mirror of https://git.ffmpeg.org/ffmpeg.git
147 lines
4.3 KiB
C
147 lines
4.3 KiB
C
/*
|
|
* 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 = ff_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"),
|
|
};
|