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Hi, I am struggling to receive multicast UDP packets on an iPad Pro (iOS 15.5) in the context of an ethernet-only lab network. The packet reception code uses a NWConnectionGroup configured with a NWMulticastGroup, as described in https://developer.apple.com/news/?id=0oi77447. This code works well on a Mac connected to the lab network with a USB ethernet adapter, provided the ethernet adapter interface has the highest priority among connected network interfaces. To make it work on iOS, I have successfully added the com.apple.developer.networking.multicast to the app, following the process detailed by @eskimo in https://developer.apple.com/forums/thread/663271 However, on the iPad, the app doesn't receive any data packet on the configured connection group, although no error shows on the console. I suspected that the issue may be related to a question of network interface selection by the receiving NWConnectionGroup, but disabling the wifi on the iPad doesn't seem to help. Searching in the dev forums, I found this message where @meaton wrote You will want to make sure that you test this on a physical device connected to Wi-Fi to know that the Multicast feature is actually working. This makes we wonder if using the Wi-Fi network is mandatory here… Hence my question: is there a way to receive multicast UDP packets on an ethernet network on an iPad? Thanks.

In the context of an app that uses a VTDecompressionSession to decode incoming ts streams, the creation of the decompression session always fails for some h264 streams with code -12911 when running on a M1 iPad (iPad Pro, 12.9-inch, 5th generation, iOS 15.5). When the same app is executed on my M1 Mac mini -as My Mac (Designed for iPad)- with the same stream, VTDecompressionSessionCreatesucceeds and the stream can be decoded. Any idea of what could cause this error on the iPad? The code: decompressionSessionCreationStatus = VTDecompressionSessionCreate(allocator: kCFAllocatorDefault,                                                                   formatDescription: videoFormatDescription!,                                                                   decoderSpecification: nil,                                                                   imageBufferAttributes: nil,                                                                   outputCallback: nil,                                                                   decompressionSessionOut: &videoDecompressionSession) if videoDecompressionSession != nil { ... } else {     NSLog("videoDecompressionSession could not be created (status: %d): video format: %@",            decompressionSessionCreationStatus, (videoFormatDescription != nil) ? (CFCopyDescription(videoFormatDescription!) as String) : "{?}") } where videoFormatDescription was previously created by extracting h264 parameter sets and calling CMVideoFormatDescriptionCreateFromH264ParameterSets. Output: videoDecompressionSession could not be created (status: -12911): video format: <CMVideoFormatDescription 0x281894360 [0x1dacc01b8]> { mediaType:'vide'  mediaSubType:'avc1'  mediaSpecific: { codecType: 'avc1' dimensions: 1920 x 1080  }  extensions: {{     CVImageBufferChromaLocationBottomField = Left;     CVImageBufferChromaLocationTopField = Left;     CVImageBufferColorPrimaries = "ITU_R_709_2";     CVImageBufferTransferFunction = "ITU_R_709_2";     CVImageBufferYCbCrMatrix = "ITU_R_709_2";     CVPixelAspectRatio =     {         HorizontalSpacing = 1;         VerticalSpacing = 1;     };     FullRangeVideo = 0;     SampleDescriptionExtensionAtoms =     {         avcC = {length = 119, bytes = 0x01640028 ffe10064 67640028 ad90a470 ... 68ff3cb0 fdf8f800 };     }; }} } Any help on this would be greatly appreciated! :)