Revision d42dc217

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libavcodec/iirfilter.c
47 47 
/// maximum supported filter order
48 48 
#define MAXORDER 30
49 49 

  		




  50
  
  
    
av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType filt_type,


  		




  
  50
  
    
av_cold struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(void *avc,


  		




  
  51
  
    
                                                enum IIRFilterType filt_type,


  		




  51
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                                                    enum IIRFilterMode filt_mode,


  		




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                                                    int order, float cutoff_ratio,


  		




  53
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                                                    float stopband, float ripple)


  		




  ......




  62
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    if(order <= 1 || (order & 1) || order > MAXORDER || cutoff_ratio >= 1.0)


  		




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        return NULL;


  		




  64
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  65
  
  
    
    c = av_malloc(sizeof(FFIIRFilterCoeffs));


  		




  66
  
  
    
    c->cx = av_malloc(sizeof(c->cx[0]) * ((order >> 1) + 1));


  		




  67
  
  
    
    c->cy = av_malloc(sizeof(c->cy[0]) * order);


  		




  
  66
  
    
    FF_ALLOCZ_OR_GOTO(avc, c,     sizeof(FFIIRFilterCoeffs),


  		




  
  67
  
    
                      init_fail);


  		




  
  68
  
    
    FF_ALLOC_OR_GOTO (avc, c->cx, sizeof(c->cx[0]) * ((order >> 1) + 1),


  		




  
  69
  
    
                      init_fail);


  		




  
  70
  
    
    FF_ALLOC_OR_GOTO (avc, c->cy, sizeof(c->cy[0]) * order,


  		




  
  71
  
    
                      init_fail);


  		




  68
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    c->order = order;


  		




  69
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  70
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    wa = 2 * tan(M_PI * 0.5 * cutoff_ratio);


  		




  ......




  110
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    c->gain /= 1 << order;


  		




  111
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    return c;


  		




  
  117
  
    

  		




  
  118
  
    
init_fail:


  		




  
  119
  
    
    ff_iir_filter_free_coeffs(c);


  		




  
  120
  
    
    return NULL;


  		




  113
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}


  		




  114
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  115
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av_cold struct FFIIRFilterState* ff_iir_filter_init_state(int order)


  		












  

    
      libavcodec/iirfilter.h
    
  





  49
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/**


  		




  50
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 * Initialize filter coefficients.


  		




  51
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 *


  		




  
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 * @param avc          a pointer to an arbitrary struct of which the first


  		




  
  53
  
    
 *                     field is a pointer to an AVClass struct


  		




  52
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 * @param filt_type    filter type (e.g. Butterworth)


  		




  53
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 * @param filt_mode    filter mode (e.g. lowpass)


  		




  54
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 * @param order        filter order


  		




  ......




  58
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 *


  		




  59
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 * @return pointer to filter coefficients structure or NULL if filter cannot be created


  		




  60
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 */


  		




  61
  
  
    
struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(enum IIRFilterType filt_type,


  		




  
  63
  
    
struct FFIIRFilterCoeffs* ff_iir_filter_init_coeffs(void *avc,


  		




  
  64
  
    
                                                enum IIRFilterType filt_type,


  		




  62
  65
  
    
                                                    enum IIRFilterMode filt_mode,


  		




  63
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                                                    int order, float cutoff_ratio,


  		




  64
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                                                    float stopband, float ripple);


  		












  

    
      libavcodec/psymodel.c
    
  





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        cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;


  		




  89
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  90
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    if (cutoff_coeff)


  		




  91
  
  
    
    ctx->fcoeffs = ff_iir_filter_init_coeffs(FF_FILTER_TYPE_BUTTERWORTH, FF_FILTER_MODE_LOWPASS,


  		




  
  91
  
    
    ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH, FF_FILTER_MODE_LOWPASS,


  		




  92
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                                             FILT_ORDER, cutoff_coeff, 0.0, 0.0);


  		




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    if (ctx->fcoeffs) {


  		




  94
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        ctx->fstate = av_mallocz(sizeof(ctx->fstate[0]) * avctx->channels);


  		












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