replicant-frameworks_native/libs/audioflinger/AudioResampler.cpp

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2008-10-21 14:00:00 +00:00
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
#include <cutils/log.h>
#include <cutils/properties.h>
#include "AudioResampler.h"
#include "AudioResamplerSinc.h"
#include "AudioResamplerCubic.h"
namespace android {
// ----------------------------------------------------------------------------
class AudioResamplerOrder1 : public AudioResampler {
public:
AudioResamplerOrder1(int bitDepth, int inChannelCount, int32_t sampleRate) :
AudioResampler(bitDepth, inChannelCount, sampleRate), mX0L(0), mX0R(0) {
}
virtual void resample(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider);
private:
// number of bits used in interpolation multiply - 15 bits avoids overflow
static const int kNumInterpBits = 15;
// bits to shift the phase fraction down to avoid overflow
static const int kPreInterpShift = kNumPhaseBits - kNumInterpBits;
void init() {}
void resampleMono16(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider);
void resampleStereo16(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider);
static inline int32_t Interp(int32_t x0, int32_t x1, uint32_t f) {
return x0 + (((x1 - x0) * (int32_t)(f >> kPreInterpShift)) >> kNumInterpBits);
}
static inline void Advance(size_t* index, uint32_t* frac, uint32_t inc) {
*frac += inc;
*index += (size_t)(*frac >> kNumPhaseBits);
*frac &= kPhaseMask;
}
int mX0L;
int mX0R;
};
// ----------------------------------------------------------------------------
AudioResampler* AudioResampler::create(int bitDepth, int inChannelCount,
int32_t sampleRate, int quality) {
// can only create low quality resample now
AudioResampler* resampler;
char value[PROPERTY_VALUE_MAX];
if (property_get("af.resampler.quality", value, 0)) {
quality = atoi(value);
LOGD("forcing AudioResampler quality to %d", quality);
}
if (quality == DEFAULT)
quality = LOW_QUALITY;
switch (quality) {
default:
case LOW_QUALITY:
resampler = new AudioResamplerOrder1(bitDepth, inChannelCount, sampleRate);
break;
case MED_QUALITY:
resampler = new AudioResamplerCubic(bitDepth, inChannelCount, sampleRate);
break;
case HIGH_QUALITY:
resampler = new AudioResamplerSinc(bitDepth, inChannelCount, sampleRate);
break;
}
// initialize resampler
resampler->init();
return resampler;
}
AudioResampler::AudioResampler(int bitDepth, int inChannelCount,
int32_t sampleRate) :
mBitDepth(bitDepth), mChannelCount(inChannelCount),
mSampleRate(sampleRate), mInSampleRate(sampleRate), mInputIndex(0),
mPhaseFraction(0) {
// sanity check on format
if ((bitDepth != 16) ||(inChannelCount < 1) || (inChannelCount > 2)) {
LOGE("Unsupported sample format, %d bits, %d channels", bitDepth,
inChannelCount);
// LOG_ASSERT(0);
}
// initialize common members
mVolume[0] = mVolume[1] = 0;
mBuffer.raw = NULL;
// save format for quick lookup
if (inChannelCount == 1) {
mFormat = MONO_16_BIT;
} else {
mFormat = STEREO_16_BIT;
}
}
AudioResampler::~AudioResampler() {
}
void AudioResampler::setSampleRate(int32_t inSampleRate) {
mInSampleRate = inSampleRate;
mPhaseIncrement = (uint32_t)((kPhaseMultiplier * inSampleRate) / mSampleRate);
}
void AudioResampler::setVolume(int16_t left, int16_t right) {
// TODO: Implement anti-zipper filter
mVolume[0] = left;
mVolume[1] = right;
}
// ----------------------------------------------------------------------------
void AudioResamplerOrder1::resample(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider) {
// should never happen, but we overflow if it does
// LOG_ASSERT(outFrameCount < 32767);
// select the appropriate resampler
switch (mChannelCount) {
case 1:
resampleMono16(out, outFrameCount, provider);
break;
case 2:
resampleStereo16(out, outFrameCount, provider);
break;
}
}
void AudioResamplerOrder1::resampleStereo16(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider) {
int32_t vl = mVolume[0];
int32_t vr = mVolume[1];
size_t inputIndex = mInputIndex;
uint32_t phaseFraction = mPhaseFraction;
uint32_t phaseIncrement = mPhaseIncrement;
size_t outputIndex = 0;
size_t outputSampleCount = outFrameCount * 2;
// LOGE("starting resample %d frames, inputIndex=%d, phaseFraction=%d, phaseIncrement=%d\n",
// outFrameCount, inputIndex, phaseFraction, phaseIncrement);
while (outputIndex < outputSampleCount) {
// buffer is empty, fetch a new one
if (mBuffer.raw == NULL) {
provider->getNextBuffer(&mBuffer);
if (mBuffer.raw == NULL)
break;
// LOGE("New buffer fetched: %d frames\n", mBuffer.frameCount);
}
int16_t *in = mBuffer.i16;
// handle boundary case
while (inputIndex == 0) {
// LOGE("boundary case\n");
out[outputIndex++] += vl * Interp(mX0L, in[0], phaseFraction);
out[outputIndex++] += vr * Interp(mX0R, in[1], phaseFraction);
Advance(&inputIndex, &phaseFraction, phaseIncrement);
if (outputIndex == outputSampleCount)
break;
}
// process input samples
// LOGE("general case\n");
while (outputIndex < outputSampleCount) {
out[outputIndex++] += vl * Interp(in[inputIndex*2-2],
in[inputIndex*2], phaseFraction);
out[outputIndex++] += vr * Interp(in[inputIndex*2-1],
in[inputIndex*2+1], phaseFraction);
Advance(&inputIndex, &phaseFraction, phaseIncrement);
if (inputIndex >= mBuffer.frameCount)
break;
}
// LOGE("loop done - outputIndex=%d, inputIndex=%d\n", outputIndex, inputIndex);
// if done with buffer, save samples
if (inputIndex >= mBuffer.frameCount) {
inputIndex -= mBuffer.frameCount;
// LOGE("buffer done, new input index", inputIndex);
mX0L = mBuffer.i16[mBuffer.frameCount*2-2];
mX0R = mBuffer.i16[mBuffer.frameCount*2-1];
provider->releaseBuffer(&mBuffer);
// verify that the releaseBuffer NULLS the buffer pointer
// LOG_ASSERT(mBuffer.raw == NULL);
}
}
// LOGE("output buffer full - outputIndex=%d, inputIndex=%d\n", outputIndex, inputIndex);
// save state
mInputIndex = inputIndex;
mPhaseFraction = phaseFraction;
}
void AudioResamplerOrder1::resampleMono16(int32_t* out, size_t outFrameCount,
AudioBufferProvider* provider) {
int32_t vl = mVolume[0];
int32_t vr = mVolume[1];
size_t inputIndex = mInputIndex;
uint32_t phaseFraction = mPhaseFraction;
uint32_t phaseIncrement = mPhaseIncrement;
size_t outputIndex = 0;
size_t outputSampleCount = outFrameCount * 2;
// LOGE("starting resample %d frames, inputIndex=%d, phaseFraction=%d, phaseIncrement=%d\n",
// outFrameCount, inputIndex, phaseFraction, phaseIncrement);
while (outputIndex < outputSampleCount) {
// buffer is empty, fetch a new one
if (mBuffer.raw == NULL) {
provider->getNextBuffer(&mBuffer);
if (mBuffer.raw == NULL)
break;
// LOGE("New buffer fetched: %d frames\n", mBuffer.frameCount);
}
int16_t *in = mBuffer.i16;
// handle boundary case
while (inputIndex == 0) {
// LOGE("boundary case\n");
int32_t sample = Interp(mX0L, in[0], phaseFraction);
out[outputIndex++] += vl * sample;
out[outputIndex++] += vr * sample;
Advance(&inputIndex, &phaseFraction, phaseIncrement);
if (outputIndex == outputSampleCount)
break;
}
// process input samples
// LOGE("general case\n");
while (outputIndex < outputSampleCount) {
int32_t sample = Interp(in[inputIndex-1], in[inputIndex],
phaseFraction);
out[outputIndex++] += vl * sample;
out[outputIndex++] += vr * sample;
Advance(&inputIndex, &phaseFraction, phaseIncrement);
if (inputIndex >= mBuffer.frameCount)
break;
}
// LOGE("loop done - outputIndex=%d, inputIndex=%d\n", outputIndex, inputIndex);
// if done with buffer, save samples
if (inputIndex >= mBuffer.frameCount) {
inputIndex -= mBuffer.frameCount;
// LOGE("buffer done, new input index", inputIndex);
mX0L = mBuffer.i16[mBuffer.frameCount-1];
provider->releaseBuffer(&mBuffer);
// verify that the releaseBuffer NULLS the buffer pointer
// LOG_ASSERT(mBuffer.raw == NULL);
}
}
// LOGE("output buffer full - outputIndex=%d, inputIndex=%d\n", outputIndex, inputIndex);
// save state
mInputIndex = inputIndex;
mPhaseFraction = phaseFraction;
}
// ----------------------------------------------------------------------------
}
; // namespace android