24 hr timecode

[Bouke Vahl]

If you use TOD on multiple cams, be sure you have the time EXACTLY the same.

Normally one would lock on cam to the other, and have them both run in free run.
Now this is accurate +/- 4 frames over a day.
But this REALLY sucks when you have to ingest entire tapes in FCP. You want continuous TC over your tapes, (rec run) to be able to dig entire tapes without endless prerolls / breaks (specially in HDV.

So next time, find a TC generator (can be anything that outputs LTC, just record some onto your Ipod or whatever, get a cheapo FM transmitter and broadcast the LTC.
Use a cheapo FM receiver and record the LTC on one of the audio channels.

Next, ingest the entrie tape and have a piece of software (i’m writing it right now) to seperate the clips, set Aux TC and re-import that into FCP.
Hassle free digitizing, immediatly syncing of your clips.

Keep an eye at my site, it will be there in a week. The FCP AUX tc application that is there does not work for you, as you don’t have RS 422 on your deck.

Bouke

http://www.videoToolShed.com
smart tools for video pro’s

[Bouke Vahl]

I was partially wrong in my previous post you referred to.
Over 422, you have to ‘ask’ the deck to tell the current timecode.
You can ask specific for Ltc, Vitc, CTL or UB. Or, and i suspect that’s what Avid does, ask for ‘auto’ and have the deck decide what is best for you.
No way the deck will decide you get UB instead of current time.
So you need an appl. that will ask the right questions. But as there is no 422 on the cheapo HDV decks, i cannot be of help here… (i don’t speak firewire, yet….)

Bouke

http://www.videoToolShed.com
smart tools for video pro’s

[Joseph Owens]

This may be beating a dead horse, but if anybody’s interested:
https://en.wikipedia.org/wiki/SMPTE_time_code

There is a big difference between “user bits” and Vertical Interval Time Code, which appears to be two terms that some people are freely interchanging.
User bits are part of the 80 bit word that comprises the time code package. They are intended to convey information, not time. The information usually is a date, or a machine number, a reel number, or anything else that can be identified with the numerals 0-9 and the letters A-F. (It is hexadecimal, after all — and if you don’t understand that, I really am flogging an expired equine.

Iterate means: the numbers change, progressing. User Bits don’t do this. They are locked to whatever you enter them as. True, the time marches on in HRS:MINS:SECS:FRMS in both Longitudinal and Vertical Interval time codes. But USER BITS are NOT time code. It is true that you can preset the VITC and LTC to be different. Ordinarily this is a bad thing and is grounds for rejection of a broadcast master. But I have seen people do it as a rough visual conform device: Edit tape LTC shows record time, and (shutting off internal VITC and passing through source VITC on unblanked vertical interval) inserted VITC is Source, so that a burn will yield a (manual) cut list guide that you could write down. We may have to go back to this with wobbly formats like HDV.

And on the subject of DV. Standard Def is 720×486 — ie Digi-Beta — and DV is 720×480. It does NOT support VITC, because the active Vertical Interval lines do not exist. Ask anybody who has requested a master telecine transfer tape with embedded Evertz/Aaton codes. No is the answer.

JPO

[Steve Braker]

> There is a big difference between “user bits” and Vertical Interval Time Code, which appears to be two terms that some people are freely interchanging

VITC and LTC are just two different ways of transporting the exact
same data. Which includes user bits, which can be used to record
time. It’s been done since the beginning of time… code. Very
common to put TOD in the user bits, as I said I used to do it all the
time. You can put GPS data in there if you’re so equipped.

> They are intended to convey information, not time. The information usually is a date, or a machine number, a reel number, or anything else that can be identified with the numerals 0-9 and the letters A-F. (It is hexadecimal, after all — and if you don’t understand that, I really am flogging an expired equine.

Well, this dead horse has used it many times. The letters aren’t used
for time, of course. We tell time with numbers.

> Iterate means: the numbers change, progressing. User Bits don’t do this. They are locked to whatever you enter them as.

Well yes, they do. If the generator has that capability, and the
operator in charge of it tells them to. My trusty old EECO
does-everything TCRG here even has a button for “Jam User Bits”. It
does exactly that – jam syncs to the incrementing time on the incoming
user bits.

Wondering why I’m writing this.

[Joseph Owens]

We are actually sort of on the same page. I’m just under the impression that the white data lines at the top of the screen are being blanket termed “User Bits” when that’s the wrong nomenclature.
We agree that VITC and LTC can serve as different transport mechanisms for the same data, with some differences due to reading technicalities.
The LTC/VITC time code word is subdivided into different areas. One area carries time code, TOD, PRESET, REGEN’ed whatever you want it to do, as you say.
Another intervleaved area carries a fixed set of data, and there are also interspersed flags set to identify DF/NDF code and other things about the video.
User bits can be embedded in both Longitudinal Code as well as VITC, but LTC can never be used to identify fields, since motion is required to read it. Also for this reason, sometimes it is unreliable to read VITC in PLAY_REVERSE.
Within the 80-bit word in either VITC or LTC, the “frames (units)” are carried as bits 1-4, first UB is bit 5-8, “frames (tens)” are 9,10 (because it never has to count past 2), then there’s the drop frame flag, the colour frame flag (You’re really old if you know what that’s for), then the second UB group, etc.
The whole listing follows:

Chapter 2) SMPTE Time Code 80-Bit Longitudinal Bit Assignments

BIT) description

1 BCD Frames Units
2 BCD Frames Units
4 BCD Frames Units
8 BCD Frames Units
Bit 0 of 1st Binary Group (User Bits)
Bit 1 of 1st Binary Group (User Bits)
Bit 2 of 1st Binary Group (User Bits)
Bit 3 of 1st Binary Group (User Bits)
10 BCD Frames Tens
20 BCD Frames Tens
Drop Frame Flag Bit
Color Frame Flag Bit
Bit 0 of 2nd Binary Group (User Bits)
Bit 1 of 2nd Binary Group (User Bits)
Bit 2 of 2nd Binary Group (User Bits)
Bit 3 of 2nd Binary Group (User Bits)
1 BCD Seconds Units
2 BCD Seconds Units
4 BCD Seconds Units
8 BCD Seconds Units
Bit 0 of 3rd Binary Group (User Bits)
Bit 1 of 3rd Binary Group (User Bits)
Bit 2 of 3rd Binary Group (User Bits)
Bit 3 of 3rd Binary Group (User Bits)
10 BCD Seconds Tens
20 BCD Seconds Tens
40 BCD Seconds Tens
Bi-Phase Mark Phase Correction Bit (0)
Bit 0 of 4th Binary Group (User Bits)
Bit 1 of 4th Binary Group (User Bits)
Bit 2 of 4th Binary Group (User Bits)
Bit 3 of 4th Binary Group (User Bits)
1 BCD Minutes Units
2 BCD Minutes Units
4 BCD Minutes Units
8 BCD Minutes Units
Bit 0 of 5th Binary Group (User Bits)
Bit 1 of 5th Binary Group (User Bits)
Bit 2 of 5th Binary Group (User Bits)
Bit 3 of 5th Binary Group (User Bits)
10 BCD Minutes Tens
20 BCD Minutes Tens
40 BCD Minutes Tens
Binary Group Flag Bit (0)
Bit 0 of 6th Binary Group (User Bits)
Bit 1 of 6th Binary Group (User Bits)
Bit 2 of 6th Binary Group (User Bits)
Bit 3 of 6th Binary Group (User Bits)
1 BCD Hours Units
2 BCD Hours Units
4 BCD Hours Units
8 BCD Hours Units
Bit 0 of 7th Binary Group (User Bits)
Bit 1 of 7th Binary Group (User Bits)
Bit 2 of 7th Binary Group (User Bits)
Bit 3 of 7th Binary Group (User Bits)
10 BCD Hours Tens
20 BCD Hours Tens
Unassigned Address Bit 58 (0)
Binary Group Flag Bit (0)
Bit 0 of 8th Binary Group (User Bits)
Bit 1 of 8th Binary Group (User Bits)
Bit 2 of 8th Binary Group (User Bits)
Bit 3 of 8th Binary Group (User Bits)
Bit 0 – Binary Sync Word (0)
Bit 1 – Binary Sync Word (0)
Bit 2 – Binary Sync Word (1)
Bit 3 – Binary Sync Word (1)
Bit 4 – Binary Sync Word (1)
Bit 5 – Binary Sync Word (1)
Bit 6 – Binary Sync Word (1)
Bit 7 – Binary Sync Word (1)
Bit 8 – Binary Sync Word (1)
Bit 9 – Binary Sync Word (1)
Bit 10 – Binary Sync Word (1)
Bit 11 – Binary Sync Word (1)
Bit 12 – Binary Sync Word (1)
Bit 13 – Binary Sync Word (1)
Bit 14 – Binary Sync Word (0)
Bit 15 – Binary Sync Word (1)

Per 80-Bit Frame, there are 32 User Binary Spare Bits, 16 Sync Bits, 31 Assigned Bits, 1 Unassigned Bit.

So, forgive me for thinking that when you say you are setting the User Bits to Time of Day, what you actually doing is setting VITC to time of day, and probably not setting the UserBits at all… they can be a bit of a bear to find on most systems.

JPO

[Steve Braker]

> So, forgive me for thinking that when you say you are setting the User Bits to Time of Day, what you actually doing is setting VITC to time of day, and probably not setting the UserBits at all… they can be a bit of a bear to find on most systems.

I do forgive you – one last time – but I said what I meant. User bits, in VITC, LTC, or both, recording the march of time. Incrementing, iterating, moving. User bits, distinct from the time code. Time of Day reco4rrded in user bits while tape time goes in the regular code. Perhaps I’m not clear enough.

Don’t knock it until you’ve tried it. Don’t say it isn’t done or possible until you’ve tried it. Don’t use it if you don’t need it. Believe it or don’t. I think my work is done here.

[Andy Mees]

hi JP

this is a specific feature of the Z1 as I recall. the processor on the camera is regenerating a UB number for each frame based on the internal TOD clock.
far from the normal application of UB data, but there you go, it allows you to set UB’s to TOD timecode.

cheers
Andy