/* * 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 = ff_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 = ff_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;        }        if (!c->eof)            samples_offset += BLOCK_SAMPLES;    }     frame->nb_samples = samples_offset;    *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   = AV_CODEC_CAP_DR1,    .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P,                                                      AV_SAMPLE_FMT_NONE },};