-/************************************************************************/\r
+/************************************************************************/\r
/*! \class RtAudio\r
\brief Realtime audio i/o C++ classes.\r
\r
// In order to satisfy WASAPI's buffer requirements, we need a means of converting sample rate\r
// between HW and the user. The convertBufferWasapi function is used to perform this conversion\r
// between HwIn->UserIn and UserOut->HwOut during the stream callback loop.\r
-// This sample rate converter favors speed over quality, and works best with conversions between\r
-// one rate and its multiple.\r
+// This sample rate converter works best with conversions between one rate and its multiple.\r
void convertBufferWasapi( char* outBuffer,\r
const char* inBuffer,\r
const unsigned int& channelCount,\r
{\r
// calculate the new outSampleCount and relative sampleStep\r
float sampleRatio = ( float ) outSampleRate / inSampleRate;\r
+ float sampleRatioInv = ( float ) 1 / sampleRatio;\r
float sampleStep = 1.0f / sampleRatio;\r
float inSampleFraction = 0.0f;\r
\r
outSampleCount = ( unsigned int ) roundf( inSampleCount * sampleRatio );\r
\r
- // frame-by-frame, copy each relative input sample into it's corresponding output sample\r
- for ( unsigned int outSample = 0; outSample < outSampleCount; outSample++ )\r
+ // if inSampleRate is a multiple of outSampleRate (or vice versa) there's no need to interpolate\r
+ if ( floor( sampleRatio ) == sampleRatio || floor( sampleRatioInv ) == sampleRatioInv )\r
{\r
- unsigned int inSample = ( unsigned int ) inSampleFraction;\r
-\r
- switch ( format )\r
+ // frame-by-frame, copy each relative input sample into it's corresponding output sample\r
+ for ( unsigned int outSample = 0; outSample < outSampleCount; outSample++ )\r
{\r
- case RTAUDIO_SINT8:\r
- memcpy( &( ( char* ) outBuffer )[ outSample * channelCount ], &( ( char* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( char ) );\r
- break;\r
- case RTAUDIO_SINT16:\r
- memcpy( &( ( short* ) outBuffer )[ outSample * channelCount ], &( ( short* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( short ) );\r
- break;\r
- case RTAUDIO_SINT24:\r
- memcpy( &( ( S24* ) outBuffer )[ outSample * channelCount ], &( ( S24* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( S24 ) );\r
- break;\r
- case RTAUDIO_SINT32:\r
- memcpy( &( ( int* ) outBuffer )[ outSample * channelCount ], &( ( int* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( int ) );\r
- break;\r
- case RTAUDIO_FLOAT32:\r
- memcpy( &( ( float* ) outBuffer )[ outSample * channelCount ], &( ( float* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( float ) );\r
- break;\r
- case RTAUDIO_FLOAT64:\r
- memcpy( &( ( double* ) outBuffer )[ outSample * channelCount ], &( ( double* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( double ) );\r
- break;\r
+ unsigned int inSample = ( unsigned int ) inSampleFraction;\r
+\r
+ switch ( format )\r
+ {\r
+ case RTAUDIO_SINT8:\r
+ memcpy( &( ( char* ) outBuffer )[ outSample * channelCount ], &( ( char* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( char ) );\r
+ break;\r
+ case RTAUDIO_SINT16:\r
+ memcpy( &( ( short* ) outBuffer )[ outSample * channelCount ], &( ( short* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( short ) );\r
+ break;\r
+ case RTAUDIO_SINT24:\r
+ memcpy( &( ( S24* ) outBuffer )[ outSample * channelCount ], &( ( S24* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( S24 ) );\r
+ break;\r
+ case RTAUDIO_SINT32:\r
+ memcpy( &( ( int* ) outBuffer )[ outSample * channelCount ], &( ( int* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( int ) );\r
+ break;\r
+ case RTAUDIO_FLOAT32:\r
+ memcpy( &( ( float* ) outBuffer )[ outSample * channelCount ], &( ( float* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( float ) );\r
+ break;\r
+ case RTAUDIO_FLOAT64:\r
+ memcpy( &( ( double* ) outBuffer )[ outSample * channelCount ], &( ( double* ) inBuffer )[ inSample * channelCount ], channelCount * sizeof( double ) );\r
+ break;\r
+ }\r
+\r
+ // jump to next in sample\r
+ inSampleFraction += sampleStep;\r
}\r
+ }\r
+ else // else interpolate\r
+ {\r
+ // frame-by-frame, copy each relative input sample into it's corresponding output sample\r
+ for ( unsigned int outSample = 0; outSample < outSampleCount; outSample++ )\r
+ {\r
+ unsigned int inSample = ( unsigned int ) inSampleFraction;\r
+ float inSampleDec = inSampleFraction - inSample;\r
+ unsigned int frameInSample = inSample * channelCount;\r
+ unsigned int frameOutSample = outSample * channelCount;\r
\r
- // jump to next in sample\r
- inSampleFraction += sampleStep;\r
+ switch ( format )\r
+ {\r
+ case RTAUDIO_SINT8:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ char fromSample = ( ( char* ) inBuffer )[ frameInSample + channel ];\r
+ char toSample = ( ( char* ) inBuffer )[ frameInSample + channelCount + channel ];\r
+ char sampleDiff = ( char ) ( ( toSample - fromSample ) * inSampleDec );\r
+ ( ( char* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ case RTAUDIO_SINT16:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ short fromSample = ( ( short* ) inBuffer )[ frameInSample + channel ];\r
+ short toSample = ( ( short* ) inBuffer )[ frameInSample + channelCount + channel ];\r
+ short sampleDiff = ( short ) ( ( toSample - fromSample ) * inSampleDec );\r
+ ( ( short* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ case RTAUDIO_SINT24:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ int fromSample = ( ( S24* ) inBuffer )[ frameInSample + channel ].asInt();\r
+ int toSample = ( ( S24* ) inBuffer )[ frameInSample + channelCount + channel ].asInt();\r
+ int sampleDiff = ( int ) ( ( toSample - fromSample ) * inSampleDec );\r
+ ( ( S24* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ case RTAUDIO_SINT32:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ int fromSample = ( ( int* ) inBuffer )[ frameInSample + channel ];\r
+ int toSample = ( ( int* ) inBuffer )[ frameInSample + channelCount + channel ];\r
+ int sampleDiff = ( int ) ( ( toSample - fromSample ) * inSampleDec );\r
+ ( ( int* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ case RTAUDIO_FLOAT32:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ float fromSample = ( ( float* ) inBuffer )[ frameInSample + channel ];\r
+ float toSample = ( ( float* ) inBuffer )[ frameInSample + channelCount + channel ];\r
+ float sampleDiff = ( toSample - fromSample ) * inSampleDec;\r
+ ( ( float* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ case RTAUDIO_FLOAT64:\r
+ {\r
+ for ( unsigned int channel = 0; channel < channelCount; channel++ )\r
+ {\r
+ double fromSample = ( ( double* ) inBuffer )[ frameInSample + channel ];\r
+ double toSample = ( ( double* ) inBuffer )[ frameInSample + channelCount + channel ];\r
+ double sampleDiff = ( toSample - fromSample ) * inSampleDec;\r
+ ( ( double* ) outBuffer )[ frameOutSample + channel ] = fromSample + sampleDiff;\r
+ }\r
+ break;\r
+ }\r
+ }\r
+\r
+ // jump to next in sample\r
+ inSampleFraction += sampleStep;\r
+ }\r
}\r
}\r
\r
projects / rtaudio-cdist.git / blobdiff