opus/silk/fixed/LTP_scale_ctrl_FIX.c
Koen Vos bf75c8ec4d SILK fixes following last codec WG meeting
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
2011-12-13 14:47:31 -05:00

53 lines
2.9 KiB
C

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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main_FIX.h"
/* Calculation of LTP state scaling */
void silk_LTP_scale_ctrl_FIX(
silk_encoder_state_FIX *psEnc, /* I/O encoder state */
silk_encoder_control_FIX *psEncCtrl, /* I/O encoder control */
opus_int condCoding /* I The type of conditional coding to use */
)
{
opus_int round_loss;
if( condCoding == CODE_INDEPENDENTLY ) {
/* Only scale if first frame in packet */
round_loss = psEnc->sCmn.PacketLoss_perc + psEnc->sCmn.nFramesPerPacket;
psEnc->sCmn.indices.LTP_scaleIndex = (opus_int8)silk_LIMIT(
silk_SMULWB( silk_SMULBB( round_loss, psEncCtrl->LTPredCodGain_Q7 ), SILK_FIX_CONST( 0.1, 9 ) ), 0, 2 );
} else {
/* Default is minimum scaling */
psEnc->sCmn.indices.LTP_scaleIndex = 0;
}
psEncCtrl->LTP_scale_Q14 = silk_LTPScales_table_Q14[ psEnc->sCmn.indices.LTP_scaleIndex ];
}