diff options
Diffstat (limited to 'ffmpeg/libavcodec/adxdec.c')
| -rw-r--r-- | ffmpeg/libavcodec/adxdec.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/adxdec.c b/ffmpeg/libavcodec/adxdec.c new file mode 100644 index 0000000..7d7fe3a --- /dev/null +++ b/ffmpeg/libavcodec/adxdec.c @@ -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", + .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, + .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), + .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, + AV_SAMPLE_FMT_NONE }, +}; |