diff options
Diffstat (limited to 'pjmedia/src/pjmedia/portaudio/pa_dither.h')
| -rw-r--r-- | pjmedia/src/pjmedia/portaudio/pa_dither.h | 182 |
1 files changed, 91 insertions, 91 deletions
diff --git a/pjmedia/src/pjmedia/portaudio/pa_dither.h b/pjmedia/src/pjmedia/portaudio/pa_dither.h index a76c8b6b..70369e18 100644 --- a/pjmedia/src/pjmedia/portaudio/pa_dither.h +++ b/pjmedia/src/pjmedia/portaudio/pa_dither.h @@ -1,91 +1,91 @@ -#ifndef PA_DITHER_H
-#define PA_DITHER_H
-/*
- * $Id: pa_dither.h,v 1.1.2.4 2003/09/20 21:06:19 rossbencina Exp $
- * 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.
- *
- * 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.
- *
- * 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.
- */
-
-/** @file
- @brief Functions for generating dither noise
-*/
-
-
-#ifdef __cplusplus
-extern "C"
-{
-#endif /* __cplusplus */
-
-
-/** @brief State needed to generate a dither signal */
-typedef struct PaUtilTriangularDitherGenerator{
- unsigned long previous;
- unsigned long randSeed1;
- unsigned long 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 long with a range of +32767 to -32768
-*/
-signed long 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 */
+#ifndef PA_DITHER_H +#define PA_DITHER_H +/* + * $Id: pa_dither.h,v 1.1.2.4 2003/09/20 21:06:19 rossbencina Exp $ + * 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. + * + * 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. + * + * 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. + */ + +/** @file + @brief Functions for generating dither noise +*/ + + +#ifdef __cplusplus +extern "C" +{ +#endif /* __cplusplus */ + + +/** @brief State needed to generate a dither signal */ +typedef struct PaUtilTriangularDitherGenerator{ + unsigned long previous; + unsigned long randSeed1; + unsigned long 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 long with a range of +32767 to -32768 +*/ +signed long 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 */ |