Vertical Interval Time Code (VITC)
Zcooger opened this issue · comments
This ticket is made to suggest adding vertical blanking time code (VITC).
Quick non-technical demonstration: https://www.youtube.com/watch?v=aU40YRBa6nk
I wondered how this feature would work but first simple idea I got is to place time information of media file played back at the current moment.
Such signal can "fake" any professional video cassette deck.
Do you have or know of any devices that can make use of the feature?
I don't have any Betacam SP or any professional gear to test that with but I will ask LD Decode guys.
I found such signal on this repair demo of Sony PVW-2800 P so there is one example:
https://www.youtube.com/watch?v=HDQB1Ck_UjY
Besides this Cassette deck there were in use timecode inserters, extractors and counters. Some displays can use OSD to show it.
I found it also on my VHS tapes with live TV recordings where it slipped to the VBI during broadcast like here:
Now I found software that reads TC out of digitized video frames: https://www.videotoolshed.com/old/vitc-reader/
@fsphil @Zcooger @captainjack64 I would like to add that this is something I actually need to be able to make use of my old videomatte vm1 video mixer. I unfortunately can't use hacktv because old video equipment like mixers etc need tbc Vertically locked signals otherwise it messed up destroys the composite signal when in use with many of these old devices. Could you please add this feature?
I've pushed a VITC inserter, you can try it with --vitc. It should work with NTSC and PAL modes, but I have only been able ot test it with ffmpeg's readvitc filter. I'd appreciate some testing with real hardware if anyone has it.
otherwise it messed up destroys the composite signal when in use with many of these old devices
This may still be an issue - right now hacktv doesn't set the colour framing bit. You might need this set, it's at https://github.com/fsphil/hacktv/blob/master/vitc.c#L136
One potential issue, the field flag seems to be in a different location for 25 fps modes vs. others. Right now it's fixed at the 25 fps position.
One potential issue, the field flag seems to be in a different location for 25 fps modes vs. others. Right now it's fixed at the 25 fps position.
have you (or anyone here) got a compiled windows build i can test?
just set up eveerything and i am ready to give it a shot.
Thanks fsphil for all your work.
You have just saved my ass on this one let me tell ya ;)
once i get a hold of a windows build i will let you know if it works.
thank you!
EDIT:
Just got one from @steeviebops.
Thanks for all the updates and all.
Cheers!
03stevensmi
UPDATE:
Well, my 2nd vga to bnc addapter broke along with my rf cable (Completely unrelated to this unluckaly)
so i have to wait until i can afford a 2nd vga-bnc for the moment.
i ofc need 2cables for my 2 fl2k devices. the original one ...works... if i wiggle it... but works.
(thank god!)
i tried to make myself a lead and use my vcr looped to input 2 but its hard to say if it is working.
however, i did at 1 point saw a few things i cant really put into words that from what i seen looked like it IS working.
so if i had to put money on it,
i would say it most likely is working exactly as i hoped it would :).
..but its hard to say until i get a cable.
so my next option until i get a hold of one wich could be a while
(personal reasons i wont get into)...
is the composite output through a rpi.
i am aware vbit2 has the ability for vbi on the rpi...
so could it be possible if there is a way to get that ld/vhs-decode tbc, or ofc
"unai.VITC" working through rpi the same way as vbit2?
like i said, it looks like it is working wich is great,
but i want to be 100% ofc.
thank you for all your work. ;)
i'm sorry that its not a deffinate yes or no, but i would say like 70% yes.
i am going to see if i can get my grandad to hook me up with one (or fix it).
No worries. I'll close the issue for the moment. If you or anyone else are able to test it, drop a note here!