Attempted to add 2nd Tuner = Disaster

[Slack]

I have a very stable STV Install.

Running SageTV 5 w/ SageMC 16:9 Skin & Web Server & Comm Skip. All working splendidly to record & playback OTA HD via (1) Vbox DTA 150 Tuner. In fact, the CPU is so low while recording & playing back (via nVidia Pure on integrated video hardware), I decided to add another tuner & say goodbye to managing conflicts during football (lots of post game padding).

Well I installed 2nd tuner. Another Vbox DTA 150. XP identified it and installed drivers automatically. Launched Sage, re-loaded default skin & proceeded to add video source. Started the channel scan & stopped it before it completed when I realized that the same channels as were enabled on the first card were enabled on this one. And I split the Antenna (with amp) before feeding both tuners. I figured same feed = same channels.

Relaunched SagetV - Still old Skin, Reloaded SageMC. Went to guide to exercise new tuners. Started two HD records, And I got the herky jerkys as soon as I touched the second tuner. SageTV was quite unresponsive,

Three finger salute - Reboot.

Then, I did some fiddling: Each card has a unique IRQ (17 & 18).
So I went to My TV again with high hopes. And played the show currently recording on Tuner 1. No problemo. Stop, Back to My TV, Play program recording on tuner 2. Again the herky jerkys. Perhaps the CPU is pegged I thought. So I launched process explorer & noticed that the CPU was NOT pegging at all while SageTV stated that both tuners were recording. But, in fact, when I accessed the second tuner it seemed that the background cpu utilization that accompanies dumping a stream (or two) to disk actually went down.

As before it was when I attempted to watch what the second tuner that was recording, that SageTV became unresponsive.

Any Ideas?

Let the second tuner complete a channel scan?

[AndyS]

You may want to post your system specs.

Your CPU is not your only potential bottleneck. Check memory utilization and disk queue length (use the Performance utility in Administrative tools for that).

Andy.

[IncredibleHat]

I've seen herkyjerks from the GPU as well, and its harder to see the 'utilization' of the GPU while watching content.

The odd part is, that you get smooth playback from recordings from ONE card, but not recordings from the SECOND card. Everything you watch is a 'recording'. Not direct feed from the cards.

So, if two cards are recording at once, writing to disk their files, and you watch either of them... the performance should be the same for either recording. Thats in theory of course!

Have you checked the "Recording Quality" of that second card? Is it set to MAXEDOUT, while the first card is reduced in quality to like maybe 'GOOD' or 'OK' ?

[GKusnick]

Originally Posted by IncredibleHat

Have you checked the "Recording Quality" of that second card?

They're HD cards. Recording quality settings aren't relevant.

My advice would be to check your driver version. I vaguely recall reading something about people having issues with two cards on certain driver versions. Try searching the AVS forum for more info.

[Slack]

After pondering it a bit more. I think the herky jerk might have been the craptastic cable I stole from an upstairs guest room, to get the antenna feed into the second tuner. It was not even an F-type connector (what I think the Threaded type are called) rather it has a split metal sheath that slides over the threads.

I noticed a lot of macro blocking / or incomplete picture when watching content from the second tuner. Which looked alot like the tuner coping with a crappy signal. I'll make a proper cable & try it out again.

@AndyS - I'll Look into the disk queu length thing.

[Slack]

Well, after another attempt it seems to be working as I had hoped it would with two tuners. Flawless playback while recording two HD streams.

It was likely the cable - new one has seemingly no issues. However,

I still think there is an issue with the second tuner hardware setup. The channel scan is slow & deletes all of the channels that are already there (from the first tuner's scan). I aborted the scan & just started using second tuner. It tunes & records the same channels as tuner 1 just fine.

I can say that upgrading to the latest VBox drivers for the DTA 150 is NOT a good idea. Sage gives an exception when attempting a record with the latest drivers.