/*
  * 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 "internal.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)
 {
     avctx->channels       = 2;
     avctx->channel_layout = AV_CH_LAYOUT_STEREO;
     avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
 
     return 0;
 }
 
 static int bmv_aud_decode_frame(AVCodecContext *avctx, void *data,
                                 int *got_frame_ptr, AVPacket *avpkt)
 {
     AVFrame *frame     = data;
     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;
 }
 
 AVCodec ff_bmv_audio_decoder = {
     .name           = "bmv_audio",
     .long_name      = NULL_IF_CONFIG_SMALL("Discworld II BMV audio"),
     .type           = AVMEDIA_TYPE_AUDIO,
     .id             = AV_CODEC_ID_BMV_AUDIO,
     .init           = bmv_aud_decode_init,
     .decode         = bmv_aud_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };