how to get NSData from video file on disk - ios

Question

Given a url like this:
file:///private/var/mobile/Applications/C133BAE7-0CBC-4E4F-826B-509B5E1EB68E/tmp/uzhMyDkL0mSI-SCVideo-Merged.mov
How can I get the NSData representation of this to send to a server? I've tried all of these:
NSData *videoData = [NSData dataWithContentsOfURL:url];
NSData *videoData = [NSData dataWithContentsOfFile:[url absoluteString]];
NSData *videoData = [[NSFileManager defaultManager] contentsAtPath:[url path]];
videoData is nil every time.
EDIT:
For more context I am trying to use SCRecorder to capture video.
- (void)recorder:(SCRecorder *__nonnull)recorder didCompleteSegment:(SCRecordSessionSegment *__nullable)segment inSession:(SCRecordSession *__nonnull)session error:(NSError *__nullable)error {
[session mergeSegmentsUsingPreset:AVAssetExportPresetHighestQuality completionHandler:^(NSURL *url, NSError *error) {
if (error == nil) {
//NSData *videoData = [NSData dataWithContentsOfURL:url];
//NSData *videoData = [NSData dataWithContentsOfFile:[url absoluteString]];
NSData *videoData = [[NSFileManager defaultManager] contentsAtPath:[url path]];
} else {
NSLog(#"Bad things happened: %#", error);
}
}];
}

Answer 1

The file URL looks correct to me but to be really sure, you should add in this method before trying to fetch NSData:
NSError *error = nil;
if ([url checkResourceIsReachableAndReturnError: &error] == FALSE)
{
NSLog(#"URL %# is not available because %#", [url absoluteString], [error localizedDescription]);
}
You can also try fetching the file via:
NSError *error = nil;
NSData *videoData = [NSData dataWithContentsOfURL:url
options: NSDataReadingUncached
error:&error];
if (videoData == nil)
{
NSLog(#"URL %# is not available because %#", [url absoluteString], [error localizedDescription]);
} else {
// you've likely got data, since videoData is not nil!
}

Answer 2

This is weird, but it works if I do this:
- (void)recorder:(SCRecorder *__nonnull)recorder didCompleteSegment:(SCRecordSessionSegment *__nullable)segment inSession:(SCRecordSession *__nonnull)session error:(NSError *__nullable)error {
[session mergeSegmentsUsingPreset:AVAssetExportPresetHighestQuality completionHandler:^(NSURL *url, NSError *error) {
if (error == nil) {
[self getDataFromUrl:url];
} else {
NSLog(#"Bad things happened: %#", error);
}
}];
}
- (void)getDataFromUrl:(NSURL *)url {
NSError *error = nil;
NSData *videoData = [NSData dataWithContentsOfURL:url
options:NSDataReadingUncached
error:&error];
if (videoData == nil)
{
NSLog(#"URL %# is not available because %#", [url absoluteString], [error localizedDescription]);
} else {
NSLog(#"GOT IT");
}
}
videoData is now valid NSData. Any explanation on why this works if separated into a different method?