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Commit 2dc1d143 authored by Antti S. Lankila's avatar Antti S. Lankila
Browse files

Remove weighing filter from loudness equalization 

I was estimating loudness based on my own hybrid A+C weighing
filter. This looks like the wrong thing to do, because the
ISO 226:2003 curves are defined for dB(SPL).

Also restoring correction back to my originally derived values,
after this bug made me lower the boosts slightly.
parent e2ba63b6

media/libeffects/cyanogen-dsp/EffectEqualizer.cpp

+7 −8
Original line number Diff line number Diff line
@@ -79,8 +79,6 @@ int32_t EffectEqualizer::command(uint32_t cmdCode, uint32_t cmdSize, void* pCmdD 
			return 0;

		}



                /* Weigher for estimating bass compensation. */

                mWeigher.setBandPass(2200.0, mSamplingRate, 0.33);

                /* 100 updates per second. */

                mNextUpdateInterval = int32_t(mSamplingRate / 100.);
@@ -196,9 +194,9 @@ int32_t EffectEqualizer::command(uint32_t cmdCode, uint32_t cmdSize, void* pCmdD 
 * sound pressure level.

 *

 * The boost can be calculated as linear scaling of the following adjustment:

 *     20 Hz +40 dB (unmodeled)

 *   62.5 Hz +20 dB

 *    250 Hz  +8 dB

 *     20 Hz +45 dB (unmodeled)

 *   62.5 Hz +24 dB

 *    250 Hz +10 dB

 *   1000 Hz   0 dB

 *   4000 Hz  -3 dB

 *  16000 Hz  +6 dB
@@ -209,7 +207,7 @@ int32_t EffectEqualizer::command(uint32_t cmdCode, uint32_t cmdSize, void* pCmdD 
 * digital sound level against the audio.

 */

float EffectEqualizer::getAdjustedBand(int32_t band) {

    const float adj[5] = { 20.0, 8.0, 0.0, -3.0, 6.0 };

    const float adj[5] = { 24.0, 10.0, 0.0, -3.0, 6.0 };



    float f = mBand[band];
@@ -275,8 +273,9 @@ int32_t EffectEqualizer::process(audio_buffer_t *in, audio_buffer_t *out) 
        int32_t tmpL = read(in, i * 2);

        int32_t tmpR = read(in, i * 2 + 1);



        /* Calculate signal loudness estimate */

        int64_t weight = mWeigher.process(tmpL + tmpR);

        /* Calculate signal loudness estimate.

         * XXX: should we be independent per channel? */

        int64_t weight = tmpL + tmpR;

        mPowerSquared += weight * weight;

     

        /* first "shelve" is just gain */

media/libeffects/cyanogen-dsp/EffectEqualizer.h

+0 −1
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ class EffectEqualizer : public Effect { 
    /* Automatic equalizer */

    float mLoudnessAdjustment;



    Biquad mWeigher;

    float mLoudness;

    int32_t mNextUpdate;

    int32_t mNextUpdateInterval;