View Full Version : Revisiting "True" 1080P/psf question


Stephen McCarthy
January 4th, 2011, 05:50 PM
Happy new year all and thanks Mike and crew for the extremely useful upgrades to the nanoFlash firmware.

I find myself needing to revisit a discussion entitled "One Last Thing About psf" that took place between a number of posters and Dan Keaton on this forum in Sept of '09. The root off the discussion for me was whether the nanoFlash's psf/3:2 pull-down removal functions are able to "reassemble" the interlaced SDI output of a native progressive camera (in this case the HDX900) into a "true" 24/1080P recording. Andy Shipsides at Abel Cine Tech sold me my nanoFlash at about that time and he's since blogged that "On an HDX900 the same method (3:2 pull-down removal) can allow you to record 1080 24p. Just set your HDX900 to 1080 24p, keep “Remove 3:2 Pulldown” on, and you’ll record true 1080 24p." This would seem to suggest that I'm able to produce something approximating a 1080P-quality master from the SDI output of my HDX900 despite that camera's being limited to 720P and 1080i at the tape recorder end.

This becomes a critical question as a number of producers I work with are undertaking new projects which would benefit from 1080P/file-based acquisition in the long run but, in the short run, this means juggling a transition with projects already in progress via more traditional tape-based work-flows. Given that most of my clients are editing in 23.94 time lines, can one honestly use the nanoFlash to enable these new projects to get underway with the "old" 1080i/24P DVCPro100 tape route for the time being while, at the same time, keeping options open to scale up to emerging file-based 1080P alternatives once a comfort level with purely file-based acquisition has been achieved?

These may seem like very old school issues to many on the board but the folks who are asking are producers who routinely turn modest documentary budgets into Emmys, DuPonts and Peabodys so the tendency to "go with what you know" is strong.

Thanks in advance and a prosperous 2011 to us all.

Stephen McCarthy
Director of Photography
Boston

Dan Keaton
January 4th, 2011, 08:27 PM
Dear Stephen,

The Panasonic HDX900 has a progressive sensor.

The HD-SDI output is not interlaced but Progressive Segmented Frames with pulldown frames added.

PSF is designed to look like interlaced, but it is not.

The nanoFlash will automatically detect the PSF Frames, provided that the frame rate is 23.976, 23.98 (same thing) or true 24p.

(For 1080psf29.97, one has to enable Video|Record PSF>Prog(ressive) option.)

Once the nanoFlash is told to, or automatically performs PSF to Progressive, one has 100% true progressive frames to work with.

Then with 23.976, 23.98, or 24 frames per second, one can enable Video|Remove Pulldown in the nanoFlash.

The nanoFlash is smart enough to analyze every frame and determine if it is a duplicate or not.

Thus, when enabled, all duplicate frames are removed.


Now, it is up to you to determine if the 1080 out of your camera is good enough for your purposes.

The sensor is not 1920 x 1080, but HDX900 owners have been very pleased with the 1080p that they get out of their cameras + nanoFlash. One reason for this is the conversion to 1080 occurs before any compression, which of course is the best way to do it.


When you add a nanoFlash, you do not lose the ability to record on tape to DVCPro HD. So you can do both.

Under carefull analysis, I predict that you will quickly agree that the nanoFlash files are better.

And we provide 24/7 customer support. So please feel free to call me.

I obviously cannot check my email 24/7, but if you do send me an email, I will respond with all of my phone numbers. Then you can call whenever you need or want assistance.

I am located in South Carolina, thus normal business hours 7 AM to 10 PM EST are best for routine questions.

I hope this helps.

Stephen McCarthy
January 4th, 2011, 08:50 PM
Dan,

Somehow I knew you'd be lurking there. Thanks for the point by point response. It hits all my issues without over-promising. My expectation is that the 900/nano combo is a good kick-start for one particular project where they haven't had time to do wide-ranging tests. No question that the nanoFlash files trump tape. I've demonstrated that in a number of edit rooms with big monitors and very controlled tests. I'd like to do a side-by-side with Panasonic 2700 for them but we've got an initial day of shooting with the central figure breathing down our necks so I needed some reinforcement to my own anecdotal evidence to get one in the can with tape get them started and possibly go back to in a pinch. In a world of compression who'd have thought that little BNC spout would anchor my lifeline. Thanks again.

best,

Stephen McCarthy

Mark Job
January 11th, 2011, 10:06 PM
Hi Dan:
Is it possible with my Flash XDR to record in the traditional 3:2 pull down removal from my Canon XL H1's 24F source, then set my XDR to play out via the HD-SDI output in PsF output mode instead ? The reason why I ask this is I have access to an NLE system which records 1080 via HD-SDI only in PsF mode. Since my workflow is setup to use my XDR with my H1, which normally would create a recorded output of 23.98p from the XDR, could just the output alone be set to *Play a 23.98p file in PsF mode* from a file which was recorded in the XDR as standard 23.98p ? I hope this makes sense.

Dan Keaton
January 12th, 2011, 09:22 AM
Hi Dan:
1. Is it possible with my Flash XDR to record in the traditional 3:2 pull down removal from my Canon XL H1's 24F source,

2. then set my XDR to play out via the HD-SDI output in PsF output mode instead ?

The reason why I ask this is I have access to an NLE system which records 1080 via HD-SDI only in PsF mode.

3. Since my workflow is setup to use my XDR with my H1, which normally would create a recorded output of 23.98p from the XDR, could just the output alone be set to *Play a 23.98p file in PsF mode* from a file which was recorded in the XDR as standard 23.98p ? I hope this makes sense.

Dear Mark,

1. Yes.

2. Yes.

3. Yes.

Just set the Video|Play Prog>PSF on.

While I believe I fully understand your question, please run a test of your workflow.