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 SP/DIF",
  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 = AFMT_AC3;
 109   return 1;
 110 }
 111
 112 static int init(sh_audio_t *sh_audio)
 113 {
 114   /* Dolby AC3 passthrough:*/
 115   sample_t *a52_samples = a52_init(0);
 116   if(a52_samples == 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_SKIP_FRAME:
 138       ac3dts_fillbuff(sh); break; // skip AC3 frame
 139       return CONTROL_TRUE;
 140   }
 141   return CONTROL_UNKNOWN;
 142 }
 143
 144
 145 static int decode_audio(sh_audio_t *sh_audio,unsigned char *buf,int minlen,int maxlen)
 146 {
 147   int len = sh_audio->a_in_buffer_len;
 148
 149   if(len <= 0)
 150     if((len = ac3dts_fillbuff(sh_audio)) <= 0)
 151       return len; /*EOF*/
 152   sh_audio->a_in_buffer_len = 0;
 153
 154   if(isdts == 1)
 155   {
 156     return decode_audio_dts(sh_audio->a_in_buffer, len, buf);
 157   }
 158   else if(isdts == 0)
 159   {
 160     buf[0] = 0x72;
 161     buf[1] = 0xF8;
 162     buf[2] = 0x1F;
 163     buf[3] = 0x4E;
 164     buf[4] = 0x01; //(length) ? data_type : 0; /* & 0x1F; */
 165     buf[5] = 0x00;
 166     buf[6] = (len << 3) & 0xFF;
 167     buf[7] = (len >> 5) & 0xFF;
 168 #ifdef WORDS_BIGENDIAN
 169     memcpy(buf + 8, sh_audio->a_in_buffer, len);  // untested
 170 #else
 171     swab(sh_audio->a_in_buffer, buf + 8, len);
 172 #endif
 173     memset(buf + 8 + len, 0, 6144 - 8 - len);
 174
 175     return 6144;
 176   }
 177   else
 178     return -1;
 179 }
 180
 181
 182 static int DTS_SAMPLEFREQS[16] =
 183 {
 184   0,
 185   8000,
 186   16000,
 187   32000,
 188   64000,
 189   128000,
 190   11025,
 191   22050,
 192   44100,
 193   88200,
 194   176400,
 195   12000,
 196   24000,
 197   48000,
 198   96000,
 199   192000
 200 };
 201
 202 static int DTS_BITRATES[30] =
 203 {
 204   32000,
 205   56000,
 206   64000,
 207   96000,
 208   112000,
 209   128000,
 210   192000,
 211   224000,
 212   256000,
 213   320000,
 214   384000,
 215   448000,
 216   512000,
 217   576000,
 218   640000,
 219   768000,
 220   896000,
 221   1024000,
 222   1152000,
 223   1280000,
 224   1344000,
 225   1408000,
 226   1411200,
 227   1472000,
 228   1536000,
 229   1920000,
 230   2048000,
 231   3072000,
 232   3840000,
 233   4096000
 234 };
 235
 236 static int dts_decode_header(uint8_t *indata_ptr, int *rate, int *nblks, int *sfreq)
 237 {
 238   int ftype;
 239   int surp;
 240   int unknown_bit;
 241   int fsize;
 242   int amode;
 243
 244   if(((indata_ptr[0] << 24) | (indata_ptr[1] << 16) | (indata_ptr[2] << 8)
 245     | (indata_ptr[3])) != 0x7ffe8001)
 246     return -1;
 247
 248   ftype = indata_ptr[4] >> 7;
 249
 250   surp = (indata_ptr[4] >> 2) & 0x1f;
 251   surp = (surp + 1) % 32;
 252
 253   unknown_bit = (indata_ptr[4] >> 1) & 0x01;
 254
 255   *nblks = (indata_ptr[4] & 0x01) << 6 | (indata_ptr[5] >> 2);
 256   *nblks = *nblks + 1;
 257
 258   fsize = (indata_ptr[5] & 0x03) << 12 | (indata_ptr[6] << 4) | (indata_ptr[7] >> 4);
 259   fsize = fsize + 1;
 260
 261   amode = (indata_ptr[7] & 0x0f) << 2 | (indata_ptr[8] >> 6);
 262   *sfreq = (indata_ptr[8] >> 2) & 0x0f;
 263   *rate = (indata_ptr[8] & 0x03) << 3 | ((indata_ptr[9] >> 5) & 0x07);
 264
 265   if(ftype != 1)
 266   {
 267     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: Termination frames not handled, REPORT BUG\n");
 268     return -1;
 269   }
 270
 271   if(*sfreq != 13)
 272   {
 273     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: Only 48kHz supported, REPORT BUG\n");
 274     return -1;
 275   }
 276
 277   if((fsize > 8192) || (fsize < 96))
 278   {
 279     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: fsize: %d invalid, REPORT BUG\n", fsize);
 280     return -1;
 281   }
 282
 283   if(*nblks != 8 &&
 284     *nblks != 16 &&
 285     *nblks != 32 &&
 286     *nblks != 64 &&
 287     *nblks != 128 &&
 288     ftype == 1)
 289   {
 290     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: nblks %d not valid for normal frame, REPORT BUG\n", *nblks);
 291     return -1;
 292   }
 293
 294   return fsize;
 295 }
 296
 297 static int dts_syncinfo(uint8_t *indata_ptr, int *flags, int *sample_rate, int *bit_rate)
 298 {
 299   int nblks;
 300   int fsize;
 301   int rate;
 302   int sfreq;
 303
 304   fsize = dts_decode_header(indata_ptr, &rate, &nblks, &sfreq);
 305   if(fsize >= 0)
 306   {
 307     if(rate >= 0 && rate <= 29)
 308       *bit_rate = DTS_BITRATES[rate];
 309     else
 310       *bit_rate = 0;
 311     if(sfreq >= 1 && sfreq <= 15)
 312       *sample_rate = DTS_SAMPLEFREQS[sfreq];
 313     else
 314       *sample_rate = 0;
 315   }
 316   return fsize;
 317 }
 318
 319
 320 static int decode_audio_dts(unsigned char *indata_ptr, int len, unsigned char *buf)
 321 {
 322   int nblks;
 323   int fsize;
 324   int rate;
 325   int sfreq;
 326   int burst_len;
 327   int nr_samples;
 328
 329   fsize = dts_decode_header(indata_ptr, &rate, &nblks, &sfreq);
 330   if(fsize < 0)
 331     return -1;
 332
 333   burst_len = fsize * 8;
 334   nr_samples = nblks * 32;
 335
 336   buf[0] = 0x72; buf[1] = 0xf8; /* iec 61937     */
 337   buf[2] = 0x1f; buf[3] = 0x4e; /*  syncword     */
 338   switch(nr_samples)
 339   {
 340   case 512:
 341     buf[4] = 0x0b;      /* DTS-1 (512-sample bursts) */
 342     break;
 343   case 1024:
 344     buf[4] = 0x0c;      /* DTS-2 (1024-sample bursts) */
 345     break;
 346   case 2048:
 347     buf[4] = 0x0d;      /* DTS-3 (2048-sample bursts) */
 348     break;
 349   default:
 350     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: %d-sample bursts not supported\n", nr_samples);
 351     buf[4] = 0x00;
 352     break;
 353   }
 354   buf[5] = 0;                      /* ?? */
 355   buf[6] = (burst_len) & 0xff;
 356   buf[7] = (burst_len >> 8) & 0xff;
 357
 358   if(fsize + 8 > nr_samples * 2 * 2)
 359   {
 360     mp_msg(MSGT_DECAUDIO, MSGL_ERR, "DTS: more data than fits\n");
 361   }
 362 #ifdef WORDS_BIGENDIAN
 363   memcpy(&buf[8], indata_ptr, fsize);  // untested
 364 #else
 365   //TODO if fzise is odd, swab doesn't copy the last byte
 366   swab(indata_ptr, &buf[8], fsize);
 367 #endif
 368   memset(&buf[fsize + 8], 0, nr_samples * 2 * 2 - (fsize + 8));
 369
 370   return nr_samples * 2 * 2;
 371 }
 372 #endif