AVXL Video Playback Problems

[Rick Sanchez]

I am using an AVXL PTHD 5.x system. I lay off stems to the protools session and I get a "video playback stopped due to buffer underrun" error. The system will record the stems, but I don't get video playback. Any solutions to this problem?

Playing back video and audio is no problem, but when I go to record audio tracks with video, I often get this error. Video is 20:1 and on a separate drive and scsi buss, so thoughput should not really be a problem.

[DigiTechSupt]

When was the last time your drives were initialized? Also, make sure midi countoff is disabled in the expanded transport window (Display>Transport Shows>Midi Controls).

-Jordan

[Rick Sanchez]

It's a new system and the drives were initialized less than one month ago by the dealer and checked by two other digi techs. Midi is turned off. I know that on Avid systems, the disk cache in the memory contol panel is usually set to 128k with virtual memory off. I have tried this with no luck as well as the system default setting.

[DigiTechSupt]

Depending on how much work you've been doing, it may be time to backup and reinitialize the drives. Yes, even after one month.

How many audio tracks and what sample rate? If the number is high, you may need to split audio tracks between multiple drives.

Make sure you're using the latest CS release for either the 5.1.3 or 5.3.1 branch, whichever you're using. If you're recording while locked to code, try increasing the minimum sync delay. Also make sure that Open Ended Record allocation in preferences is set to 20 minutes or so, rather than "use all available." If you're doing a pass that's longer, make a selection on the timeline so that Pro Tools knows how much disk space to allocate.

Disk Cache on Pro Tools should always be 512k.

-Jordan

[DigiTechSupt]

In addition to what Jordan said,

Make sure you are not using a "pre-roll" or the "Count off" option. This will sometimes cause video playback under runs.

Also, make sure the system is properly resolved, the system is seeing the sync I/O properly and both and video are resolved to video black.

Jon Connolly
Digidesign Product Specialist