Move group audio playing to Audio singletong/thread

This is a bit of a quick fix for a new bug, as but part of cleaning up the audio code and moving it to the Audio singleton

src/audio.cpp

@@ -19,13 +19,31 @@
 #include "src/core.h"
 
 #include <QDebug>
+#include <QThread>
+
+#include <cassert>
 
 std::atomic<int> Audio::userCount{0};
+Audio* Audio::instance{nullptr};
+QThread* Audio::audioThread{nullptr};
 ALCdevice* Audio::alInDev{nullptr};
 ALCdevice* Audio::alOutDev{nullptr};
-ALCcontext* Audio::alContext{0};
+ALCcontext* Audio::alContext{nullptr};
 ALuint Audio::alMainSource{0};
 
+Audio& Audio::getInstance()
+{
+    if (!instance)
+    {
+        instance = new Audio();
+        audioThread = new QThread(instance);
+        audioThread->setObjectName("qTox Audio");
+        audioThread->start();
+        instance->moveToThread(audioThread);
+    }
+    return *instance;
+}
+
 void Audio::suscribeInput()
 {
     if (!userCount++ && alInDev)
@@ -125,3 +143,64 @@ void Audio::playMono16Sound(const QByteArray& data)
     alSourcePlay(alMainSource);
     alDeleteBuffers(1, &buffer);
 }
+
+void Audio::playGroupAudioQueued(Tox*,int group, int peer, const int16_t* data,
+                        unsigned samples, uint8_t channels, unsigned sample_rate,void*)
+{
+    QMetaObject::invokeMethod(instance, "playGroupAudio", Qt::BlockingQueuedConnection,
+                              Q_ARG(int,group), Q_ARG(int,peer), Q_ARG(const int16_t*,data),
+                              Q_ARG(unsigned,samples), Q_ARG(uint8_t,channels), Q_ARG(unsigned,sample_rate));
+}
+
+void Audio::playGroupAudio(int group, int peer, const int16_t* data,
+                           unsigned samples, uint8_t channels, unsigned sample_rate)
+{
+    assert(QThread::currentThread() == audioThread);
+
+    ToxGroupCall& call = Core::groupCalls[group];
+
+    if (!call.active || call.muteVol)
+        return;
+
+    if (!call.alSources.contains(peer))
+        alGenSources(1, &call.alSources[peer]);
+
+    playAudioBuffer(call.alSources[peer], data, samples, channels, sample_rate);
+}
+
+void Audio::playAudioBuffer(ALuint alSource, const int16_t *data, int samples, unsigned channels, int sampleRate)
+{
+    assert(channels == 1 || channels == 2);
+
+    ALuint bufid;
+    ALint processed = 0, queued = 16;
+    alGetSourcei(alSource, AL_BUFFERS_PROCESSED, &processed);
+    alGetSourcei(alSource, AL_BUFFERS_QUEUED, &queued);
+    alSourcei(alSource, AL_LOOPING, AL_FALSE);
+
+    if(processed)
+    {
+        ALuint bufids[processed];
+        alSourceUnqueueBuffers(alSource, processed, bufids);
+        alDeleteBuffers(processed - 1, bufids + 1);
+        bufid = bufids[0];
+    }
+    else if(queued < 16)
+    {
+        alGenBuffers(1, &bufid);
+    }
+    else
+    {
+        qDebug() << "Audio: Dropped frame";
+        return;
+    }
+
+    alBufferData(bufid, (channels == 1) ? AL_FORMAT_MONO16 : AL_FORMAT_STEREO16, data,
+                    samples * 2 * channels, sampleRate);
+    alSourceQueueBuffers(alSource, 1, &bufid);
+
+    ALint state;
+    alGetSourcei(alSource, AL_SOURCE_STATE, &state);
+    if(state != AL_PLAYING)
+        alSourcePlay(alSource);
+}

src/audio.h

@@ -18,6 +18,8 @@
 #ifndef AUDIO_H
 #define AUDIO_H
 
+#include <QObject>
+#include <QHash>
 #include <atomic>
 
 #if defined(__APPLE__) && defined(__MACH__)
@@ -30,10 +32,17 @@
 
 class QString;
 class QByteArray;
+class QTimer;
+class QThread;
+struct Tox;
 
-class Audio
+class Audio : QObject
 {
+    Q_OBJECT
+
 public:
+    static Audio& getInstance(); ///< Returns the singleton's instance. Will construct on first call.
+
     static void suscribeInput(); ///< Call when you need to capture sound from the open input device.
     static void unsuscribeInput(); ///< Call once you don't need to capture on the open input device anymore.
 
@@ -45,15 +54,28 @@ public:
 
     static void playMono16Sound(const QByteArray& data); ///< Play a 44100Hz mono 16bit PCM sound
 
+    /// May be called from any thread, will always queue a call to playGroupAudio
+    /// The first and last argument are ignored, but allow direct compatibility with toxcore
+    static void playGroupAudioQueued(Tox*, int group, int peer, const int16_t* data,
+                        unsigned samples, uint8_t channels, unsigned sample_rate, void*);
+
+public slots:
+    /// Must be called from the audio thread, plays a group call's received audio
+    void playGroupAudio(int group, int peer, const int16_t* data,
+                        unsigned samples, uint8_t channels, unsigned sample_rate);
+
 public:
+    static QThread* audioThread;
     static ALCdevice* alOutDev, *alInDev;
     static ALCcontext* alContext;
     static ALuint alMainSource;
 
 private:
-    Audio();
+    explicit Audio()=default;
+    static void playAudioBuffer(ALuint alSource, const int16_t *data, int samples, unsigned channels, int sampleRate);
 
 private:
+    static Audio* instance;
     static std::atomic<int> userCount;
 };
 

src/core.cpp

@@ -56,8 +56,7 @@ Core::Core(Camera* cam, QThread *CoreThread, QString loadPath) :
 
     coreThread = CoreThread;
 
-    audioThread = new QThread();
+    Audio::getInstance();
-    audioThread->start();
 
     videobuf = new uint8_t[videobufsize];
 
@@ -1496,7 +1495,8 @@ int Core::joinGroupchat(int32_t friendnumber, uint8_t type, const uint8_t* frien
     else if (type == TOX_GROUPCHAT_TYPE_AV)
     {
         qDebug() << QString("Trying to join AV groupchat invite sent by friend %1").arg(friendnumber);
-        return toxav_join_av_groupchat(tox, friendnumber, friend_group_public_key, length, playGroupAudio, const_cast<Core*>(this));
+        return toxav_join_av_groupchat(tox, friendnumber, friend_group_public_key, length,
+                                       &Audio::playGroupAudioQueued, const_cast<Core*>(this));
     }
     else
     {
@@ -1641,7 +1641,7 @@ void Core::createGroup(uint8_t type)
     }
     else if (type == TOX_GROUPCHAT_TYPE_AV)
     {
-        emit emptyGroupCreated(toxav_add_av_groupchat(tox, playGroupAudio, this));
+        emit emptyGroupCreated(toxav_add_av_groupchat(tox, &Audio::playGroupAudioQueued, this));
     }
     else
     {

src/core.h

@@ -250,8 +250,6 @@ private:
     static void onAvPeerTimeout(void* toxav, int32_t call_index, void* core);
     static void onAvMediaChange(void *toxav, int32_t call_index, void* core);
 
-    static void playGroupAudio(Tox* tox, int  groupnumber, int friendgroupnumber, const int16_t* out_audio,
-                unsigned out_audio_samples, uint8_t decoder_channels, unsigned audio_sample_rate, void* userdata);
     static void sendGroupCallAudio(int groupId, ToxAv* toxav);
 
     static void prepareCall(int friendId, int callId, ToxAv *toxav, bool videoEnabled);
@@ -295,7 +293,9 @@ private:
     static const int videobufsize;
     static uint8_t* videobuf;
 
-    static QThread *coreThread, *audioThread;
+    static QThread *coreThread;
+
+    friend class Audio; ///< Audio can access our calls directly to reduce latency
 };
 
 #endif // CORE_HPP

src/coreav.cpp

@@ -23,7 +23,6 @@
 ToxCall Core::calls[TOXAV_MAX_CALLS];
 const int Core::videobufsize{TOXAV_MAX_VIDEO_WIDTH * TOXAV_MAX_VIDEO_HEIGHT * 4};
 uint8_t* Core::videobuf;
-QThread* Core::audioThread{nullptr};
 
 bool Core::anyActiveCalls()
 {
@@ -590,22 +589,6 @@ VideoSource *Core::getVideoSourceFromCall(int callNumber)
     return &calls[callNumber].videoSource;
 }
 
-void Core::playGroupAudio(Tox* /*tox*/, int  groupnumber, int friendgroupnumber, const int16_t* out_audio,
-                unsigned out_audio_samples, uint8_t decoder_channels, unsigned audio_sample_rate, void* /*userdata*/)
-{
-    if (!groupCalls[groupnumber].active)
-        return;
-
-    if (groupCalls[groupnumber].muteVol)
-        return;
-
-    if (!groupCalls[groupnumber].alSources.contains(friendgroupnumber))
-        alGenSources(1, &groupCalls[groupnumber].alSources[friendgroupnumber]);
-
-    playAudioBuffer(groupCalls[groupnumber].alSources[friendgroupnumber], out_audio,
-                    out_audio_samples, decoder_channels, audio_sample_rate);
-}
-
 void Core::joinGroupCall(int groupId)
 {
     qDebug() << QString("Core: Joining group call %1").arg(groupId);
@@ -631,7 +614,6 @@ void Core::joinGroupCall(int groupId)
     groupCalls[groupId].sendAudioTimer->setSingleShot(true);
     connect(groupCalls[groupId].sendAudioTimer, &QTimer::timeout, [=](){sendGroupCallAudio(groupId,toxav);});
     groupCalls[groupId].sendAudioTimer->start();
-    groupCalls[groupId].sendAudioTimer->moveToThread(audioThread);
 }
 
 void Core::leaveGroupCall(int groupId)

src/widget/widget.cpp

@@ -187,6 +187,7 @@ void Widget::init()
     qRegisterMetaType<vpx_image>("vpx_image");
     qRegisterMetaType<uint8_t>("uint8_t");
     qRegisterMetaType<uint16_t>("uint16_t");
+    qRegisterMetaType<const int16_t*>("const int16_t*");
     qRegisterMetaType<int32_t>("int32_t");
     qRegisterMetaType<int64_t>("int64_t");
     qRegisterMetaType<QPixmap>("QPixmap");
@@ -196,6 +197,7 @@ void Widget::init()
 
     QString profilePath = detectProfile();
     coreThread = new QThread(this);
+    coreThread->setObjectName("qTox Core");
     core = new Core(Camera::getInstance(), coreThread, profilePath);
     core->moveToThread(coreThread);
     connect(coreThread, &QThread::started, core, &Core::start);