AVAssetExportSession outputfile - iphone

Question

How should the AVAssetExportSession output file look like? I'm trying to compress a video from an ALAsset item and it doesn't work. I'm guessing the output file has something to do with it.
Here's the code i'm using:
NSString *destinationPath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents/Movie"];
[self convertVideoToLowQualityWithInputURL:asset.defaultRepresentation.url outputURL:[NSURL URLWithString:destinationPath]];
- (void)convertVideoToLowQualityWithInputURL:(NSURL*)inputURL outputURL:(NSURL*)outputURL {
if([[NSFileManager defaultManager] fileExistsAtPath:[NSString stringWithContentsOfURL:outputURL encoding: 0 error:Nil]]) [[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];
AVURLAsset *assetAV = [AVURLAsset URLAssetWithURL:inputURL options:nil];
NSLog(#"url string from asset: %#", assetAV.URL);
NSLog(#"output url: %#", [outputURL absoluteString]);
[[NSFileManager defaultManager] createFileAtPath:[outputURL path] contents:nil attributes:nil];
NSLog(#"duration: %lld", assetAV.duration.value); //it logs a valid value, so it's all good so far
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:assetAV presetName:AVAssetExportPresetLowQuality];
exportSession.outputURL = outputURL;
exportSession.outputFileType = AVFileTypeQuickTimeMovie;
[exportSession exportAsynchronouslyWithCompletionHandler:^(void) {
if (exportSession.status == AVAssetExportSessionStatusCompleted) {
NSLog(#"success");
} else {
NSLog(#"error: %#", [exportSession error]);
//error: Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo=0x2023b720 {NSLocalizedDescription=The operation could not be completed, NSUnderlyingError=0x2023bb70 "The operation couldn’t be completed. (OSStatus error -12780.)", NSLocalizedFailureReason=An unknown error occurred (-12780)}
}
}];
}
Can someone please help me?
UPDATE:
Found the solution. As I thought the problem was the output file so here is the code for generating a valid one:
NSUInteger count = 0;
NSString *filePath = nil;
do {
NSString *extension = ( NSString *)UTTypeCopyPreferredTagWithClass(( CFStringRef)AVFileTypeQuickTimeMovie, kUTTagClassFilenameExtension);
NSString *fileNameNoExtension = [[asset.defaultRepresentation.url URLByDeletingPathExtension] lastPathComponent];
NSString *fileName = [NSString stringWithFormat:#"%#-%#-%u",fileNameNoExtension , AVAssetExportPresetLowQuality, count];
filePath = NSTemporaryDirectory();
filePath = [filePath stringByAppendingPathComponent:fileName];
filePath = [filePath stringByAppendingPathExtension:extension];
count++;
} while ([[NSFileManager defaultManager] fileExistsAtPath:filePath]);
NSURL *outputURL = [NSURL fileURLWithPath:filePath];

Answer 1

Your issue is [NSURL URLWithString:destinationPath] and only that. You need to use [NSURL fileURLWithPath:xxx] like you did in your solution. Posting this just to clarify that that is the only problem.