libavcodec/dtsdec.c

   1 /*
   2  * dtsdec.c : free DTS Coherent Acoustics stream decoder.
   3  * Copyright (C) 2004 Benjamin Zores <ben@geexbox.org>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * FFmpeg 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
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avcodec.h"
  23 #include <dts.h>
  24
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #define BUFFER_SIZE 18726
  29 #define HEADER_SIZE 14
  30
  31 #ifdef LIBDTS_FIXED
  32 #define CONVERT_LEVEL (1 << 26)
  33 #define CONVERT_BIAS 0
  34 #else
  35 #define CONVERT_LEVEL 1
  36 #define CONVERT_BIAS 384
  37 #endif
  38
  39 typedef struct DTSContext {
  40     dts_state_t *state;
  41     uint8_t buf[BUFFER_SIZE];
  42     uint8_t *bufptr;
  43     uint8_t *bufpos;
  44 } DTSContext;
  45
  46 static inline int16_t
  47 convert(int32_t i)
  48 {
  49 #ifdef LIBDTS_FIXED
  50     i >>= 15;
  51 #else
  52     i -= 0x43c00000;
  53 #endif
  54     return (i > 32767) ? 32767 : ((i < -32768) ? -32768 : i);
  55 }
  56
  57 static void
  58 convert2s16_2(sample_t * _f, int16_t * s16)
  59 {
  60     int i;
  61     int32_t *f = (int32_t *) _f;
  62
  63     for(i = 0; i < 256; i++) {
  64         s16[2 * i] = convert(f[i]);
  65         s16[2 * i + 1] = convert(f[i + 256]);
  66     }
  67 }
  68
  69 static void
  70 convert2s16_4(sample_t * _f, int16_t * s16)
  71 {
  72     int i;
  73     int32_t *f = (int32_t *) _f;
  74
  75     for(i = 0; i < 256; i++) {
  76         s16[4 * i] = convert(f[i]);
  77         s16[4 * i + 1] = convert(f[i + 256]);
  78         s16[4 * i + 2] = convert(f[i + 512]);
  79         s16[4 * i + 3] = convert(f[i + 768]);
  80     }
  81 }
  82
  83 static void
  84 convert2s16_5(sample_t * _f, int16_t * s16)
  85 {
  86     int i;
  87     int32_t *f = (int32_t *) _f;
  88
  89     for(i = 0; i < 256; i++) {
  90         s16[5 * i] = convert(f[i]);
  91         s16[5 * i + 1] = convert(f[i + 256]);
  92         s16[5 * i + 2] = convert(f[i + 512]);
  93         s16[5 * i + 3] = convert(f[i + 768]);
  94         s16[5 * i + 4] = convert(f[i + 1024]);
  95     }
  96 }
  97
  98 static void
  99 convert2s16_multi(sample_t * _f, int16_t * s16, int flags)
 100 {
 101     int i;
 102     int32_t *f = (int32_t *) _f;
 103
 104     switch (flags) {
 105     case DTS_MONO:
 106         for(i = 0; i < 256; i++) {
 107             s16[5 * i] = s16[5 * i + 1] = s16[5 * i + 2] = s16[5 * i + 3] =
 108                 0;
 109             s16[5 * i + 4] = convert(f[i]);
 110         }
 111         break;
 112     case DTS_CHANNEL:
 113     case DTS_STEREO:
 114     case DTS_DOLBY:
 115         convert2s16_2(_f, s16);
 116         break;
 117     case DTS_3F:
 118         for(i = 0; i < 256; i++) {
 119             s16[5 * i] = convert(f[i]);
 120             s16[5 * i + 1] = convert(f[i + 512]);
 121             s16[5 * i + 2] = s16[5 * i + 3] = 0;
 122             s16[5 * i + 4] = convert(f[i + 256]);
 123         }
 124         break;
 125     case DTS_2F2R:
 126         convert2s16_4(_f, s16);
 127         break;
 128     case DTS_3F2R:
 129         convert2s16_5(_f, s16);
 130         break;
 131     case DTS_MONO | DTS_LFE:
 132         for(i = 0; i < 256; i++) {
 133             s16[6 * i] = s16[6 * i + 1] = s16[6 * i + 2] = s16[6 * i + 3] =
 134                 0;
 135             s16[6 * i + 4] = convert(f[i + 256]);
 136             s16[6 * i + 5] = convert(f[i]);
 137         }
 138         break;
 139     case DTS_CHANNEL | DTS_LFE:
 140     case DTS_STEREO | DTS_LFE:
 141     case DTS_DOLBY | DTS_LFE:
 142         for(i = 0; i < 256; i++) {
 143             s16[6 * i] = convert(f[i + 256]);
 144             s16[6 * i + 1] = convert(f[i + 512]);
 145             s16[6 * i + 2] = s16[6 * i + 3] = s16[6 * i + 4] = 0;
 146             s16[6 * i + 5] = convert(f[i]);
 147         }
 148         break;
 149     case DTS_3F | DTS_LFE:
 150         for(i = 0; i < 256; i++) {
 151             s16[6 * i] = convert(f[i + 256]);
 152             s16[6 * i + 1] = convert(f[i + 768]);
 153             s16[6 * i + 2] = s16[6 * i + 3] = 0;
 154             s16[6 * i + 4] = convert(f[i + 512]);
 155             s16[6 * i + 5] = convert(f[i]);
 156         }
 157         break;
 158     case DTS_2F2R | DTS_LFE:
 159         for(i = 0; i < 256; i++) {
 160             s16[6 * i] = convert(f[i + 256]);
 161             s16[6 * i + 1] = convert(f[i + 512]);
 162             s16[6 * i + 2] = convert(f[i + 768]);
 163             s16[6 * i + 3] = convert(f[i + 1024]);
 164             s16[6 * i + 4] = 0;
 165             s16[6 * i + 5] = convert(f[i]);
 166         }
 167         break;
 168     case DTS_3F2R | DTS_LFE:
 169         for(i = 0; i < 256; i++) {
 170             s16[6 * i] = convert(f[i + 256]);
 171             s16[6 * i + 1] = convert(f[i + 768]);
 172             s16[6 * i + 2] = convert(f[i + 1024]);
 173             s16[6 * i + 3] = convert(f[i + 1280]);
 174             s16[6 * i + 4] = convert(f[i + 512]);
 175             s16[6 * i + 5] = convert(f[i]);
 176         }
 177         break;
 178     }
 179 }
 180
 181 static int
 182 channels_multi(int flags)
 183 {
 184     if(flags & DTS_LFE)
 185         return 6;
 186     else if(flags & 1)          /* center channel */
 187         return 5;
 188     else if((flags & DTS_CHANNEL_MASK) == DTS_2F2R)
 189         return 4;
 190     else
 191         return 2;
 192 }
 193
 194 static int
 195 dts_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
 196                  uint8_t * buff, int buff_size)
 197 {
 198     DTSContext *s = avctx->priv_data;
 199     uint8_t *start = buff;
 200     uint8_t *end = buff + buff_size;
 201     int16_t *out_samples = data;
 202     int sample_rate;
 203     int frame_length;
 204     int flags;
 205     int bit_rate;
 206     int len;
 207     level_t level;
 208     sample_t bias;
 209     int i;
 210
 211     *data_size = 0;
 212
 213     while(1) {
 214         int length;
 215
 216         len = end - start;
 217         if(!len)
 218             break;
 219         if(len > s->bufpos - s->bufptr)
 220             len = s->bufpos - s->bufptr;
 221         memcpy(s->bufptr, start, len);
 222         s->bufptr += len;
 223         start += len;
 224         if(s->bufptr != s->bufpos)
 225             return start - buff;
 226         if(s->bufpos != s->buf + HEADER_SIZE)
 227             break;
 228
 229         length = dts_syncinfo(s->state, s->buf, &flags, &sample_rate,
 230                               &bit_rate, &frame_length);
 231         if(!length) {
 232             av_log(NULL, AV_LOG_INFO, "skip\n");
 233             for(s->bufptr = s->buf; s->bufptr < s->buf + HEADER_SIZE - 1; s->bufptr++)
 234                 s->bufptr[0] = s->bufptr[1];
 235             continue;
 236         }
 237         s->bufpos = s->buf + length;
 238     }
 239
 240     flags = 2;              /* ???????????? */
 241     level = CONVERT_LEVEL;
 242     bias = CONVERT_BIAS;
 243
 244     flags |= DTS_ADJUST_LEVEL;
 245     if(dts_frame(s->state, s->buf, &flags, &level, bias)) {
 246         av_log(avctx, AV_LOG_ERROR, "dts_frame() failed\n");
 247         goto end;
 248     }
 249
 250     avctx->sample_rate = sample_rate;
 251     avctx->channels = channels_multi(flags);
 252     avctx->bit_rate = bit_rate;
 253
 254     for(i = 0; i < dts_blocks_num(s->state); i++) {
 255         int chans;
 256
 257         if(dts_block(s->state)) {
 258             av_log(avctx, AV_LOG_ERROR, "dts_block() failed\n");
 259             goto end;
 260         }
 261
 262         chans = channels_multi(flags);
 263         convert2s16_multi(dts_samples(s->state), out_samples,
 264                           flags & (DTS_CHANNEL_MASK | DTS_LFE));
 265
 266         out_samples += 256 * chans;
 267         *data_size += 256 * sizeof(int16_t) * chans;
 268     }
 269
 270 end:
 271     s->bufptr = s->buf;
 272     s->bufpos = s->buf + HEADER_SIZE;
 273     return start - buff;
 274 }
 275
 276 static int
 277 dts_decode_init(AVCodecContext * avctx)
 278 {
 279     DTSContext *s = avctx->priv_data;
 280     s->bufptr = s->buf;
 281     s->bufpos = s->buf + HEADER_SIZE;
 282     s->state = dts_init(0);
 283     if(s->state == NULL)
 284         return -1;
 285
 286     return 0;
 287 }
 288
 289 static int
 290 dts_decode_end(AVCodecContext * avctx)
 291 {
 292     DTSContext *s = avctx->priv_data;
 293     dts_free(s->state);
 294     return 0;
 295 }
 296
 297 AVCodec dts_decoder = {
 298     "dts",
 299     CODEC_TYPE_AUDIO,
 300     CODEC_ID_DTS,
 301     sizeof(DTSContext),
 302     dts_decode_init,
 303     NULL,
 304     dts_decode_end,
 305     dts_decode_frame,
 306 };