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#define LOG_TAG "AudioSRC"
18
19#include <stdint.h>
20#include <string.h>
21#include <sys/types.h>
22#include <cutils/log.h>
23
24#include "AudioResampler.h"
25#include "AudioResamplerCubic.h"
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    // ALOG_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, mPTS);
69        if (mBuffer.raw == NULL)
70            return;
71        // ALOGW("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                                        calculateOutputPTS(outputIndex / 2));
100                if (mBuffer.raw == NULL)
101                    goto save_state;  // ugly, but efficient
102                in = mBuffer.i16;
103                // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
104            }
105
106            // advance sample state
107            advance(&left, in[inputIndex*2]);
108            advance(&right, in[inputIndex*2+1]);
109        }
110    }
111
112save_state:
113    // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
114    mInputIndex = inputIndex;
115    mPhaseFraction = phaseFraction;
116}
117
118void AudioResamplerCubic::resampleMono16(int32_t* out, size_t outFrameCount,
119        AudioBufferProvider* provider) {
120
121    int32_t vl = mVolume[0];
122    int32_t vr = mVolume[1];
123
124    size_t inputIndex = mInputIndex;
125    uint32_t phaseFraction = mPhaseFraction;
126    uint32_t phaseIncrement = mPhaseIncrement;
127    size_t outputIndex = 0;
128    size_t outputSampleCount = outFrameCount * 2;
129    size_t inFrameCount = (outFrameCount*mInSampleRate)/mSampleRate;
130
131    // fetch first buffer
132    if (mBuffer.frameCount == 0) {
133        mBuffer.frameCount = inFrameCount;
134        provider->getNextBuffer(&mBuffer, mPTS);
135        if (mBuffer.raw == NULL)
136            return;
137        // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
138    }
139    int16_t *in = mBuffer.i16;
140
141    while (outputIndex < outputSampleCount) {
142        int32_t sample;
143        int32_t x;
144
145        // calculate output sample
146        x = phaseFraction >> kPreInterpShift;
147        sample = interp(&left, x);
148        out[outputIndex++] += vl * sample;
149        out[outputIndex++] += vr * sample;
150
151        // increment phase
152        phaseFraction += phaseIncrement;
153        uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
154        phaseFraction &= kPhaseMask;
155
156        // time to fetch another sample
157        while (indexIncrement--) {
158
159            inputIndex++;
160            if (inputIndex == mBuffer.frameCount) {
161                inputIndex = 0;
162                provider->releaseBuffer(&mBuffer);
163                mBuffer.frameCount = inFrameCount;
164                provider->getNextBuffer(&mBuffer,
165                                        calculateOutputPTS(outputIndex / 2));
166                if (mBuffer.raw == NULL)
167                    goto save_state;  // ugly, but efficient
168                // ALOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
169                in = mBuffer.i16;
170            }
171
172            // advance sample state
173            advance(&left, in[inputIndex]);
174        }
175    }
176
177save_state:
178    // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
179    mInputIndex = inputIndex;
180    mPhaseFraction = phaseFraction;
181}
182
183// ----------------------------------------------------------------------------
184}
185; // namespace android
186