interf_enc.c

ffmpeg源码分析

         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }

      /* add SID type information */
      if ( frame_type == TX_SID_UPDATE )
         *stream += 0x80;
      stream++;

      /* speech mode indication */
      *stream = ( unsigned char )speech_mode;

      /* don't shift at the end of the function */
      return 6;
   }
   else if ( mode == MR475 ) {
      mask = order_MR475;
      *stream = 0;

      for ( j = 5; j < 100; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR515 ) {
      mask = order_MR515;
      *stream = 0x8;

      for ( j = 5; j < 108; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR59 ) {
      mask = order_MR59;
      *stream = 0x10;

      for ( j = 5; j < 123; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR67 ) {
      mask = order_MR67;
      *stream = 0x18;

      for ( j = 5; j < 139; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR74 ) {
      mask = order_MR74;
      *stream = 0x20;

      for ( j = 5; j < 153; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR795 ) {
      mask = order_MR795;
      *stream = 0x28;

      for ( j = 5; j < 164; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR102 ) {
      mask = order_MR102;
      *stream = 0x30;

      for ( j = 5; j < 209; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }
   else if ( mode == MR122 ) {
      mask = order_MR122;
      *stream = 0x38;

      for ( j = 5; j < 249; j++ ) {
         if ( param[ * mask] & *( mask + 1 ) )
            *stream += 0x80;
         mask += 2;

         if ( j % 8 )
            *stream >>= 1;
         else
            stream++;
      }
   }

   /* shift remaining bits */
   *stream >>= ( 8 - j % 8 );
   return( (int)block_size[mode] );
}
#endif
#endif

/*
 * Sid_Sync_reset
 *
 *
 * Parameters:
 *    st                O: state structure
 *
 * Function:
 *    Initializes state memory
 *
 * Returns:
 *    void
 */
static void Sid_Sync_reset( enc_interface_State *st )
{
   st->sid_update_counter = 3;
   st->sid_handover_debt = 0;
   st->prev_ft = TX_SPEECH_GOOD;
}


/*
 * Encoder_Interface_Encode
 *
 *
 * Parameters:
 *    st                I: pointer to state structure
 *    mode              I: Speech Mode
 *    speech            I: Input speech
 *    serial            O: Output octet structure 3GPP or
 *                         ETSI serial stream
 *    force_speech      I: Force speech in DTX
 *
 * Function:
 *    Encoding and packing one frame of speech
 *
 * Returns:
 *    number of octets
 */
int Encoder_Interface_Encode( void *st, enum Mode mode, Word16 *speech,

#ifndef ETSI
      UWord8 *serial,

#else
      Word16 *serial,
#endif

      int force_speech )
{
   Word16 prm[PRMNO_MR122];   /* speech parameters, max size */
   const Word16 *homing;   /* pointer to homing frame */
   Word16 homing_size;   /* frame size for homing frame */


   enc_interface_State * s;
   enum TXFrameType txFrameType;   /* frame type */

   int i, noHoming = 0;


   /*
    * used encoder mode,
    * if used_mode == -1, force VAD on
    */
   enum Mode used_mode = -force_speech;


   s = ( enc_interface_State * )st;

    /*
     * Checks if all samples of the input frame matches the encoder
     * homing frame pattern, which is 0x0008 for all samples.
     */
   for ( i = 0; i < 160; i++ ) {
      noHoming = speech[i] ^ 0x0008;

      if ( noHoming )
         break;
   }

   if (noHoming){
      Speech_Encode_Frame( s->encoderState, mode, speech, prm, &used_mode );
   }
   else {
      switch ( mode ) {
         case MR122:
            homing = dhf_MR122;
            homing_size = 18;
            break;

         case MR102:
            homing = dhf_MR102;
            homing_size = 12;
            break;

         case MR795:
            homing = dhf_MR795;
            homing_size = 8;
            break;

         case MR74:
            homing = dhf_MR74;
            homing_size = 7;
            break;

         case MR67:
            homing = dhf_MR67;
            homing_size = 7;
            break;

         case MR59:
            homing = dhf_MR59;
            homing_size = 7;
            break;

         case MR515:
            homing = dhf_MR515;
            homing_size = 7;
            break;

         case MR475:
            homing = dhf_MR475;
            homing_size = 7;
            break;

         default:
            homing = NULL;
            homing_size = 0;
            break;
      }
      for( i = 0; i < homing_size; i++){
         prm[i] = homing[i];
      }
      /* rest of the parameters are zero */
      memset(&prm[homing_size], 0, (PRMNO_MR122 - homing_size) << 1);
      used_mode = mode;
   }
   if ( used_mode == MRDTX ) {
      s->sid_update_counter--;

      if ( s->prev_ft == TX_SPEECH_GOOD ) {
         txFrameType = TX_SID_FIRST;
         s->sid_update_counter = 3;
      }
      else {
         /* TX_SID_UPDATE or TX_NO_DATA */
         if ( ( s->sid_handover_debt > 0 ) && ( s->sid_update_counter > 2 ) ) {
              /*
               * ensure extra updates are properly delayed after
               * a possible SID_FIRST
               */
            txFrameType = TX_SID_UPDATE;
            s->sid_handover_debt--;
         }
         else {
            if ( s->sid_update_counter == 0 ) {
               txFrameType = TX_SID_UPDATE;
               s->sid_update_counter = 8;
            }
            else {
               txFrameType = TX_NO_DATA;
               used_mode = 15;
            }
         }
      }
   }
   else {
      s->sid_update_counter = 8;
      txFrameType = TX_SPEECH_GOOD;
   }
   s->prev_ft = txFrameType;

   if ( noHoming == 0 ) {
      Speech_Encode_Frame_reset( s->encoderState, s->dtx );
      Sid_Sync_reset( s );
   }

#ifndef ETSI
#ifdef IF2
   return Encoder3GPP( used_mode, prm, serial, txFrameType, mode );

#else
   return EncoderMMS( used_mode, prm, serial, txFrameType, mode );

#endif
#else

   Prm2Bits( used_mode, prm, &serial[1] );
   serial[0] = ( Word16 )txFrameType;
   serial[245] = ( Word16 )mode;
   return 500;
#endif

}


/*
 * Encoder_Interface_init
 *
 *
 * Parameters:
 *    dtx               I: DTX flag
 *
 * Function:
 *    Allocates state memory and initializes state memory
 *
 * Returns:
 *    pointer to encoder interface structure
 */
void * Encoder_Interface_init( int dtx )
{
   enc_interface_State * s;

   /* allocate memory */
   if ( ( s = ( enc_interface_State * ) malloc( sizeof( enc_interface_State ) ) ) ==
         NULL ) {
      fprintf( stderr, "Encoder_Interface_init: "
            "can not malloc state structure\n" );
      return NULL;
   }
   s->encoderState = Speech_Encode_Frame_init( dtx );
   Sid_Sync_reset( s );
   s->dtx = dtx;
   return s;
}


/*
 * DecoderInterfaceExit
 *
 *
 * Parameters:
 *    state             I: state structure
 *
 * Function:
 *    The memory used for state memory is freed
 *
 * Returns:
 *    Void
 */
void Encoder_Interface_exit( void *state )
{
   enc_interface_State * s;
   s = ( enc_interface_State * )state;

   /* free memory */
   Speech_Encode_Frame_exit( &s->encoderState );
   free( s );
   state = NULL;
}