[mythtv-users] Is HD worth it?

Richard Freeman r-mythtv at thefreemanclan.net
Sat Sep 15 16:44:32 UTC 2007

jack snodgrass wrote:
> I like to watch US Network ( ABC/NBC/CBS/FOX ) OTA signals on my
> $25 Air2PC card. There is plenty of OTA stuff to justify a $25 HDTV
> tuner card.

I dunno.  I'd really like to be able to get AC3 audio, but unfortunately
I haven't found a way to transcode hi-def to SD in myth and keep the
audio intact.

There are a few barriers:

1.  The HD stream isn't perfect since it is off-the-air.

2.  The myth internal player doesn't like video unless it has keyframes
every 15 frames or so.  This is hard to generate, especially due to #1.

3.  With the huge change in video bitrate the audio tends to get out of
sync for whatever reason and there aren't many OSS tools to manipulate
AC3 audio.

Even on my myth backend (a A64-3200+ with a Geforce 4) HD video tends to
be choppy.  My EPIA front-end is useless for HD video.  In any case, I'm
more interested in the digital video capture (better than DirecTV OTA
channels) and the AC3 audio.

A few tools have been posted to try to make it easier to create SD video
with AC3 audio.  They aren't 100% reliable in general, and most of the
time I end up with a file that plays just fine in xine/mplayer and gets
fouled up in myth any time I seek.  (If I only knew how to make myth
handle arbitrary video keyframe intervals - I wouldn't mind rebuilding
the seektables for every one of my recordings - actually, I could
probably just do an update and multiply everything by 15...)

I'm guessing HD would work better if you just bit the bullet and
recorded it and didn't mess with it and upgraded all your hardware to
accomodate it (10X the HD space, new frontends, etc).  Not really worth
it for me...

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