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Do I need / how do i use a TBC ??
I need some TBC basic info . . . .
I’ve done lots of work for broadcast, however for a long time I had the luxery of a staff engineer. Now I’m working on a freelance gig at a very small shop and need to deal with a tech issue.
I thank anyone who has the patience to give help to someone like myself who is ignorant of some basic tech stuff.I posted this question a few days ago and now I think the issue may be TBC.
I’m capturing some old VHS footage through an AJA IO HD box.
The SVHS deck is broken so I had to hook up a consumer VHS deck to our loop (tight deadline looming)I’ve got the VHS deck running in to an ADC patch bay, then to the AJA IO HD
box,
then to the CPU.Final Cut is set to capture at AJA 525i NTSC 29.97fps “Non Controllable Device”
Final cut recognizes the signal and captures . . . . However it is
completely out of sync. The video is WAY ahead of the audio.
It looks as though the video is playing at a sped-up frame rate, but theaudio sounds
fine (the two are totally out of sync).I tried capturing with the “play back offset” in the “System settings” changed to 3 different settings . . . . first 1 then 0 then 4.
When I open the captured clip in the finder and play it in Quicktime it plays with exactly the same problems (so it was captured out of sync)
Do I have an incorrect setting in the AJA control panel??
Do I need a TBC (possibly straight from VHS to TBC, then into the chain)??I thought a TBC was not necessary with the AJA IO HD . . . am I wrong??
Dead line looming . . . would like to fix this today
Any Suggestions???? -
9 Replies
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It’s possible you are not supplying video ref to the IO HD. Look in the Control tab and see if there’s a setting for Genlock. If it has Video In, check that and see what happens when you capture. If it just has Ref in or Internal, try Internal. If that doesn’t work, route the video out of your VHS to the Ref In on the HD and then take the Loop Out of the Ref In and feed that to the Video In of the HD. Then select Ref In for the Genlock. That way the HD uses the sync in the video as ref. Hope this helps.
John
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Rory,
Do you by any chance have a a UVW-1800 Betacam deck? If so, route your VHS signal (audio and video) through the UVW-1800 and route that into the AJA IOHD.
David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los AngelesPOST-PRODUCTION WITHOUT THE USUAL INSANITY ™
A forum host of Creative COW’s Apple Final Cut Pro, Business & Marketing, and Indie Film & Documentary forums.
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[Rory Keenan] “I thought a TBC was not necessary with the AJA IO HD . . . am I wrong?? “
Rory,
I have never been able to record a VHS signal from a consumer deck without one.
If you have the ability to pass the signal thru another deck like DRW suggests will help.I have an AJA FS1 converter in my rack that offers that functionality as part of its E to E functions.
and it offers +/- one field alignment adjustments too)gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
[gary adcock] “If you have the ability to pass the signal thru another deck like DRW suggests will help.”
Yep, the UVW-1800’s internal TBC should do the trick.
David Roth Weiss
Director/Editor
David Weiss Productions, Inc.
Los AngelesPOST-PRODUCTION WITHOUT THE USUAL INSANITY ™
A forum host of Creative COW’s Apple Final Cut Pro, Business & Marketing, and Indie Film & Documentary forums.
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Rory
Even running it through the UVW has sometimes fallen short for me. When i have to deal with VHS footage, I record it onto a BetaSP Tape using my UVW 1800. It makes it easier to select the Good stuff, and it gives you a fall back should the tapes go away, or you have to recapture
If you do a capture Now with Deck control, you can grab the shots AS you bump it up!
Of course if you dont have a Pro VTR with a TBC, then you need to get one, and since you are coming off a consumer machine, all you need is a frame synchronizer, not a full tbc.
hope this helps
“I like video because its so fast!”
Bob Flood
Greer & Associates, Inc. -
Um…guys?
VTR TBCs don’t work on loop throughs…they are tied to the playback function of the machine. There is no “record side” TBC functionality.
You would have to have an independent full frame sync inside the machine for this to actually work as the VTR with the TBC has no way to send timing info back to the ungenlocked source. It would need to completely buffer the video and reconstruct sync, etc…and would also have no dropout compensation source.
Though lip sync really isn’t something a TBC would help with…if you had picture instability…sync drift, etc…that would be corrected (though with additional signal noise added) by a Time Base Corrector.
The weird lip sync thing seems odd.
Does the video look wrong going in? can you see lip sync drift when you’re playing it back? Is the error cumulative? (gets worse over time?)
I’m guessing the VHS tape is recorded at LP or SLP?
If not, you might check around to see if anyone has a professional SVHS deck with a TBC on board. That would actually play the tape back with its TBC (provided it was recorded in standard play) and stabilize it.
TimK,
Director, Consultant
Kolb Productions, -
you really need a timebase corrector.
a VHS tape deck will give a videosignal with TimeBaseError’s
a frame synchronizer won’t do the trick. a frame syncronizer is basicly used to lock nonsync but stable signal’s to houseRef. a timebase corrector is doing more. timebase error generated by the not so profesional tape transport of a VHS will not be corrected.Timebase corrector’s on Pro VTR’s are there to correct the error’s created by the tape transport in playback. if you are lucky the TBC is injected when the machine is in EtoE.
greet
Maurice -
I agree with everyone above that a TBC built into a VTR can only correct the timebase of the tape playing in that VTR. A standalone TBC that is a full frame sync is what you need.
One of the easiest ways to put your hands on one is to borrow or buy a consumer DVD recorder. Just power it on, feed your VHS into an input and feed the perfectly TBC’d component output to your capture card.
After using all kinds of expensive TBCs in my linear editing day I was amazed by the quality of the video processing of the signal passing through the both the Panasonic or Pioneer DVD recorders (others may be equally good). This is possible because chips doing the work are now of course low cost, very high quality commodities.
As noted, this will introduce just one frame of delay in the video, which by itself may be no problem, but if combined with more frames of delay may need compensation.
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I use a Canopus ADVC-300, which has a TBC built into it. It digitizes analog video to the DV codec. Costs a few hundred, though. (It’s possible their model 110 has a TBC, but I doubt it.)
If your sync is way off, I’m not sure a TBC will fix this.
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