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