diff options
| author | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2023-12-02 02:52:19 +0300 |
|---|---|---|
| committer | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2023-12-02 02:52:19 +0300 |
| commit | 8a5b7f49524841d9bf39d76e957e7917d73a81aa (patch) | |
| tree | 71d4a919d9c64c521a6085afe459629cfb35c56f | |
| parent | c7bfc72d072dda08adb4f233a0cf84ee83b3a1a5 (diff) | |
Tuning the NLSF quant mu as a function of bitrate
| -rw-r--r-- | silk/process_NLSFs.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/silk/process_NLSFs.c b/silk/process_NLSFs.c index d1308095..8266eabb 100644 --- a/silk/process_NLSFs.c +++ b/silk/process_NLSFs.c @@ -53,8 +53,10 @@ void silk_process_NLSFs( /***********************/ /* Calculate mu values */ /***********************/ - /* NLSF_mu = 0.003 - 0.0015 * psEnc->speech_activity; */ - NLSF_mu_Q20 = silk_SMLAWB( SILK_FIX_CONST( 0.003, 20 ), SILK_FIX_CONST( -0.001, 28 ), psEncC->speech_activity_Q8 ); + /* NLSF_mu = base_mu - 0.0015 * psEnc->speech_activity; + where base_mu depends on the target SNR (empirical fit) */ + NLSF_mu_Q20 = silk_DIV32( SILK_FIX_CONST( 5., 20 ), silk_max_32( 300, psEncC->SNR_dB_Q7 - 300 ) ); + NLSF_mu_Q20 = silk_SMLAWB( NLSF_mu_Q20, SILK_FIX_CONST( -0.001, 28 ), psEncC->speech_activity_Q8 ); if( psEncC->nb_subfr == 2 ) { /* Multiply by 1.5 for 10 ms packets */ NLSF_mu_Q20 = silk_ADD_RSHIFT( NLSF_mu_Q20, NLSF_mu_Q20, 1 ); |