I am trying to get an H264 streaming app working on various platforms using a combination of Apple Video Toolbox and OpenH264. There is one use-case that doesn't work and I can't find any solution. When the source uses video Toolbox on a 2011 iMac running MacOS High Sierra and the receiver is a MacBook pro running Big Sur. On the receiver the decoded image is about 3/4 green. If I scale the image down to about 1/8 of original before encoding then it works fine. If I capture the frames on the MacBook and then run exactly the same decoding software in a test program on the iMac then it decodes fine. Doing the same on the Macbook (same image of test program) give 3/4 green again. I have a similar problem when receiving from an OpenH264 encoder on a slower Windows machine. I suspect that this has something to do with temporal processing, but really don't understand H264 well enough to work it out. One thing that I did notice is that the decode call returns with no error code but a NULL pixel buffer about 70% of the time. The "guts" of the decoding part looks like this (modified from a demo on GitHub) void didDecompress(void *decompressionOutputRefCon, void *sourceFrameRefCon, OSStatus status, VTDecodeInfoFlags infoFlags, CVImageBufferRef pixelBuffer, CMTime presentationTimeStamp, CMTime presentationDuration ) { 		CVPixelBufferRef *outputPixelBuffer = (CVPixelBufferRef *)sourceFrameRefCon; 		*outputPixelBuffer = CVPixelBufferRetain(pixelBuffer); } void initVideoDecodeToolBox () 		{ 				if (!decodeSession) 				{ 						const uint8_t* parameterSetPointers[2] = { mSPS, mPPS }; 						const size_t parameterSetSizes[2] = { mSPSSize, mPPSSize }; 						OSStatus status = CMVideoFormatDescriptionCreateFromH264ParameterSets(kCFAllocatorDefault,2, //param count 																																									parameterSetPointers, 																																									parameterSetSizes, 																																									4, //nal start code size 																																									&formatDescription); 						if(status == noErr) 						{ 								CFDictionaryRef attrs = NULL; 								const void *keys[] = { kCVPixelBufferPixelFormatTypeKey, kVTDecompressionPropertyKey_RealTime }; 								uint32_t v = kCVPixelFormatType_32BGRA; 								const void *values[] = { CFNumberCreate(NULL, kCFNumberSInt32Type, &v), kCFBooleanTrue }; 								attrs = CFDictionaryCreate(NULL, keys, values, 2, NULL, NULL); 								VTDecompressionOutputCallbackRecord callBackRecord; 								callBackRecord.decompressionOutputCallback = didDecompress; 								callBackRecord.decompressionOutputRefCon = NULL; 								status = VTDecompressionSessionCreate(kCFAllocatorDefault, formatDescription, NULL, attrs, &callBackRecord, &decodeSession); 								CFRelease(attrs); 						} 						else 						{ 								NSLog(@"IOS8VT: reset decoder session failed status=%d", status); 						} 				} 		} CVPixelBufferRef decode ( const char *NALBuffer, size_t NALSize ) 		{ 				CVPixelBufferRef outputPixelBuffer = NULL; 				if (decodeSession && formatDescription ) 				{ 						// The NAL buffer has been stripped of the NAL length data, so this has to be put back in 						MemoryBlock buf ( NALSize + 4); 						memcpy ( (char*)buf.getData()+4, NALBuffer, NALSize ); 						*((uint32*)buf.getData()) = CFSwapInt32HostToBig ((uint32)NALSize); 						 						CMBlockBufferRef blockBuffer = NULL; 						OSStatus status	= CMBlockBufferCreateWithMemoryBlock(kCFAllocatorDefault, buf.getData(), NALSize+4,kCFAllocatorNull,NULL, 0, NALSize+4, 0, &blockBuffer); 						 						if(status == kCMBlockBufferNoErr) 						{ 								CMSampleBufferRef sampleBuffer = NULL; 								const size_t sampleSizeArray[] = {NALSize + 4}; 								status = CMSampleBufferCreateReady(kCFAllocatorDefault,blockBuffer,formatDescription,1, 0, NULL, 1, sampleSizeArray,&sampleBuffer); 								 								if (status == kCMBlockBufferNoErr && sampleBuffer) 								{ 										VTDecodeFrameFlags flags = 0;VTDecodeInfoFlags flagOut = 0; 										 										// The default is synchronous operation. 										// Call didDecompress and call back after returning. 										OSStatus decodeStatus = VTDecompressionSessionDecodeFrame ( decodeSession, sampleBuffer, flags, &outputPixelBuffer, &flagOut ); 										if(decodeStatus != noErr) 										{ 												DBG ( "decode failed status=" + String ( decodeStatus) ); 										} 										CFRelease(sampleBuffer); 								} 								CFRelease(blockBuffer); 						} 				} 				return outputPixelBuffer; 		}

I've been implementing in app purchases into an existing C++ app. I'm using the latest Swift StoreKit since the old ObjC interface is deprecated . There is a really weird problem where the swift/C++ bridging seems to get into a loop. After the Product structure is retrieved I have the following structure which I use to bridge to C++ public struct storeData { public var id : String public var displayName : String public var description : String public var price : String public var purchased : Bool = false public var level : Int = 0 } and this is passed back to the caller as follows public func getProducts (bridge : StoreBridge) -> [storeData] { bridge.products.sort { $0.price > $1.price } var productList : [storeData] = [] for product in bridge.products { let data : storeData = storeData(id: product.id, displayName: product.displayName, description: product.description, price: product.displayPrice, purchased: bridge.purchasedProductIds.contains(product.id) ) productList.append(data) } return productList } the "bridge" variable is a bridging class where the guts of the bridge resides, and contains the "products" array as a publishable variable. In the C++ code the data is retrieved by outProd->id = String(inProd.getId()); outProd->displayName = String(inProd.getDisplayName()); outProd->description = String(inProd.getDescription()); outProd->price = String(String(inProd.getPrice())); outProd->purchased = inProd.getPurchased(); The "String" is actually a JUCE string but that's not part of the problem. Testing this with a local StoreKit config file works fine but when I test with a sandbox AppStore the app hangs. Very specifically it hangs somewhere in the Swift thunk when retrieving the price. When I remove the line to retrieve the price everything works. And - and this is the weird bit - when I pad the price out with some random text, it now starts working (so I have a workaround). This is, however, slightly worrying behaviour. Ideas?