Merged in euclid-16418 (pull request #846)

SL-16418 move media texture updates to background thread

Approved-by: Dave Parks

7 files changed, 430 insertions, 214 deletions

diff --git a/indra/llimage/llimage.cpp b/indra/llimage/llimage.cpp
index 15b07e5318..ba7ee0b465 100644
--- a/indra/llimage/llimage.cpp
+++ b/indra/llimage/llimage.cpp
@@ -925,47 +925,73 @@ bool LLImageRaw::setSubImage(U32 x_pos, U32 y_pos, U32 width, U32 height,
 
 void LLImageRaw::clear(U8 r, U8 g, U8 b, U8 a)
 {
-	llassert( getComponents() <= 4 );
-	// This is fairly bogus, but it'll do for now.
-	if (isBufferInvalid())
-	{
-		LL_WARNS() << "Invalid image buffer" << LL_ENDL;
-		return;
-	}
+    LL_PROFILE_ZONE_SCOPED;
+    S8 components = getComponents();
+    llassert( components > 0 && components <= 4 );
 
-	U8 *pos = getData();
-	U32 x, y;
-	for (x = 0; x < getWidth(); x++)
-	{
-		for (y = 0; y < getHeight(); y++)
-		{
-			*pos = r;
-			pos++;
-			if (getComponents() == 1)
-			{
-				continue;
-			}
-			*pos = g;
-			pos++;
-			if (getComponents() == 2)
-			{
-				continue;
-			}
-			*pos = b;
-			pos++;
-			if (getComponents() == 3)
-			{
-				continue;
-			}
-			*pos = a;
-			pos++;
-		}
-	}
+    // This is fairly bogus, but it'll do for now.
+    if (isBufferInvalid())
+    {
+        LL_WARNS() << "Invalid image buffer" << LL_ENDL;
+        return;
+    }
+
+    switch (components)
+    {
+    case 1:
+        {
+            U8 *dst = getData();
+            S32 count = getWidth() * getHeight();
+            llassert(count == getDataSize());
+            std::fill_n(dst, count, r);
+            break;
+        }
+    case 2:
+        {
+            U16 *dst = (U16 *)getData();
+            S32 count = getWidth() * getHeight();
+            llassert(count == getDataSize() / 2);
+#ifdef LL_LITTLE_ENDIAN
+            U16 val = (U16)(r | g << 8);
+#else
+            U16 val = (U16)(r << 8 | g);
+#endif
+            std::fill_n(dst, count, val);
+            break;
+        }
+    case 3:
+        {
+            U8 *dst = getData();
+            S32 count = getWidth() * getHeight();
+            llassert(count == getDataSize() / 3);
+            for (S32 i = 0; i < count; i++)
+            {
+                *dst++ = r;
+                *dst++ = g;
+                *dst++ = b;
+            }
+            break;
+        }
+    case 4:
+        {
+            U32 *dst = (U32 *)getData();
+            S32 count = getWidth() * getHeight();
+            llassert(count == getDataSize() / 4);
+#ifdef LL_LITTLE_ENDIAN
+            U32 val = (U32)(r | g << 8 | b << 16 | a << 24);
+#else
+            U32 val = (U32)(r << 24 | g << 16 | b << 8 | a);
+#endif
+            std::fill_n(dst, count, val);
+            break;
+        }
+    }
 }
 
 // Reverses the order of the rows in the image
 void LLImageRaw::verticalFlip()
 {
+    LL_PROFILE_ZONE_SCOPED;
 	S32 row_bytes = getWidth() * getComponents();
 	llassert(row_bytes > 0);
 	std::vector<U8> line_buffer(row_bytes);
diff --git a/indra/llrender/llimagegl.cpp b/indra/llrender/llimagegl.cpp
index 1e9b9f642e..4b4f071171 100644
--- a/indra/llrender/llimagegl.cpp
+++ b/indra/llrender/llimagegl.cpp
@@ -1215,9 +1215,8 @@ void LLImageGL::setManualImage(U32 target, S32 miplevel, S32 intformat, S32 widt
         if (pixformat == GL_ALPHA && pixtype == GL_UNSIGNED_BYTE)
         { //GL_ALPHA is deprecated, convert to RGBA
             use_scratch = true;
-            scratch = new U32[width * height];
-
             U32 pixel_count = (U32)(width * height);
+            scratch = new U32[pixel_count];
             for (U32 i = 0; i < pixel_count; i++)
             {
                 U8* pix = (U8*)&scratch[i];
@@ -1232,9 +1231,8 @@ void LLImageGL::setManualImage(U32 target, S32 miplevel, S32 intformat, S32 widt
         if (pixformat == GL_LUMINANCE_ALPHA && pixtype == GL_UNSIGNED_BYTE)
         { //GL_LUMINANCE_ALPHA is deprecated, convert to RGBA
             use_scratch = true;
-            scratch = new U32[width * height];
-
             U32 pixel_count = (U32)(width * height);
+            scratch = new U32[pixel_count];
             for (U32 i = 0; i < pixel_count; i++)
             {
                 U8 lum = ((U8*)pixels)[i * 2 + 0];
@@ -1252,9 +1250,8 @@ void LLImageGL::setManualImage(U32 target, S32 miplevel, S32 intformat, S32 widt
         if (pixformat == GL_LUMINANCE && pixtype == GL_UNSIGNED_BYTE)
         { //GL_LUMINANCE_ALPHA is deprecated, convert to RGB
             use_scratch = true;
-            scratch = new U32[width * height];
-
             U32 pixel_count = (U32)(width * height);
+            scratch = new U32[pixel_count];
             for (U32 i = 0; i < pixel_count; i++)
             {
                 U8 lum = ((U8*)pixels)[i];
@@ -1314,10 +1311,7 @@ void LLImageGL::setManualImage(U32 target, S32 miplevel, S32 intformat, S32 widt
     }
     stop_glerror();
 
-    if (use_scratch)
-    {
-        delete[] scratch;
-    }
+    if (scratch) delete[] scratch;
 }
 
 //create an empty GL texture: just create a texture name
@@ -1471,7 +1465,49 @@ BOOL LLImageGL::createGLTexture(S32 discard_level, const LLImageRaw* imageraw, S
 	return createGLTexture(discard_level, rawdata, FALSE, usename);
 }
 
-BOOL LLImageGL::createGLTexture(S32 discard_level, const U8* data_in, BOOL data_hasmips, S32 usename)
+// Create a new GL name and allocate tex storage (unitialized) for it
+// Used to break resource contention stall in background media tex updates
+void LLImageGL::allocNewTexName()
+{
+    LL_PROFILE_ZONE_SCOPED;
+    if (on_main_thread()) return;       // Should only be called on bg update thread
+    if (!mGLTextureCreated) return;
+    if (0 != mNewTexName) return;       // only 1 rename in flight at a time
+
+    generateTextures(1, &mNewTexName);  // create new GL name
+
+    mHasMipMaps = false;                // Media textures aren't mipped
+    mMipLevels = 0;
+    // Set state to match current
+    gGL.getTexUnit(0)->bind(this, false, false, mNewTexName);
+    glTexParameteri(LLTexUnit::getInternalType(mBindTarget), GL_TEXTURE_BASE_LEVEL, 0);
+    glTexParameteri(LLTexUnit::getInternalType(mBindTarget), GL_TEXTURE_MAX_LEVEL, mMaxDiscardLevel);
+    glTexParameteri(LLTexUnit::getInternalType(mBindTarget), GL_TEXTURE_WIDTH, mWidth);
+    glTexParameteri(LLTexUnit::getInternalType(mBindTarget), GL_TEXTURE_HEIGHT, mHeight);
+    gGL.getTexUnit(0)->setHasMipMaps(mHasMipMaps);
+    gGL.getTexUnit(0)->setTextureAddressMode(mAddressMode);
+    gGL.getTexUnit(0)->setTextureFilteringOption(mFilterOption);
+
+    setManualImage(mTarget, 0, mFormatInternal, mWidth, mHeight, mFormatPrimary, mFormatType, 
+                   (GLvoid *) nullptr, mAllowCompression);
+    
+    gGL.getTexUnit(0)->unbind(mBindTarget);
+
+    mLastBindTime = sLastFrameTime;
+}
+
+// Delete no-longer-needed GL tex name (on main thread) 
+void LLImageGL::swapTexName()
+{
+    if (mNewTexName)
+    {
+        deleteTextures(1, &mTexName);
+        mTexName = mNewTexName;
+        mNewTexName = 0;
+    }
+}
+
+BOOL LLImageGL::createGLTexture(S32 discard_level, const U8* data_in, BOOL data_hasmips /* = FALSE */, S32 usename /* = 0 */)
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_TEXTURE;
     checkActiveThread();
@@ -1715,6 +1751,14 @@ void LLImageGL::destroyGLTexture()
 		mTexName = 0;		
 		mGLTextureCreated = FALSE ;
 	}	
+
+    // clean up any in-flight name change
+    if (0 != mNewTexName)
+    {
+        // Memory is transient, not tracked by sGlobalTextuerMemory
+        LLImageGL::deleteTextures(1, &mNewTexName);
+        mNewTexName = 0;
+    }
 }
 
 //force to invalidate the gl texture, most likely a sculpty texture
diff --git a/indra/llrender/llimagegl.h b/indra/llrender/llimagegl.h
index d6f4b13a51..f311170823 100644
--- a/indra/llrender/llimagegl.h
+++ b/indra/llrender/llimagegl.h
@@ -109,15 +109,17 @@ public:
 	static void setManualImage(U32 target, S32 miplevel, S32 intformat, S32 width, S32 height, U32 pixformat, U32 pixtype, const void *pixels, bool allow_compression = true);
     
 	BOOL createGLTexture() ;
-	BOOL createGLTexture(S32 discard_level, const LLImageRaw* imageraw, S32 usename = 0, BOOL to_create = TRUE,
-		S32 category = sMaxCategories-1);
+	BOOL createGLTexture(S32 discard_level, const LLImageRaw* imageraw, S32 usename = 0, BOOL to_create = TRUE, S32 category = sMaxCategories-1);
 	BOOL createGLTexture(S32 discard_level, const U8* data, BOOL data_hasmips = FALSE, S32 usename = 0);
-	void setImage(const LLImageRaw* imageraw);
+    void setImage(const LLImageRaw* imageraw);
 	BOOL setImage(const U8* data_in, BOOL data_hasmips = FALSE, S32 usename = 0);
 	BOOL setSubImage(const LLImageRaw* imageraw, S32 x_pos, S32 y_pos, S32 width, S32 height, BOOL force_fast_update = FALSE);
 	BOOL setSubImage(const U8* datap, S32 data_width, S32 data_height, S32 x_pos, S32 y_pos, S32 width, S32 height, BOOL force_fast_update = FALSE);
 	BOOL setSubImageFromFrameBuffer(S32 fb_x, S32 fb_y, S32 x_pos, S32 y_pos, S32 width, S32 height);
-	
+
+    void allocNewTexName();
+    void swapTexName();
+
 	// Read back a raw image for this discard level, if it exists
 	BOOL readBackRaw(S32 discard_level, LLImageRaw* imageraw, bool compressed_ok) const;
 	void destroyGLTexture();
diff --git a/indra/newview/llviewermedia.cpp b/indra/newview/llviewermedia.cpp
index 63f57e81cc..6c04321539 100644
--- a/indra/newview/llviewermedia.cpp
+++ b/indra/newview/llviewermedia.cpp
@@ -39,6 +39,7 @@
 #include "llfilepicker.h"
 #include "llfloaterwebcontent.h"	// for handling window close requests and geometry change requests in media browser windows.
 #include "llfocusmgr.h"
+#include "llimagegl.h"
 #include "llkeyboard.h"
 #include "lllogininstance.h"
 #include "llmarketplacefunctions.h"
@@ -78,6 +79,9 @@
 #include <boost/bind.hpp>	// for SkinFolder listener
 #include <boost/signals2.hpp>
 
+// Statics
+bool LLMediaTextureUpdateThread::sEnabled = false;
+
 class LLMediaFilePicker : public LLFilePickerThread // deletes itself when done
 {
 public:
@@ -635,6 +639,7 @@ static bool proximity_comparitor(const LLViewerMediaImpl* i1, const LLViewerMedi
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_UPDATE("Update Media");
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_SPARE_IDLE("Spare Idle");
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_UPDATE_INTEREST("Update/Interest");
+static LLTrace::BlockTimerStatHandle FTM_MEDIA_UPDATE_VOLUME("Update/Volume");
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_SORT("Media Sort");
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_SORT2("Media Sort 2");
 static LLTrace::BlockTimerStatHandle FTM_MEDIA_MISC("Misc");
@@ -1590,6 +1595,8 @@ LLViewerMediaImpl::LLViewerMediaImpl(	  const LLUUID& texture_id,
 		media_tex->setMediaImpl();
 	}
 
+    mMainQueue = LL::WorkQueue::getInstance("mainloop");
+    mTexUpdateQueue = LL::WorkQueue::getInstance("LLMediaTextureUpdate"); // Share work queue with tex loader.
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////
@@ -1604,6 +1611,25 @@ LLViewerMediaImpl::~LLViewerMediaImpl()
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////
+//static 
+void LLViewerMediaImpl::initClass(LLWindow* window, bool multi_threaded /* = false */)
+{
+    LL_PROFILE_ZONE_SCOPED;
+    if (multi_threaded)
+    {
+        LLMediaTextureUpdateThread::createInstance(window);
+    }
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////
+//static 
+void LLViewerMediaImpl::cleanupClass()
+{
+    LL_PROFILE_ZONE_SCOPED;
+    LLMediaTextureUpdateThread::deleteSingleton();
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////
 void LLViewerMediaImpl::emitEvent(LLPluginClassMedia* plugin, LLViewerMediaObserver::EMediaEvent event)
 {
 	// Broadcast to observers using the superclass version
@@ -2087,6 +2113,7 @@ void LLViewerMediaImpl::setMute(bool mute)
 //////////////////////////////////////////////////////////////////////////////////////////
 void LLViewerMediaImpl::updateVolume()
 {
+    LL_RECORD_BLOCK_TIME(FTM_MEDIA_UPDATE_VOLUME);
 	if(mMediaSource)
 	{
 		// always scale the volume by the global media volume
@@ -2799,199 +2826,252 @@ static LLTrace::BlockTimerStatHandle FTM_MEDIA_SET_SUBIMAGE("Set Subimage");
 void LLViewerMediaImpl::update()
 {
     LL_PROFILE_ZONE_SCOPED_CATEGORY_MEDIA; //LL_RECORD_BLOCK_TIME(FTM_MEDIA_DO_UPDATE);
-	if(mMediaSource == NULL)
-	{
-		if(mPriority == LLPluginClassMedia::PRIORITY_UNLOADED)
-		{
-			// This media source should not be loaded.
-		}
-		else if(mPriority <= LLPluginClassMedia::PRIORITY_SLIDESHOW)
-		{
-			// Don't load new instances that are at PRIORITY_SLIDESHOW or below.  They're just kept around to preserve state.
-		}
+    if(mMediaSource == NULL)
+    {
+        if(mPriority == LLPluginClassMedia::PRIORITY_UNLOADED)
+        {
+            // This media source should not be loaded.
+        }
+        else if(mPriority <= LLPluginClassMedia::PRIORITY_SLIDESHOW)
+        {
+            // Don't load new instances that are at PRIORITY_SLIDESHOW or below.  They're just kept around to preserve state.
+        }
         else if (!mMimeProbe.expired())
-		{
-			// this media source is doing a MIME type probe -- don't try loading it again.
-		}
-		else
-		{
-			// This media may need to be loaded.
-			if(sMediaCreateTimer.hasExpired())
-			{
-				LL_DEBUGS("PluginPriority") << this << ": creating media based on timer expiration" << LL_ENDL;
-				createMediaSource();
-				sMediaCreateTimer.setTimerExpirySec(LLVIEWERMEDIA_CREATE_DELAY);
-			}
-			else
-			{
-				LL_DEBUGS("PluginPriority") << this << ": NOT creating media (waiting on timer)" << LL_ENDL;
-			}
-		}
-	}
-	else
-	{
-		updateVolume();
+        {
+            // this media source is doing a MIME type probe -- don't try loading it again.
+        }
+        else
+        {
+            // This media may need to be loaded.
+            if(sMediaCreateTimer.hasExpired())
+            {
+                LL_DEBUGS("PluginPriority") << this << ": creating media based on timer expiration" << LL_ENDL;
+                createMediaSource();
+                sMediaCreateTimer.setTimerExpirySec(LLVIEWERMEDIA_CREATE_DELAY);
+            }
+            else
+            {
+                LL_DEBUGS("PluginPriority") << this << ": NOT creating media (waiting on timer)" << LL_ENDL;
+            }
+        }
+    }
+    else
+    {
+        updateVolume();
 
-		// TODO: this is updated every frame - is this bad?
-		// Removing this as part of the post viewer64 media update
-		// Removed as not implemented in CEF embedded browser
-		// See MAINT-8194 for a more fuller description
-		// updateJavascriptObject();
-	}
+        // TODO: this is updated every frame - is this bad?
+        // Removing this as part of the post viewer64 media update
+        // Removed as not implemented in CEF embedded browser
+        // See MAINT-8194 for a more fuller description
+        // updateJavascriptObject();
+    }
 
 
-	if(mMediaSource == NULL)
-	{
-		return;
-	}
+    if(mMediaSource == NULL)
+    {
+        return;
+    }
 
-	// Make sure a navigate doesn't happen during the idle -- it can cause mMediaSource to get destroyed, which can cause a crash.
-	setNavigateSuspended(true);
+    // Make sure a navigate doesn't happen during the idle -- it can cause mMediaSource to get destroyed, which can cause a crash.
+    setNavigateSuspended(true);
 
-	mMediaSource->idle();
+    mMediaSource->idle();
 
-	setNavigateSuspended(false);
+    setNavigateSuspended(false);
 
-	if(mMediaSource == NULL)
-	{
-		return;
-	}
+    if(mMediaSource == NULL)
+    {
+        return;
+    }
 
-	if(mMediaSource->isPluginExited())
-	{
-		resetPreviousMediaState();
-		destroyMediaSource();
-		return;
-	}
+    if(mMediaSource->isPluginExited())
+    {
+        resetPreviousMediaState();
+        destroyMediaSource();
+        return;
+    }
 
-	if(!mMediaSource->textureValid())
-	{
-		return;
-	}
+    if(!mMediaSource->textureValid())
+    {
+        return;
+    }
 
-	if(mSuspendUpdates || !mVisible)
-	{
-		return;
-	}
+    if(mSuspendUpdates || !mVisible)
+    {
+        return;
+    }
 
-	LLViewerMediaTexture* placeholder_image = updatePlaceholderImage();
 
-	if(placeholder_image)
-	{
-		LLRect dirty_rect;
+    // Push update to worker thread
+    auto main_queue = LLMediaTextureUpdateThread::sEnabled ? mMainQueue.lock() : nullptr;
+    ref();  // protect texture from deletion while active on bg queue
+    if (main_queue)
+    {
+        // replace GL name
+        //llassert(!mTextureId.isNull());
+        //LLImageGL* base_image = LLViewerTextureManager::getMediaTexture(mTextureId)->getGLTexture();
+        //GLuint retired_name = base_image->allocNew();
+        main_queue->postTo(
+            mTexUpdateQueue, // Worker thread queue
+            [this]() // work done on update worker thread
+            {
+                doMediaTexUpdate();
+            },
+            [this]() // callback to main thread
+            {
+                endMediaTexUpdate();
+                unref();
+            });
+    }
+    else
+    {
+        doMediaTexUpdate(); // otherwise, update on main thread
+        unref();
+    }
+}
 
-		// Since we're updating this texture, we know it's playing.  Tell the texture to do its replacement magic so it gets rendered.
-		placeholder_image->setPlaying(TRUE);
+//////////////////////////////////////////////////////////////////////////////////////////
+void LLViewerMediaImpl::doMediaTexUpdate()
+{
+    LL_PROFILE_ZONE_SCOPED_CATEGORY_MEDIA;
+    LLViewerMediaTexture* media_tex = updateMediaImage();
 
-		if(mMediaSource->getDirty(&dirty_rect))
-		{
-			// Constrain the dirty rect to be inside the texture
-			S32 x_pos = llmax(dirty_rect.mLeft, 0);
-			S32 y_pos = llmax(dirty_rect.mBottom, 0);
-			S32 width = llmin(dirty_rect.mRight, placeholder_image->getWidth()) - x_pos;
-			S32 height = llmin(dirty_rect.mTop, placeholder_image->getHeight()) - y_pos;
+    if (media_tex && mMediaSource)
+    {
+        llassert(mMediaSource); 
+        
+        LLRect dirty_rect;
+        S32 media_width = mMediaSource->getTextureWidth();
+        S32 media_height = mMediaSource->getTextureHeight();
+        S32 media_depth = mMediaSource->getTextureDepth();
 
-			if(width > 0 && height > 0)
-			{
+        // Since we're updating this texture, we know it's playing.  Tell the texture to do its replacement magic so it gets rendered.
+        media_tex->setPlaying(TRUE);
 
-				U8* data = NULL;
-				{
-					LL_PROFILE_ZONE_NAMED_CATEGORY_MEDIA("media get data"); //LL_RECORD_BLOCK_TIME(FTM_MEDIA_GET_DATA);
-					data = mMediaSource->getBitsData();
-				}
+        if (mMediaSource->getDirty(&dirty_rect))
+        {
+            // Constrain the dirty rect to be inside the texture
+            S32 x_pos = llmax(dirty_rect.mLeft, 0);
+            S32 y_pos = llmax(dirty_rect.mBottom, 0);
+            S32 width = llmin(dirty_rect.mRight, media_width) - x_pos;
+            S32 height = llmin(dirty_rect.mTop, media_height) - y_pos;
 
-				if(data != NULL)
-				{
-					// Offset the pixels pointer to match x_pos and y_pos
-					data += ( x_pos * mMediaSource->getTextureDepth() * mMediaSource->getBitsWidth() );
-					data += ( y_pos * mMediaSource->getTextureDepth() );
+            if (width > 0 && height > 0)
+            {
+                U8* data = NULL;
+                S32 data_width = mMediaSource->getBitsWidth();
+                S32 data_height = mMediaSource->getBitsHeight();
+                data = mMediaSource->getBitsData();
 
-					{
-						LL_PROFILE_ZONE_NAMED_CATEGORY_MEDIA("media set subimage"); //LL_RECORD_BLOCK_TIME(FTM_MEDIA_SET_SUBIMAGE);
-									placeholder_image->setSubImage(
-									data,
-									mMediaSource->getBitsWidth(),
-									mMediaSource->getBitsHeight(),
-									x_pos,
-									y_pos,
-									width,
-									height);
-					}
-				}
+                if (data != NULL)
+                {
+                    // Offset the pixels pointer to match x_pos and y_pos
+                    data += (x_pos * media_depth * data_width);
+                    data += (y_pos * media_depth);
+
+                    {
+                        LL_PROFILE_ZONE_NAMED_CATEGORY_MEDIA("media set subimage"); //LL_RECORD_BLOCK_TIME(FTM_MEDIA_SET_SUBIMAGE);
+                        media_tex->setSubImage(
+                            data,
+                            data_width,
+                            data_height,
+                            x_pos,
+                            y_pos,
+                            width,
+                            height);
+                    }
+                }
 
-			}
+            }
 
-			mMediaSource->resetDirty();
-		}
-	}
+            mMediaSource->resetDirty();
+        }
+    }
 }
 
+//////////////////////////////////////////////////////////////////////////////////////////
+// runs on main thread, but only called when bg thread updates are active
+void LLViewerMediaImpl::endMediaTexUpdate()
+{
+    LL_PROFILE_ZONE_SCOPED_CATEGORY_MEDIA;
+    LLViewerMediaTexture* base_image = LLViewerTextureManager::findMediaTexture(mTextureId);
+    llassert(base_image);
+
+    LLImageGL* image = base_image->getGLTexture();
+    image->swapTexName(); // retire old GL name
+}
 
 //////////////////////////////////////////////////////////////////////////////////////////
 void LLViewerMediaImpl::updateImagesMediaStreams()
 {
 }
 
-
 //////////////////////////////////////////////////////////////////////////////////////////
-LLViewerMediaTexture* LLViewerMediaImpl::updatePlaceholderImage()
+LLViewerMediaTexture* LLViewerMediaImpl::updateMediaImage()
 {
-	if(mTextureId.isNull())
-	{
-		// The code that created this instance will read from the plugin's bits.
-		return NULL;
-	}
-
-	LLViewerMediaTexture* placeholder_image = LLViewerTextureManager::getMediaTexture( mTextureId );
-
-	if (mNeedsNewTexture
-		|| placeholder_image->getUseMipMaps()
-		|| (placeholder_image->getWidth() != mMediaSource->getTextureWidth())
-		|| (placeholder_image->getHeight() != mMediaSource->getTextureHeight())
-		|| (mTextureUsedWidth != mMediaSource->getWidth())
-		|| (mTextureUsedHeight != mMediaSource->getHeight())
-		)
-	{
-		LL_DEBUGS("Media") << "initializing media placeholder" << LL_ENDL;
-		LL_DEBUGS("Media") << "movie image id " << mTextureId << LL_ENDL;
-
-		int texture_width = mMediaSource->getTextureWidth();
-		int texture_height = mMediaSource->getTextureHeight();
-		int texture_depth = mMediaSource->getTextureDepth();
-
-		// MEDIAOPT: check to see if size actually changed before doing work
-		placeholder_image->destroyGLTexture();
-		// MEDIAOPT: apparently just calling setUseMipMaps(FALSE) doesn't work?
-		placeholder_image->reinit(FALSE);	// probably not needed
-
-		// MEDIAOPT: seems insane that we actually have to make an imageraw then
-		// immediately discard it
-		LLPointer<LLImageRaw> raw = new LLImageRaw(texture_width, texture_height, texture_depth);
-		// Clear the texture to the background color, ignoring alpha.
-		// convert background color channels from [0.0, 1.0] to [0, 255];
-		raw->clear(int(mBackgroundColor.mV[VX] * 255.0f), int(mBackgroundColor.mV[VY] * 255.0f), int(mBackgroundColor.mV[VZ] * 255.0f), 0xff);
-		int discard_level = 0;
-
-		// ask media source for correct GL image format constants
-		placeholder_image->setExplicitFormat(mMediaSource->getTextureFormatInternal(),
-											 mMediaSource->getTextureFormatPrimary(),
-											 mMediaSource->getTextureFormatType(),
-											 mMediaSource->getTextureFormatSwapBytes());
-
-		placeholder_image->createGLTexture(discard_level, raw);
-
-		// MEDIAOPT: set this dynamically on play/stop
-		// FIXME
-//		placeholder_image->mIsMediaTexture = true;
-		mNeedsNewTexture = false;
+    LL_PROFILE_ZONE_SCOPED_CATEGORY_MEDIA;
+    if (!mMediaSource)
+    {
+        return nullptr; // not ready for updating
+    }
 
-		// If the amount of the texture being drawn by the media goes down in either width or height,
-		// recreate the texture to avoid leaving parts of the old image behind.
-		mTextureUsedWidth = mMediaSource->getWidth();
-		mTextureUsedHeight = mMediaSource->getHeight();
-	}
+    llassert(!mTextureId.isNull());
+    LLViewerMediaTexture* media_tex = LLViewerTextureManager::getMediaTexture( mTextureId );
+ 
+    // if on bg thread, create new GL tex image resource to avoid resource contention
+    if (!on_main_thread())
+    {
+        LLImageGL* image = media_tex->getGLTexture();
+        image->allocNewTexName();
+    }
 
-	return placeholder_image;
+    if ( mNeedsNewTexture
+        || media_tex->getUseMipMaps()
+        || (media_tex->getWidth() != mMediaSource->getTextureWidth())
+        || (media_tex->getHeight() != mMediaSource->getTextureHeight())
+        || (mTextureUsedWidth != mMediaSource->getWidth())
+        || (mTextureUsedHeight != mMediaSource->getHeight())
+        )
+    {
+        LL_DEBUGS("Media") << "initializing media placeholder" << LL_ENDL;
+        LL_DEBUGS("Media") << "movie image id " << mTextureId << LL_ENDL;
+
+        int texture_width = mMediaSource->getTextureWidth();
+        int texture_height = mMediaSource->getTextureHeight();
+        int texture_depth = mMediaSource->getTextureDepth();
+
+        // MEDIAOPT: check to see if size actually changed before doing work
+        media_tex->destroyGLTexture();
+        // MEDIAOPT: apparently just calling setUseMipMaps(FALSE) doesn't work?
+        media_tex->reinit(FALSE);	// probably not needed
+
+        // MEDIAOPT: seems insane that we actually have to make an imageraw then
+        // immediately discard it
+        LLPointer<LLImageRaw> raw = new LLImageRaw(texture_width, texture_height, texture_depth);
+        // Clear the texture to the background color, ignoring alpha.
+        // convert background color channels from [0.0, 1.0] to [0, 255];
+        raw->clear(int(mBackgroundColor.mV[VX] * 255.0f), int(mBackgroundColor.mV[VY] * 255.0f), int(mBackgroundColor.mV[VZ] * 255.0f), 0xff);
+
+        // ask media source for correct GL image format constants
+        media_tex->setExplicitFormat(mMediaSource->getTextureFormatInternal(),
+            mMediaSource->getTextureFormatPrimary(),
+            mMediaSource->getTextureFormatType(),
+            mMediaSource->getTextureFormatSwapBytes());
+
+        int discard_level = 0;
+        media_tex->createGLTexture(discard_level, raw);
+
+        // MEDIAOPT: set this dynamically on play/stop
+        // FIXME
+//		media_tex->mIsMediaTexture = true;
+        mNeedsNewTexture = false;
+
+        // If the amount of the texture being drawn by the media goes down in either width or height,
+        // recreate the texture to avoid leaving parts of the old image behind.
+        mTextureUsedWidth = mMediaSource->getWidth();
+        mTextureUsedHeight = mMediaSource->getHeight();
+    }
+    return media_tex;
 }
 
 
@@ -3920,3 +4000,30 @@ bool LLViewerMediaImpl::isObjectInAgentParcel(LLVOVolume *obj)
 {
 	return (LLViewerParcelMgr::getInstance()->inAgentParcel(obj->getPositionGlobal()));
 }
+
+LLMediaTextureUpdateThread::LLMediaTextureUpdateThread(LLWindow* window)
+// We want exactly one thread, of moderate capacity: there are likely only a handful
+// of media texture frames in-flight at any one time 
+    : ThreadPool("LLMediaTextureUpdate", 1, 4096)
+    , mWindow(window)
+{
+    LL_PROFILE_ZONE_SCOPED;
+    sEnabled = true;
+    mFinished = false;
+
+    mContext = mWindow->createSharedContext();
+    ThreadPool::start();
+}
+
+void LLMediaTextureUpdateThread::run()
+{
+    LL_PROFILE_ZONE_SCOPED;
+    // We must perform setup on this thread before actually servicing our
+    // WorkQueue, likewise cleanup afterwards.
+    mWindow->makeContextCurrent(mContext);
+    gGL.init();
+    ThreadPool::run();
+    LLMediaTextureUpdateThread::sEnabled = false;
+    gGL.shutdown();
+    mWindow->destroySharedContext(mContext);
+}
diff --git a/indra/newview/llviewermedia.h b/indra/newview/llviewermedia.h
index 71cec5125d..03a14421ff 100644
--- a/indra/newview/llviewermedia.h
+++ b/indra/newview/llviewermedia.h
@@ -197,7 +197,10 @@ public:
 		U8 media_loop);
 
 	~LLViewerMediaImpl();
-	
+
+    static void initClass(LLWindow* window, bool multi_threaded = false);
+    static void cleanupClass();
+
 	// Override inherited version from LLViewerMediaEventEmitter 
 	virtual void emitEvent(LLPluginClassMedia* self, LLViewerMediaObserver::EMediaEvent event);
 
@@ -266,6 +269,8 @@ public:
 	void scaleTextureCoords(const LLVector2& texture_coords, S32 *x, S32 *y);
 
 	void update();
+    void doMediaTexUpdate();
+    void endMediaTexUpdate();
 	void updateImagesMediaStreams();
 	LLUUID getMediaTextureID() const;
 	
@@ -489,7 +494,35 @@ private:
     bool mCanceling;
 
 private:
-	LLViewerMediaTexture *updatePlaceholderImage();
+	LLViewerMediaTexture *updateMediaImage();
+    LL::WorkQueue::weak_t mMainQueue;
+    LL::WorkQueue::weak_t mTexUpdateQueue;
+
+};
+
+// Define a worker thread pool for media updates (ref LLImageGLThread)
+class LLMediaTextureUpdateThread : public LLSimpleton<LLMediaTextureUpdateThread>, LL::ThreadPool
+{
+public:
+    // follows gSavedSettings "RenderGLMultiThreaded"
+    static bool sEnabled;
+
+    LLMediaTextureUpdateThread(LLWindow* window);
+
+    // post a function to be executed on the LLMediaTextureUpdateThread background thread
+    template <typename CALLABLE>
+    bool post(CALLABLE&& func)
+    {
+        return getQueue().postIfOpen(std::forward<CALLABLE>(func));
+    }
+
+    void run() override;
+
+private:
+    LLWindow* mWindow;
+    void* mContext = nullptr;
+    LLAtomicBool mFinished;
 };
 
+
 #endif	// LLVIEWERMEDIA_H
diff --git a/indra/newview/llviewertexture.cpp b/indra/newview/llviewertexture.cpp
index 5fed46f437..ccf4c5bbec 100644
--- a/indra/newview/llviewertexture.cpp
+++ b/indra/newview/llviewertexture.cpp
@@ -1629,7 +1629,6 @@ void LLViewerFetchedTexture::scheduleCreateTexture()
         mNeedsCreateTexture = TRUE;
         if (preCreateTexture())
         {
-            ref();
 #if LL_IMAGEGL_THREAD_CHECK
             //grab a copy of the raw image data to make sure it isn't modified pending texture creation
             U8* data = mRawImage->getData();
@@ -1643,6 +1642,7 @@ void LLViewerFetchedTexture::scheduleCreateTexture()
 #endif
             mNeedsCreateTexture = TRUE;
             auto mainq = LLImageGLThread::sEnabled ? mMainQueue.lock() : nullptr;
+            ref(); // protect texture from deletion while active on bg queue
             if (mainq)
             {
                 mainq->postTo(
diff --git a/indra/newview/llviewerwindow.cpp b/indra/newview/llviewerwindow.cpp
index b9a5e90df0..ba93f4f5f9 100644
--- a/indra/newview/llviewerwindow.cpp
+++ b/indra/newview/llviewerwindow.cpp
@@ -2027,6 +2027,9 @@ LLViewerWindow::LLViewerWindow(const Params& p)
 	gTextureList.init();
 	LLViewerTextureManager::init() ;
 	gBumpImageList.init();
+
+    // Init Media texture worker queue
+    LLViewerMediaImpl::initClass(mWindow, gSavedSettings.getBOOL("RenderGLMultiThreaded"));
 	
 	// Create container for all sub-views
 	LLView::Params rvp;
@@ -2416,7 +2419,8 @@ void LLViewerWindow::shutdownGL()
 
 	LLViewerTextureManager::cleanup() ;
 	SUBSYSTEM_CLEANUP(LLImageGL) ;
-
+    SUBSYSTEM_CLEANUP(LLViewerMediaImpl);
+    
 	LL_INFOS() << "All textures and llimagegl images are destroyed!" << LL_ENDL ;
 
 	LL_INFOS() << "Cleaning up select manager" << LL_ENDL;