[mythtv-users] Capturing 5.1 audio

Nathan Allen Stratton nathan at robotics.net
Sat Nov 12 19:05:32 EST 2005

On Sat, 12 Nov 2005, Michael T. Dean wrote:

> On 11/12/05 17:15, Nathan Allen Stratton wrote:
> >My current myth box uses 2 convertx boxes, but I just bought a HD-3000
> >card and monday should have my antenna. Do I need to do anything special
> >to get 5.1 channel sound?
> >
> Nope.  ATSC (US high-definition TV) is broadcast already encoded using
> the MPEG-2 system.  The audio is encoded in an AC-3 stream within the
> transport stream.  So, it's just there.
> > How is 5.1 compressed with mp3?
> >
> >
> MPEG-{1,2} Layer {2,3} audio only supports 1- or 2-channel audio.  There
> is a "stereo compatible" version called "MP3 Surround" which supports
> 5.1 channel audio in much the same way that Dolby Surround provides a
> "stereo compatible" 4.0 channel audio encoding.  However, ATSC requires
> the use of AC-3 for audio content (although they call it A/52), so no
> extra work is required to get it.

Ok, so with my hdtv card I am stuck using ac-3 for audio vs mp3, how bad
is this going to kill me on disk space?

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