libMpegTPEnc/src/tpenc_adts.cpp

   1
   2 /* -----------------------------------------------------------------------------------------------------------
   3 Software License for The Fraunhofer FDK AAC Codec Library for Android
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  73 5.    CONTACT INFORMATION
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  75 Fraunhofer Institute for Integrated Circuits IIS
  76 Attention: Audio and Multimedia Departments - FDK AAC LL
  77 Am Wolfsmantel 33
  78 91058 Erlangen, Germany
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  80 www.iis.fraunhofer.de/amm
  81 amm-info@iis.fraunhofer.de
  82 ----------------------------------------------------------------------------------------------------------- */
  83
  84 /******************************** MPEG Audio Encoder **************************
  85
  86    Initial author:       Alex Groeschel
  87    contents/description: ADTS Transport Headers support
  88
  89 ******************************************************************************/
  90
  91 #include "tpenc_adts.h"
  92
  93
  94 #include "tpenc_lib.h"
  95 #include "tpenc_asc.h"
  96
  97
  98 int adtsWrite_CrcStartReg(
  99                                  HANDLE_ADTS pAdts,          /*!< pointer to adts stucture */
 100                                  HANDLE_FDK_BITSTREAM hBs,   /*!< handle to current bit buffer structure */
 101                                  int mBits                   /*!< number of bits in crc region */
 102                                 )
 103 {
 104   if (pAdts->protection_absent) {
 105     return 0;
 106   }
 107   return ( FDKcrcStartReg(&pAdts->crcInfo, hBs, mBits) );
 108 }
 109
 110 void adtsWrite_CrcEndReg(
 111                                 HANDLE_ADTS pAdts, /*!< pointer to adts crc info stucture */
 112                                 HANDLE_FDK_BITSTREAM hBs,   /*!< handle to current bit buffer structure */
 113                                 int reg                    /*!< crc region */
 114                                )
 115 {
 116   if (pAdts->protection_absent == 0)
 117   {
 118     FDKcrcEndReg(&pAdts->crcInfo, hBs, reg);
 119   }
 120 }
 121
 122 int adtsWrite_GetHeaderBits( HANDLE_ADTS hAdts )
 123 {
 124   int bits = 0;
 125
 126   if (hAdts->currentBlock == 0) {
 127     /* Static and variable header bits */
 128     bits = 56;
 129     if (!hAdts->protection_absent) {
 130       /* Add header/ single raw data block CRC bits */
 131       bits += 16;
 132       if (hAdts->num_raw_blocks>0) {
 133         /* Add bits of raw data block position markers */
 134         bits += (hAdts->num_raw_blocks)*16;
 135       }
 136     }
 137   }
 138   if (!hAdts->protection_absent && hAdts->num_raw_blocks>0) {
 139     /* Add raw data block CRC bits. Not really part of the header, put they cause bit overhead to be accounted. */
 140     bits += 16;
 141   }
 142
 143   hAdts->headerBits = bits;
 144
 145   return bits;
 146 }
 147
 148 INT adtsWrite_Init(HANDLE_ADTS hAdts, CODER_CONFIG *config)
 149 {
 150   /* Sanity checks */
 151   if ( config->nSubFrames < 1
 152     || config->nSubFrames > 4
 153     || (int)config->aot > 4
 154     || (int)config->aot < 1 ) {
 155     return -1;
 156   }
 157
 158   /* fixed header */
 159   if (config->flags & CC_MPEG_ID) {
 160     hAdts->mpeg_id = 0; /* MPEG 4 */
 161   } else {
 162     hAdts->mpeg_id = 1; /* MPEG 2 */
 163   }
 164   hAdts->layer=0;
 165   hAdts->protection_absent = ! (config->flags & CC_PROTECTION);
 166   hAdts->profile = ((int)config->aot) - 1;
 167   hAdts->sample_freq_index = getSamplingRateIndex(config->samplingRate);
 168   hAdts->sample_freq = config->samplingRate;
 169   hAdts->private_bit=0;
 170   hAdts->channel_mode = config->channelMode;
 171   hAdts->original=0;
 172   hAdts->home=0;
 173   /* variable header */
 174   hAdts->copyright_id=0;
 175   hAdts->copyright_start=0;
 176
 177   hAdts->num_raw_blocks=config->nSubFrames-1; /* 0 means 1 raw data block */
 178
 179   FDKcrcInit(&hAdts->crcInfo, 0x8005, 0xFFFF, 16);
 180
 181   hAdts->currentBlock = 0;
 182
 183
 184   return 0;
 185 }
 186
 187 int adtsWrite_EncodeHeader(HANDLE_ADTS hAdts,
 188                                  HANDLE_FDK_BITSTREAM hBitStream,
 189                                  int buffer_fullness,
 190                                  int frame_length)
 191 {
 192   INT crcIndex = 0;
 193
 194
 195   hAdts->headerBits = adtsWrite_GetHeaderBits(hAdts);
 196
 197   FDK_ASSERT(((frame_length+hAdts->headerBits)/8)<0x2000);      /*13 bit*/
 198   FDK_ASSERT(buffer_fullness<0x800);    /* 11 bit   */
 199
 200   if (!hAdts->protection_absent) {
 201     FDKcrcReset(&hAdts->crcInfo);
 202   }
 203
 204   if (hAdts->currentBlock == 0) {
 205     FDKresetBitbuffer(hBitStream, BS_WRITER);
 206   }
 207
 208   hAdts->subFrameStartBit = FDKgetValidBits(hBitStream);
 209
 210   /* Skip new header if this is raw data block 1..n */
 211   if (hAdts->currentBlock == 0)
 212   {
 213     FDKresetBitbuffer(hBitStream, BS_WRITER);
 214
 215     if (hAdts->num_raw_blocks == 0) {
 216       crcIndex = adtsWrite_CrcStartReg(hAdts, hBitStream, 0);
 217     }
 218
 219     /* fixed header */
 220     FDKwriteBits(hBitStream, 0xFFF, 12);
 221     FDKwriteBits(hBitStream, hAdts->mpeg_id, 1);
 222     FDKwriteBits(hBitStream, hAdts->layer, 2);
 223     FDKwriteBits(hBitStream, hAdts->protection_absent, 1);
 224     FDKwriteBits(hBitStream, hAdts->profile, 2);
 225     FDKwriteBits(hBitStream, hAdts->sample_freq_index, 4);
 226     FDKwriteBits(hBitStream, hAdts->private_bit, 1);
 227     FDKwriteBits(hBitStream, getChannelConfig(hAdts->channel_mode), 3);
 228     FDKwriteBits(hBitStream, hAdts->original, 1);
 229     FDKwriteBits(hBitStream, hAdts->home, 1);
 230     /* variable header */
 231     FDKwriteBits(hBitStream, hAdts->copyright_id, 1);
 232     FDKwriteBits(hBitStream, hAdts->copyright_start, 1);
 233     FDKwriteBits(hBitStream, (frame_length + hAdts->headerBits)>>3, 13);
 234     FDKwriteBits(hBitStream, buffer_fullness, 11);
 235     FDKwriteBits(hBitStream, hAdts->num_raw_blocks, 2);
 236
 237     if (!hAdts->protection_absent) {
 238       int i;
 239
 240       /* End header CRC portion for single raw data block and write dummy zero values for unknown fields. */
 241       if (hAdts->num_raw_blocks == 0) {
 242         adtsWrite_CrcEndReg(hAdts, hBitStream, crcIndex);
 243       } else {
 244         for (i=0; i<hAdts->num_raw_blocks; i++) {
 245           FDKwriteBits(hBitStream, 0, 16);
 246         }
 247       }
 248       FDKwriteBits(hBitStream, 0, 16);
 249     }
 250   } /* End of ADTS header */
 251
 252   return 0;
 253 }
 254
 255 void adtsWrite_EndRawDataBlock(HANDLE_ADTS hAdts,
 256                           HANDLE_FDK_BITSTREAM hBs,
 257                           int *pBits)
 258 {
 259   if (!hAdts->protection_absent) {
 260     FDK_BITSTREAM bsWriter;
 261
 262     FDKinitBitStream(&bsWriter, hBs->hBitBuf.Buffer, hBs->hBitBuf.bufSize, 0, BS_WRITER);
 263     FDKpushFor(&bsWriter, 56);
 264
 265     if (hAdts->num_raw_blocks == 0) {
 266       FDKwriteBits(&bsWriter, FDKcrcGetCRC(&hAdts->crcInfo), 16);
 267     } else {
 268       int distance;
 269
 270       /* Write CRC of current raw data block */
 271       FDKwriteBits(hBs, FDKcrcGetCRC(&hAdts->crcInfo), 16);
 272
 273       /* Write distance to current data block */
 274       if (hAdts->currentBlock < hAdts->num_raw_blocks) {
 275         FDKpushFor(&bsWriter, hAdts->currentBlock*16);
 276         distance = FDKgetValidBits(hBs) - (56 + (hAdts->num_raw_blocks)*16 + 16);
 277         FDKwriteBits(&bsWriter, distance>>3, 16);
 278       }
 279     }
 280     FDKsyncCache(&bsWriter);
 281   }
 282
 283   /* Write total frame lenth for multiple raw data blocks and header CRC */
 284   if (hAdts->num_raw_blocks > 0 && hAdts->currentBlock == hAdts->num_raw_blocks) {
 285     FDK_BITSTREAM bsWriter;
 286     int crcIndex = 0;
 287
 288     FDKinitBitStream(&bsWriter, hBs->hBitBuf.Buffer, hBs->hBitBuf.bufSize, 0, BS_WRITER);
 289
 290     if (!hAdts->protection_absent) {
 291       FDKcrcReset(&hAdts->crcInfo);
 292       crcIndex = FDKcrcStartReg(&hAdts->crcInfo, &bsWriter, 0);
 293     }
 294     /* Write total frame length */
 295     FDKpushFor(&bsWriter, 56-28+2);
 296     FDKwriteBits(&bsWriter, FDKgetValidBits(hBs)>>3, 13);
 297
 298     /* Write header CRC */
 299     if (!hAdts->protection_absent) {
 300       FDKpushFor(&bsWriter, 11+2 + (hAdts->num_raw_blocks)*16);
 301       FDKcrcEndReg(&hAdts->crcInfo, &bsWriter, crcIndex);
 302       FDKwriteBits(&bsWriter, FDKcrcGetCRC(&hAdts->crcInfo), 16);
 303     }
 304     FDKsyncCache(&bsWriter);
 305   }
 306
 307   /* Correct *pBits to reflect the amount of bits of the current subframe */
 308   *pBits -= hAdts->subFrameStartBit;
 309   if (!hAdts->protection_absent && hAdts->num_raw_blocks > 0) {
 310     /* Fixup CRC bits, since they come after each raw data block */
 311     *pBits += 16;
 312   }
 313   hAdts->currentBlock++;
 314 }
 315