message: Redirect ffmpeg output to logger.
diff: @@ -52,6 +52,10 @@ export class VideoConverterWorker {
  })
  .on('error', (e: any) => {
  reject('[FFmpeg] ' + e.toString() + ' executed: ' + executedCmd);
  + })
  + .on('stderr', function (line: string) {
  + // Although this is under `stderr` event, all of ffmpeg output come here.
  + Logger.debug(line);
  });
  // set custom input options
  