66 lines
1.8 KiB
C++
66 lines
1.8 KiB
C++
/**********************************************************************
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Audacity: A Digital Audio Editor
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Steve Harris
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Markus Meyer
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**********************************************************************/
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#ifndef __AUDACITY_DITHER_H__
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#define __AUDACITY_DITHER_H__
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#include "audacity/Types.h" // for samplePtr
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template< typename Enum > class EnumSetting;
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/// These ditherers are currently available:
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enum DitherType : unsigned {
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none = 0, rectangle = 1, triangle = 2, shaped = 3 };
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class Dither
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{
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public:
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static DitherType FastDitherChoice();
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static DitherType BestDitherChoice();
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static AUDACITY_DLL_API EnumSetting< DitherType > FastSetting, BestSetting;
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/// Default constructor
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Dither();
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/// Reset state of the dither.
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void Reset();
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/// Apply the actual dithering. Expects the source sample in the
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/// 'source' variable, the destination sample in the 'dest' variable,
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/// and hints to the formats of the samples. Even if the sample formats
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/// are the same, samples are clipped, if necessary.
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void Apply(DitherType ditherType,
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constSamplePtr source, sampleFormat sourceFormat,
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samplePtr dest, sampleFormat destFormat,
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unsigned int len,
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unsigned int sourceStride = 1,
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unsigned int destStride = 1);
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private:
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// Dither methods
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float NoDither(float sample);
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float RectangleDither(float sample);
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float TriangleDither(float sample);
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float ShapedDither(float sample);
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// Dither constants
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static const int BUF_SIZE; /* = 8 */
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static const int BUF_MASK; /* = 7 */
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static const float SHAPED_BS[];
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// Dither state
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int mPhase;
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float mTriangleState;
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float mBuffer[8 /* = BUF_SIZE */];
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};
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#endif /* __AUDACITY_DITHER_H__ */
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