public Task ConvertAsync() {
if (IsRunning) {
throw new InvalidOperationException("operation in progress");
}
_state = FfmpegState.None;
_task = new TaskCompletionSource<bool>();
try {
_ffmpeg.Start();
_ffmpeg.BeginErrorReadLine();
}
catch (Exception ex) {
_task.SetException(ex);
}
return _task.Task;
}
public void Cancel() {
_state = FfmpegState.Cancelled;
// Press 'q' to quit...
_ffmpeg.StandardInput.Write('q');
}
// We have to parse the crappy FFmpeg output.
private void HandleOutput(string line) {
// We need to get the duration to work out the percentage complete later.
if (line.StartsWith(" Duration")) {
_duration = GetDuration(line);
}
// Progress updates start with either of these two things.
if (line.StartsWith("size=") || line.StartsWith("frame=")) {
var elapsed = GetElapsed(line);
if (elapsed < _duration) {
// Progress.
_state = FfmpegState.Running;
var percentage = (int)((elapsed.TotalSeconds / _duration.TotalSeconds) * 100);
OnProgress(new FfmpegProgressEventArgs(percentage));
}
else {
// Finished
_state = FfmpegState.Finished;
OnProgress(new FfmpegProgressEventArgs(100));
}
}
}
