Tri-level sync – when do we need it ?

[David Battistella]

From my pure understanding, and I know people will chime in, is that Tri-level sync is required when outputting to HDCAM at 23.98 fps.

When outputting at 59.94 a regular sync source works, this can include the KONA video OP.

I am going to do my Bob Zelin impersonation now:

“LOOK! Just sheel out all of the money in your bank account and buy a tri level sync generator. You can not call yourself a working professional if you want to chintze around and cut corners. Tri-Level sync is a necessary evil and if you are working on projects that warrant it, then you should have the budgets to afford a tri-level sync generator, otherwise you are a cheap impostor post house that does not deserve the business because you do not have correct tools for the job. ”

🙂

Peace and Love 🙂

[Dom Silverio]

You forgot to add

“Tri-sync is gonna last you longer than your $5000 G5 or $2K capture card”

Which is true. Hell It can outlast a $50K Avid or Discreet smoke.

Rule of thumb is if you are dealing with with progressive, flat frame rates (ie 60p and 24p) you will need it – especially if there is a cross conversion going on. For things like 59.94 and 29.97 based projects you can get away with your standard balck burst.

[Bob Zelin]

David did a GREAT impression !
The only time I ever use tri level sync is when the customer MUST work in 23.98 (or 24). But in my world, since everyone is using Panasonic HD VTR’s which have the 2:3 pulldown (turing the 23.98 into 59.94), or Sony JH-3 VTR’s (which do the same pulldown trick), I almost NEVER have to use a tri level sync gen, as everything is being done at standard frame rate (59.94), so a cheapie black generator works just fine for these projects. However, as David said, if you MUST output at 23.98 to (for example) a Sony HDW-M2000/10, you MUST MUST MUST use a tri level sync generator to lock everything. Since George Lucas is not one of my clients, I don’t ever see ANYONE dumping back at 24p. I guess if I lived in LA, it would be a different story.

Bob Zelin
ps – and you were right, long after the PCI-X G5, the Quad G5, the Kona 2, the Blackmagic Extreme, the AVID Adrenaline are gone, the $5000 Evertz 7750 Tri Level Sync Gen will be completely usable, just as everyone’s NTSC black genenerator they owned (back in the linear video days) is just as good as any sold today.

[Melvin Chong]

In other words if we are dealing with 24fps or 25fps progressive in PAL land, tri-level sync is not required at all ?

[Bob Zelin]

I never said this. There is a BIG DIFFERENCE between 24, 25, and 23.98. 23.98 and 24 are NOT THE SAME FRAME RATE. In the US, when you shoot 24p for television, you are actually shooting at 23.98 Hz framerate. (You can set the camera for 24 frames, but then you get into trouble when you try to output to video). 23.98 can be converted to 59.94 for US framerate. I have no idea of what happens when you want to go back to 25 frames per second for PAL if you shoot in 23.98, and what the actual frame rate is in PAL.

Bob Zelin