/* Gain scalar quantization with hysteresis, uniform on log scale */
void SKP_Silk_gains_quant(
SKP_int8 ind[ MAX_NB_SUBFR ], /* O gain indices */
SKP_int32 gain_Q16[ MAX_NB_SUBFR ], /* I/O gains (quantized out) */
SKP_int8 *prev_ind, /* I/O last index in previous frame */
const SKP_int conditional, /* I first gain is delta coded if 1 */
const SKP_int nb_subfr /* I number of subframes */
)
{
SKP_int k, double_step_size_threshold;
for( k = 0; k < nb_subfr; k++ ) {
/* Add half of previous quantization error, convert to log scale, scale, floor() */
ind[ k ] = SKP_SMULWB( SCALE_Q16, SKP_Silk_lin2log( gain_Q16[ k ] ) - OFFSET );
/* Round towards previous quantized gain (hysteresis) */
if( ind[ k ] < *prev_ind ) {
ind[ k ]++;
}
ind[ k ] = SKP_max_int( ind[ k ], 0 );
/* Compute delta indices and limit */
if( k == 0 && conditional == 0 ) {
/* Full index */
ind[ k ] = SKP_LIMIT_int( ind[ k ], *prev_ind + MIN_DELTA_GAIN_QUANT, N_LEVELS_QGAIN - 1 );
*prev_ind = ind[ k ];
} else {
/* Delta index */
ind[ k ] = ind[ k ] - *prev_ind;
/* Double the quantization step size for large gain increases, so that the max gain level can be reached */
double_step_size_threshold = 2 * MAX_DELTA_GAIN_QUANT - N_LEVELS_QGAIN + *prev_ind;
if( ind[ k ] > double_step_size_threshold ) {
ind[ k ] = double_step_size_threshold + SKP_RSHIFT( ind[ k ] - double_step_size_threshold + 1, 1 );
}
ind[ k ] = SKP_LIMIT_int( ind[ k ], MIN_DELTA_GAIN_QUANT, MAX_DELTA_GAIN_QUANT );
/* Accumulate deltas */
if( ind[ k ] > double_step_size_threshold ) {
*prev_ind += SKP_LSHIFT( ind[ k ], 1 ) - double_step_size_threshold;
} else {
*prev_ind += ind[ k ];
}
/* Shift to make non-negative */
ind[ k ] -= MIN_DELTA_GAIN_QUANT;
}
/* Convert to linear scale and scale */
gain_Q16[ k ] = SKP_Silk_log2lin( SKP_min_32( SKP_SMULWB( INV_SCALE_Q16, *prev_ind ) + OFFSET, 3967 ) ); /* 3967 = 31 in Q7 */
}
}
/* Low Bitrate Redundancy (LBRR) encoding. Reuse all parameters but encode with lower bitrate */
void SKP_Silk_LBRR_encode_FLP(
SKP_Silk_encoder_state_FLP *psEnc, /* I/O Encoder state FLP */
SKP_Silk_encoder_control_FLP *psEncCtrl, /* I/O Encoder control FLP */
SKP_uint8 *pCode, /* O Payload */
SKP_int16 *pnBytesOut, /* I/O Payload bytes; in: max; out: used */
const SKP_float xfw[] /* I Input signal */
)
{
SKP_int32 Gains_Q16[ NB_SUBFR ];
SKP_int k, TempGainsIndices[ NB_SUBFR ], frame_terminator;
SKP_int nBytes, nFramesInPayloadBuf;
SKP_float TempGains[ NB_SUBFR ];
SKP_int typeOffset, LTP_scaleIndex, Rate_only_parameters = 0;
/* Control use of inband LBRR */
SKP_Silk_LBRR_ctrl_FLP( psEnc, &psEncCtrl->sCmn );
if( psEnc->sCmn.LBRR_enabled ) {
/* Save original gains */
SKP_memcpy( TempGainsIndices, psEncCtrl->sCmn.GainsIndices, NB_SUBFR * sizeof( SKP_int ) );
SKP_memcpy( TempGains, psEncCtrl->Gains, NB_SUBFR * sizeof( SKP_float ) );
typeOffset = psEnc->sCmn.typeOffsetPrev; // Temp save as cannot be overwritten
LTP_scaleIndex = psEncCtrl->sCmn.LTP_scaleIndex;
/* Set max rate where quant signal is encoded */
if( psEnc->sCmn.fs_kHz == 8 ) {
Rate_only_parameters = 13500;
} else if( psEnc->sCmn.fs_kHz == 12 ) {
Rate_only_parameters = 15500;
} else if( psEnc->sCmn.fs_kHz == 16 ) {
Rate_only_parameters = 17500;
} else if( psEnc->sCmn.fs_kHz == 24 ) {
Rate_only_parameters = 19500;
} else {
SKP_assert( 0 );
}
if( psEnc->sCmn.Complexity > 0 && psEnc->sCmn.TargetRate_bps > Rate_only_parameters ) {
if( psEnc->sCmn.nFramesInPayloadBuf == 0 ) {
/* First frame in packet copy everything */
SKP_memcpy( &psEnc->sCmn.sNSQ_LBRR, &psEnc->sCmn.sNSQ, sizeof( SKP_Silk_nsq_state ) );
psEnc->sCmn.LBRRprevLastGainIndex = psEnc->sShape.LastGainIndex;
/* Increase Gains to get target LBRR rate */
psEncCtrl->sCmn.GainsIndices[ 0 ] += psEnc->sCmn.LBRR_GainIncreases;
psEncCtrl->sCmn.GainsIndices[ 0 ] = SKP_LIMIT_int( psEncCtrl->sCmn.GainsIndices[ 0 ], 0, N_LEVELS_QGAIN - 1 );
}
/* Decode to get gains in sync with decoder */
SKP_Silk_gains_dequant( Gains_Q16, psEncCtrl->sCmn.GainsIndices,
&psEnc->sCmn.LBRRprevLastGainIndex, psEnc->sCmn.nFramesInPayloadBuf );
/* Overwrite unquantized gains with quantized gains and convert back to Q0 from Q16 */
for( k = 0; k < NB_SUBFR; k++ ) {
psEncCtrl->Gains[ k ] = Gains_Q16[ k ] / 65536.0f;
}
/*****************************************/
/* Noise shaping quantization */
/*****************************************/
SKP_Silk_NSQ_wrapper_FLP( psEnc, psEncCtrl, xfw, psEnc->sCmn.q_LBRR, 1 );
} else {
SKP_memset( psEnc->sCmn.q_LBRR, 0, psEnc->sCmn.frame_length * sizeof( SKP_int8 ) );
psEncCtrl->sCmn.LTP_scaleIndex = 0;
}
/****************************************/
/* Initialize arithmetic coder */
/****************************************/
if( psEnc->sCmn.nFramesInPayloadBuf == 0 ) {
SKP_Silk_range_enc_init( &psEnc->sCmn.sRC_LBRR );
psEnc->sCmn.nBytesInPayloadBuf = 0;
}
/****************************************/
/* Encode Parameters */
/****************************************/
SKP_Silk_encode_parameters( &psEnc->sCmn, &psEncCtrl->sCmn, &psEnc->sCmn.sRC_LBRR, psEnc->sCmn.q_LBRR );
if( psEnc->sCmn.sRC_LBRR.error ) {
/* Encoder returned error: Clear payload buffer */
nFramesInPayloadBuf = 0;
} else {
nFramesInPayloadBuf = psEnc->sCmn.nFramesInPayloadBuf + 1;
}
/****************************************/
/* Finalize payload and copy to output */
/****************************************/
if( nFramesInPayloadBuf * FRAME_LENGTH_MS >= psEnc->sCmn.PacketSize_ms ) {
/* Check if FEC information should be added */
frame_terminator = SKP_SILK_LAST_FRAME;
/* Add the frame termination info to stream */
SKP_Silk_range_encoder( &psEnc->sCmn.sRC_LBRR, frame_terminator, SKP_Silk_FrameTermination_CDF );
/* Payload length so far */
SKP_Silk_range_coder_get_length( &psEnc->sCmn.sRC_LBRR, &nBytes );
/* Check that there is enough space in external output buffer and move data */
if( *pnBytesOut >= nBytes ) {
SKP_Silk_range_enc_wrap_up( &psEnc->sCmn.sRC_LBRR );
SKP_memcpy( pCode, psEnc->sCmn.sRC_LBRR.buffer, nBytes * sizeof( SKP_uint8 ) );
*pnBytesOut = nBytes;
} else {
/* Not enough space: Payload will be discarded */
*pnBytesOut = 0;
SKP_assert( 0 );
}
} else {
/* No payload this time */
*pnBytesOut = 0;
/* Encode that more frames follows */
frame_terminator = SKP_SILK_MORE_FRAMES;
SKP_Silk_range_encoder( &psEnc->sCmn.sRC_LBRR, frame_terminator, SKP_Silk_FrameTermination_CDF );
}
/* Restore original Gains */
SKP_memcpy( psEncCtrl->sCmn.GainsIndices, TempGainsIndices, NB_SUBFR * sizeof( SKP_int ) );
SKP_memcpy( psEncCtrl->Gains, TempGains, NB_SUBFR * sizeof( SKP_float ) );
/* Restore LTP scale index and typeoffset */
psEncCtrl->sCmn.LTP_scaleIndex = LTP_scaleIndex;
psEnc->sCmn.typeOffsetPrev = typeOffset;
}
}
