Mixing tuners - HD issue when using analog

[redlion4]

HTPC currently has 1 OTA HD tuner (KWorld ATSC-110) and 1 dual cable tuner (NVidia DualTV), running on XP SP2, an AMD XP 2500+ CPU, 2GB RAM, an ATI 9600XT 256MB video card, and a 160GB ATA hard drive dedicated to only show recording (OS and programs on a separate 120GB IDE drive). Live HD and recorded HD work very well. Only current issue here which only occurs if watching a different HD channel when HD recording is scheduled to start.

However, the minute the NVidia card is put to use - either watching or recording cable tv, the HD stream is ruined. The audio is nearly perfect but the video goes to pot, stuttering so severly that it is unviewable. This happens to the HD signal live (cable is recording) AND recording (while viewing or recording cable). The minute the cable tuner is shut down, all HD activity returns to normal.

The CPU usage only hits 60% even with all three tuners (1 HD + both NVidia cable) in use and the viewscape open. This test indicates the CPU is not likely the problem source.

Playback is set to overlay, since any 3D acceleration causes very subtle stuttering of HD content. I also believe the playback settings are unrelated, since the same problem occurs also during recordings, for example: 2 shows recorded at once - 1 HD and 1 cable, so both tuners are active. After the recording ends, any attemps to watch the HD recording displays the same problem of severe video stuttering/skipping. This occurs even if all three tuners are inactive while the recorded content is played back. This test appears to indicate the data was lost while recording, so it is not a playback issue.

I have also rearranged the cards to various different PCI slots (5 slots available to spread between 2 tuner cards, a sound card, and a firewire card). The different slot positions has not changed the problem in any way.

So what bottlenecks are left? Is this a hard drive problem (too much data volume for IDE drives, or other)? PCI bus? Please help.

[Zogg]

Your system should be able to handle that load okay, so I'd focus on the bottleneck areas.

It isn't clear to me from your message if HD recordings are affected with Nvidia SD recordings going on as well, but you are NOT trying to watch anything. The point being that if the problem ONLY happens if you are trying to watch TV while recording, but NOT if you just record and playback later, then you should focus on the video card and codecs.

In the past I've had to go into Catalyst CC and have it retest my card to enable AGP acceleration options to improve performance. Also, make sure your playback settings use the Snapstream default decoders (but not the basic decoder) as a baseline.

If it's not a playback only problem, here's a few other things to check. First, make sure the tuner cards are not sharing an interrupt with other cards. Sometimes you can't work around it, but try to minimize it, and definitely get them on different INT's.

Second, look at disk i/o. Are both drives on different IDE channels? Probably okay even if they share an IDE channel, but try watching the recording from one drive while recording to the other drive.

Third, make sure the drives are operating in UDMA mode and not PIO. That one bit me in the rear recently.

You might also try a benchmark program like Sandra to look for bottlenecks.

Good luck, Z

[redlion4]

Thanks for the response Zogg

Originally Posted by Zogg

It isn't clear to me from your message if HD recordings are affected with Nvidia SD recordings going on as well, but you are NOT trying to watch anything.

Yes, the problem is present in the case where both tuners are recording and the viewscape is shutdown totally (no concurrent viewing). This was tested by recording two shows concurrently - 1 analog cable and 1 HD with the viewscape shutdown. After the recordings were complete, the viewscape was launched and the shows were each played back while no other recording was occurring. The recorded cable show plays back perfectly while the recorded HD show is unviewable due to major video stuttering. I truely believe that HD data is being lost while the cable card is active.

Originally Posted by Zogg

In the past I've had to go into Catalyst CC and have it retest my card to enable AGP acceleration options to improve performance. Also, make sure your playback settings use the Snapstream default decoders (but not the basic decoder) as a baseline.

The default Snapstream video and audio decoders are in use, but as described above, this appears to be a data loss issue prior to playback.

Originally Posted by Zogg

If it's not a playback only problem, here's a few other things to check. First, make sure the tuner cards are not sharing an interrupt with other cards. Sometimes you can't work around it, but try to minimize it, and definitely get them on different INT's.

As of last night, both tuner cards (KWorld & NVidia) were on IRQ 16. I will do more PCI slot musical chairs tonight to see if this can be avoided. In addition, can one override the IRQ assignment within the device manager?

Originally Posted by Zogg

Second, look at disk i/o. Are both drives on different IDE channels? Probably okay even if they share an IDE channel, but try watching the recording from one drive while recording to the other drive.

I will double check this tonight. I believe the setup is each hard drive is the primary device on separate IDE channels (making the two DVD drives the secondary device on each channel).

Originally Posted by Zogg

Third, make sure the drives are operating in UDMA mode and not PIO. That one bit me in the rear recently.

This one is new to me - where can one confirm UDMA versus PIO?

On a related note, I have realized that the 160GB drive dedicated to recording/playback is NTFS using 4K clusters. I'm trying to get copies of the shows I want to keep over to the 120GB drive so that it can be reformated using 64K clusters. Will this make a difference?

[fmharr]

4K -> 64K prob will not fix your problem.

Check UDMA mode in system/Device Manager (see picture):


I can record on all 4 of my turners while watching a prerecorded show and all is perfect.

Mike

[poobah]

Originally Posted by redlion4

HTPC currently has 1 OTA HD tuner (KWorld ATSC-110) and 1 dual cable tuner (NVidia DualTV), running on XP SP2, an AMD XP 2500+ CPU, 2GB RAM, an ATI 9600XT 256MB video card, and a 160GB ATA hard drive dedicated to only show recording (OS and programs on a separate 120GB IDE drive). Live HD and recorded HD work very well. Only current issue here which only occurs if watching a different HD channel when HD recording is scheduled to start.

However, the minute the NVidia card is put to use - either watching or recording cable tv, the HD stream is ruined. The audio is nearly perfect but the video goes to pot, stuttering so severly that it is unviewable. This happens to the HD signal live (cable is recording) AND recording (while viewing or recording cable). The minute the cable tuner is shut down, all HD activity returns to normal.

The CPU usage only hits 60% even with all three tuners (1 HD + both NVidia cable) in use and the viewscape open. This test indicates the CPU is not likely the problem source.

Playback is set to overlay, since any 3D acceleration causes very subtle stuttering of HD content. I also believe the playback settings are unrelated, since the same problem occurs also during recordings, for example: 2 shows recorded at once - 1 HD and 1 cable, so both tuners are active. After the recording ends, any attemps to watch the HD recording displays the same problem of severe video stuttering/skipping. This occurs even if all three tuners are inactive while the recorded content is played back. This test appears to indicate the data was lost while recording, so it is not a playback issue.

I have also rearranged the cards to various different PCI slots (5 slots available to spread between 2 tuner cards, a sound card, and a firewire card). The different slot positions has not changed the problem in any way.

So what bottlenecks are left? Is this a hard drive problem (too much data volume for IDE drives, or other)? PCI bus? Please help.

This is a known problem with the NVidia card - it's a PCI bus contention issue. It simply doesn't play well with other cards. There's a new driver for the NVidia card, you could try that (I've been meaning to) but I doubt it fixes it. I think, in theory, if your HDTV tuner was a USB device this problem wouldn't exhibit, but I don't know that to be sure.

B.

[redlion4]

Originally Posted by fmharr

4K -> 64K prob will not fix your problem.

Check UDMA mode in system/Device Manager (see picture):

I can record on all 4 of my turners while watching a prerecorded show and all is perfect.

Mike

Thanks for the reference for UDMA. I don't have any reason to believe PIO would be selected in these, but will confirm tonight. In terms of all 4 tuners at once, are any HD? The tuners listed in your sig looks like all analog tuners (no HD).

Originally Posted by poobah

This is a known problem with the NVidia card - it's a PCI bus contention issue. It simply doesn't play well with other cards. There's a new driver for the NVidia card, you could try that (I've been meaning to) but I doubt it fixes it. I think, in theory, if your HDTV tuner was a USB device this problem wouldn't exhibit, but I don't know that to be sure.

B.

I have been suspicious of the PCI Bus myself. Are there other posts in the SnapStream forums, or other forums, where users have this same issue? This is especially irritating since I could have chose the PVR-500 MCE bundle instead of the NVidia one. NVidia was more attractive since it was bundled with PureVideo (which I'm not even using right now!). Had I known this was a problem, I would likely have opted for the PVR-500 card instead. Only had it a week now...perhaps I can request an exchange!

[Zogg]

Originally Posted by redlion4

Thanks for the reference for UDMA. I don't have any reason to believe PIO would be selected in these, but will confirm tonight. In terms of all 4 tuners at once, are any HD? The tuners listed in your sig looks like all analog tuners (no HD).

I have been suspicious of the PCI Bus myself. Are there other posts in the SnapStream forums, or other forums, where users have this same issue? This is especially irritating since I could have chose the PVR-500 MCE bundle instead of the NVidia one. NVidia was more attractive since it was bundled with PureVideo (which I'm not even using right now!). Had I known this was a problem, I would likely have opted for the PVR-500 card instead. Only had it a week now...perhaps I can request an exchange!

My system changed my fast SATA drive from UDMA mode to PIO all on it's own, claiming it was seeing too many errors. So it's worth a quick double check to make sure that didn't happen. This affected many recordings until I found it, and of course when I error-checked the drive no problems were found and I set it back to DMA mode with no problems. Thanks to fmharr for the great picture on how to check it.

Didn't know about the Nvidia driver problem since I don't have one. Hopefully they will fix it.

Some motherboards' BIOS will let you manually adjust interrupts, others won't. And sometimes Winders will let you change the interrupt, but mostly not (probably due to the hardware, if the INT's are hardwired to the slots or programmable).

Z

[tscales]

I would also guess PIO, but 64K clusters really do help. I have had as many as 8 tuners (4 sd, 4 hd) running on a P4-3.2 with an IDE hard drive, so it can be done.

[redlion4]

Consolidating links here, all of which point to an inherent conflict specific to the NVidia DualTV tuner when installed alongside ATSC PCI tuners:

HTPC Forum -
http://www.htpcnews.com/forums/index...ic=22797&st=45

The Green Button Forum -
http://thegreenbutton.com/forums/thread/163689.aspx

SnapStream Forum -
DAMN! nVidia DualTV is SUPERB!

BYO PVR Forum -
http://forum.byopvr.com/dvr/index.ph....html#msg36201

Hardware Forum (I see myktek posting here too) -
http://www.hardforum.com/showthread.php?t=1109443

AVS Forum -
http://www.avsforum.com/avs-vb/showt...hp?p=8436392&&
http://www.avsforum.com/avs-vb/showt...66#post9306866

I have submitted a tech support question to NVidia regarding this issue. Will be interested in a response. Have also emailed snapstream orders to see if the NVidia DualTV can be exchanged for the Hauppauge PVR-500 MCE (I just got the DualTV card 6 days ago).

In the mean time I will work on what I can - verify UDMA is selected, convert NTFS from 4k to 64k, and more PCI slot arrangment to redo IRQ's.

Thanks to everyone for input, suggestions, and discussion. Please keep them coming.
Ryan.

[redlion4]

As an update, both hard drives (OS and video) are using UDMA modes. However, they do share an IDE channel - the OS drive being the master device and the video drive the slave device on the same channel.

They are also both sharing IRQ 16. The AGP/PCI slots are currently configured as follows:
AGP: ATI 9600XT - IRQ 19
PCI1: NVidia DualTV tuner - IRQ 16
PCI2: Turtle Beach Sound Cruz Sound - IRQ 19
PCI3: Empty (was saving this for 2nd HD tuner)
PCI4: Firewire card - IRQ 17
PCI5: KWorld ATSC-110 HD tuner - IRQ 16

Note that PCI1 is closest to the AGP slot while PCI 5 is at the bottom of the mb. Cannot rearrange the slots until after CSI tonight or later tomorrow.

Still waiting to hear from both NVidia (tech support) and Snapstream (exchange DualTV for PVF-500).

[redlion4]

As an update, NVidia tech support has been worthless so far. They didn't even bother to read the attachment containing the computer specs, problem description, examples, and steps to turn the problem on/off.

I continued troubleshooting at home to no avail. Was able to arrange the PCI cards to eliminate all IRQ sharing. Both the NVidia and KWorld cards had their own IRQ's, but the problem persisted. There was no slot combination on the A7N8X board that would eliminate the issue - the ATSC HD data stream was always trumped by the NVidia card when it was active.

On the other hand, kudos to SnapStream who responded with a very kind email and RMA#. The NVidia DualTV card will depart via Fedex Ground tomorrow and SnapStream will exchange it for the Hauppauge PVR-500 MCE card. Thank you SnapStream!

Ryan.

[redlion4]

After 4 weeks of an open ticket with nVidia, they have NOTHING to report or discuss. Here is the last reply from them, responding to my bump indicating 3 weeks had gone by:

Hello Ryan,
Thanks for following up. We are still in process of investigating this. We'll keep you posted if and when we have a solution.

Best regards,
David

I waited another week, then highlighted the "IF" statement and informed nVidia the DualTV card had been replaced with a Hauppauge MCE PVR-500 card which solved all of the problems. HD signals are now perfect when using the PVR-500 card simultaneously.

Shame on nVidia for their poor support / drivers on the DualTV card. Really glad Snapstream RMA'd the DualTV unit and I did not wait for nVidia. Given the other posts here regarding nVidia no longer selling that unit, I guess I'm not surprised...

Ryan.

[Crooze]

Originally Posted by tscales

I would also guess PIO, but 64K clusters really do help. I have had as many as 8 tuners (4 sd, 4 hd) running on a P4-3.2 with an IDE hard drive, so it can be done.

After spending countless hours of fiddling with my antenna and watching my favorite shows with horrible stutters I figured out it wasn't my antenna. The bottle neck was my drives. So I reformatted using 64k clusters I haven't had anymore issues. It's all smooth as glass!

[redlion4]

I did convert my drives to the 64k clusters as well, which did nothing to address the PCI Bus monopolization by the NVidia DualTV card.