"Stuttering" video capture

[John Wray]

I've been transferring quite a few VHS recordings to DVD, and have run into an occasional problem during capture. Every so often, the captured video "stutters" - the video, not the sound. The sound plays without interruption, but it looks as though a few frames of the video are repeated or switched around. When the disturbance is over, the sound and picture are still in sync.

This might happen once in an hour-long capture, and when it does, it seems to last for perhaps a half second. I haven't noticed a lot of frame drops when it happens - I seem to drop perhaps one frame every ten minutes on average during capture, but I think the drops occur one at a time - I don't think I see a burst of drops that coincide with the disturbance in the capture.

I'm using a Hauppauge WinTV-Theater as my capture card, under WinXP with the Hauppauge VfW drivers. I use AVI-IO to capture, along with HuffYUV compression. The sound card is a Turtle Beach Santa Cruz. I'm running a 2.26GHz Pentium-4 system with 512M RAM, and a pair of 40GB Maxtor drives hooked up to a Promise RAID array as my capture drive, and another 60GB drive as my system disk. Defragmenting the RAID array makes no difference.

Any ideas as to where to look?

John

[smitty]

any other software running or a TSR type prog??

[Brian Ellis]

Just a question to be precise: are you observing this when playing the DVD or actually on the captured file? Does it happen at exactly the same spot each time and every time, no matter where you start the playback? If so, can you advance through this point frame-by-frame to see exactly what is happening and report back here? Are your VHS recordings protected or are they in good shape (no noise)?

[John Wray]

Brian: This is in the captured .avi video. It's in the same place every time I watch the recorded file. I haven't watched it frame-by-frame; I'll do so and get back to you. The source tapes are in good condition.


Smitty: This is XP - there are tons of other things running

I don't run any applications while capturing, other than AVI-IO and the Santa Cruz mixer.

I have Norton Anti-virus, Zone Alarm and Pop-Up Stopper running in the background, but I've disable NAV's auto-protect, and set Zone Alarm to lock-out internet use, and that doesn't seem to make any difference. XP has all sorts of processes of its own running.

John

[John Wray]

OK, I've looked at several instances of this. What seems to be happening is that, in a region of disturbance, one field of the frame seems to "stick" - one field proceeds normally, while the other stays with the same field (or possibly alternating between two different fields). It continues for roughly 6 frames. This is in the original AVI (since I'm producing progressive MPEG video from this, the de-interlacing process gets confused, so it looks somewhat worse in the MPEG than the AVI).

So I guess this is either due to AVI_IO, my capture hardware (Hauppauge) or the capture drivers. Has anyone else ever seen anything like this?

John

[Job]

I found this problem....

but on a more global scale - to do with field order.

I found I had to deinterlace my DV footage in the Premiere timeline before exporting through AVISynth to TMPGEnc for MPEG2.

Never noticed it as an intermittent issue though...

my 2c

[John Wray]

I'm de-interlacing in VirtualDub, using the Smart Deinterlace filter. But this isn't a deinterlacing artifact, it's in the original interlaced capture.

John

[smitty]

John I wonder if maybe Brian is on to something?
I use several vcrs and one stabilizes the video much better than the others. If you recapture the same section again , do you get a repeat in the same frame(s)? maybe try another playback machine.
smitty

[Eddy]

Recently I noticed a loss of vertical resolution in my captures with AVI_IO and BtWinCap drivers. This was during a capture from TV. It looked like only 1 field was captured and duplicated, causing jaggies on diagonal lines. It was especially apparrent on stationary images. Is is not just on single frames, but for periods at a time.

It sounds a bit related, and the difference might be due to the different capture driver. Maybe the BtWinCap driver uses a copy of the other field when it misses one, where your driver keeps the last field it has for that part of the frame.

Eddy.

[John Wray]

I think I've found the culprit. The RealOne player installs background tasks "rndal" and "evtsvc", and once I removed those (by renaming their .exe files), I don't think I'm seeing stuttering captures anymore.

I still need to do some more experimenting, as the stuttering was very intermittent, but I think that the cause was one or both of these tasks.

John