SKP_int SKP_Silk_decode_frame(
SKP_Silk_decoder_state *psDec, /* I/O Pointer to Silk decoder state */
SKP_int16 pOut[], /* O Pointer to output speech frame */
SKP_int16 *pN, /* O Pointer to size of output frame */
const SKP_uint8 pCode[], /* I Pointer to payload */
const SKP_int nBytes, /* I Payload length */
SKP_int action, /* I Action from Jitter Buffer */
SKP_int *decBytes /* O Used bytes to decode this frame */
)
{
SKP_Silk_decoder_control sDecCtrl;
SKP_int L, fs_Khz_old, ret = 0;
SKP_int Pulses[ MAX_FRAME_LENGTH ];
L = psDec->frame_length;
sDecCtrl.LTP_scale_Q14 = 0;
/* Safety checks */
SKP_assert( L > 0 && L <= MAX_FRAME_LENGTH );
/********************************************/
/* Decode Frame if packet is not lost */
/********************************************/
*decBytes = 0;
if( action == 0 ) {
/********************************************/
/* Initialize arithmetic coder */
/********************************************/
fs_Khz_old = psDec->fs_kHz;
if( psDec->nFramesDecoded == 0 ) {
/* Initialize range decoder state */
SKP_Silk_range_dec_init( &psDec->sRC, pCode, nBytes );
}
/********************************************/
/* Decode parameters and pulse signal */
/********************************************/
SKP_Silk_decode_parameters( psDec, &sDecCtrl, Pulses, 1 );
if( psDec->sRC.error ) {
psDec->nBytesLeft = 0;
action = 1; /* PLC operation */
/* revert fs if changed in decode_parameters */
SKP_Silk_decoder_set_fs( psDec, fs_Khz_old );
/* Avoid crashing */
*decBytes = psDec->sRC.bufferLength;
if( psDec->sRC.error == RANGE_CODER_DEC_PAYLOAD_TOO_LONG ) {
ret = SKP_SILK_DEC_PAYLOAD_TOO_LARGE;
} else {
ret = SKP_SILK_DEC_PAYLOAD_ERROR;
}
} else {
*decBytes = psDec->sRC.bufferLength - psDec->nBytesLeft;
psDec->nFramesDecoded++;
/* Update lengths. Sampling frequency could have changed */
L = psDec->frame_length;
/********************************************************/
/* Run inverse NSQ */
/********************************************************/
SKP_Silk_decode_core( psDec, &sDecCtrl, pOut, Pulses );
/********************************************************/
/* Update PLC state */
/********************************************************/
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, action );
psDec->lossCnt = 0;
psDec->prev_sigtype = sDecCtrl.sigtype;
/* A frame has been decoded without errors */
psDec->first_frame_after_reset = 0;
}
}
/*************************************************************/
/* Generate Concealment frame if packet is lost, or corrupt */
/*************************************************************/
if( action == 1 ) {
/* Handle packet loss by extrapolation */
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, action );
}
/*************************/
/* Update output buffer. */
/*************************/
SKP_memcpy( psDec->outBuf, pOut, L * sizeof( SKP_int16 ) );
/****************************************************************/
/* Ensure smooth connection of extrapolated and good frames */
/****************************************************************/
SKP_Silk_PLC_glue_frames( psDec, &sDecCtrl, pOut, L );
/************************************************/
/* Comfort noise generation / estimation */
/************************************************/
SKP_Silk_CNG( psDec, &sDecCtrl, pOut , L );
/********************************************/
/* HP filter output */
/********************************************/
SKP_assert( ( ( psDec->fs_kHz == 12 ) && ( L % 3 ) == 0 ) ||
( ( psDec->fs_kHz != 12 ) && ( L % 2 ) == 0 ) );
SKP_Silk_biquad( pOut, psDec->HP_B, psDec->HP_A, psDec->HPState, pOut, L );
/********************************************/
/* set output frame length */
/********************************************/
*pN = ( SKP_int16 )L;
/* Update some decoder state variables */
psDec->lagPrev = sDecCtrl.pitchL[ NB_SUBFR - 1 ];
return ret;
}
SKP_int SKP_Silk_decode_frame(
SKP_Silk_decoder_state *psDec, /* I/O Pointer to Silk decoder state */
ec_dec *psRangeDec, /* I/O Compressor data structure */
SKP_int16 pOut[], /* O Pointer to output speech frame */
SKP_int32 *pN, /* O Pointer to size of output frame */
const SKP_int nBytes, /* I Payload length */
SKP_int lostFlag /* I 0: no loss, 1 loss, 2 decode fec */
)
{
SKP_Silk_decoder_control sDecCtrl;
SKP_int i, L, mv_len, ret = 0;
SKP_int8 flags;
SKP_int32 LBRR_symbol;
SKP_int pulses[ MAX_FRAME_LENGTH ];
TIC(DECODE_FRAME)
L = psDec->frame_length;
sDecCtrl.LTP_scale_Q14 = 0;
/* Safety checks */
SKP_assert( L > 0 && L <= MAX_FRAME_LENGTH );
/********************************************/
/* Decode Frame if packet is not lost */
/********************************************/
if( lostFlag != PACKET_LOST && psDec->nFramesDecoded == 0 ) {
/* First decoder call for this payload */
/* Decode VAD flags and LBRR flag */
flags = SKP_RSHIFT( psRangeDec->buf[ 0 ], 7 - psDec->nFramesPerPacket ) &
( SKP_LSHIFT( 1, psDec->nFramesPerPacket + 1 ) - 1 );
psDec->LBRR_flag = flags & 1;
for( i = psDec->nFramesPerPacket - 1; i >= 0 ; i-- ) {
flags = SKP_RSHIFT( flags, 1 );
psDec->VAD_flags[ i ] = flags & 1;
}
for( i = 0; i < psDec->nFramesPerPacket + 1; i++ ) {
ec_dec_icdf( psRangeDec, SKP_Silk_uniform2_iCDF, 8 );
}
/* Decode LBRR flags */
SKP_memset( psDec->LBRR_flags, 0, sizeof( psDec->LBRR_flags ) );
if( psDec->LBRR_flag ) {
if( psDec->nFramesPerPacket == 1 ) {
psDec->LBRR_flags[ 0 ] = 1;
} else {
LBRR_symbol = ec_dec_icdf( psRangeDec, SKP_Silk_LBRR_flags_iCDF_ptr[ psDec->nFramesPerPacket - 2 ], 8 ) + 1;
for( i = 0; i < psDec->nFramesPerPacket; i++ ) {
psDec->LBRR_flags[ i ] = SKP_RSHIFT( LBRR_symbol, i ) & 1;
}
}
}
if( lostFlag == DECODE_NORMAL ) {
/* Regular decoding: skip all LBRR data */
for( i = 0; i < psDec->nFramesPerPacket; i++ ) {
if( psDec->LBRR_flags[ i ] ) {
SKP_Silk_decode_indices( psDec, psRangeDec, i, 1 );
SKP_Silk_decode_pulses( psRangeDec, pulses, psDec->indices.signalType,
psDec->indices.quantOffsetType, psDec->frame_length );
}
}
}
}
if( lostFlag == DECODE_LBRR && psDec->LBRR_flags[ psDec->nFramesDecoded ] == 0 ) {
/* Treat absent LBRR data as lost frame */
lostFlag = PACKET_LOST;
psDec->nFramesDecoded++;
}
if( lostFlag != PACKET_LOST ) {
/*********************************************/
/* Decode quantization indices of side info */
/*********************************************/
TIC(decode_indices)
SKP_Silk_decode_indices( psDec, psRangeDec, psDec->nFramesDecoded, lostFlag );
TOC(decode_indices)
/*********************************************/
/* Decode quantization indices of excitation */
/*********************************************/
TIC(decode_pulses)
SKP_Silk_decode_pulses( psRangeDec, pulses, psDec->indices.signalType,
psDec->indices.quantOffsetType, psDec->frame_length );
TOC(decode_pulses)
/********************************************/
/* Decode parameters and pulse signal */
/********************************************/
TIC(decode_params)
SKP_Silk_decode_parameters( psDec, &sDecCtrl );
TOC(decode_params)
/* Update length. Sampling frequency may have changed */
L = psDec->frame_length;
/********************************************************/
/* Run inverse NSQ */
/********************************************************/
TIC(decode_core)
SKP_Silk_decode_core( psDec, &sDecCtrl, pOut, pulses );
TOC(decode_core)
/********************************************************/
/* Update PLC state */
/********************************************************/
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, 0 );
psDec->lossCnt = 0;
psDec->prevSignalType = psDec->indices.signalType;
SKP_assert( psDec->prevSignalType >= 0 && psDec->prevSignalType <= 2 );
/* A frame has been decoded without errors */
psDec->first_frame_after_reset = 0;
psDec->nFramesDecoded++;
} else {
/* Handle packet loss by extrapolation */
SKP_Silk_PLC( psDec, &sDecCtrl, pOut, L, 1 );
}
/*************************/
/* Update output buffer. */
/*************************/
SKP_assert( psDec->ltp_mem_length >= psDec->frame_length );
mv_len = psDec->ltp_mem_length - psDec->frame_length;
SKP_memmove( psDec->outBuf, &psDec->outBuf[ psDec->frame_length ], mv_len * sizeof(SKP_int16) );
SKP_memcpy( &psDec->outBuf[ mv_len ], pOut, psDec->frame_length * sizeof( SKP_int16 ) );
/****************************************************************/
/* Ensure smooth connection of extrapolated and good frames */
/****************************************************************/
SKP_Silk_PLC_glue_frames( psDec, &sDecCtrl, pOut, L );
/************************************************/
/* Comfort noise generation / estimation */
/************************************************/
SKP_Silk_CNG( psDec, &sDecCtrl, pOut, L );
/********************************************/
/* HP filter output */
/********************************************/
TIC(HP_out)
SKP_Silk_biquad_alt( pOut, psDec->HP_B, psDec->HP_A, psDec->HPState, pOut, L );
TOC(HP_out)
/* Update some decoder state variables */
psDec->lagPrev = sDecCtrl.pitchL[ psDec->nb_subfr - 1 ];
/********************************************/
/* set output frame length */
/********************************************/
*pN = ( SKP_int16 )L;
TOC(DECODE_FRAME)
return ret;
}
