在iOS中，摄像头录制的视频是mov格式的，虽然mov兼容mp4，但是有些需求需要用到mp4格式的视频文件
AVURLAsset *avAsset = [AVURLAsset URLAssetWithURL:[NSURL fileURLWithPath:path] options:nil];
NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:avAsset];
if ([compatiblePresets containsObject:AVAssetExportPresetLowQuality]) {
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:avAsset presetName:AVAssetExportPresetPassthrough];
NSString *exportPath = [NSString stringWithFormat:@”%@/%@.mp4″, [NSHomeDirectory() stringByAppendingString:@”/tmp”], @”1″];
exportSession.outputURL = [NSURL fileURLWithPath:exportPath];
NSLog(@”%@”, exportPath);
exportSession.outputFileType = AVFileTypeMPEG4;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
switch ([exportSession status])
{ case AVAssetExportSessionStatusFailed:
NSLog(@”Export failed: %@”, [[exportSession error] localizedDescription]);
break;
case AVAssetExportSessionStatusCancelled: NSLog(@”Export canceled”);
break;
case AVAssetExportSessionStatusCompleted: NSLog(@”转换成功”);
break;
default: break; } }]; }