def freezeLastFrameIfVideoShorter(self, fAudioStream, fVideoStream):
        # If audio is longer than video, freeze final frame of video until audio is finished.
        durA = self.getDuration_s( fAudioStream )
        durV = self.getDuration_s( fVideoStream )
        t = durA - durV
        if t < 0.05:
            return fVideoStream

        fVideoStreamOut = self.tmp_filename('vidFreezeLastFrame.mp4')

        # https://superuser.com/questions/1250900/freeze-last-frame-of-a-video-with-ffmpeg
        args = ['ffmpeg',
                '-f', 'lavfi',
                '-i', 'nullsrc=s=' + self.getRes(fVideoStream) + ':d=' + str(durA),
                '-i', fVideoStream,
                '-filter_complex', '[0:v][1:v]overlay[video]',
                '-map', '[video]',
                '-shortest',
                fVideoStreamOut]

        subprocess.run(args, check=True)

        return fVideoStreamOut