yading@10: /*
yading@10:  * Westwood SNDx codecs
yading@10:  * Copyright (c) 2005 Konstantin Shishkov
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 <stdint.h>
yading@10: 
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/common.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Westwood SNDx codecs
yading@10:  *
yading@10:  * Reference documents about VQA format and its audio codecs
yading@10:  * can be found here:
yading@10:  * http://www.multimedia.cx
yading@10:  */
yading@10: 
yading@10: static const int8_t ws_adpcm_4bit[] = {
yading@10:     -9, -8, -6, -5, -4, -3, -2, -1,
yading@10:      0,  1,  2,  3,  4,  5,  6,  8
yading@10: };
yading@10: 
yading@10: static av_cold int ws_snd_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     avctx->channels       = 1;
yading@10:     avctx->channel_layout = AV_CH_LAYOUT_MONO;
yading@10:     avctx->sample_fmt     = AV_SAMPLE_FMT_U8;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int ws_snd_decode_frame(AVCodecContext *avctx, void *data,
yading@10:                                int *got_frame_ptr, AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame     = data;
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size       = avpkt->size;
yading@10: 
yading@10:     int in_size, out_size, ret;
yading@10:     int sample = 128;
yading@10:     uint8_t *samples;
yading@10:     uint8_t *samples_end;
yading@10: 
yading@10:     if (!buf_size)
yading@10:         return 0;
yading@10: 
yading@10:     if (buf_size < 4) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     out_size = AV_RL16(&buf[0]);
yading@10:     in_size  = AV_RL16(&buf[2]);
yading@10:     buf += 4;
yading@10: 
yading@10:     if (in_size > buf_size) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /* get output buffer */
yading@10:     frame->nb_samples = out_size;
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10:     samples     = frame->data[0];
yading@10:     samples_end = samples + out_size;
yading@10: 
yading@10:     if (in_size == out_size) {
yading@10:         memcpy(samples, buf, out_size);
yading@10:         *got_frame_ptr = 1;
yading@10:         return buf_size;
yading@10:     }
yading@10: 
yading@10:     while (samples < samples_end && buf - avpkt->data < buf_size) {
yading@10:         int code, smp, size;
yading@10:         uint8_t count;
yading@10:         code  = *buf >> 6;
yading@10:         count = *buf & 0x3F;
yading@10:         buf++;
yading@10: 
yading@10:         /* make sure we don't write past the output buffer */
yading@10:         switch (code) {
yading@10:         case 0:  smp = 4 * (count + 1);                break;
yading@10:         case 1:  smp = 2 * (count + 1);                break;
yading@10:         case 2:  smp = (count & 0x20) ? 1 : count + 1; break;
yading@10:         default: smp = count + 1;                      break;
yading@10:         }
yading@10:         if (samples_end - samples < smp)
yading@10:             break;
yading@10: 
yading@10:         /* make sure we don't read past the input buffer */
yading@10:         size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1;
yading@10:         if ((buf - avpkt->data) + size > buf_size)
yading@10:             break;
yading@10: 
yading@10:         switch (code) {
yading@10:         case 0: /* ADPCM 2-bit */
yading@10:             for (count++; count > 0; count--) {
yading@10:                 code = *buf++;
yading@10:                 sample += ( code       & 0x3) - 2;
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:                 sample += ((code >> 2) & 0x3) - 2;
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:                 sample += ((code >> 4) & 0x3) - 2;
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:                 sample +=  (code >> 6)        - 2;
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:             }
yading@10:             break;
yading@10:         case 1: /* ADPCM 4-bit */
yading@10:             for (count++; count > 0; count--) {
yading@10:                 code = *buf++;
yading@10:                 sample += ws_adpcm_4bit[code & 0xF];
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:                 sample += ws_adpcm_4bit[code >> 4];
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:             }
yading@10:             break;
yading@10:         case 2: /* no compression */
yading@10:             if (count & 0x20) { /* big delta */
yading@10:                 int8_t t;
yading@10:                 t = count;
yading@10:                 t <<= 3;
yading@10:                 sample += t >> 3;
yading@10:                 sample = av_clip_uint8(sample);
yading@10:                 *samples++ = sample;
yading@10:             } else { /* copy */
yading@10:                 memcpy(samples, buf, smp);
yading@10:                 samples += smp;
yading@10:                 buf     += smp;
yading@10:                 sample = buf[-1];
yading@10:             }
yading@10:             break;
yading@10:         default: /* run */
yading@10:             memset(samples, sample, smp);
yading@10:             samples += smp;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     frame->nb_samples = samples - frame->data[0];
yading@10:     *got_frame_ptr    = 1;
yading@10: 
yading@10:     return buf_size;
yading@10: }
yading@10: 
yading@10: AVCodec ff_ws_snd1_decoder = {
yading@10:     .name           = "ws_snd1",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_WESTWOOD_SND1,
yading@10:     .init           = ws_snd_decode_init,
yading@10:     .decode         = ws_snd_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"),
yading@10: };