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189 lines
5.6 KiB
189 lines
5.6 KiB
/* |
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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 "bitstream.h" |
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#include "internal.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 = ff_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_S16P; |
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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, int offset, |
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const uint8_t *in, int ch) |
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{ |
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ADXChannelState *prev = &c->prev[ch]; |
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BitstreamContext bc; |
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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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bitstream_init(&bc, in + 2, (BLOCK_SIZE - 2) * 8); |
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out += offset; |
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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 = bitstream_read_signed(&bc, 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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} |
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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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AVFrame *frame = data; |
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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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int samples_offset; |
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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 = ff_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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frame->nb_samples = num_blocks * BLOCK_SAMPLES; |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 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 **)frame->extended_data; |
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samples_offset = 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], samples_offset, 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_offset += BLOCK_SAMPLES; |
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} |
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*got_frame_ptr = 1; |
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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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.long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = AV_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 = AV_CODEC_CAP_DR1, |
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.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, |
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AV_SAMPLE_FMT_NONE }, |
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};
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