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Change OpenSL ES input stream from stereo to mono #6

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Change OpenSL ES input stream from stereo to mono #6

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75cfece
Change OpenSL ES input stream from stereo to mono
dturner Oct 31, 2017
c6a7471
Only requesting mono input on Android 8.0
dturner Nov 1, 2017
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43 changes: 33 additions & 10 deletions Android/app/src/main/jni/SuperpoweredLatency.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,12 @@ static latencyMeasurer *measurer;
static bool hasAAudio = false;
static bool isRunning = false;

constexpr int kChannelCountMono = 1;
constexpr int kChannelCountStereo = 2;
constexpr int kBytesIn16BitSample = 2;
constexpr int kBytesPerStereoAudioFrame = kChannelCountStereo * kBytesIn16BitSample;


// ---------
// OPENSL ES
// ---------
Expand All @@ -28,14 +34,26 @@ static struct {
SLAndroidSimpleBufferQueueItf outputBufferQueueInterface, inputBufferQueueInterface;
short int *inputBuffers[NUMOPENSLESBUFFERS], *outputBuffers[NUMOPENSLESBUFFERS];
int samplerateFromJava, buffersizeFromJava, inputBufferWriteIndex, inputBufferReadIndex, inputBuffersAvailable, outputBufferWriteIndex;
SLuint32 inputChannelCount = kChannelCountStereo;
} openSLES;

// Note: input array must be at least 2 * numFrames in size
static void convertBufferToStereo(short int *buffer, const int numFrames){
for (int i = numFrames - 1; i >=0; --i) {
buffer[i*2] = buffer[i];
buffer[(i*2)+1] = buffer[i];
}
}

// Audio input comes here.
static void openSLESInputCallback(SLAndroidSimpleBufferQueueItf caller, __unused void *pContext) {
__sync_fetch_and_add(&openSLES.inputBuffersAvailable, 1);
short int *inputBuffer = openSLES.inputBuffers[openSLES.inputBufferWriteIndex];
if (openSLES.inputBufferWriteIndex < NUMOPENSLESBUFFERS - 1) openSLES.inputBufferWriteIndex++; else openSLES.inputBufferWriteIndex = 0;
(*caller)->Enqueue(caller, inputBuffer, (SLuint32)buffersize * 4);
(*caller)->Enqueue(caller, inputBuffer, (SLuint32)buffersize * openSLES.inputChannelCount * kBytesIn16BitSample);
if (openSLES.inputChannelCount == kChannelCountMono){
convertBufferToStereo(inputBuffer, (SLuint32)buffersize);
}
}

// Audio output must be provided here.
Expand All @@ -50,28 +68,33 @@ static void openSLESOutputCallback(SLAndroidSimpleBufferQueueItf caller, __unuse

measurer->processInput(inputBuffer, samplerate, buffersize);
measurer->processOutput(outputBuffer);
if (measurer->state == -1) memcpy(outputBuffer, inputBuffer, (size_t)buffersize * 4);
} else memset(outputBuffer, 0, (size_t)buffersize * 4);
if (measurer->state == -1) memcpy(outputBuffer, inputBuffer, (size_t)buffersize * kChannelCountStereo * kBytesIn16BitSample);
} else memset(outputBuffer, 0, (size_t)buffersize * kChannelCountStereo * kBytesIn16BitSample);

(*caller)->Enqueue(caller, outputBuffer, (SLuint32)buffersize * 4);
(*caller)->Enqueue(caller, outputBuffer, (SLuint32)buffersize * kChannelCountStereo * kBytesIn16BitSample);
}

static void startOpenSLES() {
hasAAudio = false;
samplerate = openSLES.samplerateFromJava;
buffersize = openSLES.buffersizeFromJava;

// If on Android 8.0 then use a mono input stream
if (__ANDROID_API__ == __ANDROID_API_O__) openSLES.inputChannelCount = kChannelCountMono;

openSLES.inputBufferWriteIndex = 1; // Start from 1, because we enqueue one buffer when we start the input buffer queue.
openSLES.inputBufferReadIndex = 0;
openSLES.inputBuffersAvailable = 0;
openSLES.outputBufferWriteIndex = 1; // Start from 1, because we enqueue one buffer when we start the output buffer queue.

// Allocating audio buffers for input and output.
// Note that regardless of the input channel count we still allocate enough for stereo audio
// frames so we can do the mono->stereo conversion.
for (int n = 0; n < NUMOPENSLESBUFFERS; n++) {
openSLES.inputBuffers[n] = (short int *)malloc(((size_t)buffersize + 16) * 4);
openSLES.outputBuffers[n] = (short int *)malloc(((size_t)buffersize + 16) * 4);
memset(openSLES.inputBuffers[n], 0, (size_t)buffersize * 4);
memset(openSLES.outputBuffers[n], 0, (size_t)buffersize * 4);
openSLES.inputBuffers[n] = (short int *)malloc(((size_t)buffersize + 16) * kBytesPerStereoAudioFrame);
openSLES.outputBuffers[n] = (short int *)malloc(((size_t)buffersize + 16) * kBytesPerStereoAudioFrame);
memset(openSLES.inputBuffers[n], 0, (size_t)buffersize * kBytesPerStereoAudioFrame);
memset(openSLES.outputBuffers[n], 0, (size_t)buffersize * kBytesPerStereoAudioFrame);
};

const SLboolean requireds[2] = { SL_BOOLEAN_TRUE, SL_BOOLEAN_FALSE };
Expand All @@ -88,7 +111,7 @@ static void startOpenSLES() {

// Create the output buffer queue.
SLDataLocator_AndroidSimpleBufferQueue outputLocator = { SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 1 };
SLDataFormat_PCM outputFormat = { SL_DATAFORMAT_PCM, 2, (SLuint32)samplerate * 1000, SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16, SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, SL_BYTEORDER_LITTLEENDIAN };
SLDataFormat_PCM outputFormat = { SL_DATAFORMAT_PCM, kChannelCountStereo, (SLuint32)samplerate * 1000, SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16, SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, SL_BYTEORDER_LITTLEENDIAN };
SLDataSource outputSource = { &outputLocator, &outputFormat };
const SLInterfaceID outputInterfaces[1] = { SL_IID_BUFFERQUEUE };
SLDataSink outputSink = { &outputMixLocator, NULL };
Expand All @@ -99,7 +122,7 @@ static void startOpenSLES() {
SLDataLocator_IODevice deviceInputLocator = { SL_DATALOCATOR_IODEVICE, SL_IODEVICE_AUDIOINPUT, SL_DEFAULTDEVICEID_AUDIOINPUT, NULL };
SLDataSource inputSource = { &deviceInputLocator, NULL };
SLDataLocator_AndroidSimpleBufferQueue inputLocator = { SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 1 };
SLDataFormat_PCM inputFormat = { SL_DATAFORMAT_PCM, 2, (SLuint32)samplerate * 1000, SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16, SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, SL_BYTEORDER_LITTLEENDIAN };
SLDataFormat_PCM inputFormat = { SL_DATAFORMAT_PCM, openSLES.inputChannelCount, (SLuint32)samplerate * 1000, SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16, SL_SPEAKER_FRONT_CENTER, SL_BYTEORDER_LITTLEENDIAN };
SLDataSink inputSink = { &inputLocator, &inputFormat };
const SLInterfaceID inputInterfaces[2] = { SL_IID_ANDROIDSIMPLEBUFFERQUEUE, SL_IID_ANDROIDCONFIGURATION };
(*openSLEngineInterface)->CreateAudioRecorder(openSLEngineInterface, &openSLES.inputBufferQueue, &inputSource, &inputSink, 2, inputInterfaces, requireds);
Expand Down