/* * Discworld II BMV audio decoder * Copyright (c) 2011 Konstantin Shishkov * * 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/channel_layout.h"#include "libavutil/common.h" #include "avcodec.h"#include "codec_internal.h"#include "decode.h" static const int bmv_aud_mults[16] = {    16512, 8256, 4128, 2064, 1032, 516, 258, 192, 129, 88, 64, 56, 48, 40, 36, 32}; static av_cold int bmv_aud_decode_init(AVCodecContext *avctx){    av_channel_layout_uninit(&avctx->ch_layout);    avctx->ch_layout      = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;    avctx->sample_fmt     = AV_SAMPLE_FMT_S16;     return 0;} static int bmv_aud_decode_frame(AVCodecContext *avctx, AVFrame *frame,                                int *got_frame_ptr, AVPacket *avpkt){    const uint8_t *buf = avpkt->data;    int buf_size = avpkt->size;    int blocks = 0, total_blocks, i;    int ret;    int16_t *output_samples;    int scale[2];     total_blocks = *buf++;    if (buf_size < total_blocks * 65 + 1) {        av_log(avctx, AV_LOG_ERROR, "expected %d bytes, got %d\n",               total_blocks * 65 + 1, buf_size);        return AVERROR_INVALIDDATA;    }     /* get output buffer */    frame->nb_samples = total_blocks * 32;    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)        return ret;    output_samples = (int16_t *)frame->data[0];     for (blocks = 0; blocks < total_blocks; blocks++) {        uint8_t code = *buf++;        code = (code >> 1) | (code << 7);        scale[0] = bmv_aud_mults[code & 0xF];        scale[1] = bmv_aud_mults[code >> 4];        for (i = 0; i < 32; i++) {            *output_samples++ = av_clip_int16((scale[0] * (int8_t)*buf++) >> 5);            *output_samples++ = av_clip_int16((scale[1] * (int8_t)*buf++) >> 5);        }    }     *got_frame_ptr = 1;     return buf_size;} const FFCodec ff_bmv_audio_decoder = {    .p.name         = "bmv_audio",    CODEC_LONG_NAME("Discworld II BMV audio"),    .p.type         = AVMEDIA_TYPE_AUDIO,    .p.id           = AV_CODEC_ID_BMV_AUDIO,    .init           = bmv_aud_decode_init,    FF_CODEC_DECODE_CB(bmv_aud_decode_frame),    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,};