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Could it be my hardware?
http://forum.linhes.org/viewtopic.php?f=2&t=11695		 Page 1 of 3
Author:  Gibble [ Mon Sep 18, 2006 12:12 pm ]
Post subject:  Could it be my hardware?
I'm having problems getting good reception, though, I'm no longer thinking it's actually the reception OR the tuner cards...I'm thinking this PC just isn't fast enough to handle two cards.

The computer is an Intel P3-667 (or 700...not sure which I used) and I believe it has 512Mb of ram.

I've intalled two PVR-150s and have it setup with R5C7 as both a master and slave.

The problems I'm having are outlined here...and the steps I've allready taken to try and rectify the problem.
re: http://mysettopbox.tv/phpBB2/viewtopic.php?t=11286

Most channels work, but some, are choppy...and it's mostly sports stations that have this problem...or when coming back from commercials to the show it might be choppy for a few seconds then clear up.

...I'd like to get this issue sorted out.
Author:  tjc [ Mon Sep 18, 2006 5:31 pm ]
Post subject: 
If the box is old enough you might have a harddisk controller on the motherboard that can't do DMA reliably. I know this was the case with the Intel motherboard in my old Dell machine of roughly the same vintage. You really need DMA to reliably stream the captured data to disk.
Author:  Gibble [ Tue Sep 19, 2006 9:15 am ]
Post subject: 
I'll have to double check which mobo I'm using, but since it was working perfectly when I only had one pvr-150 card in there, and this happens when I'm only using one of the cards at a time...I wouldn't think that would be it.

I'll check the mobo tonight.
Author:  tjc [ Tue Sep 19, 2006 6:58 pm ]
Post subject: 
Huh? Sure it could. Without DMA you've only got a reliable realtime bandwidth of X within the required buffer overflow/underflow latency, with DMA you've got 10*X. Let's say that the X for your drive/controller/MoBo is somewhere between 1.05 and 1.95 times the required bandwidth for live TV on one PVR card. It ought to be obvious what happens when you add a second card or another high disk activity tasks like flagging commercials. I actually ran into this with my first KM box when DMA got turned off, which is how I know about it.

BTW - You can measure and calculate this. Use "hdparm -tT" to measure the disk bandwidth. At 2.2Gb/hour (the default 480x480 PVR recording profile) you're talking about 0.66Mb/second, for LiveTV it's both writing and reading this amount of data at the same time. How does the lower number reported by hdparm compare to that?
Author:  Gibble [ Wed Sep 20, 2006 10:09 am ]
Post subject: 
I understand that...but if the second tuner isn't doing anything why would it work differently than it did with just one tuner? That's what I don't understand. Then again...this isn't my area of expertise, so I'll take your word for it.

Ok, I checked the mobo I'm using and it's an MSI K7T Turbo (Limited Edition) and I have 512 MB ram.


Code:
/dev/hda:
 Timing cached reads:   456 MB in  2.01 seconds = 226.90 MB/sec
 Timing buffered disk reads:  44 MB in  3.04 seconds =  14.49 MB/sec

/dev/hdc:
 Timing cached reads:   444 MB in  2.01 seconds = 220.60 MB/sec
 Timing buffered disk reads:   54 MB in  3.01 seconds =  17.92 MB/sec

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hda1              4820232   4576212         0 100% /
/dev/hda3              9354312     51712   9302600   1% /myth
/dev/hdc1             39577704  28842276   8724976  77% /myth/tv
Author:  tjc [ Wed Sep 20, 2006 5:50 pm ]
Post subject: 
Could also be interupt contention. Do a "lspci -v" and see if they're sharing an interupt.
Author:  Gibble [ Wed Sep 20, 2006 9:21 pm ]
Post subject: 
Code:
0000:00:08.0 Multimedia video controller: Internext Compression Inc iTVC16 (CX23
416) MPEG-2 Encoder (rev 01)
        Subsystem: Hauppauge computer works Inc.: Unknown device 8003
        Flags: bus master, medium devsel, latency 64, IRQ 11
        Memory at dc000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [44] Power Management version 2

0000:00:09.0 Multimedia video controller: Internext Compression Inc iTVC16 (CX23
416) MPEG-2 Encoder (rev 01)
        Subsystem: Hauppauge computer works Inc.: Unknown device 8003
        Flags: bus master, medium devsel, latency 64, IRQ 5
        Memory at e0000000 (32-bit, prefetchable) [size=64M]
        Capabilities: [44] Power Management version 2


Doesn't appear to be...unless i'm missing something :p
Author:  Gibble [ Fri Sep 22, 2006 8:28 am ]
Post subject: 
Thanks so far.

Any other ideas?
Author:  Gibble [ Mon Sep 25, 2006 9:07 am ]
Post subject: 
Guess not :( Bummer.
Author:  Gibble [ Tue Oct 03, 2006 4:56 pm ]
Post subject: 
Ok, so I did some more research, thinking maybe the flicker/stutter was because my computer just couldn't play the files back fast enough. So I copied an episode that was recorded to another computer, and it did the exact same thing.

So I now know the problem is related to the recording of the video.

Also, is there an app (windows preferably) I can download so I can cut out a portion of a mpg so you can see what exactly I mean by a "flickering".
Author:  mjl [ Tue Oct 03, 2006 6:20 pm ]
Post subject: 
Hi,
Since it did work ok, I would suspect that it may be something as basic as commercial flagging. Maybe try turning it off until there is quiet time (over night?)

The ~700mhz I would think not have issue recording as it doesn't do much until it is playback time. If you ran a 350 also then the video out would also be off loaded..

I run a single 350 on a Dell 400mhz 256mem and it keeps up but right on the edge. "Extra activities" I do on it sometimes will give me quick glitch but even that is rare.

Mike
Author:  Gibble [ Tue Oct 03, 2006 8:57 pm ]
Post subject: 
I would have thought it was commercial flagging, but it happens in live TV as well...or does commercial flagging happen while it's recording?
Author:  mjl [ Tue Oct 03, 2006 9:17 pm ]
Post subject: 
Hi,
Go through the settings, I think there is a button to start flag as soon as you start recording. Double check each one just to be sure and can rule them out.

Mike
Author:  Gibble [ Tue Oct 03, 2006 11:17 pm ]
Post subject: 
I found the screen...but for some reason, my fonts are little messed up. They're too large and don't quite fit on the screen :?

Anyhow, it's the third option of three on the page (a few pages into the general section), that starts out like "Start Auto-Commercial Flagging when the " and then I can't read anymore! What does it actually say?

Currently this is NOT checked.
Author:  Gibble [ Fri Oct 06, 2006 8:59 am ]
Post subject: 
Well I turned comm flagging off completely...no change.

Then I tried removing one pvr150 card...and oddly...no change?!?

I am pretty sure it was working fine BEFORE I put in the 2nd card. I'll try swapping them later and see what happens...

This is really getting annoying.
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