[mythtv-users] Plextor Convertx CPU Usage

[Steve Peters - Priority Electronics]

>
>>
>>
>> Here is my main issue: I have 2 pvr-500's in my mythbox, but I have  
>> these
>> annoying vertical lines that show up over every recording, 
>even when  
>> the
>> source is my cable box svideo input. I don't think it's 
>specifically  
>> the
>> cards, but something else internally, because when I uplug 
>my system  
>> fax,
>> the lines lessen, but are still there. So I was thinking of getting
>> something USB to try to fix the issue. I'd probably get a couple of  
>> these
>> convertx's if they are good replacements for my pvr-500's.
>
>I'd try and find out what your hardware problem is. If unplugging  
>something reduces your problem that's what you have. Not sure if you  
>meant unplugging the fax phone line or your modem card, but either  
>means you have problems.
>
>>
>>
>> What do you think? If I had 2-3 of these guys going, would the pcm  
>> audio
>> converting (that I heard your system has to do) take much 
>cpu up? Do  
>> you
>> ever have audio out of sync issues, or any other issues with it for  
>> that
>> matter?




I mean the system fan, not fax. (just a typo)




>
>The main problem I've run into with them has to do with common mode  
>interference, AKA AC hum. The problem is that the unit is grounded at  
>least 3 ways: The DC power supply, the USB connection and the RF  
>connector, and maybe your audio/video inputs. Often these are all at  
>slightly different ground potentials, so you have to be very careful  
>or you will have visible hum bars in your pictures.
>
>Since you already have the PVRs I'd just keep them if you can fix the  
>bar problem. The Plextors buy you extra AC adapters and associated  
>cables, as well as the USB cable, but they free up PCI slots and are  
>the only way I'm aware of (pending the Hauppauge unit) to do 
>MPEG-4 in  
>hardware with Myth.


I do have a hunch that it is AC Hum. But how would I go about fixing that?
I've already gotten a upc battery backup to help ground the mythbox. Didn't
help much though. But any other ideas to fix this would be greatly
appreciated.

Also, one reason I want to get something usb is to free up a pci slot so I
can add firewire. That would be a nicety, and $50 for a usb tuner is cheaper
than a hd home run, since I'll be able to get those hd channels (I hope) by
putting in a pci firewire slot. I'll probably be going for the new hd-pvr
when it comes out, but at $50, the plextor seems like a steal.

--Thanks
-Steve