[mythtv-users] Think SDTV PiP is possible with ATA33 IDE controller?

Levander levander at mindspring.com
Sun Dec 2 04:49:52 UTC 2007


I've got a dual PIII 550 / 512 MB RAM / nVidia 6200 / PVR 500 on an old box I've got a MythTV frontend and backend set up on.  SDTV for watching a single live channel is working fine on this one box with component output and the standard mpeg decoder.  However, when I turn on PiP, the video is "skipping" momentarily and I'm getting prebuffering pauses in mythfrontend.log.

What I'm wondering is the reason I'm getting these prebuffering pauses is because the PIII motherboard is based on the Intel 440BX chipset and only supports ATA33.  I could take a stab at doing the math to see how much disk bandwidth I'd need to be watching live TV with PiP, but I've rarely done math based on disk access and I'm sure I'd get something wrong.  I figure the math would go something like: 1.) how many bits of data are in each channel of the live Tv? 2.) Times this number by two to figure out how much I would need to be able to write to the disk.  3.) Use the number found in 2.) to figure out how much bandwidth I'd need to read from the disk at the same time I was writing all that data to disk.

But, maybe all that math is no good anyway in real world scenarios?  I don't even know if the data from the capture is written to disk before it's decoded and sent to the video card?  Maybe there's some in-memory buffer that prevents the hard disk from being the bottleneck.

Anyway, in theory, is SDTV PiP possible with an ATA33 IDE controller?

I'm trying to get the box set up so that it was two disks in it, each one on a different IDE ribbon, but I'm having problems.  Please keep this thread just about whether Myth can do PiP with this hardware, despite what I must do to achieve the different ribbons thing working.  I'm asking for help getting the IDE ribbons set up in a different place:

http://forums.storagereview.net/index.php?showtopic=26250

-Levander


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