Intensity Pro Gradually Desyncs in capture apps, please help!

[swiftor]

For almost half a year I used my Black Magic Intensity Pro with VHMulticam and Flash Media Encoder Live just fine, no latency or sync issues. But now it quickly goes out of sync, almost as if Vhmulticam has trouble capturing it.

The captured video (at 720p at 59.94 fps) starts off synced and gradually get delayed and after a few minutes you could see the video actually start chugging and dropping frames in multicam. Although, if I view the captured video in Blackmagics native Media Express recording/viewing app, the captured video is perfectly in sync regardless of how long.

I use Windows XP 32-bit with an i7 processor and 4 gigs of ram, and that has not changed.

I tried capturing the card directly with Flash Media Encoder Live and it's delayed there too.

Why would it be delayed in multicam and FME all the sudden? And still be fine in the capturing app?

I've tried updating my video card, rolling back my video card drivers a few months, reinstalling the klite codec pack. I went as far as to install a fresh instance of windows xp 32-bit, installing only the black magic drivers, video card drivers, and multicam, and get the same results.

What would be causing VHMulticam and other apps to suddenly chug?

[Kristian Lam]

Hi swiftor,

Can you recall at when this started happening? Possibly after a driver update?

I think I can narrow this down to DirectShow as Media Express is not using DirectShow to capture video, hence the difference. I'll get the QA guys to check this out but if you recall which version this stopped working, it will be very helpful.

[swiftor]

Hi Kristian!

All is well now after getting a new video card (yeah, a bit extreme). Replaced my ATI Radeon 4830 with a newer Nvidia card, and all seems well.

Unrelated, but during the process I did have to downgrade the Intensity drivers from 3.7 to 3.4 since it seems I need Media Express 1.1 to change resolution and fps settings for other applications.

Thanks!

[nethab]

I am having the exact same problem but with the Intensity Shuttle. Initially everything worked fine, but after we loaded the system onto a truck and drove it to an event, we started experiencing the diminishing framerate in every app except Media Express. It definitely sounds like it's DirectShow related.

We started on driver 7.7.1 and just upgraded to 7.7.3 with no change, I even tried rolling back the system to a day when it was known to work just fine. Still no luck.

As for my system I also have a Core i7 with 4GB of RAM and an ATI Radeon HD 4550.

And unfortunately I'm not able to replace the video card as it's a corporate system under IT control.

[Kristian Lam]

Hi nethab,

Thanks for the report. We'll check this one out to see what's going on.

[nethab]

I potentially have more information which may be of help.

Background: The Adobe Flash Media Live Encoder software (like many video capture applications) has 2 video preview windows so you can see the effect of whatever settings you apply alongside the original input stream.

While capturing (in my case to H.264) if you disable the "Input Video" preview window (the original stream) and just leave the "Output Video" (ie. compressed/resized stream) there is no sync or framerate issue even after 30 minutes. If you enable the "Input Video" window (whether by itself, or alongside the "Output" window) the video gets out of sync and the framerate starts to drop after only a minute or so.

However, while NOT capturing, the "Input Video" and "Output Video" are essentially one and the same (probably pulled from the same DirectShow buffer). So while NOT capturing having either the Input, Output (or BOTH) showing causes the sync/framerate issue.