Capturing HD XDCAM 720/24 over 60 to 24p timeline

[Shane Ross]

Question….did you shoot 720p over 60? Or 1080p? Just curious because I know that the Kona LHe can’t do cross conversion.

Also…what capture settings are you using? ProRes, Uncompressed?

Shane

GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def

[John Sharaf]

Hi Shane,

I’ve learned quite a bit since we talked yesterday.

I shot 720/24 over 60p in the PDW700’s upon the advise of an expert well known on these forums that is was “just like the Varicam” and conformed to RP188 TC standards, which I interpreted to mean that there were flagged “A” frames so that FCP or KONA could reverse telecine the media and I could capture a 24p timeline. This was important to us because we intend to bring this feature doc to film out for theatrical distribution and because we have 180 hours (so far) of material and storage economies are an issue.

I now know from communication with Jon Thorn from AJA and our own forensic examination, that the Sony camera does NOT write flag frames as part of its 2:3 pull down process and the material can not therefore be reverse telecined.

I chose this format reluctantly, as I would have much preferred 1080/24p, but the implementation of this format was delayed in delivery from Sony until just recently, in fact after I returned from the 60 day shoot abroad. It required both the new V1.5 software and a $5000 card in the PDW-HD1500 deck and a $4500 software key in the camera. In hindsight 1080/25p would have been a better choice.

I spent all day yesterday with my buddy Tony Salgado, who is very knowledgable about these things and he was able to design a workaround that we think is satisfactory. We’ll capture at 720/59.94 in ProRes Proxy, which keeps the storage requirements within reason and the offline quality just fine, edit the project in a timeline of the of the same speed (there is also quite a bit of 50i archival footage) and then after on-line use a technique we found on Phillip Bloom’s website to essentially play the 60 back in a 24 timeline as slow motion and then speed it up with cinema tools and compressor to match the length of the sound. It’s very clever and looks quite good.

Of course we’ll need to test the film out on this approach, as we are screwing with the temperal motion a bhit, but there is another advantage that we get a 60p video version and then a 24p film out version.

My wife has lowered the suicide watch and I was able to sleep soundly last night knowing that there is at least one version of a fix that can get the project to the movie theater.

Maybe this more complete explanation of the “problem”, which of course came from own faulty assumptions based on reliance on advise of an “expert” who in this case did not really know what he was talking about, and then proceeding without testing, will help you or others think of another fix or suggested workflow. There is still a few days, as i wait for my XRAID to format to consider alternatives, and I welcome and seek other suggestions.

JS

[Rafael Amador]

[john sharaf] “I shot 720/24 over 60p in the PDW700”
Hi John,
If I don’t miss understand, you have recorded 720/p24 overcranked to p60.
isn’t it?
The file you get is a p24 slow motion.
As long as I know, there is no pulldown involved here.
Cheers,
rafael

http://www.nagavideo.com

[John Sharaf]

Hi Raphael,

Yes, there is a 2:3 pulldown just like a Varicam, so that the 24 frames are repeated alternately twice or three times to add up to 60 frames per second, as opposed to 60p which is 60 distinct frames per second (which if dropped into a 24p timeline would give you a 2.5x smooth slow motion effect). One can confirm this by single framing through the media, you’ll see two identical frames and then three more identical frames. This cadence is continued throughout.

The rationale for the 720/24p over 60p in the PDW700 XDCAM (as it is also in the Varicam) is to give a film look to video production, just like film would look after telecine processing (aka film to tape).

In the Varicam, the first of each repeated frame is marked by an “A” in the user bits as well as a “24” (or whatever the set framerate is) to tell the post processors (hardware and software alike) what frame rate the shooter intended. This allows the capture card or software in NLE programs to “pull” just the 24 distinct frames and create a 24fps timeline which is useful both for film out and to save hard disk space (as 24 is only 40% of 60, with a comparable savings in storage requirement). In addition, the framerate metadata also is useful in processing slow and fast framerates back to 24 or 30fps, but you probably knew all this.

The problem is that the Sony PDW700/800 does not write these markers, so the KONA card and FCP have no way of identifying the discreet 24 frames to make a 24fps clip, which is useful both to create a project for film out and also to conserve storage space, as 24 is just 40% or 60 and you realize a similar savings in hard disc space.

Furthermore many people including myself and the “expert” I consulted before the shoot, mistakenly assumed that Sony had implemented a similar strategy as Panasonic vis-a-vis this 24 over 60 feature, but we were all mistaken. This is how you really learn things, by making big mistakes!

JS

[Jeremy Garchow]

You can check to see if there’s VFR info just by checking out the timecode tab of the Kona CP. What if you went a tapeless route?

Test test test everyone. Test this stuff before you do the real thing.

[John Sharaf]

Hi Jeremy,

Must have forgot to mention that that is precisely how we determined that there was no A frame nor frame rate info, by looking at the TC tab on the Kona CP. There was nothing there, zilch, nada, zeros. When we attached a Varicam, voila, all the stuff we wanted to see. Also confirmed by connecting PDW700 and 800 directly to Kona whilst set at 720/24 over 60 and same results, nothing.

As regards going file based with XDCAM Transfer, that would be great but only options are 720/50i and 720/59.94, no 720/23.98 as in EX XDCAM, and besides, no A frames no reverse telecine, simple as that. Sony has given me another reason to hate them. Don’t get me started!

JS

[Jeremy Garchow]

[john sharaf] “As regards going file based with XDCAM Transfer, that would be great but only options are 720/50i and 720/59.94, no 720/23.98 as in EX XDCAM, and besides, no A frames no reverse telecine, simple as that. Sony has given me another reason to hate them. Don’t get me started! “

Bummer. Sorry, John. What I would try though, is to see if Compressor can pick up the A frames on a test clip. Use the reverse telecine option. If you need help with that, I can guide you through a preset.

I’d be curious to see if it works on 720p footage, I know it works on 29.97i footage with 3:2 pulldown.

Jeremy

[Shane Ross]

Well I’m glad that Tony was able to help you out. Interesting workflow…Glad to see it works. The brilliance of some people astounds me.

Sorry that you were initially led astray…

Shane

GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def

[John Sharaf]

Shane,

To be honest, we’re still exploring options, as the “MacGuyver” fix described earlier does result in objectionable motion artifacts. Best fix would be a real time reverse telecine on injest to FCP which identifies cadence probably from time code frame “zeros” and “fives”. But that still leaves conforming issues. This is a complex one-of-a-kind problem that does not lend itself to simple fix.

Still open to suggestion.

JS

[Jeremy Garchow]

Compressor? It auto detects A frames on standard 3:2 material, it might just do the same on 720p. You just have to use the reverse telecine feature of Compressor.