Do you drop frames?

[jmac698]

Hi,
I was working on something where I needed multiple caps which were exactly the same. What I found was that I was dropping frames with no indication in VirtualDub at all. Then I made a system to analyze these "hidden" dropped frames.
I have posted the new filter under Avisynth Usage.
I would be interested if someone would test it with their system and let me know if it detected any drops. If there were problems, please post the analysis file (timecode.txt), along with card brand, name, model, OS, driver version, and capture program used with version.
Thanks.

ps here is my preliminary results; Pinnacle Systems PCTV 800i, Driver 3.1.1.49, XP Pro SP3 32bit, Virtualdub 1.9.10

Has glitches in this pattern, correct, dupe, next frame, dropped frame, correct, repeats every 13,15,17 frames
Like this: 0, 0, 2, 4...

This is important because it really messes up your video, you can't IVTC anymore.

"Let's do the frame drop again..."

[jmac698]

I got it to work for my card. In VirtualDub 1.9.10:
capture timing options
Only the following should be checked:
-correct timing
-auto disable sync

I think the ignore videotimestamps feature was giving me dropped frames (every 7 frames, in my last test).
What's *still* bad though, is that this was not reported in any way!

Considering it's possible to have dropped frames with no indication whatsoever, I really like the utility I made, it's a great way to make *sure* everything is working. I think I'll add some other features to test true YUY2 is working and to calibrate levels, maybe jitter and frequency response... of course much later.

[GrofLuigi]

I think it depends mostly on the capture card (chip), and also on the signal quality from the VCR. I haven't captured VHS for quite same time, but AFAIR, I didn't notice rogue frame drops/inserts on my very old Pinnacle PCTV Rave that couldn't be attributed to a visible tape glitch (sometimes 2 or more frames back).

So you need to find the combination of options that works for your card.

GL

[jmac698]

Ahh.. the really sad thing is, I was capturing from a stable DVD source... there was no point in even trying VHS at this point.
I'm now testing various realtime lossless codecs...