replaygain_analysis.c

tcpmp.src.0.72RC1 优秀的多媒体播放器TCPMP的源代码

    size_t  k;

    for ( i = 0; i < nSamples; i++ ) {
        y = input[i] * b[0];
        for ( k = 1; k <= order; k++ )
            y += input[i-k] * b[k] - output[i-k] * a[k];
        output[i] = (Float_t)y;
    }
}

/* returns a INIT_GAIN_ANALYSIS_OK if successful, INIT_GAIN_ANALYSIS_ERROR if not */

int
ResetSampleFrequency ( long samplefreq ) {
    int  i;

    /* zero out initial values */
    for ( i = 0; i < MAX_ORDER; i++ )
        linprebuf[i] = lstepbuf[i] = loutbuf[i] = rinprebuf[i] = rstepbuf[i] = routbuf[i] = 0.;

    switch ( (int)(samplefreq) ) {
        case 48000: freqindex = 0; break;
        case 44100: freqindex = 1; break;
        case 32000: freqindex = 2; break;
        case 24000: freqindex = 3; break;
        case 22050: freqindex = 4; break;
        case 16000: freqindex = 5; break;
        case 12000: freqindex = 6; break;
        case 11025: freqindex = 7; break;
        case  8000: freqindex = 8; break;
        default:    return INIT_GAIN_ANALYSIS_ERROR;
    }

    sampleWindow = (int) ceil (samplefreq * RMS_WINDOW_TIME);

    lsum         = 0.;
    rsum         = 0.;
    totsamp      = 0;

    memset ( A, 0, sizeof(A) );

	return INIT_GAIN_ANALYSIS_OK;
}

int
InitGainAnalysis ( long samplefreq )
{
	if (ResetSampleFrequency(samplefreq) != INIT_GAIN_ANALYSIS_OK) {
		return INIT_GAIN_ANALYSIS_ERROR;
	}

    linpre       = linprebuf + MAX_ORDER;
    rinpre       = rinprebuf + MAX_ORDER;
    lstep        = lstepbuf  + MAX_ORDER;
    rstep        = rstepbuf  + MAX_ORDER;
    lout         = loutbuf   + MAX_ORDER;
    rout         = routbuf   + MAX_ORDER;

    memset ( B, 0, sizeof(B) );

    return INIT_GAIN_ANALYSIS_OK;
}

/* returns GAIN_ANALYSIS_OK if successful, GAIN_ANALYSIS_ERROR if not */

int
AnalyzeSamples ( const Float_t* left_samples, const Float_t* right_samples, size_t num_samples, int num_channels )
{
    const Float_t*  curleft;
    const Float_t*  curright;
    long            batchsamples;
    long            cursamples;
    long            cursamplepos;
    int             i;

    if ( num_samples == 0 )
        return GAIN_ANALYSIS_OK;

    cursamplepos = 0;
    batchsamples = num_samples;

    switch ( num_channels) {
    case  1: right_samples = left_samples;
    case  2: break;
    default: return GAIN_ANALYSIS_ERROR;
    }

    if ( num_samples < MAX_ORDER ) {
        memcpy ( linprebuf + MAX_ORDER, left_samples , num_samples * sizeof(Float_t) );
        memcpy ( rinprebuf + MAX_ORDER, right_samples, num_samples * sizeof(Float_t) );
    }
    else {
        memcpy ( linprebuf + MAX_ORDER, left_samples,  MAX_ORDER   * sizeof(Float_t) );
        memcpy ( rinprebuf + MAX_ORDER, right_samples, MAX_ORDER   * sizeof(Float_t) );
    }

    while ( batchsamples > 0 ) {
        cursamples = batchsamples > (long)(sampleWindow-totsamp)  ?  (long)(sampleWindow - totsamp)  :  batchsamples;
        if ( cursamplepos < MAX_ORDER ) {
            curleft  = linpre+cursamplepos;
            curright = rinpre+cursamplepos;
            if (cursamples > MAX_ORDER - cursamplepos )
                cursamples = MAX_ORDER - cursamplepos;
        }
        else {
            curleft  = left_samples  + cursamplepos;
            curright = right_samples + cursamplepos;
        }

        filter ( curleft , lstep + totsamp, cursamples, AYule[freqindex], BYule[freqindex], YULE_ORDER );
        filter ( curright, rstep + totsamp, cursamples, AYule[freqindex], BYule[freqindex], YULE_ORDER );

        filter ( lstep + totsamp, lout + totsamp, cursamples, AButter[freqindex], BButter[freqindex], BUTTER_ORDER );
        filter ( rstep + totsamp, rout + totsamp, cursamples, AButter[freqindex], BButter[freqindex], BUTTER_ORDER );

        for ( i = 0; i < cursamples; i++ ) {             /* Get the squared values */
            lsum += lout [totsamp+i] * lout [totsamp+i];
            rsum += rout [totsamp+i] * rout [totsamp+i];
        }

        batchsamples -= cursamples;
        cursamplepos += cursamples;
        totsamp      += cursamples;
        if ( totsamp == sampleWindow ) {  /* Get the Root Mean Square (RMS) for this set of samples */
            double  val  = STEPS_per_dB * 10. * log10 ( (lsum+rsum) / totsamp * 0.5 + 1.e-37 );
            int     ival = (int) val;
            if ( ival <                     0 ) ival = 0;
            if ( ival >= (int)(sizeof(A)/sizeof(*A)) ) ival = (int)(sizeof(A)/sizeof(*A)) - 1;
            A [ival]++;
            lsum = rsum = 0.;
            memmove ( loutbuf , loutbuf  + totsamp, MAX_ORDER * sizeof(Float_t) );
            memmove ( routbuf , routbuf  + totsamp, MAX_ORDER * sizeof(Float_t) );
            memmove ( lstepbuf, lstepbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
            memmove ( rstepbuf, rstepbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
            totsamp = 0;
        }
        if ( totsamp > sampleWindow )   /* somehow I really screwed up: Error in programming! Contact author about totsamp > sampleWindow */
            return GAIN_ANALYSIS_ERROR;
    }
    if ( num_samples < MAX_ORDER ) {
        memmove ( linprebuf,                           linprebuf + num_samples, (MAX_ORDER-num_samples) * sizeof(Float_t) );
        memmove ( rinprebuf,                           rinprebuf + num_samples, (MAX_ORDER-num_samples) * sizeof(Float_t) );
        memcpy  ( linprebuf + MAX_ORDER - num_samples, left_samples,          num_samples             * sizeof(Float_t) );
        memcpy  ( rinprebuf + MAX_ORDER - num_samples, right_samples,         num_samples             * sizeof(Float_t) );
    }
    else {
        memcpy  ( linprebuf, left_samples  + num_samples - MAX_ORDER, MAX_ORDER * sizeof(Float_t) );
        memcpy  ( rinprebuf, right_samples + num_samples - MAX_ORDER, MAX_ORDER * sizeof(Float_t) );
    }

    return GAIN_ANALYSIS_OK;
}


static Float_t
analyzeResult ( Uint32_t* Array, size_t len )
{
    Uint32_t  elems;
    Int32_t   upper;
    size_t    i;

    elems = 0;
    for ( i = 0; i < len; i++ )
        elems += Array[i];
    if ( elems == 0 )
        return GAIN_NOT_ENOUGH_SAMPLES;

    upper = (Int32_t) ceil (elems * (1. - RMS_PERCENTILE));
    for ( i = len; i-- > 0; ) {
        if ( (upper -= Array[i]) <= 0 )
            break;
    }

    return (Float_t) ((Float_t)PINK_REF - (Float_t)i / (Float_t)STEPS_per_dB);
}


Float_t
GetTitleGain ( void )
{
    Float_t  retval;
    unsigned int    i;

    retval = analyzeResult ( A, sizeof(A)/sizeof(*A) );

    for ( i = 0; i < sizeof(A)/sizeof(*A); i++ ) {
        B[i] += A[i];
        A[i]  = 0;
    }

    for ( i = 0; i < MAX_ORDER; i++ )
        linprebuf[i] = lstepbuf[i] = loutbuf[i] = rinprebuf[i] = rstepbuf[i] = routbuf[i] = 0.f;

    totsamp = 0;
    lsum    = rsum = 0.;
    return retval;
}


Float_t
GetAlbumGain ( void )
{
    return analyzeResult ( B, sizeof(B)/sizeof(*B) );
}

/* end of replaygain_analysis.c */