raexactresampler.h

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

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#ifndef _RAEXACTRESAMPLER_H_
#define _RAEXACTRESAMPLER_H_

#include "hxresult.h"

class RAExactResampler
{
public:
    // resampler quality
    enum {
        qualityVeryLow= 0, // as low a quality as we dare
        qualityLow    = 1, // somewhat better
        qualityMedium = 2, // probably sufficient for the player
        qualityHigh   = 3, // the default, giving CD quality,
        qualityHyper  = 4  // better than CD quality (think DSD)
    } ;

    // Create a resampler with a given quality level.
    static HX_RESULT Create(RAExactResampler** pRes, int inrate, int outrate, int chans, int intype, int quality = qualityHigh) ;

    // If you know the specs your resampler is required to have, use one of these functions.
    static HX_RESULT Create(RAExactResampler** pRes, int inrate, int outrate, int chans, int intype, float atten, float trans, float dcgain) ;

    static HX_RESULT Create(RAExactResampler** pRes, int inrate, int outrate, int chans, int intype, float atten, float passband, float stopband, float dcgain) ;

    virtual ~RAExactResampler() ;

    // this is the input data type.
    enum {
        _INT16 = 0,
        _INT32 = 1,
        _FLOAT = 2
    } ;

    /*
     * insamps is the number of samples (not sample frames) you are handing the resampler.
     * Note that in the case of stereo, this must be divisible by two.
     */
    virtual int Resample(void *inbuf, int insamps, signed short *outbuf) = 0 ;
    virtual int Resample(void *inbuf, int insamps, signed int *outbuf) = 0 ;
    /*
     * The maximum output, in samples, that could be produced by
     * insamps input samples.
     */
    virtual int GetMaxOutput(int insamps) = 0 ;
    /*
     * The minimum input, in samples, that will produce at least
     * outsamps output samples.
     */
    virtual int GetMinInput(int outsamps) = 0 ;
    /*
     * The delay of this filter, in frames of output frequency.
     */
    virtual int GetDelay() = 0 ;

protected:
    RAExactResampler() ; // make this protected -- use the Create() function!
};

#endif // _RAEXACTRESAMPLER_H_