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Diffstat (limited to 'portaudio/src/common/pa_converters.h')
| -rw-r--r-- | portaudio/src/common/pa_converters.h | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/portaudio/src/common/pa_converters.h b/portaudio/src/common/pa_converters.h new file mode 100644 index 0000000..3d75758 --- /dev/null +++ b/portaudio/src/common/pa_converters.h @@ -0,0 +1,263 @@ +#ifndef PA_CONVERTERS_H +#define PA_CONVERTERS_H +/* + * $Id: pa_converters.h,v 1.1 2010/11/04 20:43:52 rbd Exp $ + * Portable Audio I/O Library sample conversion mechanism + * + * 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 Conversion functions used to convert buffers of samples from one + format to another. +*/ + + +#include "portaudio.h" /* for PaSampleFormat */ + +#ifdef __cplusplus +extern "C" +{ +#endif /* __cplusplus */ + + +struct PaUtilTriangularDitherGenerator; + + +/** Choose an available sample format which is most appropriate for + representing the requested format. If the requested format is not available + higher quality formats are considered before lower quality formates. + @param availableFormats A variable containing the logical OR of all available + formats. + @param format The desired format. + @return The most appropriate available format for representing the requested + format. +*/ +PaSampleFormat PaUtil_SelectClosestAvailableFormat( + PaSampleFormat availableFormats, PaSampleFormat format ); + + +/* high level conversions functions for use by implementations */ + + +/** The generic sample converter prototype. Sample converters convert count + samples from sourceBuffer to destinationBuffer. The actual type of the data + pointed to by these parameters varys for different converter functions. + @param destinationBuffer A pointer to the first sample of the destination. + @param destinationStride An offset between successive destination samples + expressed in samples (not bytes.) It may be negative. + @param sourceBuffer A pointer to the first sample of the source. + @param sourceStride An offset between successive source samples + expressed in samples (not bytes.) It may be negative. + @param count The number of samples to convert. + @param ditherState State information used to calculate dither. Converters + that do not perform dithering will ignore this parameter, in which case + NULL or invalid dither state may be passed. +*/ +typedef void PaUtilConverter( + void *destinationBuffer, signed int destinationStride, + void *sourceBuffer, signed int sourceStride, + unsigned int count, struct PaUtilTriangularDitherGenerator *ditherGenerator ); + + +/** Find a sample converter function for the given source and destinations + formats and flags (clip and dither.) + @return + A pointer to a PaUtilConverter which will perform the requested + conversion, or NULL if the given format conversion is not supported. + For conversions where clipping or dithering is not necessary, the + clip and dither flags are ignored and a non-clipping or dithering + version is returned. + If the source and destination formats are the same, a function which + copies data of the appropriate size will be returned. +*/ +PaUtilConverter* PaUtil_SelectConverter( PaSampleFormat sourceFormat, + PaSampleFormat destinationFormat, PaStreamFlags flags ); + + +/** The generic buffer zeroer prototype. Buffer zeroers copy count zeros to + destinationBuffer. The actual type of the data pointed to varys for + different zeroer functions. + @param destinationBuffer A pointer to the first sample of the destination. + @param destinationStride An offset between successive destination samples + expressed in samples (not bytes.) It may be negative. + @param count The number of samples to zero. +*/ +typedef void PaUtilZeroer( + void *destinationBuffer, signed int destinationStride, unsigned int count ); + + +/** Find a buffer zeroer function for the given destination format. + @return + A pointer to a PaUtilZeroer which will perform the requested + zeroing. +*/ +PaUtilZeroer* PaUtil_SelectZeroer( PaSampleFormat destinationFormat ); + +/*----------------------------------------------------------------------------*/ +/* low level functions and data structures which may be used for + substituting conversion functions */ + + +/** The type used to store all sample conversion functions. + @see paConverters; +*/ +typedef struct{ + PaUtilConverter *Float32_To_Int32; + PaUtilConverter *Float32_To_Int32_Dither; + PaUtilConverter *Float32_To_Int32_Clip; + PaUtilConverter *Float32_To_Int32_DitherClip; + + PaUtilConverter *Float32_To_Int24; + PaUtilConverter *Float32_To_Int24_Dither; + PaUtilConverter *Float32_To_Int24_Clip; + PaUtilConverter *Float32_To_Int24_DitherClip; + + PaUtilConverter *Float32_To_Int16; + PaUtilConverter *Float32_To_Int16_Dither; + PaUtilConverter *Float32_To_Int16_Clip; + PaUtilConverter *Float32_To_Int16_DitherClip; + + PaUtilConverter *Float32_To_Int8; + PaUtilConverter *Float32_To_Int8_Dither; + PaUtilConverter *Float32_To_Int8_Clip; + PaUtilConverter *Float32_To_Int8_DitherClip; + + PaUtilConverter *Float32_To_UInt8; + PaUtilConverter *Float32_To_UInt8_Dither; + PaUtilConverter *Float32_To_UInt8_Clip; + PaUtilConverter *Float32_To_UInt8_DitherClip; + + PaUtilConverter *Int32_To_Float32; + PaUtilConverter *Int32_To_Int24; + PaUtilConverter *Int32_To_Int24_Dither; + PaUtilConverter *Int32_To_Int16; + PaUtilConverter *Int32_To_Int16_Dither; + PaUtilConverter *Int32_To_Int8; + PaUtilConverter *Int32_To_Int8_Dither; + PaUtilConverter *Int32_To_UInt8; + PaUtilConverter *Int32_To_UInt8_Dither; + + PaUtilConverter *Int24_To_Float32; + PaUtilConverter *Int24_To_Int32; + PaUtilConverter *Int24_To_Int16; + PaUtilConverter *Int24_To_Int16_Dither; + PaUtilConverter *Int24_To_Int8; + PaUtilConverter *Int24_To_Int8_Dither; + PaUtilConverter *Int24_To_UInt8; + PaUtilConverter *Int24_To_UInt8_Dither; + + PaUtilConverter *Int16_To_Float32; + PaUtilConverter *Int16_To_Int32; + PaUtilConverter *Int16_To_Int24; + PaUtilConverter *Int16_To_Int8; + PaUtilConverter *Int16_To_Int8_Dither; + PaUtilConverter *Int16_To_UInt8; + PaUtilConverter *Int16_To_UInt8_Dither; + + PaUtilConverter *Int8_To_Float32; + PaUtilConverter *Int8_To_Int32; + PaUtilConverter *Int8_To_Int24; + PaUtilConverter *Int8_To_Int16; + PaUtilConverter *Int8_To_UInt8; + + PaUtilConverter *UInt8_To_Float32; + PaUtilConverter *UInt8_To_Int32; + PaUtilConverter *UInt8_To_Int24; + PaUtilConverter *UInt8_To_Int16; + PaUtilConverter *UInt8_To_Int8; + + PaUtilConverter *Copy_8_To_8; /* copy without any conversion */ + PaUtilConverter *Copy_16_To_16; /* copy without any conversion */ + PaUtilConverter *Copy_24_To_24; /* copy without any conversion */ + PaUtilConverter *Copy_32_To_32; /* copy without any conversion */ +} PaUtilConverterTable; + + +/** A table of pointers to all required converter functions. + PaUtil_SelectConverter() uses this table to lookup the appropriate + conversion functions. The fields of this structure are initialized + with default conversion functions. Fields may be NULL, indicating that + no conversion function is available. User code may substitue optimised + conversion functions by assigning different function pointers to + these fields. + + @note + If the PA_NO_STANDARD_CONVERTERS preprocessor variable is defined, + PortAudio's standard converters will not be compiled, and all fields + of this structure will be initialized to NULL. In such cases, users + should supply their own conversion functions if the require PortAudio + to open a stream that requires sample conversion. + + @see PaUtilConverterTable, PaUtilConverter, PaUtil_SelectConverter +*/ +extern PaUtilConverterTable paConverters; + + +/** The type used to store all buffer zeroing functions. + @see paZeroers; +*/ +typedef struct{ + PaUtilZeroer *ZeroU8; /* unsigned 8 bit, zero == 128 */ + PaUtilZeroer *Zero8; + PaUtilZeroer *Zero16; + PaUtilZeroer *Zero24; + PaUtilZeroer *Zero32; +} PaUtilZeroerTable; + + +/** A table of pointers to all required zeroer functions. + PaUtil_SelectZeroer() uses this table to lookup the appropriate + conversion functions. The fields of this structure are initialized + with default conversion functions. User code may substitue optimised + conversion functions by assigning different function pointers to + these fields. + + @note + If the PA_NO_STANDARD_ZEROERS preprocessor variable is defined, + PortAudio's standard zeroers will not be compiled, and all fields + of this structure will be initialized to NULL. In such cases, users + should supply their own zeroing functions for the sample sizes which + they intend to use. + + @see PaUtilZeroerTable, PaUtilZeroer, PaUtil_SelectZeroer +*/ +extern PaUtilZeroerTable paZeroers; + +#ifdef __cplusplus +} +#endif /* __cplusplus */ +#endif /* PA_CONVERTERS_H */ |