gecko/media/libopus/silk/control_SNR.c
Ralph Giles 3ae1b38243 Bug 916807 - Update opus to 1.1 prerelease. r=derf
Update our opus implementation to a prerelease of 1.1. This
brings many performance and encoder improvements and we believe
it is stable enough to switch. This import does not enable any
of the new assembly optimizations.

The imported code is https://git.xiph.org/opus.git master
commit f2446c25c6519bae190152f7a579310b83dc43fd.
2013-09-16 14:48:00 -07:00

82 lines
3.6 KiB
C

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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "main.h"
#include "tuning_parameters.h"
/* Control SNR of redidual quantizer */
opus_int silk_control_SNR(
silk_encoder_state *psEncC, /* I/O Pointer to Silk encoder state */
opus_int32 TargetRate_bps /* I Target max bitrate (bps) */
)
{
opus_int k, ret = SILK_NO_ERROR;
opus_int32 frac_Q6;
const opus_int32 *rateTable;
/* Set bitrate/coding quality */
TargetRate_bps = silk_LIMIT( TargetRate_bps, MIN_TARGET_RATE_BPS, MAX_TARGET_RATE_BPS );
if( TargetRate_bps != psEncC->TargetRate_bps ) {
psEncC->TargetRate_bps = TargetRate_bps;
/* If new TargetRate_bps, translate to SNR_dB value */
if( psEncC->fs_kHz == 8 ) {
rateTable = silk_TargetRate_table_NB;
} else if( psEncC->fs_kHz == 12 ) {
rateTable = silk_TargetRate_table_MB;
} else {
rateTable = silk_TargetRate_table_WB;
}
/* Reduce bitrate for 10 ms modes in these calculations */
if( psEncC->nb_subfr == 2 ) {
TargetRate_bps -= REDUCE_BITRATE_10_MS_BPS;
}
/* Find bitrate interval in table and interpolate */
for( k = 1; k < TARGET_RATE_TAB_SZ; k++ ) {
if( TargetRate_bps <= rateTable[ k ] ) {
frac_Q6 = silk_DIV32( silk_LSHIFT( TargetRate_bps - rateTable[ k - 1 ], 6 ),
rateTable[ k ] - rateTable[ k - 1 ] );
psEncC->SNR_dB_Q7 = silk_LSHIFT( silk_SNR_table_Q1[ k - 1 ], 6 ) + silk_MUL( frac_Q6, silk_SNR_table_Q1[ k ] - silk_SNR_table_Q1[ k - 1 ] );
break;
}
}
/* Reduce coding quality whenever LBRR is enabled, to free up some bits */
if( psEncC->LBRR_enabled ) {
psEncC->SNR_dB_Q7 = silk_SMLABB( psEncC->SNR_dB_Q7, 12 - psEncC->LBRR_GainIncreases, SILK_FIX_CONST( -0.25, 7 ) );
}
}
return ret;
}