message: Add FFmpeg prefix on log lines.
diff: @@ -55,7 +55,7 @@ export class VideoConverterWorker {
  })
  .on('stderr', function (line: string) {
  // Although this is under `stderr` event, all of ffmpeg output come here.
  - Logger.debug(line);
  + Logger.debug('[FFmpeg] ' + line);
  });
  // set custom input options
  