK_SAMPLES; i++) {
d = get_sbits(&gb, 4);
s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
s2 = s1;
s1 = av_clip_int16(s0);
*out = s1;
out += c->channels;
}
prev->s1 = s1;
prev->s2 = s2;
return 0;
}
static int adx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
AVPacket *avpkt)
{
int buf_size = avpkt->size;
ADXContext *c = avctx->priv_data;
int16_t *samples = data;
const uint8_t *buf = avpkt->data;
int num_blocks, ch;
if (c->eof) {
*data_size = 0;
return buf_size;
}
/* 18 bytes of data are expanded into 32*2 bytes of audio,
so guard against buffer overflows */
num_blocks = buf_size / (BLOCK_SIZE * c->channels);
if (num_blocks > *data_size / (BLOCK_SAMPLES * c->channels)) {
buf_size = (*data_size / (BLOCK_SAMPLES * c->channels)) * BLOCK_SIZE;
num_blocks = buf_size / (BLOCK_SIZE * c->channels);
}
if (!buf_size || buf_size % (BLOCK_SIZE * avctx->channels)) {
if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
c->eof = 1;
*data_size = 0;
return avpkt->size;
}
return AVERROR_INVALIDDATA;
}
while (num_blocks--) {
for (ch = 0; ch < c->channels; ch++) {
if (adx_decode(c, samples + ch, buf, ch)) {
c->eof = 1;
buf = avpkt->data + avpkt->size;
break;
}
buf_size -= BLOCK_SIZE;
buf += BLOCK_SIZE;
}
samples += BLOCK_SAMPLES * c->channels;
}
*data_size = (uint8_t*)samples - (uint8_t*)data;
return buf - avpkt->data;
}
AVCodec ff_adpcm_adx_decoder = {
.name = "adpcm_adx",
.type = AVMEDIA_TYPE_AUDIO,
.id = CODEC_ID_ADPCM_ADX,
.priv_data_size = sizeof(ADXContext),
.init = adx_decode_init,
.decode = adx_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
};
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