[mythtv-users] Time to take the next step...

[VCRAddict]

At 02:12 PM 11/16/08 -0800, Yeechang Lee wrote:
 >
 > VCRAddict <MythTV_01 at appropriate-tech.net> says:
 > > But you're talking about a system which includes a Front-End (and
 > > one which supports high-def playback, at that).
 > 
 > [...]
 > 
 > > I'm using [XvMC} now on the existing (stand-alone) FE/BE system, and
 > > it seems to do just fine -- tho' admittedly, I've yet to try playing
 > > back any high-def content.
 > 
 > These two statements are contradictory, unless I interpret them to
 > mean that you *believe* your existing 1.6GHz Pentium 4 MythTV box can
 > act as a high-definition frontend, but have not actually tried it out
 > as such yet.

Well...  Almost, but not quite.

We were talking about several different things, and those two comments were
in response to two different statements made by Allen Edwards.
Specifically, the first was in response to his contention that an AMD
Athlon XP 3000+ would be inadequate for my proposed Back-End-Only system
(which I find implausible, to say the least); the latter was in response to
his blanket condemnation of XvMC (which I subsequently noted seems to work
fine on the aforementioned 1.6GHz P4 FE/BE box).

As for whether or not the existing FE will prove adequate for playback of
the stuff the new Back-End captures... that remains to be seen; but I
suspect that I'll *have* to use XvMC for it to work acceptably.

 > As noted, you are not in fact going to be able to play back actual
 > 720p or 1080i MythTV recordings with your existing MythTV box,
 > regardless of whether you take the backend load off it. A Pentium 4
 > 3.0 GHz is the minimum.

Even with XvMC?  I find that surprising, given other comments & reports
I've read.  I seem to recall a lot of folks using things like those little
EPIA micro boards for super-quiet dedicated FE-only systems.  ISTM that if
a VIA C3 can work even moderately well, 1.6GHz P4 should not have a
problem.  This chart:

    <http://www.mythtv.org/wiki/index.php/XvMC:Example_CPU_Savings>

also seems to imply that I'll have enough raw hardware horsepower, if
perhaps little or none to spare.

 > > Why, pray tell, would I not want to run XvMC?  
 > 
 > More or less broken for most people with high-definition recordings.

Can you expand on this, or at least point me to a more definitive
explanation of what you're talking about?

 > > That is not the situation I'm dealing with.  The new system will be
 > > a Back-End ONLY.  My understanding is that this reduces the host
 > > system CPU/memory requirements *drastically*, as compared to a FE/BE
 > > system.
 > 
 > Memory, yes.
 > 
 > CPU? Not so much. As noted, recording ATSC streams from a HDHomerun is
 > very easy from a processing perspective.

Now it seems to be you who is contradicting himself.

As noted several times so far in this thread, "recording ATSC streams" is
*all* this box is destined to do.  It will not be providing any sort of
MythTV "front-end" functions, and it will not be supporting NTSC recording
(except perhaps if I steal some of its disk space for the overflow from the
existing FE/BE box; but I don't really expect that to happen).  So by your
won statement, that should make life VERY easy for that system's CPU.  Now,
once I have it in place and see how well the existing FE/BE box deals with
the captured high-def recordings, I *may* then have the new Back-End also
do some sort of auto-transcoding (particularly if/when the existing FE/BE
moves to the MBR, where it will have to deal with a conventional NTSC 4:3
TV set).  But I'll cross that bridge when I come to it.

 > No. It's a network device and backends communicate with it via the
 > network. As noted, one HDHomerun is distinct from another from a
 > network-topology perspective.

Yes, others have now mentioned this; and as a result, a pair of HDHRs is
now the leading contender of how I'll handle the tuner issue.

Thanks.