[LUAU] Re: Putting the UG back in LUG

[Matt Darnell]

On 2/2/06, Eric Hattemer <hattenator at imapmail.org> wrote:
>
> Matt Darnell wrote:
> >> I just have to remember to play with the udev settings
> >> after any major rpm upgrade.
> >>
> > Not sure what that means....but I am sure some of the boys will!
> >
> >
> Oh, I should explain.  It's suggested that for simplicity sake, you
> start by running mythbackend as root.  I did that for a while, then
> decided it might be better/safer to run it as it's own unprivileged
> user.  This meant that all of the devices the program needs need to be
> accessible by the user that runs mythbackend.  By default, Fedora makes
> the video capture cards only accessible by root, and the sound card
> either by root, or the user logged into X11 on console.  I needed to
> change that, so I played with their udev script, which sets the
> permissions on a reboot.  Everytime I upgrade my rpms seriously, that
> script gets overwritten.  I finally learned that I could make an addon
> script with a higher number that wouldn't get overwritten, but I haven't
> rebooted or upgraded since that.



I will make sure people think about that.


> Wow that install guide is awesome!  The hardware guide is worth the price
> > alone.
> >
> > Have you ever used the knoppix mythtv distro?  When you said FC4, I
> assume
> > you built it from source.
> >
> >
> I haven't used the knopmyth, but I hear it almost surely works out of
> the box with most hardware, quite well.  It might take some setup on
> every reboot, but maybe you can store the settings on the hard drive.  I
> don't know.
> > I have an iMac for my machine at home...I wonder if you can stream to
> it.  I
> > use 802.11g
> >
> >
> It probably won't be a big problem.  They worked out a mythfrontend for
> OSX.  You can probably compile it with the Apple Developer Tools.  You
> probably need to compile a whole bunch of libraries, install fink, or
> hope they have a binary version.  I haven't looked at the Apple stuff,
> though.  If you can find a mythtv/nuppelvideo decoder for your favorite
> media player, then you don't need the mythfrontend to watch pre-recorded
> stuff (you need a very special codec to watch live TV).  I believe the
> standard codec pack for MPlayer comes with nuppelvideo.


I will check that out.



> Thanks for the feedback!  Do you mind giving you hardware specs -
> > motherboard part #, CPU, which bttv cap card.
> >
> My old motherboard blew a set of capacitors.  I kept swearing that there
> was a redhat kernel problem, because I'd get random panics once a week
> or so.  I kept bugging Warren.  The redhat kernel specialist told me to
> look at the motherboard.  Sure enough, there was brown goo oozing out of
> most of my capacitors.
>
> My new motherboard that I've had for a few months is the MSI K7N2GM-V.
> The motherboard isn't really that important for this, unless you are
> going for a shuttle setup.  A lot of people are using shuttles and via
> processors for their mythtv machines because they are small and
> passively cooled (quiet).  I don't care about either of those factors.
>
> I'm using an Athlon XP.  I forget which PR number it is, but it's
> 1141MHz with 2252 bogomips.  I think it was an 1800+.  I put in 1GB of
> RAM just for fun (I was ordering RAM for my Windows gaming machine, and
> just wanted to grab some for the Linux machine too).
>
> The TV card is an ATi TV Wonder PCI.  It was like $70 in the year 2000.
> It has an onboard MPEG-1 encoder only (useless).  MPEG-1 takes up
> massive amounts of space, so mythtv doesn't use MPEG1.  This means I
> have to encode to some other video format, which uses the processor.  I
> can get max quality mp3 with 640x480 180-quality RTJPEG using probably
> around 60-70% CPU.  I only use DivX (MPEG4) anymore on low quality
> stuff, and use 900kbit/sec rating.  I used to do mpeg4 encoding on the
> fly on high quality stuff, but this ramped up the processor into the
> danger zone.  If I run low on space, I can use the nice-19 transcoder
> function to re-encode my rtjpeg stuff to divx over maybe the time it
> would take for the show to run twice.  But I have a 250GB hard drive, so
> that's not too much of a problem.  You should note, that you will want
> outrageous amounts of disk space for your mythtv box.  I was thinking
> about setting up a TB array.  But in the end, you start to realize that
> the hard drive is just a buffer between the time you tape the show and
> the time you watch it.  If your schedule is anywhat consistent, you will
> need to eventually delete things without watching them if you tape too
> much.  My divx 900kb/s shows are about 10MB/min (keep in mind the sound
> gets added in).  The RTJPEG 480x320 at 160 stuff is about 40MB/min.  The
> RTJPEG 640x480 at 180 stuff is just over 50MB/min.  That means an hour show
> takes up about 3GB.  I could optimize these a bit, turn transcoding back
> on, etc., but I haven't palyed with these in a while.  Since I got my
> $3000 1080p TV (a week ago), I probably should ramp up all resolutions
> to 640x480 (the max the card handles and the max SDTV comes in at).  The
> divx 320x240 at 900kb/s looks pretty goofy when it's not on my 20"
> monitor.  Maybe I'll up the res, but keep the bitrate the same.  Mostly
> I just tape talk shows at this quality level, anyway.  It's just that at
> the same bitrate, large frame sizes give good stills, and small frame
> sizes give good motion.  If I did 640x480 at 900kb/s, I'd get insane
> macroblocking.  But that's not relevant for talk shows.
>
> With any of the cards with the MPEG2 encoders builtin, you can tape to
> MPEG2 directly.  This uses negligible cpu (I think someone said about
> 4%).  Even at max quality, the shows don't take up an unreasonable
> amount of space.  You can then run the transcoder in the background at
> minimum priority (in mythtv, you setup a recording profile that
> automatically transcodes certain shows you pick).  I think the Haupauge
> 150/250/350 cards are the most common ones with builtin MPEG2 encoders.
> There are cards with 720p capabilities, but since I have SD cable, I've
> never looked into that.
>
> -Eric Hattemer



Great stuff  Eric!

You confirmed my belief that I should get one of the Haupauge cards.  I
think the 150 will do me fine..just want to take on last look at the
differences.

Speaking of 1080p......when should I show up for the Superbowl?

-Matt