View Full Version : Workflow with Final Cut and XDCam HD


Dan Brazda
August 12th, 2007, 07:44 PM
We have a V1U that we use as a B-Cam with our XDCam HD 350's. The two work seamlessly in a XDCam 35mbps 24P VBR timeline even though the V1U footage comes off tape at 1080/60i (shot at 24P). Should we shoot the V1U at 24PA or 24P when mixing in a XDCam HD 35mbps VBR/24P timeline? We're mastering to XDCam HD not film. I heard we should be shooting at 24PA on the V1U if you are working in a 24P timeline but when doing so the cam resets timecode to find the A frame every time you stop and start the cam. When we go to digitize this leaves Final Cut in a funk if you want to digitize an entire tape in one fell swoop because it has to think about the timecode rest for about 7 seconds after each shot thereby losing that much footage (even if you tell it to ignore timecode breaks). We can work around it by digitizing one shot at a time with at least 5-7 seconds preroll but- in our workflow do we lose anything by just shooting 24P instead of 24PA?

Nate Weaver
August 12th, 2007, 08:16 PM
24P (as opposed to 24PA) on that camera is 24P, but inside a 29.97 stream. AKA 24p w/pulldown added.

So if you shoot straight 24p mode (which is really 29.97), and then drop that 29.97 in a native 23.98 timeline, FCP drops all the wrong fields making it work. You'll wind up with 24p from the V1 that has serious cadence issues.

I'd recommend shooting 24PA, but changing the preroll/postroll times to 1sec. You'll have the same problem as before, but it will be less of a timesuck.

Nate Weaver
August 14th, 2007, 01:45 AM
Dan, I have to correct myself. I was full of it. I mistakenly went on the word of somebody else when I only had limited experience with the V1U.

Now that I've got the thing in my hands, I now know both 24p modes add pulldown and record a 29.97 stream. Seems the only difference is 24PA starts each shot with the same cadence, while 24P starts wherever the cadence happens to be when you hit record.

BTW, when testing with freerun timecode, FCP6 is not stopping on timecode breaks...it's plowing right through them and not losing time.

What I find amazing is that FCP6 is allowing 24p inside a 29.97 stream on a 24P XDCAM timeline, and not making a mess of the cadence! It boggles the mind...it should NOT work unless FCP is smart enough to remove the V1U pulldown on the fly, which looks like it might be doing!

[edit: 24P mode V1U clips brought into a 24p XDCAM timeline more often than not exhibit the cadence mess I expected. I think further study would bear out that 4 out of 5 times they are messed up, with 1 out of 5 shots just happening to start on the "A" frame. 24PA mode shots ALWAYS work in the XDCAM 24p timeline, because FCP seems to always be able to remove the pulldown!]

Greg Boston
August 14th, 2007, 08:20 AM
Nate,

24P is 2:3:2:3 cadence while 24pa is 2:3:3:2. As you observed, both are wrapped in 29.97 (or 60i), but the latter can extract 24 complete frames by removing pulldown and gets edited in a 24p timeline. Maybe that's why FCP6 can work with that mode without screwing up the cadence. No fields get blended together with this mode to create the 29.97 output whereas with regular 24p they do. IOW, don't they behave the same way as their SD equivalents?

Just thinking out loud here.

-gb-

Nate Weaver
August 14th, 2007, 11:12 AM
24P is 2:3:2:3 cadence while 24pa is 2:3:3:2. IOW, don't they behave the same way as their SD equivalents?


Not on the V1U. My mistake was assuming 24P mode was 24p inside 29.97 with 2:3:2:3, and 24PA was actually a 23.98 stream to tape, much like the JVC handles things with repeat flags.

In both modes the cadence is 2:3:2:3, 29.97. I checked. You confirm this by looking for 3 progressive frames followed by 2 frames that are interlaced.

The difference on the V1 is that 24PA mode always starts the cadence off the same way. 24P mode starts recording without regard to where the cadence is.

Steve Mullen
August 14th, 2007, 04:22 PM
Nate,

24P is 2:3:2:3 cadence while 24PA is 2:3:3:2.



-gb-

Think of the "A" not as Panasonic's "ADVANCED" but as "clips always start on an A frame."

XDCAM HD can shoot two kinds of 24p. One is 1080p24 and the other 1080i60/24p. The latter has 2-3 pulldown.

IF -- big if -- FCP is handling the V1 24p footage it may "assume" the V1's footage is XDCAM HD 24p footage. How is a good question.

I assume XDCAM HD clips always begin with an A frame. Therefore, I would use 24PA mode.

Nate Weaver
August 14th, 2007, 04:38 PM
Think of the "A" not as Panasonic's "ADVANCED" but as "clips always start on an A frame."

Yup. That was my lesson.

XDCAM HD can shoot two kinds of 24p. One is 1080p24 and the other 1080i60/24p. The latter has 2-3 pulldown.

No, it doesn't. I own one, so does Greg. There is only one 24p mode shooting HD, and it's native frames with no pulldown added.

Shooting DVCAM mode on the 330 or 350, the 24p mode is ONLY with pulldown added, and only 2:3:2:3. No 2:3:3:2 choice offered.

Piotr Wozniacki
August 15th, 2007, 01:33 AM
XDCAM HD can shoot two kinds of 24p. One is 1080p24 and the other 1080i60/24p. The latter has 2-3 pulldown.

Sorry for off topic Steve, but I've noticed you have just answered the question I asked many times on the new EX forum, between your lines!

So, are you saying that the XDCAM HD (and EX, hopefully) is capable of both native 24p, and the 24PsF? I've just heard that the XDCAM HD chips are interlaced, so how does it do it?

Steve Mullen
August 15th, 2007, 03:26 AM
There is only one 24p mode shooting HD, and it's native frames with no pulldown added.

Shooting DVCAM mode on the 330 or 350, the 24p mode is ONLY with pulldown added, and only 2:3:2:3.

That's the problem with reading marketing material. It does both, but only on different formats.

Piotr Wozniacki
August 15th, 2007, 03:58 AM
But, here is what Greg said answering my question on the XDCAM HD 24p nature:

XDCAM HD captures as 24PsF which is progressive segmented frame. The sensors are progressive and capture a progressive image, but it gets segmented into two fields. However, those two fields don't have any motion delay between them because they are captured at the same point in time.


Now, I'm really lost:)

Dan Brazda
August 29th, 2007, 07:24 AM
Back to the original topic. We are shooting 24pA with the V1U and working seamlessly with XDCam HD in a 35mbps VBR Final Cut timeline, BUT... I can't help but feel there is a better way to import the V1U footage without the hassles we're running into. Is there not a way to import a full tape of V1U HDV material shot in 24pA without having to batch digitize individual clips and working around the camera stop/start points? Some have said use "non-controllable device" in Log and Capture and just Capture Now the manual rolled tape- tried it, doesn't work. Some say dub it to XDCam HD- haven't tried it but again, what a hassle. Others say they use iMovie HD to import their footage and then import the QTs into their FCP project-OY!

We're just getting by with the V1U until the EX comes out and hopefully will integrate much better as a B Cam with our XDCam HD 350s. Who else is using XDCam HD shot at 24p in 35mbps VBR and mixing with V1U footage shot at 24pA? What is your workflow?

Greg Boston
August 29th, 2007, 08:09 AM
Who else is using XDCam HD shot at 24p in 35mbps VBR and mixing with V1U footage shot at 24pA? What is your workflow?

Hey Dan, Nate just bought one of these off the classifieds so perhaps he'll be able to duplicate your issues and figures something out. In the meantime, did you catch Nate's mention above about using free run timecode on the V1? Seems FCP was a happy camper at capturing whole tapes that way.

-gb-

Dan Brazda
August 29th, 2007, 09:34 AM
I saw that and will give it a try- kind of defies logic when using 24pA because the whole point is you want to start with an A frame after each cam start/stop. Sometimes logic isn't the answer though so it's worth a shot.

Nate Weaver
August 30th, 2007, 11:42 PM
Yeah, I'm not sure what to say, I can digitize a whole tape shot in 24pa and while it breaks up the shots, FCP doesn't stop the tape for every shot. It just sails through.

I'm using FCP6.01....you too?

I gotta say, once I got this little camera set up right, it is FRIGHTENLY close to my 350. I can see the compression nasties and the aliasing in 24p pretty easy, but other than that...