[mythtv-users] Another performance question...

[Curtis Wood]

On my setup....

p2.4 hz
7200 maxtor hd (80g)
ATI 8500, DVI->HDTV
Running on gentoo (performance increase from rh or mandrake)

I still get choppy video every once in a while - however, one thing I
have noticed from doing a lot playing around is that tuning makes a
difference. For example, if I pipe the video from STB into composite - I
get very little no choopy video and no lockups. If your stuck with the
tuner - play with it, adjust the finetune setting in the database to
where the pictures color is maxed out and then use the adjustments to
make it look good.

Also as note, in the docs them selves - they say a fast harddrive is
critical...

Curtis

On Sat, 2003-12-06 at 00:14, Mark Frey wrote:
> Not to add more noise on this sort of issue, but...I suppose I am
> going to add more noise ;)
>  
> I find myself unable to get live tv stutter-free on the following
> machine:
>  
> Intel P4 2.0GHz
> 512 MB ram
> 5400rpm HD (hdparm says throughput = 30MB/s, DMA is on)
> NVidia GeforceFX 5200 video card with open source drivers
> Latest Alsa with drivers for MAudio Delta66 soundcard
> bt878 capture card, using btaudio (quite new version of bttv, whatever
> installed with Fedora Core)
> Latest MythTV from CVS
>  
> If I try and run with the default live-TV settings (480x480, RTJpeg),
> I'll be fine for "talking-head" type shows (News, etc.), but sports
> programming (basketball for example) will cause more-or-less constant
> stuttering (quarter second lurches every 1 or 2 seconds). Processor
> usage stays near but below 50%.
>  
> I've read through all the posts I can find, and it seems like some
> people have no problem with performance with this spec machine, while
> others have trouble with even beefier machines. I'm trying to figure
> out what the magic is to make this work. I've instrumented the code to
> try and determine where my machine is falling down. So far, from what
> I can tell the decoder thread winds up spending alot of time waiting
> for the ring buffer read thread to fetch data. Whether this is because
> the hard drive is unable to keep up (the size on disk of each frame is
> bigger for sports programming because it doesn't compress as well), or
> because the read thread is getting starved because
> compression/decompression is taking alot of processor time I don't
> know. I'm kind of new to Linux so I don't know the best way to monitor
> hard drive use (any pointers?)
>  
> I've turned jitter reduction on and off, messed with the audio
> buffering settings, all to no avail.
>  
> My question is: Should this machine be able to do this? Are others
> able to get smooth playback with this sort of setup, specifically for
> sports programming?
>  
> Thanks for any tips anyone can offer.
>  
> -Mark
>  
> 
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