Is this technical solution reasonable about WKWebView on cross-domain issues ? Hi，all My project use WKWebView to load offline package, such as .html/.css/.js，and also request some resources from remote server to update pages. So there is a cross-domain problem with local file(file://xxx) and remote domain (https://xxx), is this following technical solution reasonable to fix this problem: 1. Create a custom URLSchemeHandler which conforms to WKURLSchemeHandler 2.Unify local file and remote domain request to https request 3. Hook WKWebView https request 4. Implement WKURLSchemeHandler delegate method (void)webView:(WKWebView *)webView startURLSchemeTask:(id)urlSchemeTask { NSURL *url = urlSchemeTask.request.URL; if ([url.pathExtension isEqualToString:@"html"]) { NSData *data = [[NSData alloc] initWithContentsOfFile:localFilePath]; NSMutableDictionary resHeader = [NSMutableDictionary new]; [resHeader setValue:@"" forKey:@"Access-Control-Allow-Origin"]; [resHeader setValue:@"charset=UTF-8" forKey:@"Content-Type"]; [resHeader setValue:@"text/html" forKey:@"Content-Type"]; NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:url statusCode:200 HTTPVersion:@"HTTP/1.1" headerFields:resHeader]; [urlSchemeTask didReceiveResponse:response]; [urlSchemeTask didReceiveData:data]; [urlSchemeTask didFinish]; } else { NSURLSession *defaultSession = [NSURLSession sharedSession]; NSURLSessionTask *dataTask = [defaultSession dataTaskWithRequest:urlSchemeTask.request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) { [urlSchemeTask didReceiveResponse:response]; [urlSchemeTask didReceiveData:data]; [urlSchemeTask didFinish]; }]; [dataTask resume]; } } Is this technical solution reasonable? and is there any issues that I haven't considered? Sincerely, Looking forward to your reply

Hi, I'm trying to decode a HLS livestream with VideoToolbox. The CMSampleBuffer is successfully created (OSStatus == noErr). When I enqueue the CMSampleBuffer to a AVSampleBufferDisplayLayer the view isn't displaying anything and the status of the AVSampleBufferDisplayLayer is 1 (rendering). When I use a VTDecompressionSession to convert the CMSampleBuffer to a CVPixelBuffer the VTDecompressionOutputCallback returns a -8969 (bad data error). What do I need to fix in my code? Do I incorrectly parse the data from the segment for the CMSampleBuffer? let segmentData = try await downloadSegment(from: segment.url) let (sps, pps, idr) = try parseH264FromTSSegment(tsData: segmentData) if self.formatDescription == nil { self.formatDescription = try CMFormatDescription(h264ParameterSets: [sps, pps]) } if let sampleBuffer = try createSampleBuffer(from: idr, segment: segment) { try self.decodeSampleBuffer(sampleBuffer) } func parseH264FromTSSegment(tsData: Data) throws -> (sps: Data, pps: Data, idr: Data) { let tsSize = 188 var pesData = Data() for i in stride(from: 0, to: tsData.count, by: tsSize) { let tsPacket = tsData.subdata(in: i..<min(i + tsSize, tsData.count)) guard let payload = extractPayloadFromTSPacket(tsPacket) else { continue } pesData.append(payload) } let nalUnits = parseNalUnits(from: pesData) var sps: Data? var pps: Data? var idr: Data? for nalUnit in nalUnits { guard let firstByte = nalUnit.first else { continue } let nalType = firstByte & 0x1F switch nalType { case 7: // SPS sps = nalUnit case 8: // PPS pps = nalUnit case 5: // IDR idr = nalUnit default: break } if sps != nil, pps != nil, idr != nil { break } } guard let validSPS = sps, let validPPS = pps, let validIDR = idr else { throw NSError() } return (validSPS, validPPS, validIDR) } func extractPayloadFromTSPacket(_ tsPacket: Data) -> Data? { let syncByte: UInt8 = 0x47 guard tsPacket.count == 188, tsPacket[0] == syncByte else { return nil } let payloadStart = (tsPacket[1] & 0x40) != 0 let adaptationFieldControl = (tsPacket[3] & 0x30) >> 4 var payloadOffset = 4 if adaptationFieldControl == 2 || adaptationFieldControl == 3 { let adaptationFieldLength = Int(tsPacket[4]) payloadOffset += 1 + adaptationFieldLength } guard adaptationFieldControl == 1 || adaptationFieldControl == 3 else { return nil } let payload = tsPacket.subdata(in: payloadOffset..<tsPacket.count) return payloadStart ? payload : nil } func parseNalUnits(from h264Data: Data) -> [Data] { let startCode = Data([0x00, 0x00, 0x00, 0x01]) var nalUnits: [Data] = [] var searchRange = h264Data.startIndex..<h264Data.endIndex while let range = h264Data.range(of: startCode, options: [], in: searchRange) { let nextStart = h264Data.range(of: startCode, options: [], in: range.upperBound..<h264Data.endIndex)?.lowerBound ?? h264Data.endIndex let nalUnit = h264Data.subdata(in: range.upperBound..<nextStart) nalUnits.append(nalUnit) searchRange = nextStart..<h264Data.endIndex } return nalUnits } private func createSampleBuffer(from data: Data, segment: HLSSegment) throws -> CMSampleBuffer? { var blockBuffer: CMBlockBuffer? let alignedData = UnsafeMutableRawPointer.allocate(byteCount: data.count, alignment: MemoryLayout<UInt8>.alignment) data.copyBytes(to: alignedData.assumingMemoryBound(to: UInt8.self), count: data.count) let blockStatus = CMBlockBufferCreateWithMemoryBlock( allocator: kCFAllocatorDefault, memoryBlock: alignedData, blockLength: data.count, blockAllocator: nil, customBlockSource: nil, offsetToData: 0, dataLength: data.count, flags: 0, blockBufferOut: &blockBuffer ) guard blockStatus == kCMBlockBufferNoErr, let validBlockBuffer = blockBuffer else { alignedData.deallocate() throw NSError() } var sampleBuffer: CMSampleBuffer? var timing = [calculateTiming(for: segment)] var sampleSizes = [data.count] let sampleStatus = CMSampleBufferCreate( allocator: kCFAllocatorDefault, dataBuffer: validBlockBuffer, dataReady: true, makeDataReadyCallback: nil, refcon: nil, formatDescription: formatDescription, sampleCount: 1, sampleTimingEntryCount: 1, sampleTimingArray: &timing, sampleSizeEntryCount: sampleSizes.count, sampleSizeArray: &sampleSizes, sampleBufferOut: &sampleBuffer ) guard sampleStatus == noErr else { alignedData.deallocate() throw NSError() } return sampleBuffer } private func decodeSampleBuffer(_ sampleBuffer: CMSampleBuffer) throws { guard let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer) else { throw NSError() } if decompressionSession == nil { try setupDecompressionSession(formatDescription: formatDescription) } guard let session = decompressionSession else { throw NSError() } let flags: VTDecodeFrameFlags = [._EnableAsynchronousDecompression, ._EnableTemporalProcessing] var flagOut = VTDecodeInfoFlags() let status = VTDecompressionSessionDecodeFrame( session, sampleBuffer: sampleBuffer, flags: flags, frameRefcon: nil, infoFlagsOut: nil) if status != noErr { throw NSError() } } private func setupDecompressionSession(formatDescription: CMFormatDescription) throws { self.formatDescription = formatDescription if let session = decompressionSession { VTDecompressionSessionInvalidate(session) self.decompressionSession = nil } var decompressionSession: VTDecompressionSession? var callback = VTDecompressionOutputCallbackRecord( decompressionOutputCallback: decompressionOutputCallback, decompressionOutputRefCon: Unmanaged.passUnretained(self).toOpaque()) let status = VTDecompressionSessionCreate( allocator: kCFAllocatorDefault, formatDescription: formatDescription, decoderSpecification: nil, imageBufferAttributes: nil, outputCallback: &callback, decompressionSessionOut: &decompressionSession ) if status != noErr { throw NSError() } self.decompressionSession = decompressionSession } let decompressionOutputCallback: VTDecompressionOutputCallback = { ( decompressionOutputRefCon, sourceFrameRefCon, status, infoFlags, imageBuffer, presentationTimeStamp, presentationDuration ) in guard status == noErr else { print("Callback: \(status)") return } if let imageBuffer = imageBuffer { } }

Hello, I'm writing a program to create CMAF compliant HLS files, with encryption. I have a copy of ISO_IEC_23001-7_2023 to attempt to follow the spec. I am following the 1:9 pattern encryption using CBCS, so for every 16 bytes of encrypted NAL unit data (of type 1 and 5), there's 144 bytes of clear data. When testing my output in Safari with 'identity' keys Quickly Diagnosing Content Key and IV Issues, Safari will request the identity key from my test server and first few bytes of the CMAF renditions, but will not play and console gives away no clues to the error. I am setting the subsample bytesofclear/protected data in the senc boxes. What I'm not sure of, is whether HLS/Safari/iOS acknowledges the senc/saiz/saio boxes of the MP4. There are other third party packagers Bento4, who suggest that they do not: those clients ignore the explicit encryption layout metadata found in saio/saiz boxes, and instead rely purely on the video slice header size to determine the portions of the sample that is encrypted So now I'm fairly sure I need to decipher the video slice header size, and apply the protected blocks from that point on. My question is, is that all there is to it? And is there a better way to debug my output? mediastreamvalidator will only work against unencrypted variants (which I'm outputting okay). Thanks in advance!