diff options
Diffstat (limited to 'libs/qm-dsp/dsp/rateconversion/Decimator.h')
| -rw-r--r-- | libs/qm-dsp/dsp/rateconversion/Decimator.h | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/libs/qm-dsp/dsp/rateconversion/Decimator.h b/libs/qm-dsp/dsp/rateconversion/Decimator.h index f8a113a0db..e3913f8722 100644 --- a/libs/qm-dsp/dsp/rateconversion/Decimator.h +++ b/libs/qm-dsp/dsp/rateconversion/Decimator.h @@ -15,12 +15,15 @@ #ifndef DECIMATOR_H #define DECIMATOR_H -class Decimator +/** + * Decimator carries out a fast downsample by a power-of-two + * factor. Only a limited number of factors are supported, from two to + * whatever getHighestSupportedFactor() returns. This is much faster + * than Resampler but has a worse signal-noise ratio. + */ +class Decimator { public: - void process( const double* src, double* dst ); - void process( const float* src, float* dst ); - /** * Construct a Decimator to operate on input blocks of length * inLength, with decimation factor decFactor. inLength should be @@ -34,11 +37,28 @@ public: Decimator( unsigned int inLength, unsigned int decFactor ); virtual ~Decimator(); + /** + * Process inLength samples (as supplied to constructor) from src + * and write inLength / decFactor samples to dst. Note that src + * and dst may be the same or overlap (an intermediate buffer is + * used). + */ + void process( const double* src, double* dst ); + + /** + * Process inLength samples (as supplied to constructor) from src + * and write inLength / decFactor samples to dst. Note that src + * and dst may be the same or overlap (an intermediate buffer is + * used). + */ + void process( const float* src, float* dst ); + int getFactor() const { return m_decFactor; } static int getHighestSupportedFactor() { return 8; } -private: void resetFilter(); + +private: void deInitialise(); void initialise( unsigned int inLength, unsigned int decFactor ); void doAntiAlias( const double* src, double* dst, unsigned int length ); @@ -55,8 +75,8 @@ private: double a[ 9 ]; double b[ 9 ]; - + double* decBuffer; }; -#endif // +#endif // |