diff options
Diffstat (limited to 'portaudio/src/common/pa_dither.h')
-rw-r--r-- | portaudio/src/common/pa_dither.h | 106 |
1 files changed, 0 insertions, 106 deletions
diff --git a/portaudio/src/common/pa_dither.h b/portaudio/src/common/pa_dither.h deleted file mode 100644 index 4f81123..0000000 --- a/portaudio/src/common/pa_dither.h +++ /dev/null @@ -1,106 +0,0 @@ -#ifndef PA_DITHER_H -#define PA_DITHER_H -/* - * $Id$ - * Portable Audio I/O Library triangular dither generator - * - * Based on the Open Source API proposed by Ross Bencina - * Copyright (c) 1999-2002 Phil Burk, Ross Bencina - * - * Permission is hereby granted, free of charge, to any person obtaining - * a copy of this software and associated documentation files - * (the "Software"), to deal in the Software without restriction, - * including without limitation the rights to use, copy, modify, merge, - * publish, distribute, sublicense, and/or sell copies of the Software, - * and to permit persons to whom the Software is furnished to do so, - * subject to the following conditions: - * - * The above copyright notice and this permission notice shall be - * included in all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, - * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF - * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. - * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR - * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF - * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION - * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. - */ - -/* - * The text above constitutes the entire PortAudio license; however, - * the PortAudio community also makes the following non-binding requests: - * - * Any person wishing to distribute modifications to the Software is - * requested to send the modifications to the original developer so that - * they can be incorporated into the canonical version. It is also - * requested that these non-binding requests be included along with the - * license above. - */ - -/** @file - @ingroup common_src - - @brief Functions for generating dither noise -*/ - -#include "pa_types.h" - - -#ifdef __cplusplus -extern "C" -{ -#endif /* __cplusplus */ - -/* Note that the linear congruential algorithm requires 32 bit integers - * because it uses arithmetic overflow. So use PaUint32 instead of - * unsigned long so it will work on 64 bit systems. - */ - -/** @brief State needed to generate a dither signal */ -typedef struct PaUtilTriangularDitherGenerator{ - PaUint32 previous; - PaUint32 randSeed1; - PaUint32 randSeed2; -} PaUtilTriangularDitherGenerator; - - -/** @brief Initialize dither state */ -void PaUtil_InitializeTriangularDitherState( PaUtilTriangularDitherGenerator *ditherState ); - - -/** - @brief Calculate 2 LSB dither signal with a triangular distribution. - Ranged for adding to a 1 bit right-shifted 32 bit integer - prior to >>15. eg: -<pre> - signed long in = * - signed long dither = PaUtil_Generate16BitTriangularDither( ditherState ); - signed short out = (signed short)(((in>>1) + dither) >> 15); -</pre> - @return - A signed 32-bit integer with a range of +32767 to -32768 -*/ -PaInt32 PaUtil_Generate16BitTriangularDither( PaUtilTriangularDitherGenerator *ditherState ); - - -/** - @brief Calculate 2 LSB dither signal with a triangular distribution. - Ranged for adding to a pre-scaled float. -<pre> - float in = * - float dither = PaUtil_GenerateFloatTriangularDither( ditherState ); - // use smaller scaler to prevent overflow when we add the dither - signed short out = (signed short)(in*(32766.0f) + dither ); -</pre> - @return - A float with a range of -2.0 to +1.99999. -*/ -float PaUtil_GenerateFloatTriangularDither( PaUtilTriangularDitherGenerator *ditherState ); - - - -#ifdef __cplusplus -} -#endif /* __cplusplus */ -#endif /* PA_DITHER_H */ |