Bring back FMOD, to be used on Fedora only, though

https://megapahit.com/show_bug.cgi?id=64

Dullahan is still not working, something in webrtc-voice is breaking
it too. But at least we're halfway now that we don't have to use
Fedora's OpenAL that is in conflict with Dullahan/CEF.

7 files changed, 1660 insertions, 0 deletions

diff --git a/indra/llaudio/CMakeLists.txt b/indra/llaudio/CMakeLists.txt
index ba043f8fec..f36da83c69 100644
--- a/indra/llaudio/CMakeLists.txt
+++ b/indra/llaudio/CMakeLists.txt
@@ -4,6 +4,7 @@ project(llaudio)
 
 include(00-Common)
 include(LLAudio)
+include(FMODSTUDIO)
 include(OPENAL)
 include(LLCommon)
 
@@ -24,6 +25,20 @@ set(llaudio_HEADER_FILES
     llwindgen.h
     )
 
+if (TARGET ll::fmodstudio)
+    list(APPEND llaudio_SOURCE_FILES
+         llaudioengine_fmodstudio.cpp
+         lllistener_fmodstudio.cpp
+         llstreamingaudio_fmodstudio.cpp
+         )
+
+    list(APPEND llaudio_HEADER_FILES
+         llaudioengine_fmodstudio.h
+         lllistener_fmodstudio.h
+         llstreamingaudio_fmodstudio.h
+         )
+endif ()
+
 if (TARGET ll::openal)
   list(APPEND llaudio_SOURCE_FILES
     llaudioengine_openal.cpp
diff --git a/indra/llaudio/llaudioengine_fmodstudio.cpp b/indra/llaudio/llaudioengine_fmodstudio.cpp
new file mode 100644
index 0000000000..b4e8407083
--- /dev/null
+++ b/indra/llaudio/llaudioengine_fmodstudio.cpp
@@ -0,0 +1,756 @@
+/**
+ * @file audioengine_fmodstudio.cpp
+ * @brief Implementation of LLAudioEngine class abstracting the audio
+ * support as a FMODSTUDIO implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+
+#include "llstreamingaudio.h"
+#include "llstreamingaudio_fmodstudio.h"
+
+#include "llaudioengine_fmodstudio.h"
+#include "lllistener_fmodstudio.h"
+
+#include "llerror.h"
+#include "llmath.h"
+#include "llrand.h"
+
+#include "fmodstudio/fmod.hpp"
+#include "fmodstudio/fmod_errors.h"
+#include "lldir.h"
+#include "llapr.h"
+
+#include "sound_ids.h"
+
+FMOD_RESULT F_CALLBACK windCallback(FMOD_DSP_STATE *dsp_state, float *inbuffer, float *outbuffer, unsigned int length, int inchannels, int *outchannels);
+
+FMOD::ChannelGroup *LLAudioEngine_FMODSTUDIO::mChannelGroups[LLAudioEngine::AUDIO_TYPE_COUNT] = {0};
+
+LLAudioEngine_FMODSTUDIO::LLAudioEngine_FMODSTUDIO(bool enable_profiler)
+:   mInited(false),
+    mWindGen(NULL),
+    mWindDSP(NULL),
+    mSystem(NULL),
+    mEnableProfiler(enable_profiler),
+    mWindDSPDesc(NULL)
+{
+}
+
+
+LLAudioEngine_FMODSTUDIO::~LLAudioEngine_FMODSTUDIO()
+{
+    // mWindDSPDesc, mWindGen and mWindDSP get cleaned up on cleanupWind in LLAudioEngine::shutdown()
+    // mSystem gets cleaned up at shutdown()
+}
+
+
+static inline bool Check_FMOD_Error(FMOD_RESULT result, const char *string)
+{
+    if (result == FMOD_OK)
+        return false;
+    LL_DEBUGS("FMOD") << string << " Error: " << FMOD_ErrorString(result) << LL_ENDL;
+    return true;
+}
+
+bool LLAudioEngine_FMODSTUDIO::init(void* userdata, const std::string &app_title)
+{
+    U32 version;
+    FMOD_RESULT result;
+
+    LL_DEBUGS("AppInit") << "LLAudioEngine_FMODSTUDIO::init() initializing FMOD" << LL_ENDL;
+
+    result = FMOD::System_Create(&mSystem);
+    if (Check_FMOD_Error(result, "FMOD::System_Create"))
+        return false;
+
+    //will call LLAudioEngine_FMODSTUDIO::allocateListener, which needs a valid mSystem pointer.
+    LLAudioEngine::init(userdata, app_title);
+
+    result = mSystem->getVersion(&version);
+    Check_FMOD_Error(result, "FMOD::System::getVersion");
+
+    if (version < FMOD_VERSION)
+    {
+        LL_WARNS("AppInit") << "FMOD Studio version mismatch, actual: " << version
+            << " expected:" << FMOD_VERSION << LL_ENDL;
+    }
+
+    // In this case, all sounds, PLUS wind and stream will be software.
+    result = mSystem->setSoftwareChannels(LL_MAX_AUDIO_CHANNELS + 2);
+    Check_FMOD_Error(result, "FMOD::System::setSoftwareChannels");
+
+    FMOD_ADVANCEDSETTINGS settings;
+    memset(&settings, 0, sizeof(settings));
+    settings.cbSize = sizeof(FMOD_ADVANCEDSETTINGS);
+    settings.resamplerMethod = FMOD_DSP_RESAMPLER_LINEAR;
+
+    result = mSystem->setAdvancedSettings(&settings);
+    Check_FMOD_Error(result, "FMOD::System::setAdvancedSettings");
+
+    // FMOD_INIT_THREAD_UNSAFE Disables thread safety for API calls.
+    // Only use this if FMOD is being called from a single thread, and if Studio API is not being used.
+    U32 fmod_flags = FMOD_INIT_NORMAL | FMOD_INIT_3D_RIGHTHANDED | FMOD_INIT_THREAD_UNSAFE;
+    if (mEnableProfiler)
+    {
+        fmod_flags |= FMOD_INIT_PROFILE_ENABLE;
+    }
+
+#if LL_LINUX
+    bool audio_ok = false;
+
+    if (!audio_ok)
+    {
+        const char* env_string = getenv("LL_BAD_FMOD_PULSEAUDIO");
+        if (NULL == env_string)
+        {
+            LL_DEBUGS("AppInit") << "Trying PulseAudio audio output..." << LL_ENDL;
+            if (mSystem->setOutput(FMOD_OUTPUTTYPE_PULSEAUDIO) == FMOD_OK &&
+                (result = mSystem->init(LL_MAX_AUDIO_CHANNELS + 2, fmod_flags, const_cast<char*>(app_title.c_str()))) == FMOD_OK)
+            {
+                LL_DEBUGS("AppInit") << "PulseAudio output initialized OKAY" << LL_ENDL;
+                audio_ok = true;
+            }
+            else
+            {
+                Check_FMOD_Error(result, "PulseAudio audio output FAILED to initialize");
+            }
+        }
+        else
+        {
+            LL_DEBUGS("AppInit") << "PulseAudio audio output SKIPPED" << LL_ENDL;
+        }
+    }
+    if (!audio_ok)
+    {
+        const char* env_string = getenv("LL_BAD_FMOD_ALSA");
+        if (NULL == env_string)
+        {
+            LL_DEBUGS("AppInit") << "Trying ALSA audio output..." << LL_ENDL;
+            if (mSystem->setOutput(FMOD_OUTPUTTYPE_ALSA) == FMOD_OK &&
+                (result = mSystem->init(LL_MAX_AUDIO_CHANNELS + 2, fmod_flags, 0)) == FMOD_OK)
+            {
+                LL_DEBUGS("AppInit") << "ALSA audio output initialized OKAY" << LL_ENDL;
+                audio_ok = true;
+            }
+            else
+            {
+                Check_FMOD_Error(result, "ALSA audio output FAILED to initialize");
+            }
+        }
+        else
+        {
+            LL_DEBUGS("AppInit") << "ALSA audio output SKIPPED" << LL_ENDL;
+        }
+    }
+    if (!audio_ok)
+    {
+        LL_WARNS("AppInit") << "Overall audio init failure." << LL_ENDL;
+        return false;
+    }
+
+    // We're interested in logging which output method we
+    // ended up with, for QA purposes.
+    FMOD_OUTPUTTYPE output_type;
+    mSystem->getOutput(&output_type);
+    switch (output_type)
+    {
+    case FMOD_OUTPUTTYPE_NOSOUND:
+        LL_INFOS("AppInit") << "Audio output: NoSound" << LL_ENDL; break;
+    case FMOD_OUTPUTTYPE_PULSEAUDIO:
+        LL_INFOS("AppInit") << "Audio output: PulseAudio" << LL_ENDL; break;
+    case FMOD_OUTPUTTYPE_ALSA:
+        LL_INFOS("AppInit") << "Audio output: ALSA" << LL_ENDL; break;
+    default:
+        LL_INFOS("AppInit") << "Audio output: Unknown!" << LL_ENDL; break;
+    };
+#else // LL_LINUX
+
+    // initialize the FMOD engine
+    // number of channel in this case looks to be identiacal to number of max simultaneously
+    // playing objects and we can set practically any number
+    result = mSystem->init(LL_MAX_AUDIO_CHANNELS + 2, fmod_flags, 0);
+    if (Check_FMOD_Error(result, "Error initializing FMOD Studio with default settins, retrying with other format"))
+    {
+        result = mSystem->setSoftwareFormat(44100, FMOD_SPEAKERMODE_STEREO, 0/*- ignore*/);
+        if (Check_FMOD_Error(result, "Error setting sotware format. Can't init."))
+        {
+            return false;
+        }
+        result = mSystem->init(LL_MAX_AUDIO_CHANNELS + 2, fmod_flags, 0);
+    }
+    if (Check_FMOD_Error(result, "Error initializing FMOD Studio"))
+    {
+        // If it fails here and (result == FMOD_ERR_OUTPUT_CREATEBUFFER),
+        // we can retry with other settings
+        return false;
+    }
+#endif
+
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init() FMOD Studio initialized correctly" << LL_ENDL;
+
+    int r_numbuffers, r_samplerate, r_channels;
+    unsigned int r_bufferlength;
+    char r_name[512];
+    int latency = 100;
+    mSystem->getDSPBufferSize(&r_bufferlength, &r_numbuffers);
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init(): r_bufferlength=" << r_bufferlength << " bytes" << LL_ENDL;
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init(): r_numbuffers=" << r_numbuffers << LL_ENDL;
+
+    mSystem->getDriverInfo(0, r_name, 511, NULL, &r_samplerate, NULL, &r_channels);
+    r_name[511] = '\0';
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init(): r_name=\"" << r_name << "\"" << LL_ENDL;
+
+    if (r_samplerate != 0)
+        latency = (int)(1000.0f * r_bufferlength * r_numbuffers / r_samplerate);
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init(): latency=" << latency << "ms" << LL_ENDL;
+
+    mInited = true;
+
+    LL_INFOS("AppInit") << "LLAudioEngine_FMODSTUDIO::init(): initialization complete." << LL_ENDL;
+
+    return true;
+}
+
+
+std::string LLAudioEngine_FMODSTUDIO::getDriverName(bool verbose)
+{
+    llassert_always(mSystem);
+    if (verbose)
+    {
+        U32 version;
+        if (!Check_FMOD_Error(mSystem->getVersion(&version), "FMOD::System::getVersion"))
+        {
+            return llformat("FMOD Studio %1x.%02x.%02x (Firelight Technologies Pty Ltd)", version >> 16, version >> 8 & 0x000000FF, version & 0x000000FF);
+        }
+    }
+    return "FMOD STUDIO";
+}
+
+
+// create our favourite FMOD-native streaming audio implementation
+LLStreamingAudioInterface *LLAudioEngine_FMODSTUDIO::createDefaultStreamingAudioImpl() const
+{
+    return new LLStreamingAudio_FMODSTUDIO(mSystem);
+}
+
+
+void LLAudioEngine_FMODSTUDIO::allocateListener(void)
+{
+    mListenerp = (LLListener *) new LLListener_FMODSTUDIO(mSystem);
+    if (!mListenerp)
+    {
+        LL_WARNS("FMOD") << "Listener creation failed" << LL_ENDL;
+    }
+}
+
+
+void LLAudioEngine_FMODSTUDIO::shutdown()
+{
+    stopInternetStream();
+
+    LL_INFOS("FMOD") << "About to LLAudioEngine::shutdown()" << LL_ENDL;
+    LLAudioEngine::shutdown();
+
+    LL_INFOS("FMOD") << "LLAudioEngine_FMODSTUDIO::shutdown() closing FMOD Studio" << LL_ENDL;
+    if (mSystem)
+    {
+        mSystem->close();
+        mSystem->release();
+    }
+    LL_INFOS("FMOD") << "LLAudioEngine_FMODSTUDIO::shutdown() done closing FMOD Studio" << LL_ENDL;
+
+    delete mListenerp;
+    mListenerp = NULL;
+}
+
+
+LLAudioBuffer * LLAudioEngine_FMODSTUDIO::createBuffer()
+{
+    return new LLAudioBufferFMODSTUDIO(mSystem);
+}
+
+
+LLAudioChannel * LLAudioEngine_FMODSTUDIO::createChannel()
+{
+    return new LLAudioChannelFMODSTUDIO(mSystem);
+}
+
+bool LLAudioEngine_FMODSTUDIO::initWind()
+{
+    mNextWindUpdate = 0.0;
+
+    if (!mWindDSPDesc)
+    {
+        mWindDSPDesc = new FMOD_DSP_DESCRIPTION();
+    }
+
+    if (!mWindDSP)
+    {
+        memset(mWindDSPDesc, 0, sizeof(*mWindDSPDesc)); //Set everything to zero
+        strncpy(mWindDSPDesc->name, "Wind Unit", sizeof(mWindDSPDesc->name));
+        mWindDSPDesc->pluginsdkversion = FMOD_PLUGIN_SDK_VERSION;
+        mWindDSPDesc->read = &windCallback; // Assign callback - may be called from arbitrary threads
+        if (Check_FMOD_Error(mSystem->createDSP(mWindDSPDesc, &mWindDSP), "FMOD::createDSP"))
+            return false;
+
+        if (mWindGen)
+            delete mWindGen;
+
+        int frequency = 44100;
+
+        FMOD_SPEAKERMODE mode;
+        if (Check_FMOD_Error(mSystem->getSoftwareFormat(&frequency, &mode, nullptr), "FMOD::System::getSoftwareFormat"))
+        {
+            cleanupWind();
+            return false;
+        }
+
+        mWindGen = new LLWindGen<MIXBUFFERFORMAT>((U32)frequency);
+
+        if (Check_FMOD_Error(mWindDSP->setUserData((void*)mWindGen), "FMOD::DSP::setUserData"))
+        {
+            cleanupWind();
+            return false;
+        }
+        if (Check_FMOD_Error(mWindDSP->setChannelFormat(FMOD_CHANNELMASK_STEREO, 2, mode), "FMOD::DSP::setChannelFormat"))
+        {
+            cleanupWind();
+            return false;
+        }
+    }
+
+    // *TODO:  Should this guard against multiple plays?
+    if (Check_FMOD_Error(mSystem->playDSP(mWindDSP, nullptr, false, nullptr), "FMOD::System::playDSP"))
+    {
+        cleanupWind();
+        return false;
+    }
+    return true;
+}
+
+
+void LLAudioEngine_FMODSTUDIO::cleanupWind()
+{
+    if (mWindDSP)
+    {
+        FMOD::ChannelGroup* master_group = NULL;
+        if (!Check_FMOD_Error(mSystem->getMasterChannelGroup(&master_group), "FMOD::System::getMasterChannelGroup")
+            && master_group)
+        {
+            master_group->removeDSP(mWindDSP);
+        }
+        mWindDSP->release();
+        mWindDSP = NULL;
+    }
+
+    delete mWindDSPDesc;
+    mWindDSPDesc = NULL;
+
+    delete mWindGen;
+    mWindGen = NULL;
+}
+
+
+//-----------------------------------------------------------------------
+void LLAudioEngine_FMODSTUDIO::updateWind(LLVector3 wind_vec, F32 camera_height_above_water)
+{
+    LLVector3 wind_pos;
+    F64 pitch;
+    F64 center_freq;
+
+    if (!mEnableWind)
+    {
+        return;
+    }
+
+    if (mWindUpdateTimer.checkExpirationAndReset(LL_WIND_UPDATE_INTERVAL))
+    {
+
+        // wind comes in as Linden coordinate (+X = forward, +Y = left, +Z = up)
+        // need to convert this to the conventional orientation DS3D and OpenAL use
+        // where +X = right, +Y = up, +Z = backwards
+
+        wind_vec.setVec(-wind_vec.mV[1], wind_vec.mV[2], -wind_vec.mV[0]);
+
+        // cerr << "Wind update" << endl;
+
+        pitch = 1.0 + mapWindVecToPitch(wind_vec);
+        center_freq = 80.0 * pow(pitch, 2.5*(mapWindVecToGain(wind_vec) + 1.0));
+
+        mWindGen->mTargetFreq = (F32)center_freq;
+        mWindGen->mTargetGain = (F32)mapWindVecToGain(wind_vec) * mMaxWindGain;
+        mWindGen->mTargetPanGainR = (F32)mapWindVecToPan(wind_vec);
+    }
+}
+
+//-----------------------------------------------------------------------
+void LLAudioEngine_FMODSTUDIO::setInternalGain(F32 gain)
+{
+    if (!mInited)
+    {
+        return;
+    }
+
+    gain = llclamp(gain, 0.0f, 1.0f);
+
+    FMOD::ChannelGroup* master_group = NULL;
+    if (!Check_FMOD_Error(mSystem->getMasterChannelGroup(&master_group), "FMOD::System::getMasterChannelGroup")
+        && master_group)
+    {
+        master_group->setVolume(gain);
+    }
+
+    LLStreamingAudioInterface *saimpl = getStreamingAudioImpl();
+    if (saimpl)
+    {
+        // fmod likes its streaming audio channel gain re-asserted after
+        // master volume change.
+        saimpl->setGain(saimpl->getGain());
+    }
+}
+
+//
+// LLAudioChannelFMODSTUDIO implementation
+//
+
+LLAudioChannelFMODSTUDIO::LLAudioChannelFMODSTUDIO(FMOD::System *system) : LLAudioChannel(), mSystemp(system), mChannelp(NULL), mLastSamplePos(0)
+{
+}
+
+
+LLAudioChannelFMODSTUDIO::~LLAudioChannelFMODSTUDIO()
+{
+    cleanup();
+}
+
+bool LLAudioChannelFMODSTUDIO::updateBuffer()
+{
+    if (!mCurrentSourcep)
+    {
+        // This channel isn't associated with any source, nothing
+        // to be updated
+        return false;
+    }
+
+    if (LLAudioChannel::updateBuffer())
+    {
+        // Base class update returned true, which means that we need to actually
+        // set up the channel for a different buffer.
+
+        LLAudioBufferFMODSTUDIO *bufferp = (LLAudioBufferFMODSTUDIO *)mCurrentSourcep->getCurrentBuffer();
+
+        // Grab the FMOD sample associated with the buffer
+        FMOD::Sound *soundp = bufferp->getSound();
+        if (!soundp)
+        {
+            // This is bad, there should ALWAYS be a sound associated with a legit
+            // buffer.
+            LL_ERRS() << "No FMOD sound!" << LL_ENDL;
+            return false;
+        }
+
+
+        // Actually play the sound.  Start it off paused so we can do all the necessary
+        // setup.
+        if (!mChannelp)
+        {
+            FMOD_RESULT result = getSystem()->playSound(soundp, NULL /*free channel?*/, true, &mChannelp);
+            Check_FMOD_Error(result, "FMOD::System::playSound");
+        }
+
+        // Setting up channel mChannelID
+    }
+
+    // If we have a source for the channel, we need to update its gain.
+    if (mCurrentSourcep)
+    {
+        // SJB: warnings can spam and hurt framerate, disabling
+        //FMOD_RESULT result;
+
+        mChannelp->setVolume(getSecondaryGain() * mCurrentSourcep->getGain());
+        //Check_FMOD_Error(result, "FMOD::Channel::setVolume");
+
+        mChannelp->setMode(mCurrentSourcep->isLoop() ? FMOD_LOOP_NORMAL : FMOD_LOOP_OFF);
+        /*if(Check_FMOD_Error(result, "FMOD::Channel::setMode"))
+        {
+        S32 index;
+        mChannelp->getIndex(&index);
+        LL_WARNS() << "Channel " << index << "Source ID: " << mCurrentSourcep->getID()
+        << " at " << mCurrentSourcep->getPositionGlobal() << LL_ENDL;
+        }*/
+    }
+
+    return true;
+}
+
+
+void LLAudioChannelFMODSTUDIO::update3DPosition()
+{
+    if (!mChannelp)
+    {
+        // We're not actually a live channel (i.e., we're not playing back anything)
+        return;
+    }
+
+    LLAudioBufferFMODSTUDIO  *bufferp = (LLAudioBufferFMODSTUDIO  *)mCurrentBufferp;
+    if (!bufferp)
+    {
+        // We don't have a buffer associated with us (should really have been picked up
+        // by the above if.
+        return;
+    }
+
+    if (mCurrentSourcep->isForcedPriority())
+    {
+        // Prioritized UI and preview sounds don't need to do any positional updates.
+        set3DMode(false);
+    }
+    else
+    {
+        // Localized sound.  Update the position and velocity of the sound.
+        set3DMode(true);
+
+        LLVector3 float_pos;
+        float_pos.setVec(mCurrentSourcep->getPositionGlobal());
+        FMOD_RESULT result = mChannelp->set3DAttributes((FMOD_VECTOR*)float_pos.mV, (FMOD_VECTOR*)mCurrentSourcep->getVelocity().mV);
+        Check_FMOD_Error(result, "FMOD::Channel::set3DAttributes");
+    }
+}
+
+
+void LLAudioChannelFMODSTUDIO::updateLoop()
+{
+    if (!mChannelp)
+    {
+        // May want to clear up the loop/sample counters.
+        return;
+    }
+
+    //
+    // Hack:  We keep track of whether we looped or not by seeing when the
+    // sample position looks like it's going backwards.  Not reliable; may
+    // yield false negatives.
+    //
+    U32 cur_pos;
+    mChannelp->getPosition(&cur_pos, FMOD_TIMEUNIT_PCMBYTES);
+
+    if (cur_pos < (U32)mLastSamplePos)
+    {
+        mLoopedThisFrame = true;
+    }
+    mLastSamplePos = cur_pos;
+}
+
+
+void LLAudioChannelFMODSTUDIO::cleanup()
+{
+    if (!mChannelp)
+    {
+        // Aborting cleanup with no channel handle.
+        return;
+    }
+
+    //Cleaning up channel mChannelID
+    Check_FMOD_Error(mChannelp->stop(), "FMOD::Channel::stop");
+
+    mCurrentBufferp = NULL;
+    mChannelp = NULL;
+}
+
+
+void LLAudioChannelFMODSTUDIO::play()
+{
+    if (!mChannelp)
+    {
+        LL_WARNS() << "Playing without a channel handle, aborting" << LL_ENDL;
+        return;
+    }
+
+    Check_FMOD_Error(mChannelp->setPaused(false), "FMOD::Channel::pause");
+
+    getSource()->setPlayedOnce(true);
+
+    if (LLAudioEngine_FMODSTUDIO::mChannelGroups[getSource()->getType()])
+        mChannelp->setChannelGroup(LLAudioEngine_FMODSTUDIO::mChannelGroups[getSource()->getType()]);
+}
+
+
+void LLAudioChannelFMODSTUDIO::playSynced(LLAudioChannel *channelp)
+{
+    LLAudioChannelFMODSTUDIO *fmod_channelp = (LLAudioChannelFMODSTUDIO*)channelp;
+    if (!(fmod_channelp->mChannelp && mChannelp))
+    {
+        // Don't have channels allocated to both the master and the slave
+        return;
+    }
+
+    U32 cur_pos;
+    if (Check_FMOD_Error(mChannelp->getPosition(&cur_pos, FMOD_TIMEUNIT_PCMBYTES), "Unable to retrieve current position"))
+        return;
+
+    cur_pos %= mCurrentBufferp->getLength();
+
+    // Try to match the position of our sync master
+    Check_FMOD_Error(mChannelp->setPosition(cur_pos, FMOD_TIMEUNIT_PCMBYTES), "Unable to set current position");
+
+    // Start us playing
+    play();
+}
+
+
+bool LLAudioChannelFMODSTUDIO::isPlaying()
+{
+    if (!mChannelp)
+    {
+        return false;
+    }
+
+    bool paused, playing;
+    mChannelp->getPaused(&paused);
+    mChannelp->isPlaying(&playing);
+    return !paused && playing;
+}
+
+
+//
+// LLAudioChannelFMODSTUDIO implementation
+//
+
+
+LLAudioBufferFMODSTUDIO::LLAudioBufferFMODSTUDIO(FMOD::System *system) : mSystemp(system), mSoundp(NULL)
+{
+}
+
+
+LLAudioBufferFMODSTUDIO::~LLAudioBufferFMODSTUDIO()
+{
+    if (mSoundp)
+    {
+        mSoundp->release();
+        mSoundp = NULL;
+    }
+}
+
+
+bool LLAudioBufferFMODSTUDIO::loadWAV(const std::string& filename)
+{
+    // Try to open a wav file from disk.  This will eventually go away, as we don't
+    // really want to block doing this.
+    if (filename.empty())
+    {
+        // invalid filename, abort.
+        return false;
+    }
+
+    if (!gDirUtilp->fileExists(filename))
+    {
+        // File not found, abort.
+        return false;
+    }
+
+    if (mSoundp)
+    {
+        // If there's already something loaded in this buffer, clean it up.
+        mSoundp->release();
+        mSoundp = NULL;
+    }
+
+    FMOD_MODE base_mode = FMOD_LOOP_NORMAL;
+    FMOD_CREATESOUNDEXINFO exinfo;
+    memset(&exinfo, 0, sizeof(exinfo));
+    exinfo.cbsize = sizeof(exinfo);
+    exinfo.suggestedsoundtype = FMOD_SOUND_TYPE_WAV;    //Hint to speed up loading.
+    // Load up the wav file into an fmod sample (since 1.05 fmod studio expects everything in UTF-8)
+    FMOD_RESULT result = getSystem()->createSound(filename.c_str(), base_mode, &exinfo, &mSoundp);
+
+    if (result != FMOD_OK)
+    {
+        // We failed to load the file for some reason.
+        LL_WARNS() << "Could not load data '" << filename << "': " << FMOD_ErrorString(result) << LL_ENDL;
+
+        //
+        // If we EVER want to load wav files provided by end users, we need
+        // to rethink this!
+        //
+        // file is probably corrupt - remove it.
+        LLFile::remove(filename);
+        return false;
+    }
+
+    // Everything went well, return true
+    return true;
+}
+
+
+U32 LLAudioBufferFMODSTUDIO::getLength()
+{
+    if (!mSoundp)
+    {
+        return 0;
+    }
+
+    U32 length;
+    mSoundp->getLength(&length, FMOD_TIMEUNIT_PCMBYTES);
+    return length;
+}
+
+
+void LLAudioChannelFMODSTUDIO::set3DMode(bool use3d)
+{
+    FMOD_MODE current_mode;
+    if (mChannelp->getMode(&current_mode) != FMOD_OK)
+        return;
+    FMOD_MODE new_mode = current_mode;
+    new_mode &= ~(use3d ? FMOD_2D : FMOD_3D);
+    new_mode |= use3d ? FMOD_3D : FMOD_2D;
+
+    if (current_mode != new_mode)
+    {
+        mChannelp->setMode(new_mode);
+    }
+}
+
+// *NOTE:  This is almost certainly being called on the mixer thread,
+// not the main thread.  May have implications for callees or audio
+// engine shutdown.
+
+FMOD_RESULT F_CALLBACK windCallback(FMOD_DSP_STATE *dsp_state, float *inbuffer, float *outbuffer, unsigned int length, int inchannels, int *outchannels)
+{
+    // inbuffer = fmod's original mixbuffer.
+    // outbuffer = the buffer passed from the previous DSP unit.
+    // length = length in samples at this mix time.
+
+    LLWindGen<LLAudioEngine_FMODSTUDIO::MIXBUFFERFORMAT> *windgen = NULL;
+    FMOD::DSP *thisdsp = (FMOD::DSP *)dsp_state->instance;
+
+    thisdsp->getUserData((void **)&windgen);
+
+    if (windgen)
+    {
+        windgen->windGenerate((LLAudioEngine_FMODSTUDIO::MIXBUFFERFORMAT *)outbuffer, length);
+    }
+
+    return FMOD_OK;
+}
diff --git a/indra/llaudio/llaudioengine_fmodstudio.h b/indra/llaudio/llaudioengine_fmodstudio.h
new file mode 100644
index 0000000000..eb346e0466
--- /dev/null
+++ b/indra/llaudio/llaudioengine_fmodstudio.h
@@ -0,0 +1,131 @@
+/**
+ * @file audioengine_fmodstudio.h
+ * @brief Definition of LLAudioEngine class abstracting the audio
+ * support as a FMODSTUDIO implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_AUDIOENGINE_FMODSTUDIO_H
+#define LL_AUDIOENGINE_FMODSTUDIO_H
+
+#include "llaudioengine.h"
+#include "llwindgen.h"
+
+//Stubs
+class LLAudioStreamManagerFMODSTUDIO;
+namespace FMOD
+{
+    class System;
+    class Channel;
+    class ChannelGroup;
+    class Sound;
+    class DSP;
+}
+typedef struct FMOD_DSP_DESCRIPTION FMOD_DSP_DESCRIPTION;
+
+//Interfaces
+class LLAudioEngine_FMODSTUDIO : public LLAudioEngine
+{
+public:
+    LLAudioEngine_FMODSTUDIO(bool enable_profiler);
+    virtual ~LLAudioEngine_FMODSTUDIO();
+
+    // initialization/startup/shutdown
+    virtual bool init(void *user_data, const std::string &app_title);
+    virtual std::string getDriverName(bool verbose);
+    virtual LLStreamingAudioInterface* createDefaultStreamingAudioImpl() const;
+    virtual void allocateListener();
+
+    virtual void shutdown();
+
+    /*virtual*/ bool initWind();
+    /*virtual*/ void cleanupWind();
+
+    /*virtual*/void updateWind(LLVector3 direction, F32 camera_height_above_water);
+
+    typedef F32 MIXBUFFERFORMAT;
+
+    FMOD::System *getSystem()               const {return mSystem;}
+protected:
+    /*virtual*/ LLAudioBuffer *createBuffer(); // Get a free buffer, or flush an existing one if you have to.
+    /*virtual*/ LLAudioChannel *createChannel(); // Create a new audio channel.
+
+    /*virtual*/ void setInternalGain(F32 gain);
+
+    bool mInited;
+
+    LLWindGen<MIXBUFFERFORMAT> *mWindGen;
+
+    FMOD_DSP_DESCRIPTION *mWindDSPDesc;
+    FMOD::DSP *mWindDSP;
+    FMOD::System *mSystem;
+    bool mEnableProfiler;
+
+public:
+    static FMOD::ChannelGroup *mChannelGroups[LLAudioEngine::AUDIO_TYPE_COUNT];
+};
+
+
+class LLAudioChannelFMODSTUDIO : public LLAudioChannel
+{
+public:
+    LLAudioChannelFMODSTUDIO(FMOD::System *audioengine);
+    virtual ~LLAudioChannelFMODSTUDIO();
+
+protected:
+    /*virtual*/ void play();
+    /*virtual*/ void playSynced(LLAudioChannel *channelp);
+    /*virtual*/ void cleanup();
+    /*virtual*/ bool isPlaying();
+
+    /*virtual*/ bool updateBuffer();
+    /*virtual*/ void update3DPosition();
+    /*virtual*/ void updateLoop();
+
+    void set3DMode(bool use3d);
+protected:
+    FMOD::System *getSystem()   const {return mSystemp;}
+    FMOD::System *mSystemp;
+    FMOD::Channel *mChannelp;
+    S32 mLastSamplePos;
+};
+
+
+class LLAudioBufferFMODSTUDIO : public LLAudioBuffer
+{
+public:
+    LLAudioBufferFMODSTUDIO(FMOD::System *audioengine);
+    virtual ~LLAudioBufferFMODSTUDIO();
+
+    /*virtual*/ bool loadWAV(const std::string& filename);
+    /*virtual*/ U32 getLength();
+    friend class LLAudioChannelFMODSTUDIO;
+protected:
+    FMOD::System *getSystem()   const {return mSystemp;}
+    FMOD::System *mSystemp;
+    FMOD::Sound *getSound()     const{ return mSoundp; }
+    FMOD::Sound *mSoundp;
+};
+
+
+#endif // LL_AUDIOENGINE_FMODSTUDIO_H
diff --git a/indra/llaudio/lllistener_fmodstudio.cpp b/indra/llaudio/lllistener_fmodstudio.cpp
new file mode 100644
index 0000000000..9dc55eec79
--- /dev/null
+++ b/indra/llaudio/lllistener_fmodstudio.cpp
@@ -0,0 +1,136 @@
+/**
+ * @file listener_fmodstudio.cpp
+ * @brief Implementation of LISTENER class abstracting the audio
+ * support as a FMODSTUDIO implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+#include "llaudioengine.h"
+#include "lllistener_fmodstudio.h"
+#include "fmodstudio/fmod.hpp"
+
+//-----------------------------------------------------------------------
+// constructor
+//-----------------------------------------------------------------------
+LLListener_FMODSTUDIO::LLListener_FMODSTUDIO(FMOD::System *system)
+{
+    mSystem = system;
+    init();
+}
+
+//-----------------------------------------------------------------------
+LLListener_FMODSTUDIO::~LLListener_FMODSTUDIO()
+{
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::init(void)
+{
+    // do inherited
+    LLListener::init();
+    mDopplerFactor = 1.0f;
+    mRolloffFactor = 1.0f;
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::translate(LLVector3 offset)
+{
+    LLListener::translate(offset);
+
+    mSystem->set3DListenerAttributes(0, (FMOD_VECTOR*)mPosition.mV, NULL, (FMOD_VECTOR*)mListenAt.mV, (FMOD_VECTOR*)mListenUp.mV);
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::setPosition(LLVector3 pos)
+{
+    LLListener::setPosition(pos);
+
+    mSystem->set3DListenerAttributes(0, (FMOD_VECTOR*)mPosition.mV, NULL, (FMOD_VECTOR*)mListenAt.mV, (FMOD_VECTOR*)mListenUp.mV);
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::setVelocity(LLVector3 vel)
+{
+    LLListener::setVelocity(vel);
+
+    mSystem->set3DListenerAttributes(0, NULL, (FMOD_VECTOR*)mVelocity.mV, (FMOD_VECTOR*)mListenAt.mV, (FMOD_VECTOR*)mListenUp.mV);
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::orient(LLVector3 up, LLVector3 at)
+{
+    LLListener::orient(up, at);
+
+    // at = -at; by default Fmod studio is 'left-handed' but we are providing
+    // flag FMOD_INIT_3D_RIGHTHANDED so no correction are needed
+
+    mSystem->set3DListenerAttributes(0, NULL, NULL, (FMOD_VECTOR*)at.mV, (FMOD_VECTOR*)up.mV);
+}
+
+//-----------------------------------------------------------------------
+void LLListener_FMODSTUDIO::commitDeferredChanges()
+{
+    if (!mSystem)
+    {
+        return;
+    }
+
+    mSystem->update();
+}
+
+
+void LLListener_FMODSTUDIO::setRolloffFactor(F32 factor)
+{
+    //An internal FMOD optimization skips 3D updates if there have not been changes to the 3D sound environment.
+    // (this was true for FMODex, looks to be still true for FMOD STUDIO, but needs a recheck)
+    //Sadly, a change in rolloff is not accounted for, thus we must touch the listener properties as well.
+    //In short: Changing the position ticks a dirtyflag inside fmod, which makes it not skip 3D processing next update call.
+    if (mRolloffFactor != factor)
+    {
+        LLVector3 pos = mPosition - LLVector3(0.f, 0.f, .1f);
+        mSystem->set3DListenerAttributes(0, (FMOD_VECTOR*)pos.mV, NULL, NULL, NULL);
+        mSystem->set3DListenerAttributes(0, (FMOD_VECTOR*)mPosition.mV, NULL, NULL, NULL);
+    }
+    mRolloffFactor = factor;
+    mSystem->set3DSettings(mDopplerFactor, 1.f, mRolloffFactor);
+}
+
+
+F32 LLListener_FMODSTUDIO::getRolloffFactor()
+{
+    return mRolloffFactor;
+}
+
+
+void LLListener_FMODSTUDIO::setDopplerFactor(F32 factor)
+{
+    mDopplerFactor = factor;
+    mSystem->set3DSettings(mDopplerFactor, 1.f, mRolloffFactor);
+}
+
+
+F32 LLListener_FMODSTUDIO::getDopplerFactor()
+{
+    return mDopplerFactor;
+}
diff --git a/indra/llaudio/lllistener_fmodstudio.h b/indra/llaudio/lllistener_fmodstudio.h
new file mode 100644
index 0000000000..5287cbedc6
--- /dev/null
+++ b/indra/llaudio/lllistener_fmodstudio.h
@@ -0,0 +1,65 @@
+/**
+ * @file listener_fmodstudio.h
+ * @brief Description of LISTENER class abstracting the audio support
+ * as an FMOD 3D implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_LISTENER_FMODSTUDIO_H
+#define LL_LISTENER_FMODSTUDIO_H
+
+#include "lllistener.h"
+
+//Stubs
+namespace FMOD
+{
+    class System;
+}
+
+//Interfaces
+class LLListener_FMODSTUDIO : public LLListener
+{
+public:
+    LLListener_FMODSTUDIO(FMOD::System *system);
+    virtual ~LLListener_FMODSTUDIO();
+    virtual void init();
+
+    virtual void translate(LLVector3 offset);
+    virtual void setPosition(LLVector3 pos);
+    virtual void setVelocity(LLVector3 vel);
+    virtual void orient(LLVector3 up, LLVector3 at);
+    virtual void commitDeferredChanges();
+
+    virtual void setDopplerFactor(F32 factor);
+    virtual F32 getDopplerFactor();
+    virtual void setRolloffFactor(F32 factor);
+    virtual F32 getRolloffFactor();
+protected:
+    FMOD::System *mSystem;
+    F32 mDopplerFactor;
+    F32 mRolloffFactor;
+};
+
+#endif
+
+
diff --git a/indra/llaudio/llstreamingaudio_fmodstudio.cpp b/indra/llaudio/llstreamingaudio_fmodstudio.cpp
new file mode 100644
index 0000000000..22fc86c0cd
--- /dev/null
+++ b/indra/llaudio/llstreamingaudio_fmodstudio.cpp
@@ -0,0 +1,481 @@
+/**
+ * @file streamingaudio_fmodstudio.cpp
+ * @brief LLStreamingAudio_FMODSTUDIO implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#include "linden_common.h"
+
+#include "llmath.h"
+
+#include "fmodstudio/fmod.hpp"
+#include "fmodstudio/fmod_errors.h"
+
+#include "llstreamingaudio_fmodstudio.h"
+
+
+class LLAudioStreamManagerFMODSTUDIO
+{
+public:
+    LLAudioStreamManagerFMODSTUDIO(FMOD::System *system, const std::string& url);
+    FMOD::Channel* startStream();
+    bool stopStream(); // Returns true if the stream was successfully stopped.
+    bool ready();
+
+    const std::string& getURL()     { return mInternetStreamURL; }
+
+    FMOD_OPENSTATE getOpenState(unsigned int* percentbuffered = NULL, bool* starving = NULL, bool* diskbusy = NULL);
+protected:
+    FMOD::System* mSystem;
+    FMOD::Channel* mStreamChannel;
+    FMOD::Sound* mInternetStream;
+    bool mReady;
+
+    std::string mInternetStreamURL;
+};
+
+
+
+//---------------------------------------------------------------------------
+// Internet Streaming
+//---------------------------------------------------------------------------
+LLStreamingAudio_FMODSTUDIO::LLStreamingAudio_FMODSTUDIO(FMOD::System *system) :
+mSystem(system),
+mCurrentInternetStreamp(NULL),
+mFMODInternetStreamChannelp(NULL),
+mGain(1.0f),
+mRetryCount(0)
+{
+    // Number of milliseconds of audio to buffer for the audio card.
+    // Must be larger than the usual Second Life frame stutter time.
+    const U32 buffer_seconds = 10;      //sec
+    const U32 estimated_bitrate = 128;  //kbit/sec
+    FMOD_RESULT result = mSystem->setStreamBufferSize(estimated_bitrate * buffer_seconds * 128/*bytes/kbit*/, FMOD_TIMEUNIT_RAWBYTES);
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << "setStreamBufferSize error: " << FMOD_ErrorString(result) << LL_ENDL;
+    }
+
+    // Here's where we set the size of the network buffer and some buffering
+    // parameters.  In this case we want a network buffer of 16k, we want it
+    // to prebuffer 40% of that when we first connect, and we want it
+    // to rebuffer 80% of that whenever we encounter a buffer underrun.
+
+    // Leave the net buffer properties at the default.
+    //FSOUND_Stream_Net_SetBufferProperties(20000, 40, 80);
+}
+
+
+LLStreamingAudio_FMODSTUDIO::~LLStreamingAudio_FMODSTUDIO()
+{
+    if (mCurrentInternetStreamp)
+    {
+        // Isn't supposed to hapen, stream should be clear by now,
+        // and if it does, we are likely going to crash.
+        LL_WARNS("FMOD") << "mCurrentInternetStreamp not null on shutdown!" << LL_ENDL;
+        stop();
+    }
+
+    // Kill dead internet streams, if possible
+    killDeadStreams();
+
+    if (!mDeadStreams.empty())
+    {
+        // LLStreamingAudio_FMODSTUDIO was inited on startup
+        // and should be destroyed on shutdown, it should
+        // wait for streams to die to not cause crashes or
+        // leaks.
+        // Ideally we need to wait on some kind of callback
+        // to release() streams correctly, but 200 ms should
+        // be enough and we can't wait forever.
+        LL_INFOS("FMOD") << "Waiting for " << (S32)mDeadStreams.size() << " streams to stop" << LL_ENDL;
+        for (S32 i = 0; i < 20; i++)
+        {
+            const U32 ms_delay = 10;
+            ms_sleep(ms_delay); // rude, but not many options here
+            killDeadStreams();
+            if (mDeadStreams.empty())
+            {
+                LL_INFOS("FMOD") << "All streams stopped after " << (S32)((i + 1) * ms_delay) << "ms" << LL_ENDL;
+                break;
+            }
+        }
+    }
+
+    if (!mDeadStreams.empty())
+    {
+        LL_WARNS("FMOD") << "Failed to kill some audio streams" << LL_ENDL;
+    }
+}
+
+void LLStreamingAudio_FMODSTUDIO::killDeadStreams()
+{
+    std::list<LLAudioStreamManagerFMODSTUDIO *>::iterator iter;
+    for (iter = mDeadStreams.begin(); iter != mDeadStreams.end();)
+    {
+        LLAudioStreamManagerFMODSTUDIO *streamp = *iter;
+        if (streamp->stopStream())
+        {
+            LL_INFOS("FMOD") << "Closed dead stream" << LL_ENDL;
+            delete streamp;
+            iter = mDeadStreams.erase(iter);
+        }
+        else
+        {
+            iter++;
+        }
+    }
+}
+
+void LLStreamingAudio_FMODSTUDIO::start(const std::string& url)
+{
+    //if (!mInited)
+    //{
+    //  LL_WARNS() << "startInternetStream before audio initialized" << LL_ENDL;
+    //  return;
+    //}
+
+    // "stop" stream but don't clear url, etc. in case url == mInternetStreamURL
+    stop();
+
+    if (!url.empty())
+    {
+        LL_INFOS("FMOD") << "Starting internet stream: " << url << LL_ENDL;
+        mCurrentInternetStreamp = new LLAudioStreamManagerFMODSTUDIO(mSystem, url);
+        mURL = url;
+    }
+    else
+    {
+        LL_INFOS("FMOD") << "Set internet stream to null" << LL_ENDL;
+        mURL.clear();
+    }
+
+    mRetryCount = 0;
+}
+
+
+void LLStreamingAudio_FMODSTUDIO::update()
+{
+    // Kill dead internet streams, if possible
+    killDeadStreams();
+
+    // Don't do anything if there are no streams playing
+    if (!mCurrentInternetStreamp)
+    {
+        return;
+    }
+
+    unsigned int progress;
+    bool starving;
+    bool diskbusy;
+    FMOD_OPENSTATE open_state = mCurrentInternetStreamp->getOpenState(&progress, &starving, &diskbusy);
+
+    if (open_state == FMOD_OPENSTATE_READY)
+    {
+        // Stream is live
+
+        // start the stream if it's ready
+        if (!mFMODInternetStreamChannelp &&
+            (mFMODInternetStreamChannelp = mCurrentInternetStreamp->startStream()))
+        {
+            // Reset volume to previously set volume
+            setGain(getGain());
+            mFMODInternetStreamChannelp->setPaused(false);
+        }
+        mRetryCount = 0;
+    }
+    else if (open_state == FMOD_OPENSTATE_ERROR)
+    {
+        LL_INFOS("FMOD") << "State: FMOD_OPENSTATE_ERROR"
+            << " Progress: " << U32(progress)
+            << " Starving: " << S32(starving)
+            << " Diskbusy: " << S32(diskbusy) << LL_ENDL;
+        if (mRetryCount < 2)
+        {
+            // Retry
+            std::string url = mURL;
+            stop(); // might drop mURL, drops mCurrentInternetStreamp
+
+            mRetryCount++;
+
+            if (!url.empty())
+            {
+                LL_INFOS("FMOD") << "Restarting internet stream: " << url  << ", attempt " << (mRetryCount + 1) << LL_ENDL;
+                mCurrentInternetStreamp = new LLAudioStreamManagerFMODSTUDIO(mSystem, url);
+                mURL = url;
+            }
+        }
+        else
+        {
+            stop();
+        }
+        return;
+    }
+
+    if (mFMODInternetStreamChannelp)
+    {
+        FMOD::Sound *sound = NULL;
+
+        if (mFMODInternetStreamChannelp->getCurrentSound(&sound) == FMOD_OK && sound)
+        {
+            FMOD_TAG tag;
+            S32 tagcount, dirtytagcount;
+
+            if (sound->getNumTags(&tagcount, &dirtytagcount) == FMOD_OK && dirtytagcount)
+            {
+                for (S32 i = 0; i < tagcount; ++i)
+                {
+                    if (sound->getTag(NULL, i, &tag) != FMOD_OK)
+                        continue;
+
+                    if (tag.type == FMOD_TAGTYPE_FMOD)
+                    {
+                        if (!strcmp(tag.name, "Sample Rate Change"))
+                        {
+                            LL_INFOS("FMOD") << "Stream forced changing sample rate to " << *((float *)tag.data) << LL_ENDL;
+                            mFMODInternetStreamChannelp->setFrequency(*((float *)tag.data));
+                        }
+                        continue;
+                    }
+                }
+            }
+
+            if (starving)
+            {
+                bool paused = false;
+                mFMODInternetStreamChannelp->getPaused(&paused);
+                if (!paused)
+                {
+                    LL_INFOS("FMOD") << "Stream starvation detected! Pausing stream until buffer nearly full." << LL_ENDL;
+                    LL_INFOS("FMOD") << "  (diskbusy=" << diskbusy << ")" << LL_ENDL;
+                    LL_INFOS("FMOD") << "  (progress=" << progress << ")" << LL_ENDL;
+                    mFMODInternetStreamChannelp->setPaused(true);
+                }
+            }
+            else if (progress > 80)
+            {
+                mFMODInternetStreamChannelp->setPaused(false);
+            }
+        }
+    }
+}
+
+void LLStreamingAudio_FMODSTUDIO::stop()
+{
+    if (mFMODInternetStreamChannelp)
+    {
+        mFMODInternetStreamChannelp->setPaused(true);
+        mFMODInternetStreamChannelp->setPriority(0);
+        mFMODInternetStreamChannelp = NULL;
+    }
+
+    if (mCurrentInternetStreamp)
+    {
+        LL_INFOS("FMOD") << "Stopping internet stream: " << mCurrentInternetStreamp->getURL() << LL_ENDL;
+        if (mCurrentInternetStreamp->stopStream())
+        {
+            delete mCurrentInternetStreamp;
+        }
+        else
+        {
+            LL_WARNS("FMOD") << "Pushing stream to dead list: " << mCurrentInternetStreamp->getURL() << LL_ENDL;
+            mDeadStreams.push_back(mCurrentInternetStreamp);
+        }
+        mCurrentInternetStreamp = NULL;
+        //mURL.clear();
+    }
+}
+
+void LLStreamingAudio_FMODSTUDIO::pause(int pauseopt)
+{
+    if (pauseopt < 0)
+    {
+        pauseopt = mCurrentInternetStreamp ? 1 : 0;
+    }
+
+    if (pauseopt)
+    {
+        if (mCurrentInternetStreamp)
+        {
+            LL_INFOS("FMOD") << "Pausing internet stream" << LL_ENDL;
+            stop();
+        }
+    }
+    else
+    {
+        start(getURL());
+    }
+}
+
+
+// A stream is "playing" if it has been requested to start.  That
+// doesn't necessarily mean audio is coming out of the speakers.
+int LLStreamingAudio_FMODSTUDIO::isPlaying()
+{
+    if (mCurrentInternetStreamp)
+    {
+        return 1; // Active and playing
+    }
+    else if (!mURL.empty())
+    {
+        return 2; // "Paused"
+    }
+    else
+    {
+        return 0;
+    }
+}
+
+
+F32 LLStreamingAudio_FMODSTUDIO::getGain()
+{
+    return mGain;
+}
+
+
+std::string LLStreamingAudio_FMODSTUDIO::getURL()
+{
+    return mURL;
+}
+
+
+void LLStreamingAudio_FMODSTUDIO::setGain(F32 vol)
+{
+    mGain = vol;
+
+    if (mFMODInternetStreamChannelp)
+    {
+        vol = llclamp(vol * vol, 0.f, 1.f); //should vol be squared here?
+
+        mFMODInternetStreamChannelp->setVolume(vol);
+    }
+}
+
+///////////////////////////////////////////////////////
+// manager of possibly-multiple internet audio streams
+
+LLAudioStreamManagerFMODSTUDIO::LLAudioStreamManagerFMODSTUDIO(FMOD::System *system, const std::string& url) :
+mSystem(system),
+mStreamChannel(NULL),
+mInternetStream(NULL),
+mReady(false)
+{
+    mInternetStreamURL = url;
+
+    FMOD_RESULT result = mSystem->createStream(url.c_str(), FMOD_2D | FMOD_NONBLOCKING | FMOD_IGNORETAGS, 0, &mInternetStream);
+
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << "Couldn't open fmod stream, error "
+            << FMOD_ErrorString(result)
+            << LL_ENDL;
+        mReady = false;
+        return;
+    }
+
+    mReady = true;
+}
+
+FMOD::Channel *LLAudioStreamManagerFMODSTUDIO::startStream()
+{
+    // We need a live and opened stream before we try and play it.
+    if (!mInternetStream || getOpenState() != FMOD_OPENSTATE_READY)
+    {
+        LL_WARNS("FMOD") << "No internet stream to start playing!" << LL_ENDL;
+        return NULL;
+    }
+
+    if (mStreamChannel)
+        return mStreamChannel;  //Already have a channel for this stream.
+
+    FMOD_RESULT result = mSystem->playSound(mInternetStream, NULL, true, &mStreamChannel);
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << FMOD_ErrorString(result) << LL_ENDL;
+    }
+    return mStreamChannel;
+}
+
+bool LLAudioStreamManagerFMODSTUDIO::stopStream()
+{
+    if (mInternetStream)
+    {
+
+
+        bool close = true;
+        switch (getOpenState())
+        {
+        case FMOD_OPENSTATE_CONNECTING:
+            close = false;
+            break;
+        default:
+            close = true;
+        }
+
+        if (close)
+        {
+            mInternetStream->release();
+            mStreamChannel = NULL;
+            mInternetStream = NULL;
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+    else
+    {
+        return true;
+    }
+}
+
+FMOD_OPENSTATE LLAudioStreamManagerFMODSTUDIO::getOpenState(unsigned int* percentbuffered, bool* starving, bool* diskbusy)
+{
+    FMOD_OPENSTATE state;
+    FMOD_RESULT result = mInternetStream->getOpenState(&state, percentbuffered, starving, diskbusy);
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << FMOD_ErrorString(result) << LL_ENDL;
+    }
+    return state;
+}
+
+void LLStreamingAudio_FMODSTUDIO::setBufferSizes(U32 streambuffertime, U32 decodebuffertime)
+{
+    FMOD_RESULT result = mSystem->setStreamBufferSize(streambuffertime / 1000 * 128 * 128, FMOD_TIMEUNIT_RAWBYTES);
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << "setStreamBufferSize error: " << FMOD_ErrorString(result) << LL_ENDL;
+        return;
+    }
+    FMOD_ADVANCEDSETTINGS settings;
+    memset(&settings, 0, sizeof(settings));
+    settings.cbSize = sizeof(settings);
+    settings.defaultDecodeBufferSize = decodebuffertime;//ms
+    result = mSystem->setAdvancedSettings(&settings);
+    if (result != FMOD_OK)
+    {
+        LL_WARNS("FMOD") << "setAdvancedSettings error: " << FMOD_ErrorString(result) << LL_ENDL;
+    }
+}
diff --git a/indra/llaudio/llstreamingaudio_fmodstudio.h b/indra/llaudio/llstreamingaudio_fmodstudio.h
new file mode 100644
index 0000000000..2127841809
--- /dev/null
+++ b/indra/llaudio/llstreamingaudio_fmodstudio.h
@@ -0,0 +1,76 @@
+/**
+ * @file streamingaudio_fmodstudio.h
+ * @brief Definition of LLStreamingAudio_FMODSTUDIO implementation
+ *
+ * $LicenseInfo:firstyear=2020&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2020, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_STREAMINGAUDIO_FMODSTUDIO_H
+#define LL_STREAMINGAUDIO_FMODSTUDIO_H
+
+#include "stdtypes.h" // from llcommon
+
+#include "llstreamingaudio.h"
+#include "lltimer.h"
+
+//Stubs
+class LLAudioStreamManagerFMODSTUDIO;
+namespace FMOD
+{
+    class System;
+    class Channel;
+}
+
+//Interfaces
+class LLStreamingAudio_FMODSTUDIO : public LLStreamingAudioInterface
+{
+public:
+    LLStreamingAudio_FMODSTUDIO(FMOD::System *system);
+    /*virtual*/ ~LLStreamingAudio_FMODSTUDIO();
+
+    /*virtual*/ void start(const std::string& url);
+    /*virtual*/ void stop();
+    /*virtual*/ void pause(S32 pause);
+    /*virtual*/ void update();
+    /*virtual*/ S32 isPlaying();
+    /*virtual*/ void setGain(F32 vol);
+    /*virtual*/ F32 getGain();
+    /*virtual*/ std::string getURL();
+
+    /*virtual*/ bool supportsAdjustableBufferSizes(){return true;}
+    /*virtual*/ void setBufferSizes(U32 streambuffertime, U32 decodebuffertime);
+private:
+    void killDeadStreams();
+
+    FMOD::System *mSystem;
+
+    LLAudioStreamManagerFMODSTUDIO *mCurrentInternetStreamp;
+    FMOD::Channel *mFMODInternetStreamChannelp;
+    std::list<LLAudioStreamManagerFMODSTUDIO *> mDeadStreams;
+
+    std::string mURL;
+    F32 mGain;
+    S32 mRetryCount;
+};
+
+
+#endif // LL_STREAMINGAUDIO_FMODSTUDIO_H