JVC TBC cause dropped frames, TBC off okay?

[idan182]

Hi all.
Tested with 4 different "standard" VCRs and I don't experienced the problem.
I'm using Windows 7 along with Avermedia C039 USB capture card, 16GB ram and I7-3770.

With both VirtualDub or Amarec (I use Amarec because sound sync issues but that's another story).
Capture is good with continuous 25 fps 0 frame drops.

I have this JVC 7960 PAL machine.
With TBC *OFF* - I still get continuous 25 fps 0 frame drops.
With TBC *ON* - I get weird slow motion video. This is expressed in FPS drops (not frames) which you can see in this photo of Amarec (fps goes down to 13.73-24 for a second).



And when I use "FRAPS" to show the FPS in real time when playing the video on VLC - I can see it drops from 25 to 22 on 00:06 at the video.



I have uploaded a sample video with and without the TBC.
You can see on 00:06-00:08 the fps drop, and the man that goes down the water slide is not smooth.

[latreche34]

This is the case where you need a frame TBC or at least a suggested Panasonic DVD recorder. Alternatively check your settings in the capture software and maybe allow the program to run as a priority.

[lordsmurf]

The attached samples doesn't match the description. The samples are fine.

What I see is awful video, with compounded timing errors. Not just wiggly, but erratic signal and movements. Strong TBCs will be needed, not just the JVC line TBC.

The JVC line is just not adequate here, the ES10/15 will be needed for line duty. But again, the signal is erratic. The non-TBC frame sync of the ES10/15 will still pass errors on tapes like this. So an actual frame TBC will be required.

The reason that low-end units "don't have the problem" is because those all just push out whatever crappy signal exists on the tape, and you get whatever you get. Often unwatchable garbage, low quality at best.

But your findings have variables that make "don't have problems" highly suspect. Main (1) in general, AmaRecTV is not fixing anything, it's just hides issues. In some cases, you didn't probably tweak the defaults on VirtualDub. I would never accept AmaRecTV as any sort of test constant, too unreliable. And (2) Avermedia has (almost) never made a quality card. It's not fully removed as a suspect.

BTW, if you see drops at exactly 00:06, the framerate is wrong somewhere.

Proper troubleshooting would have you use another recommended JVC PAL S-VHS VCR with line TBC, to verify your current unit is functioning properly. Just know that odds of is malfunctioning is extremely low, near-0% chance of that.

I think it really is as easy as
(1) getting a quality frame TBC
(2) getting a properly functioning ES10/15 type for strong+crippled line TBC

What you're encountering here is not unusual whatsoever. It just needs proper tools to allow a quality transfer. And not an incomplete workflow.

[idan182]

I've got the Panasonic ES10 connected and JVC TBC off.
Not a single drop right now and no freeze anymore!

[lordsmurf]

If you get no drops, either
(a) lucky, enjoy!
(b) using software that does not reliably report drops -- and AmaRecTV is such a software

ES10/15 mostly dupes, but also drops. The output from the line TBC is not frame timed, and the non-TBC frame sync is unbuffered output that rough locks to a clock.

I'm using my ES10 this very moment, sometimes we have zero choice, the tapes are awful. But I chase with TBC-100, and the output contains 0 drops, 0 inserts, due to any faulty frame output from the ES10. Without that TBC-100, I get higher insert and drop count, more than 0.

Try VirtualDub again as well. It wil report more accurately. Odds are your sound sync issue is resolved as well, due to the overall scenario here. (In general, this isn't a fix for audio sync issue. Just here, this exact situation.)