AVAssetExportSession stuck (not starting) export

Question

I have attempted to export videos from Photo Library, but the export callback is never executed. I periodically check the progress of the export, and the progress is always zero

Answer 1

I saw this issue a couple of times on some Github projects and usually it had something to do with how the URL was created. Not sure if the code you put in your question was just some placeholder but I think you should create a fileURL like this instead of "string".

var tempFileUrl = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0].appendingPathComponent("temp_video_data.mp4", isDirectory: false)
tempFileUrl = URL(fileURLWithPath: tempFileUrl.path)
exportSession.outputURL = tempFileUrl

Perhaps this will fix it?