yading@10: /*
yading@10:  * ADX ADPCM codecs
yading@10:  * Copyright (c) 2001,2003 BERO
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "adx.h"
yading@10: #include "get_bits.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * SEGA CRI adx codecs.
yading@10:  *
yading@10:  * Reference documents:
yading@10:  * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
yading@10:  * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
yading@10:  */
yading@10: 
yading@10: static av_cold int adx_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     ADXContext *c = avctx->priv_data;
yading@10:     int ret, header_size;
yading@10: 
yading@10:     if (avctx->extradata_size >= 24) {
yading@10:         if ((ret = avpriv_adx_decode_header(avctx, avctx->extradata,
yading@10:                                             avctx->extradata_size, &header_size,
yading@10:                                             c->coeff)) < 0) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10:         c->channels      = avctx->channels;
yading@10:         c->header_parsed = 1;
yading@10:     }
yading@10: 
yading@10:     avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Decode 32 samples from 18 bytes.
yading@10:  *
yading@10:  * A 16-bit scalar value is applied to 32 residuals, which then have a
yading@10:  * 2nd-order LPC filter applied to it to form the output signal for a single
yading@10:  * channel.
yading@10:  */
yading@10: static int adx_decode(ADXContext *c, int16_t *out, int offset,
yading@10:                       const uint8_t *in, int ch)
yading@10: {
yading@10:     ADXChannelState *prev = &c->prev[ch];
yading@10:     GetBitContext gb;
yading@10:     int scale = AV_RB16(in);
yading@10:     int i;
yading@10:     int s0, s1, s2, d;
yading@10: 
yading@10:     /* check if this is an EOF packet */
yading@10:     if (scale & 0x8000)
yading@10:         return -1;
yading@10: 
yading@10:     init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8);
yading@10:     out += offset;
yading@10:     s1 = prev->s1;
yading@10:     s2 = prev->s2;
yading@10:     for (i = 0; i < BLOCK_SAMPLES; i++) {
yading@10:         d  = get_sbits(&gb, 4);
yading@10:         s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS;
yading@10:         s2 = s1;
yading@10:         s1 = av_clip_int16(s0);
yading@10:         *out++ = s1;
yading@10:     }
yading@10:     prev->s1 = s1;
yading@10:     prev->s2 = s2;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int adx_decode_frame(AVCodecContext *avctx, void *data,
yading@10:                             int *got_frame_ptr, AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame      = data;
yading@10:     int buf_size        = avpkt->size;
yading@10:     ADXContext *c       = avctx->priv_data;
yading@10:     int16_t **samples;
yading@10:     int samples_offset;
yading@10:     const uint8_t *buf  = avpkt->data;
yading@10:     const uint8_t *buf_end = buf + avpkt->size;
yading@10:     int num_blocks, ch, ret;
yading@10: 
yading@10:     if (c->eof) {
yading@10:         *got_frame_ptr = 0;
yading@10:         return buf_size;
yading@10:     }
yading@10: 
yading@10:     if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) {
yading@10:         int header_size;
yading@10:         if ((ret = avpriv_adx_decode_header(avctx, buf, buf_size, &header_size,
yading@10:                                             c->coeff)) < 0) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n");
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         }
yading@10:         c->channels      = avctx->channels;
yading@10:         c->header_parsed = 1;
yading@10:         if (buf_size < header_size)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         buf      += header_size;
yading@10:         buf_size -= header_size;
yading@10:     }
yading@10:     if (!c->header_parsed)
yading@10:         return AVERROR_INVALIDDATA;
yading@10: 
yading@10:     /* calculate number of blocks in the packet */
yading@10:     num_blocks = buf_size / (BLOCK_SIZE * c->channels);
yading@10: 
yading@10:     /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF
yading@10:        packet */
yading@10:     if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) {
yading@10:         if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) {
yading@10:             c->eof = 1;
yading@10:             *got_frame_ptr = 0;
yading@10:             return avpkt->size;
yading@10:         }
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /* get output buffer */
yading@10:     frame->nb_samples = num_blocks * BLOCK_SAMPLES;
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10:     samples = (int16_t **)frame->extended_data;
yading@10:     samples_offset = 0;
yading@10: 
yading@10:     while (num_blocks--) {
yading@10:         for (ch = 0; ch < c->channels; ch++) {
yading@10:             if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) {
yading@10:                 c->eof = 1;
yading@10:                 buf = avpkt->data + avpkt->size;
yading@10:                 break;
yading@10:             }
yading@10:             buf_size -= BLOCK_SIZE;
yading@10:             buf      += BLOCK_SIZE;
yading@10:         }
yading@10:         samples_offset += BLOCK_SAMPLES;
yading@10:     }
yading@10: 
yading@10:     *got_frame_ptr = 1;
yading@10: 
yading@10:     return buf - avpkt->data;
yading@10: }
yading@10: 
yading@10: static void adx_decode_flush(AVCodecContext *avctx)
yading@10: {
yading@10:     ADXContext *c = avctx->priv_data;
yading@10:     memset(c->prev, 0, sizeof(c->prev));
yading@10:     c->eof = 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_adpcm_adx_decoder = {
yading@10:     .name           = "adpcm_adx",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_ADPCM_ADX,
yading@10:     .priv_data_size = sizeof(ADXContext),
yading@10:     .init           = adx_decode_init,
yading@10:     .decode         = adx_decode_frame,
yading@10:     .flush          = adx_decode_flush,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"),
yading@10:     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,
yading@10:                                                       AV_SAMPLE_FMT_NONE },
yading@10: };