[mythtv-users] Another performance question...

[mythtv]

Mark,

30Mb/s is kinda slow I would think. I am getting 60mb/s with my single
drive. I would try turning down the bitrate on the RTJPEG to something
very minimal. If this fixes it, then you will prob need a newer HD.
Also, try recording a few minutes of a program and see if it stutters.

Try these 2 things and I would think you could narrow the cause down.

Bruce

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 2.0GHz512 MB
> ram5400rpm HD (hdparm says throughput = 30MB/s, DMA is on)NVidia
> GeforceFX 5200 video card with open source driversLatest Alsa with
> drivers for MAudio Delta66 soundcardbt878 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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