I've noticed that with TV recordings you get hiss and other problems in VHS-to-DVD conversions and to a lesser extent on Straight-to-DVD recordings. Below is a short Straight-to-DVD video recorded off the TV where it seems like there's a low sounding swirling artifact on the bottom of the spectrum. I've also provided a WAV and another WAV with that sound removed so you can hear the difference.

Short MPEG2. I chose this sample because there's barely any movement in the ring so the noise is not coming from them.
Amient or Noise.wav?
Noise Removed.wav I know I ruined the audio here but it's just to show you what it sounds like without the swirling noise so you can identify more easily on the Ambient or Noise.wav file.

So is the swirling noise supposed to be there or is it an artifact?