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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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4
silk/structs.h
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@ -150,7 +150,6 @@ typedef struct {
opus_int minInternal_fs_Hz; /* Minimum internal sampling frequency (Hz) */
opus_int desiredInternal_fs_Hz; /* Soft request for internal sampling frequency (Hz) */
opus_int fs_kHz; /* Internal sampling frequency (kHz) */
opus_int delay; /* Number of samples of delay to apply */
opus_int nb_subfr; /* Number of 5 ms subframes in a frame */
opus_int frame_length; /* Frame length (samples) */
opus_int subfr_length; /* Subframe length (samples) */
@ -194,7 +193,6 @@ typedef struct {
/* Input/output buffering */
opus_int16 inputBuf[ MAX_FRAME_LENGTH + 2 ]; /* Buffer containing input signal */
opus_int16 delayBuf[MAX_ENCODER_DELAY];
opus_int inputBufIx;
opus_int nFramesPerPacket;
opus_int nFramesEncoded; /* Number of frames analyzed in current packet */
@ -261,8 +259,6 @@ typedef struct {
opus_int32 exc_Q10[ MAX_FRAME_LENGTH ];
opus_int32 sLPC_Q14_buf[ MAX_LPC_ORDER ];
opus_int16 outBuf[ MAX_FRAME_LENGTH + 2 * MAX_SUB_FRAME_LENGTH ]; /* Buffer for output signal */
opus_int16 delayBuf[ MAX_DECODER_DELAY ]; /* Buffer for delaying the SILK output prior to resampling */
opus_int delay; /* How much decoder delay to add */
opus_int lagPrev; /* Previous Lag */
opus_int8 LastGainIndex; /* Previous gain index */
opus_int fs_kHz; /* Sampling frequency in kHz */