libmpcodecs/ad_hwac3.c

   1
   2 // Reference: DOCS/tech/hwac3.txt !!!!!
   3
   4 /* DTS code based on "ac3/decode_dts.c" and "ac3/conversion.c" from "ogle 0.9"
   5    (see http://www.dtek.chalmers.se/~dvd/)
   6 */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <unistd.h>
  12
  13 #include "config.h"
  14 #ifdef USE_LIBA52
  15
  16 #include "mp_msg.h"
  17 #include "help_mp.h"
  18
  19 #include "ad_internal.h"
  20
  21 #include "liba52/a52.h"
  22
  23
  24 static int isdts = -1;
  25
  26 static ad_info_t info =
  27 {
  28   "AC3/DTS pass-through S/PDIF",
  29   "hwac3",
  30   "Nick Kurshev/Peter Schüller",
  31   "???",
  32   ""
  33 };
  34
  35 LIBAD_EXTERN(hwac3)
  36
  37
  38 static int dts_syncinfo(uint8_t *indata_ptr, int *flags, int *sample_rate, int *bit_rate);
  39 static int decode_audio_dts(unsigned char *indata_ptr, int len, unsigned char *buf);
  40
  41
  42 static int ac3dts_fillbuff(sh_audio_t *sh_audio)
  43 {
  44   int length = 0;
  45   int flags = 0;
  46   int sample_rate = 0;
  47   int bit_rate = 0;
  48
  49   sh_audio->a_in_buffer_len = 0;
  50   /* sync frame:*/
  51   while(1)
  52   {
  53     // DTS has a 10 byte header
  54     while(sh_audio->a_in_buffer_len < 10)
  55     {
  56       int c = demux_getc(sh_audio->ds);
  57       if(c<0)
  58         return -1; /* EOF*/
  59       sh_audio->a_in_buffer[sh_audio->a_in_buffer_len++] = c;
  60     }
  61
  62     length = dts_syncinfo(sh_audio->a_in_buffer, &flags, &sample_rate, &bit_rate);
  63     if(length >= 10)
  64     {
  65       if(isdts != 1)
  66       {
  67         mp_msg(MSGT_DECAUDIO, MSGL_STATUS, "hwac3: switched to DTS, %d bps, %d Hz\n", bit_rate, sample_rate);
  68         isdts = 1;
  69       }
  70       break;
  71     }
  72     length = a52_syncinfo(sh_audio->a_in_buffer, &flags, &sample_rate, &bit_rate);
  73     if(length >= 7 && length <= 3840)
  74     {
  75       if(isdts != 0)
  76       {
  77         mp_msg(MSGT_DECAUDIO, MSGL_STATUS, "hwac3: switched to AC3, %d bps, %d Hz\n", bit_rate, sample_rate);
  78         isdts = 0;
  79       }
  80       break; /* we're done.*/
  81     }
  82     /* bad file => resync*/
  83     memcpy(sh_audio->a_in_buffer, sh_audio->a_in_buffer + 1, 9);
  84     --sh_audio->a_in_buffer_len;
  85   }
  86   mp_msg(MSGT_DECAUDIO, MSGL_DBG2, "ac3dts: %s len=%d  flags=0x%X  %d Hz %d bit/s\n", isdts == 1 ? "DTS" : isdts == 0 ? "AC3" : "unknown", length, flags, sample_rate, bit_rate);
  87
  88   sh_audio->samplerate = sample_rate;
  89   sh_audio->i_bps = bit_rate / 8;
  90   demux_read_data(sh_audio->ds, sh_audio->a_in_buffer + 10, length - 10);
  91   sh_audio->a_in_buffer_len = length;
  92
  93   // TODO: is DTS also checksummed?
  94   if(isdts == 0 && crc16_block(sh_audio->a_in_buffer + 2, length - 2) != 0)
  95     mp_msg(MSGT_DECAUDIO, MSGL_STATUS, "a52: CRC check failed!  \n");
  96
  97   return length;
  98 }
  99
 100
 101 static int preinit(sh_audio_t *sh)
 102 {
 103   /* Dolby AC3 audio: */
 104   sh->audio_out_minsize = 128 * 32 * 2 * 2; // DTS seems to need more than AC3
 105   sh->audio_in_minsize = 8192;
 106   sh->channels = 2;
 107   sh->samplesize = 2;
 108   sh->sample_format = AF_FORMAT_AC3;
 109   return 1;
 110 }
 111
 112 static int init(sh_audio_t *sh_audio)
 113 {
 114   /* Dolby AC3 passthrough:*/
 115   a52_state_t *a52_state = a52_init(0);
 116   if(a52_state == NULL)
 117   {
 118     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "A52 init failed\n");
 119     return 0;
 120   }
 121   if(ac3dts_fillbuff(sh_audio) < 0)
 122   {
 123     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "AC3/DTS sync failed\n");
 124     return 0;
 125   }
 126   return 1;
 127 }
 128
 129 static void uninit(sh_audio_t *sh)
 130 {
 131 }
 132
 133 static int control(sh_audio_t *sh,int cmd,void* arg, ...)
 134 {
 135   switch(cmd)
 136   {
 137   case ADCTRL_RESYNC_STREAM:
 138   case ADCTRL_SKIP_FRAME:
 139       ac3dts_fillbuff(sh);
 140       return CONTROL_TRUE;
 141   }
 142   return CONTROL_UNKNOWN;
 143 }
 144
 145
 146 static int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen)
 147 {
 148   int len = sh_audio->a_in_buffer_len;
 149
 150   if(len <= 0)
 151     if((len = ac3dts_fillbuff(sh_audio)) <= 0)
 152       return len; /*EOF*/
 153   sh_audio->a_in_buffer_len = 0;
 154
 155   if(isdts == 1)
 156   {
 157     return decode_audio_dts(sh_audio->a_in_buffer, len, buf);
 158   }
 159   else if(isdts == 0)
 160   {
 161     buf[0] = 0x72;
 162     buf[1] = 0xF8;
 163     buf[2] = 0x1F;
 164     buf[3] = 0x4E;
 165     buf[4] = 0x01; //(length) ? data_type : 0; /* & 0x1F; */
 166     buf[5] = 0x00;
 167     buf[6] = (len << 3) & 0xFF;
 168     buf[7] = (len >> 5) & 0xFF;
 169 #ifdef WORDS_BIGENDIAN
 170     memcpy(buf + 8, sh_audio->a_in_buffer, len);  // untested
 171 #else
 172     swab(sh_audio->a_in_buffer, buf + 8, len);
 173 #endif
 174     memset(buf + 8 + len, 0, 6144 - 8 - len);
 175
 176     return 6144;
 177   }
 178   else
 179     return -1;
 180 }
 181
 182
 183 static int DTS_SAMPLEFREQS[16] =
 184 {
 185   0,
 186   8000,
 187   16000,
 188   32000,
 189   64000,
 190   128000,
 191   11025,
 192   22050,
 193   44100,
 194   88200,
 195   176400,
 196   12000,
 197   24000,
 198   48000,
 199   96000,
 200   192000
 201 };
 202
 203 static int DTS_BITRATES[30] =
 204 {
 205   32000,
 206   56000,
 207   64000,
 208   96000,
 209   112000,
 210   128000,
 211   192000,
 212   224000,
 213   256000,
 214   320000,
 215   384000,
 216   448000,
 217   512000,
 218   576000,
 219   640000,
 220   768000,
 221   896000,
 222   1024000,
 223   1152000,
 224   1280000,
 225   1344000,
 226   1408000,
 227   1411200,
 228   1472000,
 229   1536000,
 230   1920000,
 231   2048000,
 232   3072000,
 233   3840000,
 234   4096000
 235 };
 236
 237 static int dts_decode_header(uint8_t *indata_ptr, int *rate, int *nblks, int *sfreq)
 238 {
 239   int ftype;
 240   int surp;
 241   int unknown_bit;
 242   int fsize;
 243   int amode;
 244
 245   if(((indata_ptr[0] << 24) | (indata_ptr[1] << 16) | (indata_ptr[2] << 8)
 246     | (indata_ptr[3])) != 0x7ffe8001)
 247     return -1;
 248
 249   ftype = indata_ptr[4] >> 7;
 250
 251   surp = (indata_ptr[4] >> 2) & 0x1f;
 252   surp = (surp + 1) % 32;
 253
 254   unknown_bit = (indata_ptr[4] >> 1) & 0x01;
 255
 256   *nblks = (indata_ptr[4] & 0x01) << 6 | (indata_ptr[5] >> 2);
 257   *nblks = *nblks + 1;
 258
 259   fsize = (indata_ptr[5] & 0x03) << 12 | (indata_ptr[6] << 4) | (indata_ptr[7] >> 4);
 260   fsize = fsize + 1;
 261
 262   amode = (indata_ptr[7] & 0x0f) << 2 | (indata_ptr[8] >> 6);
 263   *sfreq = (indata_ptr[8] >> 2) & 0x0f;
 264   *rate = (indata_ptr[8] & 0x03) << 3 | ((indata_ptr[9] >> 5) & 0x07);
 265
 266   if(ftype != 1)
 267   {
 268     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: Termination frames not handled, REPORT BUG\n");
 269     return -1;
 270   }
 271
 272   if(*sfreq != 13)
 273   {
 274     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: Only 48kHz supported, REPORT BUG\n");
 275     return -1;
 276   }
 277
 278   if((fsize > 8192) || (fsize < 96))
 279   {
 280     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: fsize: %d invalid, REPORT BUG\n", fsize);
 281     return -1;
 282   }
 283
 284   if(*nblks != 8 &&
 285     *nblks != 16 &&
 286     *nblks != 32 &&
 287     *nblks != 64 &&
 288     *nblks != 128 &&
 289     ftype == 1)
 290   {
 291     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: nblks %d not valid for normal frame, REPORT BUG\n", *nblks);
 292     return -1;
 293   }
 294
 295   return fsize;
 296 }
 297
 298 static int dts_syncinfo(uint8_t *indata_ptr, int *flags, int *sample_rate, int *bit_rate)
 299 {
 300   int nblks;
 301   int fsize;
 302   int rate;
 303   int sfreq;
 304
 305   fsize = dts_decode_header(indata_ptr, &rate, &nblks, &sfreq);
 306   if(fsize >= 0)
 307   {
 308     if(rate >= 0 && rate <= 29)
 309       *bit_rate = DTS_BITRATES[rate];
 310     else
 311       *bit_rate = 0;
 312     if(sfreq >= 1 && sfreq <= 15)
 313       *sample_rate = DTS_SAMPLEFREQS[sfreq];
 314     else
 315       *sample_rate = 0;
 316   }
 317   return fsize;
 318 }
 319
 320
 321 static int decode_audio_dts(unsigned char *indata_ptr, int len, unsigned char *buf)
 322 {
 323   int nblks;
 324   int fsize;
 325   int rate;
 326   int sfreq;
 327   int burst_len;
 328   int nr_samples;
 329
 330   fsize = dts_decode_header(indata_ptr, &rate, &nblks, &sfreq);
 331   if(fsize < 0)
 332     return -1;
 333
 334   burst_len = fsize * 8;
 335   nr_samples = nblks * 32;
 336
 337   buf[0] = 0x72; buf[1] = 0xf8; /* iec 61937     */
 338   buf[2] = 0x1f; buf[3] = 0x4e; /*  syncword     */
 339   switch(nr_samples)
 340   {
 341   case 512:
 342     buf[4] = 0x0b;      /* DTS-1 (512-sample bursts) */
 343     break;
 344   case 1024:
 345     buf[4] = 0x0c;      /* DTS-2 (1024-sample bursts) */
 346     break;
 347   case 2048:
 348     buf[4] = 0x0d;      /* DTS-3 (2048-sample bursts) */
 349     break;
 350   default:
 351     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: %d-sample bursts not supported\n", nr_samples);
 352     buf[4] = 0x00;
 353     break;
 354   }
 355   buf[5] = 0;                      /* ?? */
 356   buf[6] = (burst_len) & 0xff;
 357   buf[7] = (burst_len >> 8) & 0xff;
 358
 359   if(fsize + 8 > nr_samples * 2 * 2)
 360   {
 361     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: more data than fits\n");
 362   }
 363 #ifdef WORDS_BIGENDIAN
 364   memcpy(&buf[8], indata_ptr, fsize);  // untested
 365 #else
 366   //TODO if fzise is odd, swab doesn't copy the last byte
 367   swab(indata_ptr, &buf[8], fsize);
 368   if (fsize & 1)
 369     buf[8+fsize] = indata_ptr[fsize];
 370 #endif
 371   memset(&buf[fsize + 8], 0, nr_samples * 2 * 2 - (fsize + 8));
 372
 373   return nr_samples * 2 * 2;
 374 }
 375 #endif