libavcodec/8svx.c

   1 /*
   2  * 8SVX audio decoder
   3  * Copyright (C) 2008 Jaikrishnan Menon
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * 8svx audio decoder
  25  * @author Jaikrishnan Menon
  26  *
  27  * supports: fibonacci delta encoding
  28  *         : exponential encoding
  29  */
  30
  31 #include "avcodec.h"
  32 #include "internal.h"
  33 #include "libavutil/common.h"
  34
  35 /** decoder context */
  36 typedef struct EightSvxContext {
  37     uint8_t fib_acc[2];
  38     const int8_t *table;
  39
  40     /* buffer used to store the whole first packet.
  41        data is only sent as one large packet */
  42     uint8_t *data[2];
  43     int data_size;
  44     int data_idx;
  45 } EightSvxContext;
  46
  47 static const int8_t fibonacci[16]   = { -34, -21, -13,  -8, -5, -3, -2, -1,
  48                                           0,   1,   2,   3,  5,  8, 13, 21 };
  49 static const int8_t exponential[16] = { -128, -64, -32, -16, -8, -4, -2, -1,
  50                                            0,   1,   2,   4,  8, 16, 32, 64 };
  51
  52 #define MAX_FRAME_SIZE 32768
  53
  54 /**
  55  * Delta decode the compressed values in src, and put the resulting
  56  * decoded samples in dst.
  57  *
  58  * @param[in,out] state starting value. it is saved for use in the next call.
  59  */
  60 static void delta_decode(uint8_t *dst, const uint8_t *src, int src_size,
  61                          uint8_t *state, const int8_t *table)
  62 {
  63     uint8_t val = *state;
  64
  65     while (src_size--) {
  66         uint8_t d = *src++;
  67         val = av_clip_uint8(val + table[d & 0xF]);
  68         *dst++ = val;
  69         val = av_clip_uint8(val + table[d >> 4]);
  70         *dst++ = val;
  71     }
  72
  73     *state = val;
  74 }
  75
  76 static void raw_decode(uint8_t *dst, const int8_t *src, int src_size)
  77 {
  78     while (src_size--)
  79         *dst++ = *src++ + 128;
  80 }
  81
  82 /** decode a frame */
  83 static int eightsvx_decode_frame(AVCodecContext *avctx, void *data,
  84                                  int *got_frame_ptr, AVPacket *avpkt)
  85 {
  86     EightSvxContext *esc = avctx->priv_data;
  87     AVFrame *frame       = data;
  88     int buf_size;
  89     int ch, ret;
  90     int is_compr = (avctx->codec_id != AV_CODEC_ID_PCM_S8_PLANAR);
  91
  92     /* for the first packet, copy data to buffer */
  93     if (avpkt->data) {
  94         int hdr_size  = is_compr ? 2 : 0;
  95         int chan_size = (avpkt->size - hdr_size * avctx->channels) / avctx->channels;
  96
  97         if (avpkt->size < hdr_size * avctx->channels) {
  98             av_log(avctx, AV_LOG_ERROR, "packet size is too small\n");
  99             return AVERROR(EINVAL);
 100         }
 101         if (esc->data[0]) {
 102             av_log(avctx, AV_LOG_ERROR, "unexpected data after first packet\n");
 103             return AVERROR(EINVAL);
 104         }
 105
 106         if (is_compr) {
 107         esc->fib_acc[0] = avpkt->data[1] + 128;
 108         if (avctx->channels == 2)
 109             esc->fib_acc[1] = avpkt->data[2+chan_size+1] + 128;
 110         }
 111
 112         esc->data_idx  = 0;
 113         esc->data_size = chan_size;
 114         if (!(esc->data[0] = av_malloc(chan_size)))
 115             return AVERROR(ENOMEM);
 116         if (avctx->channels == 2) {
 117             if (!(esc->data[1] = av_malloc(chan_size))) {
 118                 av_freep(&esc->data[0]);
 119                 return AVERROR(ENOMEM);
 120             }
 121         }
 122         memcpy(esc->data[0], &avpkt->data[hdr_size], chan_size);
 123         if (avctx->channels == 2)
 124             memcpy(esc->data[1], &avpkt->data[2*hdr_size+chan_size], chan_size);
 125     }
 126     if (!esc->data[0]) {
 127         av_log(avctx, AV_LOG_ERROR, "unexpected empty packet\n");
 128         return AVERROR(EINVAL);
 129     }
 130
 131     /* decode next piece of data from the buffer */
 132     buf_size = FFMIN(MAX_FRAME_SIZE, esc->data_size - esc->data_idx);
 133     if (buf_size <= 0) {
 134         *got_frame_ptr = 0;
 135         return avpkt->size;
 136     }
 137
 138     /* get output buffer */
 139     frame->nb_samples = buf_size * (is_compr + 1);
 140     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
 141         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 142         return ret;
 143     }
 144
 145     for (ch = 0; ch < avctx->channels; ch++) {
 146         if (is_compr) {
 147             delta_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
 148                          buf_size, &esc->fib_acc[ch], esc->table);
 149         } else {
 150             raw_decode(frame->data[ch], &esc->data[ch][esc->data_idx],
 151                        buf_size);
 152         }
 153     }
 154
 155     esc->data_idx += buf_size;
 156
 157     *got_frame_ptr = 1;
 158
 159     return avpkt->size;
 160 }
 161
 162 /** initialize 8svx decoder */
 163 static av_cold int eightsvx_decode_init(AVCodecContext *avctx)
 164 {
 165     EightSvxContext *esc = avctx->priv_data;
 166
 167     if (avctx->channels < 1 || avctx->channels > 2) {
 168         av_log(avctx, AV_LOG_ERROR, "8SVX does not support more than 2 channels\n");
 169         return AVERROR(EINVAL);
 170     }
 171
 172     switch(avctx->codec->id) {
 173         case AV_CODEC_ID_8SVX_FIB:
 174           esc->table = fibonacci;
 175           break;
 176         case AV_CODEC_ID_8SVX_EXP:
 177           esc->table = exponential;
 178           break;
 179         case AV_CODEC_ID_PCM_S8_PLANAR:
 180             break;
 181         default:
 182           return -1;
 183     }
 184     avctx->sample_fmt = AV_SAMPLE_FMT_U8P;
 185
 186     return 0;
 187 }
 188
 189 static av_cold int eightsvx_decode_close(AVCodecContext *avctx)
 190 {
 191     EightSvxContext *esc = avctx->priv_data;
 192
 193     av_freep(&esc->data[0]);
 194     av_freep(&esc->data[1]);
 195
 196     return 0;
 197 }
 198
 199 AVCodec ff_eightsvx_fib_decoder = {
 200   .name           = "8svx_fib",
 201   .type           = AVMEDIA_TYPE_AUDIO,
 202   .id             = AV_CODEC_ID_8SVX_FIB,
 203   .priv_data_size = sizeof (EightSvxContext),
 204   .init           = eightsvx_decode_init,
 205   .close          = eightsvx_decode_close,
 206   .decode         = eightsvx_decode_frame,
 207   .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
 208   .long_name      = NULL_IF_CONFIG_SMALL("8SVX fibonacci"),
 209   .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
 210                                                     AV_SAMPLE_FMT_NONE },
 211 };
 212
 213 AVCodec ff_eightsvx_exp_decoder = {
 214   .name           = "8svx_exp",
 215   .type           = AVMEDIA_TYPE_AUDIO,
 216   .id             = AV_CODEC_ID_8SVX_EXP,
 217   .priv_data_size = sizeof (EightSvxContext),
 218   .init           = eightsvx_decode_init,
 219   .close          = eightsvx_decode_close,
 220   .decode         = eightsvx_decode_frame,
 221   .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
 222   .long_name      = NULL_IF_CONFIG_SMALL("8SVX exponential"),
 223   .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
 224                                                     AV_SAMPLE_FMT_NONE },
 225 };
 226
 227 AVCodec ff_pcm_s8_planar_decoder = {
 228     .name           = "pcm_s8_planar",
 229     .type           = AVMEDIA_TYPE_AUDIO,
 230     .id             = AV_CODEC_ID_PCM_S8_PLANAR,
 231     .priv_data_size = sizeof(EightSvxContext),
 232     .init           = eightsvx_decode_init,
 233     .close          = eightsvx_decode_close,
 234     .decode         = eightsvx_decode_frame,
 235     .capabilities   = CODEC_CAP_DELAY | CODEC_CAP_DR1,
 236     .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 8-bit planar"),
 237     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_U8P,
 238                                                       AV_SAMPLE_FMT_NONE },
 239 };