[mythtv-users] Just built MythTV, beginner questions

[Dirk Aust]

Am Sonntag, 14. März 2004 05:02 schrieb maarten:
> Hi,
>
> Forgive me for some MythTV-newbie questions.
>
> First and foremost, I did not find such info in the documentation pages but
> if anyone can point me to more additional info I'd be grateful.
>
> I just built and compiled mythtv on some older hardware I had laying
> around, to see if I could get it working.  It works now (after some ugly
> problems), so I'm planning to go out and buy some much faster hardware. 
> But...
>
> During testing I had some troubles, and they relate to the fact that this
> old hardware seems severely underpowered.  So much so that when I select
> "watch TV" to check my card's output for a preview, the picture lags at
> least several seconds (upto 10 seconds) to what I'm feeding it.

That's normal, because the capture module writes the video to the disk and 
afterwards the playback module plays it. Imagine, if you press "STOP" in 
LiveTV the lag will become even greater.

>
> The hardware is:  Celeron 500 MHz, 256MB, 8G hdd. Two Miro PCTV cards.
> Is the slowness, as described, to be expected with this hardware ?
> (yes, DMA is on)

8G seems to be very limited, only depending on the resolution I would guess 
you only have a few hours.

> I have not had the cards' tuner set to the channels yet, since I don't know
> how to go about that in a smart manner.  Do you have to do that with Xawtv
> and record the settings used there for mythtv ?
> I have an old but okay listing somewhere but it's Kwintv format, I have to
> figure out how to translate.  Is there a quicker way than either of these ?
> (I'm in holland, so xmltv doesn't take care of this, I reckon)

Try to use http://nxtvepg.sourceforge.net, it works fine for Germany.

> How can one select whether the TV- or the composite input is selected ?  I
> did some trials with a composite signal since that would be sharp and clear
> in contrast to the un-tuned TV signals. I played around with the video
> sources and connectors and whatnot but I get confused by it...
> However, I managed to make one recording off the composite signal (straight
> off DVD), and the quality is very disappointing (real blocky, like a jpeg
> saved at Q=20, or even less). So, I have a lot of tuning to do...
> Some questions regarding that:
> What is 'better' to use, rtjpeg or mpeg4 ? I also notice mpeg2 in some
> menus, but there is no option to select mpeg2 in the other [encoding] menus
> ? Does it matter whether I leave the resolution at 480x480 (default) or
> better at 1/2 PAL 384x288 (current setting) for my system ?
> Where do you select what resolution settings (default,live-tv,low-q,high-q)
> gets used when recording ? I did not see (or read) that anywhere.

You should use rtjpeg, because your CPU is quite slow and rtjpeg consumes less 
CPU power.

> Onto some hardware questions again,
> Do you reckon I should buy a PVR250, or it an AMD 2600+ well capable of
> using the two plain old PCTV cards ? (see also next question)

Your CPU will hardly manage ONE capture but never 2, I would guess buying a 
PVR-250, it works well for me, but should try if you can playback at least 
MPEG1 on your machine.

> I get the impression the TV picture quality is rather bad (I don't mean
> blockyness but interference and 'snow'). Is that an often-heard symptom of
> the used cheap cards, or should I investigate some sort of shielding ?
> This would be good to know in advance; if a PVR250 gives a better overall
> picture then I should maybe reconsider the athlon altogether and buy a
> PVR250 instead (so I can keep using this hardware).
>
> TIA,
> Maarten