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SILK fixes following last codec WG meeting

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decoder:
- fixed incorrect scaling of filter states for the smallest quantization
  step sizes
- NLSF2A now limits the prediction gain of LPC filters

encoder:
- increased damping of LTP coefficients in LTP analysis
- increased white noise fraction in noise shaping LPC analysis
- introduced maximum total prediction gain.  Used by Burg's method to
  exit early if prediction gain is exceeded.  This improves packet
  loss robustness and numerical robustness in Burg's method
- Prefiltered signal is now in int32 Q10 domain, from int16 Q0
- Increased max number of iterations in CBR gain control loop from 5 to 6
- Removed useless code from LTP scaling control
- Optimization: smarter LPC loop unrolling
- Switched default win32 compile mode to be floating-point

resampler:
- made resampler have constant delay of 0.75 ms; removed delay
  compensation from silk code.
- removed obsolete table entries (~850 Bytes)
- increased downsampling filter order from 16 to 18/24/36 (depending on
  frequency ratio)
- reoptimized filter coefficients
This commit is contained in:
Koen Vos 2011-12-13 14:47:31 -05:00 • committed by Jean-Marc Valin
parent 6619a73637
commit bf75c8ec4d
71 changed files with 961 additions and 1005 deletions
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10
silk/NLSF_encode.c
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@ -79,7 +79,7 @@ opus_int32 silk_NLSF_encode( /* O Returns
/* Residual after first stage */
pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ ind1 * psNLSF_CB->order ];
for( i = 0; i < psNLSF_CB->order; i++ ) {
NLSF_tmp_Q15[ i ] = silk_LSHIFT16( ( opus_int16 )pCB_element[ i ], 7 );
NLSF_tmp_Q15[ i ] = silk_LSHIFT16( (opus_int16)pCB_element[ i ], 7 );
res_Q15[ i ] = pNLSF_Q15[ i ] - NLSF_tmp_Q15[ i ];
}
@ -88,13 +88,13 @@ opus_int32 silk_NLSF_encode( /* O Returns
/* Apply square-rooted weights */
for( i = 0; i < psNLSF_CB->order; i++ ) {
W_tmp_Q9 = silk_SQRT_APPROX( silk_LSHIFT( ( opus_int32 )W_tmp_QW[ i ], 18 - NLSF_W_Q ) );
res_Q10[ i ] = ( opus_int16 )silk_RSHIFT( silk_SMULBB( res_Q15[ i ], W_tmp_Q9 ), 14 );
W_tmp_Q9 = silk_SQRT_APPROX( silk_LSHIFT( (opus_int32)W_tmp_QW[ i ], 18 - NLSF_W_Q ) );
res_Q10[ i ] = (opus_int16)silk_RSHIFT( silk_SMULBB( res_Q15[ i ], W_tmp_Q9 ), 14 );
}
/* Modify input weights accordingly */
for( i = 0; i < psNLSF_CB->order; i++ ) {
W_adj_Q5[ i ] = silk_DIV32_16( silk_LSHIFT( ( opus_int32 )pW_QW[ i ], 5 ), W_tmp_QW[ i ] );
W_adj_Q5[ i ] = silk_DIV32_16( silk_LSHIFT( (opus_int32)pW_QW[ i ], 5 ), W_tmp_QW[ i ] );
}
/* Unpack entropy table indices and predictor for current CB1 index */
@ -118,7 +118,7 @@ opus_int32 silk_NLSF_encode( /* O Returns
/* Find the lowest rate-distortion error */
silk_insertion_sort_increasing( RD_Q25, &bestIndex, nSurvivors, 1 );
NLSFIndices[ 0 ] = ( opus_int8 )tempIndices1[ bestIndex ];
NLSFIndices[ 0 ] = (opus_int8)tempIndices1[ bestIndex ];
silk_memcpy( &NLSFIndices[ 1 ], &tempIndices2[ bestIndex * MAX_LPC_ORDER ], psNLSF_CB->order * sizeof( opus_int8 ) );
/* Decode */