New DTX that works in all modes (SILK/CELT/HYBRID)
[opus.git] / silk / HP_variable_cutoff.c
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27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31 #ifdef FIXED_POINT
32 #include "main_FIX.h"
33 #else
34 #include "main_FLP.h"
35 #endif
36 #include "tuning_parameters.h"
37
38 /* High-pass filter with cutoff frequency adaptation based on pitch lag statistics */
39 void silk_HP_variable_cutoff(
40     silk_encoder_state_Fxx          state_Fxx[]                         /* I/O  Encoder states                              */
41 )
42 {
43    opus_int   quality_Q15;
44    opus_int32 pitch_freq_Hz_Q16, pitch_freq_log_Q7, delta_freq_Q7;
45    silk_encoder_state *psEncC1 = &state_Fxx[ 0 ].sCmn;
46
47    /* Adaptive cutoff frequency: estimate low end of pitch frequency range */
48    if( psEncC1->prevSignalType == TYPE_VOICED ) {
49       /* difference, in log domain */
50       pitch_freq_Hz_Q16 = silk_DIV32_16( silk_LSHIFT( silk_MUL( psEncC1->fs_kHz, 1000 ), 16 ), psEncC1->prevLag );
51       pitch_freq_log_Q7 = silk_lin2log( pitch_freq_Hz_Q16 ) - ( 16 << 7 );
52
53       /* adjustment based on quality */
54       quality_Q15 = psEncC1->input_quality_bands_Q15[ 0 ];
55       pitch_freq_log_Q7 = silk_SMLAWB( pitch_freq_log_Q7, silk_SMULWB( silk_LSHIFT( -quality_Q15, 2 ), quality_Q15 ),
56             pitch_freq_log_Q7 - ( silk_lin2log( SILK_FIX_CONST( VARIABLE_HP_MIN_CUTOFF_HZ, 16 ) ) - ( 16 << 7 ) ) );
57
58       /* delta_freq = pitch_freq_log - psEnc->variable_HP_smth1; */
59       delta_freq_Q7 = pitch_freq_log_Q7 - silk_RSHIFT( psEncC1->variable_HP_smth1_Q15, 8 );
60       if( delta_freq_Q7 < 0 ) {
61          /* less smoothing for decreasing pitch frequency, to track something close to the minimum */
62          delta_freq_Q7 = silk_MUL( delta_freq_Q7, 3 );
63       }
64
65       /* limit delta, to reduce impact of outliers in pitch estimation */
66       delta_freq_Q7 = silk_LIMIT_32( delta_freq_Q7, -SILK_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ), SILK_FIX_CONST( VARIABLE_HP_MAX_DELTA_FREQ, 7 ) );
67
68       /* update smoother */
69       psEncC1->variable_HP_smth1_Q15 = silk_SMLAWB( psEncC1->variable_HP_smth1_Q15,
70             silk_SMULBB( psEncC1->speech_activity_Q8, delta_freq_Q7 ), SILK_FIX_CONST( VARIABLE_HP_SMTH_COEF1, 16 ) );
71
72       /* limit frequency range */
73       psEncC1->variable_HP_smth1_Q15 = silk_LIMIT_32( psEncC1->variable_HP_smth1_Q15,
74             silk_LSHIFT( silk_lin2log( VARIABLE_HP_MIN_CUTOFF_HZ ), 8 ),
75             silk_LSHIFT( silk_lin2log( VARIABLE_HP_MAX_CUTOFF_HZ ), 8 ) );
76    }
77 }