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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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15
silk/decoder_set_fs.c
View file

@ -31,13 +31,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "main.h"
static const int dec_delay_matrix[3][5] = {
/*SILK API 8 12 16 24 48 */
/* 8 */ {3, 0, 2, 0, 0},
/*12 */ {0, 8, 5, 7, 5},
/*16 */ {0, 0, 8, 5, 5}
};
/* Set decoder sampling rate */
opus_int silk_decoder_set_fs(
silk_decoder_state *psDec, /* I/O Decoder state pointer */
@ -60,13 +53,9 @@ opus_int silk_decoder_set_fs(
opus_int16 temp_buf[ MAX_FRAME_LENGTH_MS * MAX_API_FS_KHZ ];
silk_resampler_state_struct temp_resampler_state;
/* New delay value */
psDec->delay = dec_delay_matrix[ rateID( silk_SMULBB( fs_kHz, 1000 ) ) ][ rateID( fs_API_Hz ) ];
silk_assert( psDec->delay <= MAX_DECODER_DELAY );
if( psDec->fs_kHz != fs_kHz && psDec->fs_kHz > 0 ) {
/* Initialize resampler for temporary resampling of outBuf data to the new internal sampling rate */
ret += silk_resampler_init( &temp_resampler_state, silk_SMULBB( psDec->fs_kHz, 1000 ), silk_SMULBB( fs_kHz, 1000 ) );
ret += silk_resampler_init( &temp_resampler_state, silk_SMULBB( psDec->fs_kHz, 1000 ), silk_SMULBB( fs_kHz, 1000 ), 0 );
/* Temporary resampling of outBuf data to the new internal sampling rate */
silk_memcpy( temp_buf, psDec->outBuf, psDec->frame_length * sizeof( opus_int16 ) );
@ -74,7 +63,7 @@ opus_int silk_decoder_set_fs(
}
/* Initialize the resampler for dec_API.c preparing resampling from fs_kHz to API_fs_Hz */
ret += silk_resampler_init( &psDec->resampler_state, silk_SMULBB( fs_kHz, 1000 ), fs_API_Hz );
ret += silk_resampler_init( &psDec->resampler_state, silk_SMULBB( fs_kHz, 1000 ), fs_API_Hz, 0 );
/* Correct resampler state by resampling buffered data from fs_kHz to API_fs_Hz */
ret += silk_resampler( &psDec->resampler_state, temp_buf, psDec->outBuf, frame_length );