AudioResamplerSinc.h revision 3348e36c51e91e78020bcc6578eda83d97c31bec 
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 <cutils/log.h>
23
24#include "AudioResampler.h"
25
26namespace android {
27
28
29typedef const int32_t * (*readCoefficientsFn)(bool upDownSample);
30typedef int32_t (*readResampleFirNumCoeffFn)();
31typedef int32_t (*readResampleFirLerpIntBitsFn)();
32
33// ----------------------------------------------------------------------------
34
35class AudioResamplerSinc : public AudioResampler {
36public:
37    AudioResamplerSinc(int inChannelCount, int32_t sampleRate,
38            src_quality quality = HIGH_QUALITY);
39
40    virtual ~AudioResamplerSinc();
41
42    virtual void resample(int32_t* out, size_t outFrameCount,
43            AudioBufferProvider* provider);
44private:
45    void init();
46
47    virtual void setVolume(int16_t left, int16_t right);
48
49    template<int CHANNELS>
50    void 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