WHAT is Varicam REALLY doing when you shoot 48fps for slo-motion effect?

[Gary Adcock]

[BRussell] “Hmm, okay, let me ask it this why then.”

1)
the Varicam Flags do not pass thru on a down-covert, so there cannot be any flags to remove on the down-converted file.

2)
that being said, file conversion must be done prior to the downconvert – since the flags do not work.

3)
only DVCPROHD content works in either the Hardware or Software versions of the frame rate converter.

4)
720p content ALWAYS has to play back at 60p ( 59.94 in the US / JAPAN)

5)
720p content is always progressive- so there is no way or need to have advanced pulldown.
it does not exist in a progressive only capture.

does this help?

gary adcock
Varicamp Post instructor

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows

[Hamish Boyd]

This has been a great thread guys.
I’ve been keen to look into varicam for shoot options myself. But the technicalities have always confused me to bits.

I’m still pretty confused, but I’m going to read this thread carefully a few times, I’m sure the penny will drop soon…hahaha

On a more general note..
Would you recommend during a shoot to keep all slo mo effects at the one speed on the one tape, seperate from real time shots?
As from what I understand slo mo is setting in the camera (to flag frames) even though the camera is always recording at 60frames. Yes?
So in theory it shouldn’t matter, but….

Cheers

[Jeremy Garchow]

[Seamus] “So in theory it shouldn’t matter, but….”

No it shouldn’t but it’s easier to keep track of them when they are on separate tapes and also your cadence will be the same across the 23.98 tapes which will help with capturing. It’s also helps if you slate them (have the camera shoot the slate) with the frame rate on it so you know what you are going to get, slomo or fastmo. 😀 Be sure to roll plenty of heads/tails for all off-speed stuff to aid in capture as well. On paper, the Varicam process seems a bit confusing, but when you use it you will be amazed at how it works, and how good it looks.

Jeremy

[Gary Adcock]

[Seamus] “I’m still pretty confused, but I’m going to read this thread carefully a few times, I’m sure the penny will drop soon…hahaha”

remember
It was designed to be like a film camera, so all of the motion effects are optimized for 24 frame workflows.

It always lays 60 progressive frames to tape no matter what frame rate is shot.
Frame Rate Flags are only retained on camera to deck transfers and deck to deck clones of your master tapes.

Flags are only available via DVCPROHD ( camera native) content, if you capture as some other format – there are no flags.

Currently only the Kona cards are doing realtime HDSDI acquisition of the VFR data -variable frame rate – needed if you plan on doing any greenscreen and do not want to work in the compressed DVCPROHD space for keying.

While the BMD cards handle it differently and it then requires a fair amount of post processing when the capture is complete, with the Kona cards the VFR capture does not need any additional time for post process to extract the redundant frames from the HDSDI stream,it stops when you do.

“Would you recommend during a shoot to keep all slo mo effects at the one speed on the one tape, seperate from real time shots?”

While that is the optimum workflow, it is not always possible. SLATE all offspeed frame rates, make sure you have lots of pre and post roll so there are not any capture issues.
( that would be at least 10 seconds of tape before and after the shot at your shooting frame rate)

“As from what I understand slo mo is setting in the camera (to flag frames) even though the camera is always recording at 60frames. Yes?”

see line 2 above

“So in theory it shouldn’t matter, but…. “

yes it does.
handling the files in a proper manner makes it easier for the editor to understand what was done, and it will save you time in post.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows