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      1 /*
      2  * Copyright (C) 2007 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_AUDIO_RESAMPLER_SINC_H
     18 #define ANDROID_AUDIO_RESAMPLER_SINC_H
     19 
     20 #include <stdint.h>
     21 #include <sys/types.h>
     22 #include <android/log.h>
     23 
     24 #include <media/AudioResampler.h>
     25 
     26 namespace android {
     27 
     28 
     29 typedef const int32_t * (*readCoefficientsFn)(bool upDownSample);
     30 typedef int32_t (*readResampleFirNumCoeffFn)();
     31 typedef int32_t (*readResampleFirLerpIntBitsFn)();
     32 
     33 // ----------------------------------------------------------------------------
     34 
     35 class AudioResamplerSinc : public AudioResampler {
     36 public:
     37     AudioResamplerSinc(int inChannelCount, int32_t sampleRate,
     38             src_quality quality = HIGH_QUALITY);
     39 
     40     virtual ~AudioResamplerSinc();
     41 
     42     virtual size_t resample(int32_t* out, size_t outFrameCount,
     43             AudioBufferProvider* provider);
     44 private:
     45     void init();
     46 
     47     virtual void setVolume(float left, float right);
     48 
     49     template<int CHANNELS>
     50     size_t resample(int32_t* out, size_t outFrameCount,
     51             AudioBufferProvider* provider);
     52 
     53     template<int CHANNELS>
     54     inline void filterCoefficient(
     55             int32_t* out, uint32_t phase, const int16_t *samples, uint32_t vRL);
     56 
     57     template<int CHANNELS>
     58     inline void interpolate(
     59             int32_t& l, int32_t& r,
     60             const int32_t* coefs, size_t offset,
     61             int32_t lerp, const int16_t* samples);
     62 
     63     template<int CHANNELS>
     64     inline void read(int16_t*& impulse, uint32_t& phaseFraction,
     65             const int16_t* in, size_t inputIndex);
     66 
     67     int16_t *mState;
     68     int16_t *mImpulse;
     69     int16_t *mRingFull;
     70     int32_t mVolumeSIMD[2];
     71 
     72     const int32_t * mFirCoefs;
     73     static const uint32_t mFirCoefsDown[];
     74     static const uint32_t mFirCoefsUp[];
     75 
     76     // ----------------------------------------------------------------------------
     77     static const int32_t RESAMPLE_FIR_NUM_COEF       = 8;
     78     static const int32_t RESAMPLE_FIR_LERP_INT_BITS  = 7;
     79 
     80     struct Constants {
     81         int coefsBits;
     82         int cShift;
     83         uint32_t cMask;
     84         int pShift;
     85         uint32_t pMask;
     86         // number of zero-crossing on each side
     87         unsigned int halfNumCoefs;
     88     };
     89 
     90     static Constants highQualityConstants;
     91     static Constants veryHighQualityConstants;
     92     const Constants *mConstants;    // points to appropriate set of coefficient parameters
     93 
     94     static void init_routine();
     95 };
     96 
     97 // ----------------------------------------------------------------------------
     98 } // namespace android
     99 
    100 #endif /*ANDROID_AUDIO_RESAMPLER_SINC_H*/
    101