[go: nahoru, domu]
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 "AudioResamplerCubic"
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
35size_t 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        return resampleMono16(out, outFrameCount, provider);
45    case 2:
46        return resampleStereo16(out, outFrameCount, provider);
47    default:
48        LOG_ALWAYS_FATAL("invalid channel count: %d", mChannelCount);
49        return 0;
50    }
51}
52
53size_t AudioResamplerCubic::resampleStereo16(int32_t* out, size_t outFrameCount,
54        AudioBufferProvider* provider) {
55
56    int32_t vl = mVolume[0];
57    int32_t vr = mVolume[1];
58
59    size_t inputIndex = mInputIndex;
60    uint32_t phaseFraction = mPhaseFraction;
61    uint32_t phaseIncrement = mPhaseIncrement;
62    size_t outputIndex = 0;
63    size_t outputSampleCount = outFrameCount * 2;
64    size_t inFrameCount = getInFrameCountRequired(outFrameCount);
65
66    // fetch first buffer
67    if (mBuffer.frameCount == 0) {
68        mBuffer.frameCount = inFrameCount;
69        provider->getNextBuffer(&mBuffer);
70        if (mBuffer.raw == NULL) {
71            return 0;
72        }
73        // ALOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
74    }
75    int16_t *in = mBuffer.i16;
76
77    while (outputIndex < outputSampleCount) {
78        int32_t x;
79
80        // calculate output sample
81        x = phaseFraction >> kPreInterpShift;
82        out[outputIndex++] += vl * interp(&left, x);
83        out[outputIndex++] += vr * interp(&right, x);
84        // out[outputIndex++] += vr * in[inputIndex*2];
85
86        // increment phase
87        phaseFraction += phaseIncrement;
88        uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
89        phaseFraction &= kPhaseMask;
90
91        // time to fetch another sample
92        while (indexIncrement--) {
93
94            inputIndex++;
95            if (inputIndex == mBuffer.frameCount) {
96                inputIndex = 0;
97                provider->releaseBuffer(&mBuffer);
98                mBuffer.frameCount = inFrameCount;
99                provider->getNextBuffer(&mBuffer);
100                if (mBuffer.raw == NULL) {
101                    goto save_state;  // ugly, but efficient
102                }
103                in = mBuffer.i16;
104                // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
105            }
106
107            // advance sample state
108            advance(&left, in[inputIndex*2]);
109            advance(&right, in[inputIndex*2+1]);
110        }
111    }
112
113save_state:
114    // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
115    mInputIndex = inputIndex;
116    mPhaseFraction = phaseFraction;
117    return outputIndex / 2 /* channels for stereo */;
118}
119
120size_t AudioResamplerCubic::resampleMono16(int32_t* out, size_t outFrameCount,
121        AudioBufferProvider* provider) {
122
123    int32_t vl = mVolume[0];
124    int32_t vr = mVolume[1];
125
126    size_t inputIndex = mInputIndex;
127    uint32_t phaseFraction = mPhaseFraction;
128    uint32_t phaseIncrement = mPhaseIncrement;
129    size_t outputIndex = 0;
130    size_t outputSampleCount = outFrameCount * 2;
131    size_t inFrameCount = getInFrameCountRequired(outFrameCount);
132
133    // fetch first buffer
134    if (mBuffer.frameCount == 0) {
135        mBuffer.frameCount = inFrameCount;
136        provider->getNextBuffer(&mBuffer);
137        if (mBuffer.raw == NULL) {
138            return 0;
139        }
140        // ALOGW("New buffer: offset=%p, frames=%d", mBuffer.raw, mBuffer.frameCount);
141    }
142    int16_t *in = mBuffer.i16;
143
144    while (outputIndex < outputSampleCount) {
145        int32_t sample;
146        int32_t x;
147
148        // calculate output sample
149        x = phaseFraction >> kPreInterpShift;
150        sample = interp(&left, x);
151        out[outputIndex++] += vl * sample;
152        out[outputIndex++] += vr * sample;
153
154        // increment phase
155        phaseFraction += phaseIncrement;
156        uint32_t indexIncrement = (phaseFraction >> kNumPhaseBits);
157        phaseFraction &= kPhaseMask;
158
159        // time to fetch another sample
160        while (indexIncrement--) {
161
162            inputIndex++;
163            if (inputIndex == mBuffer.frameCount) {
164                inputIndex = 0;
165                provider->releaseBuffer(&mBuffer);
166                mBuffer.frameCount = inFrameCount;
167                provider->getNextBuffer(&mBuffer);
168                if (mBuffer.raw == NULL) {
169                    goto save_state;  // ugly, but efficient
170                }
171                // ALOGW("New buffer: offset=%p, frames=%dn", mBuffer.raw, mBuffer.frameCount);
172                in = mBuffer.i16;
173            }
174
175            // advance sample state
176            advance(&left, in[inputIndex]);
177        }
178    }
179
180save_state:
181    // ALOGW("Done: index=%d, fraction=%u", inputIndex, phaseFraction);
182    mInputIndex = inputIndex;
183    mPhaseFraction = phaseFraction;
184    return outputIndex;
185}
186
187// ----------------------------------------------------------------------------
188} // namespace android
189