录制高清视频，保存低质量视频

Question

我目前正在使用UIImagePickerController录制视频并保存。我使用1080p质量，因此短视频仍然可以很大。在我的应用程序中，用户可以通过电子邮件发送他们录制的视频，所以有一个大的视频是不可以的。有没有办法我可以保存两个版本的视频（高质量和低质量），一个保存在~/app folder/video-name.mov，然后另一个保存到~/app older/video-name-SD.mov？或者保存高清视频，但不知何故有一个SD版本？欢迎所有解决方案，而不仅仅是保存SD版本。以下是我正在做的事情：

  - (BOOL)startCameraControllerFromViewController:(UIViewController *)controller
                                      usingDelegate:(id)delegate {
//setup for video recording
//imagePickerWithout is a subclass of UIImagePicker
        imagePickerWithout *cameraUI = [[imagePickerWithout alloc] init];
        cameraUI.videoQuality = UIImagePickerControllerQualityTypeHigh;
        [controller presentViewController:cameraUI animated:YES completion:nil];
        return YES;
    }
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
//setup video
        NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];
        NSData *videoData = [NSData dataWithContentsOfURL:videoURL];
            //pseudocode :(
            NSData *lowQualData = [NSData LOW_QUALITY_VERSION_OF_URL:videoURL];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        int random = arc4random() % 80085;
        NSString *tempPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@_%@_%@_%d.mov", self.person.first, self.person.last, self.person.age, random]];
NSString *sdPath = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@_%@_%@_%dLOWQUAL.mov", self.person.first, self.person.last, self.person.age, random]];
        NSFileManager *fileManager = [NSFileManager defaultManager];
        BOOL success = [videoData writeToFile:tempPath atomically:YES];
            BOOL success = [lowQualData writeToFile:sdPath atomically:YES];
        NSError *error = nil;
        [_managedObjectContext save:&error]
}
[self dismissViewControllerAnimated:YES completion:nil];
}

Answer 1

首先以高质量录制视频，然后使用AVAssetWriter或AVAssetExportSession制作低质量副本，如下所述：

iPhone：用程序压缩录制的视频以共享？