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#include <stdint.h>
18#include <string.h>
19#include <sys/types.h>
20#include <cutils/log.h>
21
22#include "AudioResampler.h"
23#include "AudioResamplerCubic.h"
24
25#define LOG_TAG "AudioSRC"
26
27namespace android {
28// ----------------------------------------------------------------------------
29
30void AudioResamplerCubic::init() {
31    memset(&left, 0, sizeof(state));
32    memset(&right, 0, sizeof(state));
33}
34
35void AudioResamplerCubic::resample(int32_t* out, size_t outFrameCount,
36        AudioBufferProvider* provider) {
37
38    // should never happen, but we overflow if it does
39    // LOG_ASSERT(outFrameCount < 32767);
40
41    // select the appropriate resampler
42    switch (mChannelCount) {
43    case 1:
44        resampleMono16(out, outFrameCount, provider);
45        break;
46    case 2:
47        resampleStereo16(out, outFrameCount, provider);
48        break;
49    }
50}
51
52void AudioResamplerCubic::resampleStereo16(int32_t* out, size_t outFrameCount,
53        AudioBufferProvider* provider) {
54
55    int32_t vl = mVolume[0];
56    int32_t vr = mVolume[1];
57
58    size_t inputIndex = mInputIndex;
59    uint32_t phaseFraction = mPhaseFraction;
60    uint32_t phaseIncrement = mPhaseIncrement;
61    size_t outputIndex = 0;
62    size_t outputSampleCount = outFrameCount * 2;
63    size_t inFrameCount = (outFrameCount*mInSampleRate)/mSampleRate;
64
65    // fetch first buffer
66    if (mBuffer.frameCount == 0) {
67        mBuffer.frameCount = inFrameCount;
68        provider->getNextBuffer(&mBuffer);
69        if (mBuffer.raw == NULL)
70            return;
71        // LOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
72    }
73    int16_t *in = mBuffer.i16;
74
75    while (outputIndex < outputSampleCount) {
76        int32_t sample;
77        int32_t x;
78
79        // calculate output sample
80        x = phaseFraction >> kPreInterpShift;
81        out[outputIndex++] += vl * interp(&left, x);
82        out[outputIndex++] += vr * interp(&right, x);
83        // out[outputIndex++] += vr * in[inputIndex*2];
84
85        // increment phase
86        phaseFraction += phaseIncrement;
87        uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
88        phaseFraction &= kPhaseMask;
89
90        // time to fetch another sample
91        while (indexIncrement--) {
92
93            inputIndex++;
94            if (inputIndex == mBuffer.frameCount) {
95                inputIndex = 0;
96                provider->releaseBuffer(&mBuffer);
97                mBuffer.frameCount = inFrameCount;
98                provider->getNextBuffer(&mBuffer);
99                if (mBuffer.raw == NULL)
100                    goto save_state;  // ugly, but efficient
101                in = mBuffer.i16;
102                // LOGW("New buffer: offset=%p, frames=%d\n", mBuffer.raw, mBuffer.frameCount);
103            }
104
105            // advance sample state
106            advance(&left, in[inputIndex*2]);
107            advance(&right, in[inputIndex*2+1]);
108        }
109    }
110
111save_state:
112    // LOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
113    mInputIndex = inputIndex;
114    mPhaseFraction = phaseFraction;
115}
116
117void AudioResamplerCubic::resampleMono16(int32_t* out, size_t outFrameCount,
118        AudioBufferProvider* provider) {
119
120    int32_t vl = mVolume[0];
121    int32_t vr = mVolume[1];
122
123    size_t inputIndex = mInputIndex;
124    uint32_t phaseFraction = mPhaseFraction;
125    uint32_t phaseIncrement = mPhaseIncrement;
126    size_t outputIndex = 0;
127    size_t outputSampleCount = outFrameCount * 2;
128    size_t inFrameCount = (outFrameCount*mInSampleRate)/mSampleRate;
129
130    // fetch first buffer
131    if (mBuffer.frameCount == 0) {
132        mBuffer.frameCount = inFrameCount;
133        provider->getNextBuffer(&mBuffer);
134        if (mBuffer.raw == NULL)
135            return;
136        // LOGW("New buffer: offset=%p, frames=%d\n", mBuffer.raw, mBuffer.frameCount);
137    }
138    int16_t *in = mBuffer.i16;
139
140    while (outputIndex < outputSampleCount) {
141        int32_t sample;
142        int32_t x;
143
144        // calculate output sample
145        x = phaseFraction >> kPreInterpShift;
146        sample = interp(&left, x);
147        out[outputIndex++] += vl * sample;
148        out[outputIndex++] += vr * sample;
149
150        // increment phase
151        phaseFraction += phaseIncrement;
152        uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
153        phaseFraction &= kPhaseMask;
154
155        // time to fetch another sample
156        while (indexIncrement--) {
157
158            inputIndex++;
159            if (inputIndex == mBuffer.frameCount) {
160                inputIndex = 0;
161                provider->releaseBuffer(&mBuffer);
162                mBuffer.frameCount = inFrameCount;
163                provider->getNextBuffer(&mBuffer);
164                if (mBuffer.raw == NULL)
165                    goto save_state;  // ugly, but efficient
166                // LOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
167                in = mBuffer.i16;
168            }
169
170            // advance sample state
171            advance(&left, in[inputIndex]);
172        }
173    }
174
175save_state:
176    // LOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
177    mInputIndex = inputIndex;
178    mPhaseFraction = phaseFraction;
179}
180
181// ----------------------------------------------------------------------------
182}
183; // namespace android
184
185