0,0 → 1,187 |
/* |
* ADX ADPCM codecs |
* Copyright (c) 2001,2003 BERO |
* |
* This file is part of FFmpeg. |
* |
* FFmpeg 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. |
* |
* FFmpeg 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 FFmpeg; 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" |
#include "internal.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) { |
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; |
c->header_parsed = 1; |
} |
|
avctx->sample_fmt = AV_SAMPLE_FMT_S16P; |
|
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, int offset, |
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); |
out += offset; |
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; |
} |
prev->s1 = s1; |
prev->s2 = s2; |
|
return 0; |
} |
|
static int adx_decode_frame(AVCodecContext *avctx, void *data, |
int *got_frame_ptr, AVPacket *avpkt) |
{ |
AVFrame *frame = data; |
int buf_size = avpkt->size; |
ADXContext *c = avctx->priv_data; |
int16_t **samples; |
int samples_offset; |
const uint8_t *buf = avpkt->data; |
const uint8_t *buf_end = buf + avpkt->size; |
int num_blocks, ch, ret; |
|
if (c->eof) { |
*got_frame_ptr = 0; |
return buf_size; |
} |
|
if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) { |
int header_size; |
if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size, |
c->coeff)) < 0) { |
av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); |
return AVERROR_INVALIDDATA; |
} |
c->channels = avctx->channels; |
c->header_parsed = 1; |
if (buf_size < header_size) |
return AVERROR_INVALIDDATA; |
buf += header_size; |
buf_size -= header_size; |
} |
if (!c->header_parsed) |
return AVERROR_INVALIDDATA; |
|
/* calculate number of blocks in the packet */ |
num_blocks = buf_size / (BLOCK_SIZE * c->channels); |
|
/* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF |
packet */ |
if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) { |
if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) { |
c->eof = 1; |
*got_frame_ptr = 0; |
return avpkt->size; |
} |
return AVERROR_INVALIDDATA; |
} |
|
/* get output buffer */ |
frame->nb_samples = num_blocks * BLOCK_SAMPLES; |
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
return ret; |
samples = (int16_t **)frame->extended_data; |
samples_offset = 0; |
|
while (num_blocks--) { |
for (ch = 0; ch < c->channels; ch++) { |
if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) { |
c->eof = 1; |
buf = avpkt->data + avpkt->size; |
break; |
} |
buf_size -= BLOCK_SIZE; |
buf += BLOCK_SIZE; |
} |
samples_offset += BLOCK_SAMPLES; |
} |
|
*got_frame_ptr = 1; |
|
return buf - avpkt->data; |
} |
|
static void adx_decode_flush(AVCodecContext *avctx) |
{ |
ADXContext *c = avctx->priv_data; |
memset(c->prev, 0, sizeof(c->prev)); |
c->eof = 0; |
} |
|
AVCodec ff_adpcm_adx_decoder = { |
.name = "adpcm_adx", |
.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), |
.type = AVMEDIA_TYPE_AUDIO, |
.id = AV_CODEC_ID_ADPCM_ADX, |
.priv_data_size = sizeof(ADXContext), |
.init = adx_decode_init, |
.decode = adx_decode_frame, |
.flush = adx_decode_flush, |
.capabilities = CODEC_CAP_DR1, |
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, |
AV_SAMPLE_FMT_NONE }, |
}; |