Trimming video with Monotouch fails with “The operation could not be completed”

Question

I am trying to trim a video to 5 seconds programmatically. Here is my implementation.

AVAssetExportSession exportSession= new AVAssetExportSession(videoAsset,AVA         


        

Answer 1

Try this code below. I modified exportSession.OutputUrl and how you initialize your CMTimeRange. Are you trimming it down to a 4 second clip?

var compatiblePresets= AVAssetExportSession.ExportPresetsCompatibleWithAsset(videoAsset).ToList();
var preset="";

if(compatiblePresets.Contains("AVAssetExportPresetLowQuality"))
{
    preset="AVAssetExportPresetLowQuality";
}
else
{
    preset=compatiblePresets.FirstOrDefault();
}

using (var exportSession = new AVAssetExportSession(videoAsset, preset))
{
    int SystemVersion = Convert.ToInt16(UIDevice.CurrentDevice.SystemVersion.Split('.')[0]);
    string filename;
    if (SystemVersion >= 8)
    {
        var documents = NSFileManager.DefaultManager.GetUrls(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User)[0].Path;
        filename = Path.Combine(documents, "trimmed.mov");
    }
    else
    {
        var documents = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); // iOS 7 and earlier
        filename = Path.Combine(documents, "trimmed.mov");
    }

    exportSession.OutputUrl = NSUrl.FromFilename(filename);
    exportSession.OutputFileType = AVFileType.QuickTimeMovie;

    var range = new CMTimeRange();
    range.Start = CMTime.FromSeconds (1, videoAsset.Duration.TimeScale);
    range.Duration = CMTime.FromSeconds (5, videoAsset.Duration.TimeScale);
    exportSession.TimeRange = range;
}

ExportTrimmedVideo( exportSession);