See https://build.webkit.org/results/Apple-Monterey-Debug-WK2-Tests/261013@main%20(7232)/imported/w3c/web-platform-tests/mediacapture-record/MediaRecorder-pause-resume-crash-log.txt 2023-03-01 13:41:55.282 com.apple.WebKit.GPU.Development[94325:38781352] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '*** -[AVAssetWriterInput appendSampleBuffer:] Cannot append sample buffer: Must start a session (using -[AVAssetWriter startSessionAtSourceTime:) first' *** First throw call stack: ( 0 CoreFoundation 0x00007ff81b27e1e3 __exceptionPreprocess + 242 1 libobjc.A.dylib 0x00007ff81afdec13 objc_exception_throw + 48 2 AVFCore 0x00007ff82dda83f4 __41-[AVAssetWriterInput appendSampleBuffer:]_block_invoke + 0 3 WebCore 0x00000001079d0eee _ZZN7WebCore26MediaRecorderPrivateWriter28flushCompressedSampleBuffersEON3WTF8FunctionIFvvEEEEN3$_3clEv + 398 4 WebCore 0x00000001079d143d _ZZN3WTF8BlockPtrIFvvEE12fromCallableIZN7WebCore26MediaRecorderPrivateWriter28flushCompressedSampleBuffersEONS_8FunctionIS1_EEE3$_3EES2_T_ENKUlPvE_clESB_ + 29 5 WebCore 0x00000001079d1415 _ZZN3WTF8BlockPtrIFvvEE12fromCallableIZN7WebCore26MediaRecorderPrivateWriter28flushCompressedSampleBuffersEONS_8FunctionIS1_EEE3$_3EES2_T_ENUlPvE_8__invokeESB_ + 21 6 AVFCore 0x00007ff82ddb16cd -[AVAssetWriterInputMediaDataRequester requestMediaDataIfNecessary] + 84 7 libdispatch.dylib 0x00007ff81af800cc _dispatch_call_block_and_release + 12 8 libdispatch.dylib 0x00007ff81af81317 _dispatch_client_callout + 8 9 libdispatch.dylib 0x00007ff81af8dc78 _dispatch_main_queue_drain + 943 10 libdispatch.dylib 0x00007ff81af8d8bb _dispatch_main_queue_callback_4CF + 31 11 CoreFoundation 0x00007ff81b2409c7 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 9 12 CoreFoundation 0x00007ff81b20193f __CFRunLoopRun + 2771 13 CoreFoundation 0x00007ff81b2007ac CFRunLoopRunSpecific + 562 14 Foundation 0x00007ff81c054d9a -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 216 15 Foundation 0x00007ff81c0df8d7 -[NSRunLoop(NSRunLoop) run] + 76 16 libxpc.dylib 0x00007ff81ae80816 _xpc_objc_main + 773 17 libxpc.dylib 0x00007ff81ae80239 xpc_main + 99 18 WebKit 0x0000000131f22a42 _ZN6WebKit14XPCServiceMainEiPPKc + 834 19 WebKit 0x000000013402eccb WKXPCServiceMain + 27 20 com.apple.WebKit.GPU.Development 0x0000000100b44f22 main + 34 21 dyld 0x0000000104efb51e start + 462 )
<rdar://problem/106128729>