/**
* @brief Loads the OpenAL extension methods needed for echo cancellation
* @param dev OpenAL device used for the output
* @return True when functions successfully loaded, false otherwise
*/
bool OpenAL2::loadOpenALExtensions(ALCdevice* dev)
{
// load OpenAL extension functions
GET_PROC_ADDR(dev, alcLoopbackOpenDeviceSOFT);
checkAlcError(dev);
if (!alcLoopbackOpenDeviceSOFT) {
qDebug() << "Failed to load alcLoopbackOpenDeviceSOFT function!";
return false;
}
GET_PROC_ADDR(dev, alcIsRenderFormatSupportedSOFT);
checkAlcError(dev);
if (!alcIsRenderFormatSupportedSOFT) {
qDebug() << "Failed to load alcIsRenderFormatSupportedSOFT function!";
return false;
}
GET_PROC_ADDR(dev, alGetSourcedvSOFT);
checkAlcError(dev);
if (!alGetSourcedvSOFT) {
qDebug() << "Failed to load alGetSourcedvSOFT function!";
return false;
}
GET_PROC_ADDR(dev, alcRenderSamplesSOFT);
checkAlcError(dev);
if (!alcRenderSamplesSOFT) {
qDebug() << "Failed to load alcRenderSamplesSOFT function!";
return false;
}
return true;
}
/**
* @brief Open an audio output device
*/
bool OpenAL2::initOutput(const QString& deviceName)
{
peerSources.clear();
outputInitialized = false;
if (!Settings::getInstance().getAudioOutDevEnabled()) {
return false;
}
qDebug() << "Opening audio output" << deviceName;
assert(!alOutDev);
const QByteArray qDevName = deviceName.toUtf8();
const ALchar* tmpDevName = qDevName.isEmpty() ? nullptr : qDevName.constData();
alOutDev = alcOpenDevice(tmpDevName);
if (!alOutDev) {
qWarning() << "Cannot open output audio device" << deviceName;
return false;
}
qDebug() << "Opened audio output" << deviceName;
alOutContext = alcCreateContext(alOutDev, nullptr);
checkAlcError(alOutDev);
if (!alcMakeContextCurrent(alOutContext)) {
qWarning() << "Cannot create output audio context";
return false;
}
// try to init echo cancellation
echoCancelSupported = initOutputEchoCancel();
if (!echoCancelSupported) {
// fallback to normal, no proxy device needed
qDebug() << "Echo cancellation disabled";
alProxyDev = alOutDev;
alProxyContext = alOutContext;
}
alGenSources(1, &alMainSource);
checkAlError();
// init master volume
alListenerf(AL_GAIN, Settings::getInstance().getOutVolume() * 0.01f);
checkAlError();
Core* core = Core::getInstance();
if (core) {
// reset each call's audio source
core->getAv()->invalidateCallSources();
}
// ensure alProxyContext is active
alcMakeContextCurrent(alProxyContext);
outputInitialized = true;
return true;
}
/**
* @brief Handle audio output
*/
void OpenAL2::doOutput()
{
alcMakeContextCurrent(alOutContext);
ALuint bufids[PROXY_BUFFER_COUNT];
ALint processed = 0, queued = 0;
alGetSourcei(alProxySource, AL_BUFFERS_PROCESSED, &processed);
alGetSourcei(alProxySource, AL_BUFFERS_QUEUED, &queued);
if (processed > 0) {
// unqueue all processed buffers
alSourceUnqueueBuffers(alProxySource, processed, bufids);
// delete all but the first buffer, reuse first for new data
alDeleteBuffers(processed - 1, bufids + 1);
} else if (queued < PROXY_BUFFER_COUNT) {
// create new buffer until the maximum is reached
alGenBuffers(1, bufids);
} else {
alcMakeContextCurrent(alProxyContext);
return;
}
ALdouble latency[2] = {0};
alGetSourcedvSOFT(alProxySource, AL_SEC_OFFSET_LATENCY_SOFT, latency);
checkAlError();
ALshort outBuf[AUDIO_FRAME_SAMPLE_COUNT] = {0};
alcMakeContextCurrent(alProxyContext);
alcRenderSamplesSOFT(alProxyDev, outBuf, AUDIO_FRAME_SAMPLE_COUNT);
checkAlcError(alProxyDev);
alcMakeContextCurrent(alOutContext);
alBufferData(bufids[0], AL_FORMAT_MONO16, outBuf, AUDIO_FRAME_SAMPLE_COUNT * 2, AUDIO_SAMPLE_RATE);
alSourceQueueBuffers(alProxySource, 1, bufids);
// initialize echo canceler if supported
if (!filterer) {
filterer = new_filter_audio(AUDIO_SAMPLE_RATE);
int16_t filterLatency = latency[1] * 1000 * 2 + AUDIO_FRAME_DURATION;
qDebug() << "Setting filter delay to: " << filterLatency << "ms";
set_echo_delay_ms(filterer, filterLatency);
enable_disable_filters(filterer, 1, 1, 1, 0);
}
// do echo cancel
pass_audio_output(filterer, outBuf, AUDIO_FRAME_SAMPLE_COUNT);
ALint state;
alGetSourcei(alProxySource, AL_SOURCE_STATE, &state);
if (state != AL_PLAYING) {
qDebug() << "Proxy source underflow detected";
alSourcePlay(alProxySource);
}
alcMakeContextCurrent(alProxyContext);
}
/**
* @brief Open an audio output device
*/
bool Audio::initOutput(const QString& deviceName)
{
outSources.clear();
outputInitialized = false;
if (!Settings::getInstance().getAudioOutDevEnabled())
return false;
qDebug() << "Opening audio output" << deviceName;
assert(!alOutDev);
const QByteArray qDevName = deviceName.toUtf8();
const ALchar* tmpDevName = qDevName.isEmpty()
? nullptr
: qDevName.constData();
alOutDev = alcOpenDevice(tmpDevName);
if (!alOutDev)
{
qWarning() << "Cannot open output audio device" << deviceName;
return false;
}
qDebug() << "Opened audio output" << deviceName;
alOutContext = alcCreateContext(alOutDev, nullptr);
checkAlcError(alOutDev);
if (!alcMakeContextCurrent(alOutContext))
{
qWarning() << "Cannot create output audio context";
return false;
}
alGenSources(1, &alMainSource);
checkAlError();
// init master volume
alListenerf(AL_GAIN, Settings::getInstance().getOutVolume() * 0.01f);
checkAlError();
Core* core = Core::getInstance();
if (core)
{
// reset each call's audio source
core->getAv()->invalidateCallSources();
}
outputInitialized = true;
return true;
}
/**
* @brief Initializes the output with echo cancelling enabled
* @return true on success, false otherwise
* Creates a loopback device and a proxy source on the main output device.
* If this function returns true only the proxy source should be used for
* audio output.
*/
bool OpenAL2::initOutputEchoCancel()
{
// check for the needed extensions for echo cancelation
if (alcIsExtensionPresent(alOutDev, "ALC_SOFT_loopback") != AL_TRUE) {
qDebug() << "Device doesn't support loopback";
return false;
}
if (alIsExtensionPresent("AL_SOFT_source_latency") != AL_TRUE) {
qDebug() << "Device doesn't support source latency";
return false;
}
if (!loadOpenALExtensions(alOutDev)) {
qDebug() << "Couldn't load needed OpenAL extensions";
return false;
}
// source for proxy output
alGenSources(1, &alProxySource);
checkAlError();
// configuration for the loopback device
ALCint attrs[] = {ALC_FORMAT_CHANNELS_SOFT,
ALC_MONO_SOFT,
ALC_FORMAT_TYPE_SOFT,
ALC_SHORT_SOFT,
ALC_FREQUENCY,
Audio::AUDIO_SAMPLE_RATE,
0}; // End of List
alProxyDev = alcLoopbackOpenDeviceSOFT(NULL);
checkAlcError(alProxyDev);
if (!alProxyDev) {
qDebug() << "Couldn't create proxy device";
alDeleteSources(1, &alProxySource); // cleanup source
return false;
}
if (!alcIsRenderFormatSupportedSOFT(alProxyDev, attrs[5], attrs[1], attrs[3])) {
qDebug() << "Unsupported format for loopback";
alcCloseDevice(alProxyDev); // cleanup loopback dev
alDeleteSources(1, &alProxySource); // cleanup source
return false;
}
alProxyContext = alcCreateContext(alProxyDev, attrs);
checkAlcError(alProxyDev);
if (!alProxyContext) {
qDebug() << "Couldn't create proxy context";
alcCloseDevice(alProxyDev); // cleanup loopback dev
alDeleteSources(1, &alProxySource); // cleanup source
return false;
}
if (!alcMakeContextCurrent(alProxyContext)) {
qDebug() << "Cannot activate proxy context";
alcDestroyContext(alProxyContext);
alcCloseDevice(alProxyDev); // cleanup loopback dev
alDeleteSources(1, &alProxySource); // cleanup source
return false;
}
qDebug() << "Echo cancelation enabled";
return true;
}
