My FX1 Cineframe 24 investigation

[chalbers]

I went to the DVExpo this week and the Sony person presenting the HDR Z1U told me Cineframe 24 is real 2:3 pulldown 24p !

So I asked him if that is the case, you can take out the 2:3 pulldown and get clean 24p footage ? He said yes !

Off course me beeing as sceptical as ever, I asked him if they could show me footage where it was already done. He couldn't proove it to me, but he was 100 % sure you could do it with the new HD support in Vegas 5.0

So , once home, I installed a fully usuable 30 day trial copy of Vegas 5.0b . I also found some Cineframe 24 footage online that someone shot in clean m2t (mpeg 2 transport stream format used for FX1).

I was able to look at the footage and indeed saw a recuring 2:3 pulldown pattern. But was it real 2:3 ??

I tried to take out the 2:3 but the option was NOT available for any other footage then avi DV format ( it's in the help file). I was very dissapointed.

So I downloaded the demo version of DVMaker to take out the 2:3 pulldown of the m2t file. It tells me it CAN't do that right now with mpeg 2 movies !!

So I downressed the footage to DV format ( keeping the fileds correct which in m2t somehow seems to be upper field first ). Once in DV format I tried to take out the 2:3 pulldown. I tried in several ways by setting on which frame to start the removal, but I just couldn't get 24p footage.

So ... for now I don't believe that FX1 Cineframe is in any way usuable unless somebody proofs me otherwise

Frank

[Barry_Green]

It is completely unusable, but not necessarily for the reasons you found.

Cineframe 24 is recorded to tape using 2:3 pulldown. If Vegas allowed 2:3 pulldown removal on HDV footage, you could reverse the pulldown sequence and end up with 24 frames per second. BUT: they're not right. That's the problem with CineFrame 24. It's not sampled 24 times per second, it's an odd field-blended field-swapped mishmash that's not in any way an accurate film simulation.

So yes you'd have 24 distinct frames with pulldown removed, but that doesn't make it equivalent to 24P, because 24P gets sampled 24 times per second, a full frame at a time. CineFrame 24 gets sampled 60 times a second, a field at a time, and then the camera tries to de-interlace and copy fields to simulate 24fps motion, but it doesn't work. You end up with a really odd stutter and some double-images.

[Guest]

Plus it has a 1/60th shutter which will make your footage look strobey. Best bet for the closest approximation of 24P would be to use the Z1 and shoot in CF25fps mode, then conform it to 24fps. This method has been discussed before.

I would avoid CF24fps, and why Sony even included it is stoopid. Future revisions should see this feature removed. It is as stoopid as those JVC Streamcorders.

[cineman9]

It's all about 24fps motion sampling...and this camera doesn't do it.

[chalbers]

Well ... I did a test this morning and you guys are totally correct.
I figured out a way to get the full frames out of the 2:3 pulldown of the m2t stream. The result of the test is dissapointing.

The result is downloadable (7.5 meg):
http://home.comcast.net/~chalbers/fx1_24ptest.mov

This is what I did to get the Cineframe 24p 2:3 pulldown removed to 24p.

1. I moved the m2t clip one line up because hdv streams are upper field first (I have no clue why it's different from DV). This way I changed it so that lower field are first for futher tests.
2. I seperated both fields and resized them to 720*240
3. I interlaced the fields back together to 720*480 with lower field first.
4. I imported to vegas and changed it into a 29.9i DV avi file.
5. Then I changed my Vegas scene to 24p, imported the DV file I just created and took out the 2:3 pulldown of the footage.
6. I Exported the result into a quicktime file to view

I right away noticed the strobing on the passing biker in the 24p footage. At first I thought it was shutter speed strobing since it was probably shot with 1/60 th. But then after walking through the frames I noticed that the motion distances between frames of the biker was different and not constant. This pretty much shows it's not really shot in a 24p time base.

So much for my FX1 excitement !

Frank

[cineman9]

Thanks for posting the clip. *Man, that doesn't look good at all. *So much for "simulated" progressive look. *Who's gonna tolerate those jaggies? *I am at a loss as for the practical applications of CineFrame 24. *Does Sony think people are actually gonna use this?

[Hayden_Rivers]

Jesus, is that what CF24 looks like? I am not exagerrating when I say my stomach actually got ill looking at that.