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186 lines
5.4 KiB
C
186 lines
5.4 KiB
C
/*
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* ADX ADPCM codecs
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* Copyright (c) 2001,2003 BERO
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "adx.h"
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#include "get_bits.h"
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/**
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* @file
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* SEGA CRI adx codecs.
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*
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* Reference documents:
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* http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
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* adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
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*/
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static av_cold int adx_decode_init(AVCodecContext *avctx)
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{
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ADXContext *c = avctx->priv_data;
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int ret, header_size;
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if (avctx->extradata_size >= 24) {
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if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
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avctx->extradata_size, &header_size,
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c->coeff)) < 0) {
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av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
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return AVERROR_INVALIDDATA;
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}
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c->channels = avctx->channels;
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c->header_parsed = 1;
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}
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avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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avcodec_get_frame_defaults(&c->frame);
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avctx->coded_frame = &c->frame;
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return 0;
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}
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/**
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* Decode 32 samples from 18 bytes.
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*
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* A 16-bit scalar value is applied to 32 residuals, which then have a
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* 2nd-order LPC filter applied to it to form the output signal for a single
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* channel.
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*/
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static int adx_decode(ADXContext *c, int16_t *out, const uint8_t *in, int ch)
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{
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ADXChannelState *prev = &c->prev[ch];
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GetBitContext gb;
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int scale = AV_RB16(in);
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int i;
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int s0, s1, s2, d;
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/* check if this is an EOF packet */
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if (scale & 0x8000)
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return -1;
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init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
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s1 = prev->s1;
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s2 = prev->s2;
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for (i = 0; i < BLOCK_SAMPLES; i++) {
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d = get_sbits(&gb, 4);
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s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
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s2 = s1;
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s1 = av_clip_int16(s0);
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*out = s1;
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out += c->channels;
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}
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prev->s1 = s1;
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prev->s2 = s2;
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return 0;
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}
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static int adx_decode_frame(AVCodecContext *avctx, void *data,
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int *got_frame_ptr, AVPacket *avpkt)
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{
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int buf_size = avpkt->size;
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ADXContext *c = avctx->priv_data;
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int16_t *samples;
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const uint8_t *buf = avpkt->data;
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int num_blocks, ch, ret;
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if (c->eof) {
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*got_frame_ptr = 0;
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return buf_size;
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}
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if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
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int header_size;
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if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
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c->coeff)) < 0) {
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av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
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return AVERROR_INVALIDDATA;
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}
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c->channels = avctx->channels;
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c->header_parsed = 1;
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if (buf_size < header_size)
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return AVERROR_INVALIDDATA;
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buf += header_size;
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buf_size -= header_size;
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}
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if (!c->header_parsed)
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return AVERROR_INVALIDDATA;
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/* calculate number of blocks in the packet */
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num_blocks = buf_size / (BLOCK_SIZE * c->channels);
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/* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
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packet */
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if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
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if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
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c->eof = 1;
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*got_frame_ptr = 0;
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return avpkt->size;
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}
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return AVERROR_INVALIDDATA;
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}
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/* get output buffer */
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c->frame.nb_samples = num_blocks * BLOCK_SAMPLES;
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if ((ret = avctx->get_buffer(avctx, &c->frame)) < 0) {
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av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return ret;
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}
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samples = (int16_t *)c->frame.data[0];
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while (num_blocks--) {
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for (ch = 0; ch < c->channels; ch++) {
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if (adx_decode(c, samples + ch, buf, ch)) {
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c->eof = 1;
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buf = avpkt->data + avpkt->size;
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break;
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}
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buf_size -= BLOCK_SIZE;
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buf += BLOCK_SIZE;
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}
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samples += BLOCK_SAMPLES * c->channels;
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}
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*got_frame_ptr = 1;
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*(AVFrame *)data = c->frame;
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return buf - avpkt->data;
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}
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static void adx_decode_flush(AVCodecContext *avctx)
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{
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ADXContext *c = avctx->priv_data;
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memset(c->prev, 0, sizeof(c->prev));
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c->eof = 0;
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}
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AVCodec ff_adpcm_adx_decoder = {
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.name = "adpcm_adx",
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.type = AVMEDIA_TYPE_AUDIO,
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.id = CODEC_ID_ADPCM_ADX,
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.priv_data_size = sizeof(ADXContext),
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.init = adx_decode_init,
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.decode = adx_decode_frame,
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.flush = adx_decode_flush,
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.capabilities = CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
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};
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