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Commit 1319a4af authored by Robert Wu's avatar Robert Wu Committed by Android (Google) Code Review
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Merge "AAudio: Resampler should not filter when upscaling"

parents f85cb5c4 cc90d54e

media/libaaudio/src/flowgraph/resampler/MultiChannelResampler.cpp

+3 −4
Original line number Diff line number Diff line
@@ -135,10 +135,9 @@ void MultiChannelResampler::generateCoefficients(int32_t inputRate, 
    int coefficientIndex = 0;

    double phase = 0.0; // ranges from 0.0 to 1.0, fraction between samples

    // Stretch the sinc function for low pass filtering.

    const float cutoffScaler = normalizedCutoff *

            ((outputRate < inputRate)

             ? ((float)outputRate / inputRate)

             : ((float)inputRate / outputRate));

    const float cutoffScaler = (outputRate < inputRate)

             ? (normalizedCutoff * (float)outputRate / inputRate)

             : 1.0f; // Do not filter when upsampling.

    const int numTapsHalf = getNumTaps() / 2; // numTaps must be even.

    const float numTapsHalfInverse = 1.0f / numTapsHalf;

    for (int i = 0; i < numRows; i++) {

media/libaaudio/src/flowgraph/resampler/MultiChannelResampler.h

+7 −0
Original line number Diff line number Diff line
@@ -111,6 +111,9 @@ public: 
         * Set lower to reduce aliasing.

         * Default is 0.70.

         *

         * Note that this value is ignored when upsampling, which is when

         * the outputRate is higher than the inputRate.

         *

         * @param normalizedCutoff anti-aliasing filter cutoff

         * @return address of this builder for chaining calls

         */
@@ -227,6 +230,10 @@ protected: 


    /**

     * Generate the filter coefficients in optimal order.

     *

     * Note that normalizedCutoff is ignored when upsampling, which is when

     * the outputRate is higher than the inputRate.

     *

     * @param inputRate sample rate of the input stream

     * @param outputRate  sample rate of the output stream

     * @param numRows number of rows in the array that contain a set of tap coefficients

media/libaaudio/tests/test_resampler.cpp

+3 −4
Original line number Diff line number Diff line
@@ -193,10 +193,9 @@ TEST(test_resampler, resampler_11025_44100_best) { 
    checkResampler(11025, 44100, MultiChannelResampler::Quality::Best);

}



// TODO This fails because the output is very low.

//TEST(test_resampler, resampler_11025_88200_best) {

//    checkResampler(11025, 88200, MultiChannelResampler::Quality::Best);

//}

TEST(test_resampler, resampler_11025_88200_best) {

    checkResampler(11025, 88200, MultiChannelResampler::Quality::Best);

}



TEST(test_resampler, resampler_16000_48000_best) {

    checkResampler(16000, 48000, MultiChannelResampler::Quality::Best);