[mythtv-users] combined HD frontend/backend on P4 3.2Ghz

[John P Poet]

On 11/21/06, Ali Asad Lotia <ali.asad.lotia at gmail.com> wrote:
> On 11/21/06, John P Poet <jppoet at gmail.com> wrote:
>
> > > what distro are you running?
> >
> > Fedora Core 5.
> >
> > > i wonder if the slightly faster
> > > clockspeed on my machine will allow commflagging to go on at the same
> > > time or if i will have to upgrade processors.
> >
> > Linux stresses CPUs far more than XP does.  Makes it a bit harder to
> > have a stables, over-clocked machine.
> >
> > > is HD commflagging as
> > > processor intensive as HD playback?
> >
> > In a way, yes, but not really.  The commflagger has to decode the
> > show, just like it would to display it on your screen, however, it
> > does not have to do it in real time.
> >
> > The commflagger can run at three speeds: High, Medium and Low.  High
> > speed means it uses all the CPU the scheduler will let it.  Medium
> > means it runs at a lower priority.  Low means it runs at a lower
> > priority, and will "sleep" a lot to make sure other processes get
> > plenty of CPU.
> >
> > On the 2.6 MHz HT P4, even setting it run at Low kills performance too
> > much to watch a HD program.  I have a feeling this may have as much to
> > do with disk performance, as CPU performance.
> >
> >
> > > i love the performance of myth
> > > with SD and really don't want to have to deal with stuttering etc.
> > > when viewing content. i guess trying it is the best way to find out.
> >
> >
> > Yup.  As Mark Lehrer said, he has had a very hard time making this
> > work on similar hardware.  There are a lot of variables, including
> > disk performance, which go into the equation.  Even the BIOS on your
> > motherboard could influence how well this all works for you.
> >
> >
> > > thanks all for replying. any other input would be much appreciated.
> >
> > Your welcome.
>
> Also does deinterlacing incur the marjority of the CPU load or is it
> simply decoding the MPEG2 files?

Decoding takes a lot more horse power than deinterlacing, but
deinterlacing can up the ante a bit.

>I shouldn't need to do any
> deinterlacing since I will have an external scaler/deinterlacer.

Unfortunately, it does not work that way for most people.  What video
card are you using?  The vast majority of video cards do not send out
interlaced video correctly on anything but the  composit/s-video
connector.  This means that to maintain HD resolutions, you must
deinterlace in Myth, even when feeding an interlaced (CRT) display.

John