I'm dealing with a PAL UMatic tape, which was stored in a humid attic for 35 years. Upon receiving it, it was moldy to hell. I took the tape to a well respected video recovery unit nearby, and the tape is completely clean now. Now the problem, is flagging upon playback.
For the recovery, we had to chop off the first 15 seconds of tape, because the outter-most portion exposed to humidity was far too damaged to risk running it in a machine. It's been replaced with a different leader, albeit in NTSC. The capture we have was accidentally captured in 720x486 but in 25fps, but that's besides the point.
In the video samples, you can see the flagging at the top, and we're confident it's down to the tape itself being recorded on a poorly calibrated machine back in the 80s- not the accumulated mold. We took the tape to another service to see if the signal can be reclocked, but every player gave varying degrees of bad playback. They all have TBC's in them, my guess is that the TBC's inside the players aren't strong enough to handle this wild animal of a tape.
Can anyone think of a possible solution? I'm learning towards somehow daisychaining an ES10, but that only has proven success with VHS to my knowledge. Maybe another TBC that can replace line capability?
If the contents of the tapes are available on modern digital formats (judging from the samples), in my opinion it's just waste of time and money, Having said that try the ES-15, though that's not exactly flagging, It's sort of the top image has lost timing entirely which is located on the edge of the tape, possibly due to poor storage condition.
If only it were that easy, the content is not available on DVD, nor VHS. Money isn't a concern as long as we have a way to test and prove a solution.
I have an ES15, but I'd need to import a PAL one for sure. How does it work as far as flag correction goes? I know it works and does so effectively, but I don't understand the science *how*. Any insight would be appreciated, as I can propose it to our current unit who has the UMatic decks.
I have a small bit of experience with NTSC 3/4" U-matic. I've never seen flagging on a U-matic. The second sample does show a bit of curving/flagging at the top left edge of the frame, which would make me think it is flagging.
I have not tried using a broadcast style TBC that was intended to be used with 3/4". I mostly deal with VHS/Beta, so I use a Datavideo TBC or a Panasonic DMR-ES10. I think I'd read on this forum that ES10 was "strongest", and ES15 had less "strength". That's why I chose an ES10. These Panasonic pass thrus also provide frame stabilization, it's just not technically a frame TBC.
I cannot explain all the science you may want to know. I'll just share one instance I had using it on a 3/4" tape that had very low signal strength and was not able to maintain a solid frame sync. The video had a "rolling" effect, sort of like what you'd see long ago on tube TVs when the vertical hold wasn't working. Basically, the timing signal on the tape was weak. Flagging video occurs for a similar reason, a weak video signal. When using the ES10 between the U-matic and the capture card, the result was a stable frame sync, be it with a bit of vertical jitter that one sometimes sees when using a line or frame TBC. I expect the jitter was because the signal was so weak, and the ES10 was not able to restore things perfectly. So this imperfect frame timing caused some fields/frames to jitter up and down a bit at times. However, it did much better at attempting to restore the frame sync than the Datavideo frame TBC I had.
So, this is an example where a pass thru was able to provide a rather strong frame sync to an input signal that did not have one. I am not entirely certain if a reason for flagging is poor frame sync. But I do know I can remove flagging when I use an ES10. So the output from an ES10 is considerably solid. I would suggest trying one, it is probably the lowest cost option. If it doesn't work, you didn't spend much, and you could probably get most/all of you money back reselling it.
We are talking about the same video signal format whether it is the out to TV from a VHS or from a U-matic. The pass thru expects a signal intended for a TV, So I think using a pass thru that is known to remove flagging would work regardless of what kind of video deck is involved. All that matters is you feed it the correct output from the video deck. I'm not sure if chaining a pass thru such as the ES10 with other TBCs would help. I would think the ES10/15 would alter the frame timing enough that another TBC would either have no effect or would not work with the ES10/15's timing or considerably strong signal. However, I'm just hypothesizing. I would try whatever I could and find out for myself what's best. Theory only goes so far.
