#pragma mark - helper
- (NSURL *)convert2Mp4:(NSURL *)movUrl {
NSURL *mp4Url = nil;
AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:movUrl options:nil];
NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];
if ([compatiblePresets containsObject:AVAssetExportPresetHighestQuality]) {
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:avAsset
presetName:AVAssetExportPresetHighestQuality];
mp4Url = [movUrl copy];
mp4Url = [mp4Url URLByDeletingPathExtension];
mp4Url = [mp4Url URLByAppendingPathExtension:@"mp4"];
exportSession.outputURL = mp4Url;
exportSession.shouldOptimizeForNetworkUse = YES;
exportSession.outputFileType = AVFileTypeMPEG4;
dispatch_semaphore_t wait = dispatch_semaphore_create(0l);
[exportSession exportAsynchronouslyWithCompletionHandler:^{
switch ([exportSession status]) {
case AVAssetExportSessionStatusFailed: {
NSLog(@"failed, error:%@.", exportSession.error);
} break;
case AVAssetExportSessionStatusCancelled: {
NSLog(@"cancelled.");
} break;
case AVAssetExportSessionStatusCompleted: {
NSLog(@"completed.");
} break;
default: {
NSLog(@"others.");
} break;
}
dispatch_semaphore_signal(wait);
}];
long timeout = dispatch_semaphore_wait(wait, DISPATCH_TIME_FOREVER);
if (timeout) {
NSLog(@"timeout.");
}
if (wait) {
//dispatch_release(wait);
wait = nil;
}
}
return mp4Url;
}