Videos shot from android phones get ruined after editing with AVFoundation iOS

Question

I am working on an app that requires editing videos(setting overlays).Now,while the videos shot from iPhones are edited fine,the ones shot from android phones are getting blank after editing.

I can't imagine what the problem could be.I would appreciate an immediate help.

This is one of the methods(Trim functionality).

- (IBAction)cutButtonTapped:(id)sender {

    hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    hud.mode = MBProgressHUDModeText;
    hud.labelText = @"Encoding...";

    [self.playButton setBackgroundImage:[UIImage imageNamed:@"video_pause.png"] forState:UIControlStateNormal];



    NSString *uniqueString = [[NSProcessInfo processInfo]globallyUniqueString];

//do this to export video
    NSURL *videoFileUrl = [NSURL fileURLWithPath:[AppHelper userDefaultsForKey:@"videoURL"]];

    AVAsset *anAsset = [[AVURLAsset alloc] initWithURL:videoFileUrl options:nil];
    NSArray *compatiblePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:anAsset];

    if ([compatiblePresets containsObject:AVAssetExportPresetMediumQuality]) {

        self.exportSession_ = [[AVAssetExportSession alloc]
                           initWithAsset:anAsset presetName:AVAssetExportPresetPassthrough];
    // Implementation continues.

   //        NSURL *furl = [self newURLWithName:[uniqueString stringByAppendingString:@".mov"]];
          NSURL *furl = [self newURLWithName:[uniqueString stringByAppendingString:[NSString stringWithFormat:@".%@",[videoFileUrl pathExtension]]]];

    self.exportSession_.outputURL = furl;
    self.exportSession_.outputFileType = AVFileTypeMPEG4;

    CMTime start = CMTimeMakeWithSeconds(self.startTime, anAsset.duration.timescale);
    CMTime duration = CMTimeMakeWithSeconds(self.stopTime-self.startTime, anAsset.duration.timescale);
    CMTimeRange range = CMTimeRangeMake(start, duration);
    CMTimeShow( self.exportSession_.timeRange.duration);
    self.exportSession_.timeRange = range;
    CMTimeShow( self.exportSession_.timeRange.duration);

    [self.exportSession_ exportAsynchronouslyWithCompletionHandler:^{

        switch ([self.exportSession_ status]) {
            case AVAssetExportSessionStatusFailed:
                NSLog(@"Export failed: %@", [[self.exportSession_ error] localizedDescription]);
                break;
            case AVAssetExportSessionStatusCancelled:
                NSLog(@"Export canceled");
                break;
            default:
                NSLog(@"NONE");
                dispatch_async(dispatch_get_main_queue(), ^{

//                            [self playDocumentDirectoryVideoWithURLString:[uniqueString stringByAppendingString:@".mov"]];
                        [self playDocumentDirectoryVideoWithURLString:[uniqueString stringByAppendingString:[NSString stringWithFormat:@".%@",[videoFileUrl pathExtension]]]];

                });
        }
    }];
}

}

Could anyone please help me with this?

Answer 1

First of all, I recommend you to check duration & range values. It seems like an issue with CMTime and decoding. And second, try to initialise your AVURLAsset with an option to force duration extraction:

AVAsset *anAsset = [[AVURLAsset alloc] initWithURL:videoFileUrl options:@{AVURLAssetPreferPreciseDurationAndTimingKey: @(YES)}];