[mythtv-users] Some questions about HDTV recording

Brad Templeton brad+myth at templetons.com
Sat Dec 11 04:41:52 UTC 2004

On Fri, Dec 10, 2004 at 07:09:54PM -0600, Nate Carlson wrote:
> Hey all,
> I'm considering adding a PCHDTV card to my MythTV setup, and have a few 
> questions about it before I order the card.
> 1) How does recording schedulding work for HDTV? My PVR-250's are hooked 
> up to the local cable feed; the PCHDTV card will be set up for OTA. If a 
> show is available via both HDTV and cable, how do I tell it I prefer the 
> HDTV version?

The HDTV channels are different channels to the system.  You would
select "record this show on this channel."  I believe there is also
a priority system for channels and tuners so you can tell it to prefer
the HD tuner.

However, that turns out to be a problem.  SD shows appear on the HD
channels, but unfortunately, they appear in HD, and not at a very reduced
bitrate.  So even if you record a half hour of SDTV on an HDTV channel
it will take 3gb or so.

You want a fancier system that knows when a program is truly HD, and
records it HD if it is, but from either the twinned SD channel when it
isn't or from the cable.

Mind you, the HD recording of the SD program is better quality than the
cable, and oddly it's better quality than the twinned SD channel (FOX,
NBC and a few other channels in my area run a twinned SD channel on the
2nd sub-channel.  It's 480i though not 480p.)

> 2) Is it possible to set up separate transcoding profiles for the HDTV 
> card than the standard cards? I'd like to be able to transcode the HDTV, 
> but still preserve the AC3 audio and such. I was really impressed with a 
> XVid show I grabbed via BitTorrent - it was ~300mb for a 20min show with 
> AC3 audio, and looked great on my 50" TV! Don't see any reason to keep 
> files that are 1gb/10min around.  :)

This is a feature I have requested before, others too, but it is not there.

You can do it manually, though.  I mean by shell script you write.
> 3) Are there any other got'chas I need to worry about?

Tons of them.  HD is new to MythTV.  AC-3 audio also creates problems
in myth and its sound drivers.
> Thanks for any comments!

More information about the mythtv-users mailing list