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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"
/**
* @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)
{
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 void adx_decode(int16_t *out, const uint8_t *in, ADXChannelState *prev)
{
int scale = AV_RB16(in);
int i;
int s0, s1, s2, d;
in += 2;
s1 = prev->s1;
s2 = prev->s2;
for (i = 0; i < 16; i++) {
d = in[i];
d = (signed char)d >> 4;
s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14;
s2 = s1;
s1 = av_clip_int16(s0);
*out++ = s1;
d = in[i];
d = (signed char)(d << 4) >> 4;
s0 = (BASEVOL * d * scale + SCALE1 * s1 - SCALE2 * s2) >> 14;
s2 = s1;
s1 = av_clip_int16(s0);
*out++ = s1;
}
prev->s1 = s1;
prev->s2 = s2;
}
static void adx_decode_stereo(int16_t *out,const uint8_t *in,
ADXChannelState *prev)
{
short tmp[32*2];
int i;
adx_decode(tmp, in, prev);
adx_decode(tmp+32, in+18, prev+1);
for (i = 0; i < 32; i++) {
out[i*2 ] = tmp[i ];
out[i*2+1] = tmp[i+32];
}
}
/**
* Decode stream header.
*
* @param avctx codec context
* @param buf packet data
* @param bufsize packet size
* @return data offset or negative error code if header is invalid
*/
static int adx_decode_header(AVCodecContext *avctx, const uint8_t *buf,
int bufsize)
{
int offset;
if (buf[0] != 0x80)
return AVERROR_INVALIDDATA;
offset = (AV_RB32(buf) ^ 0x80000000) + 4;
if (bufsize < offset || memcmp(buf + offset - 6, "(c)CRI", 6))
return AVERROR_INVALIDDATA;
avctx->channels = buf[7];
if (avctx->channels > 2)
return AVERROR_INVALIDDATA;
avctx->sample_rate = AV_RB32(buf + 8);
if (avctx->sample_rate < 1 ||
avctx->sample_rate > INT_MAX / (avctx->channels * 18 * 8))
return AVERROR_INVALIDDATA;
avctx->bit_rate = avctx->sample_rate * avctx->channels * 18 * 8 / 32;
return offset;
}
static int adx_decode_frame(AVCodecContext *avctx, void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf0 = avpkt->data;
int buf_size = avpkt->size;
ADXContext *c = avctx->priv_data;
int16_t *samples = data;
const uint8_t *buf = buf0;
int rest = buf_size;
if (!c->header_parsed) {
int hdrsize = adx_decode_header(avctx, buf, rest);
if (hdrsize < 0) {
av_log(avctx, AV_LOG_ERROR, "invalid stream header\n");
return hdrsize;
}
c->header_parsed = 1;
buf += hdrsize;
rest -= hdrsize;
}
/* 18 bytes of data are expanded into 32*2 bytes of audio,
so guard against buffer overflows */
if (rest / 18 > *data_size / 64)
rest = (*data_size / 64) * 18;
if (c->in_temp) {
int copysize = 18 * avctx->channels - c->in_temp;
memcpy(c->dec_temp + c->in_temp, buf, copysize);
rest -= copysize;
buf += copysize;
if (avctx->channels == 1) {
adx_decode(samples, c->dec_temp, c->prev);
samples += 32;
} else {
adx_decode_stereo(samples, c->dec_temp, c->prev);
samples += 32*2;
}
}
if (avctx->channels == 1) {
while (rest >= 18) {
adx_decode(samples, buf, c->prev);
rest -= 18;
buf += 18;
samples += 32;
}
} else {
while (rest >= 18 * 2) {
adx_decode_stereo(samples, buf, c->prev);
rest -= 18 * 2;
buf += 18 * 2;
samples += 32 * 2;
}
}
c->in_temp = rest;
if (rest) {
memcpy(c->dec_temp, buf, rest);
buf += rest;
}
*data_size = (uint8_t*)samples - (uint8_t*)data;
return buf - buf0;
}
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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