C100 HDMI Capture - 60i Pulldown

I’m trying to figure out to use my Canon C100 for HDMI capture via the BlackMagic UltraStudio Mini Recorder. I’m able to capture to my MacBook Pro, but the problem is that unlike the Atomos Ninja 2, the Mini Recorder does not automatically perform the 60i to 24p pulldown.

My understanding is the FCPX will automatically do the pulldown if you add 60i footage to a 24p timeline. I’ve done some testing and it appears that the pulldown does work. The problem I’ve noticed is that the quality of the footage is significantly reduced. There seems to be much more noise/grain in the 60i captured clip vs the identical clip recorded at 24p using an SD card (which captures the footage as AVCHD, 4:2:0).

SAMPLE IMAGES

Mini Recorder 24p Clip (in 60i wrapper)
bit.ly/1rj2Ay0

Internal AVCHD 24p Clip
bit.ly/1nkWBDU


I thought that pulldown just meant “extracting” the original 24p from the 60i “wrapper”. So why would the quality be so reduced? Am I missing steps in FCPX?

Is it possible that because the Mini Recorder is “baking in” the 60i, I’ve lost the original quality of the 24p? In other words, to maintain the full quality original 24p, does the pulldown have to be done on the fly, or is there a way to extract the original 24p, full-quality clip from a 60i file?

60i is interlaced, 24p is progressive. Going from one to the other isn't always the best workflow.

As for 24p in a 60i wrapper, that's not what all cameras do. Not familiar with your camera, so I can't answer if that is what the C100 does or not. It was something Panasonic came up with, since Firewire could only stream a 60i video stream, so they marked frames with metadata. Since cameras are all digital now, I'm not sure what the point is.

Is it that the C100 won't output 24p via HDMI?

There is a checkbox to remove pulldown in the import window.

Shouldn't the question be if your camera has the pulldown flags built into the signal. IIRC, there have been some issues with Canon cameras and the fake 24p wrapped into 60i.

The C100 records a progressive movie in an interlaced wrapper for all 24,25,30p modes. Interlaced is interlaced.

Hope this helps.

The "remove pulldown" checkbox is grayed out when I try to import the .MOV clips recorded with the Mini Recorder. I think it only works when importing from tape-based media, or something like that.

I understand the limitations of the C100's 60i wrapper. My question is about the way that FCPX is handling that 60i footage.

It seems there are two ways to deal with pulldown. Option 1 is to remove it on the fly as it's being recorded, which is what the Atomos Ninja 2 does. Option 2 is to record the video as 60i then use some kind of software to do a "reverse pulldown" and extract the original 24p clip. None of BlackMagic's hardware will do the reverse pulldown on the fly, so I'm stuck with Option 2.

If you refer to my original post, I included two screenshots of identical clips in FCPX...one of the clips came from the footage recorded internally to the SD card (as AVCHD 4:2:0) and the other came from the same clip recorded simultaneously via HDMI with the Mini Recorder (as ProRes 422). You can see that FCPX did a perfect job of "reverse pulldown" in the sense that it removed the interlacing so that the two frames are essentially identical.

My problem is that clip from the Mini Recorder seems to be at much lower quality. If you didn't know which clip was which you'd probably get them reversed...the lower quality image looks like 4:2:0 material while the other looks like 4:2:2. So why the quality loss? I thought reverse pulldown just reorganized the fields/frames back into their original order and positions.

The 60i clip from the Mini Recorder looks very similar to the quality loss I get when I record 60i internally for the purpose of de-interlacing for slomo (the C100 doesn't have a 720p60 mode, so I have to use the 60i work around). In the case of shooting 60i for slomo, I know to expect quality loss because each field is interpolated for purpose of creating double the frames.

So all that is really just a long way of asking this...Is there a way of doing reverse pulldown in post that maintains the same exact quality as the reverse pulldown being done on the fly by the Ninja 2?

I would simply use another method, i don't know much about the mini recorder. I only use the Atomos Blade / Internal.


I always use Clipwrap to convert the AVCHD, so i dont get this at all. But I know that if I import the C100 footage into FCPX from the card, I loose half the resolution, and the image introduces moire and aliasing. My way to overcome this is to set the timeline to progressive and ensure the clips are not getting De-interlaced by FCPX.

I hightly recommend Clipwrap for all C100 users.

Hope this helps.

The footage that you lose half the resolution on, is it 60i footage being recorded internally? Everything I shoot internally is 24p and I don't experience any quality loss that I'm aware of.

Why are you recording via HDMI, and not internally to SD cards, anyway?

Recording internally to SD cards captures footage as AVCHD, 24 Mbps, 4:2:0 color space. Recording externally via HDMI allows for capture of the raw, uncompressed video stream at much higher data rates, like ProRes HQ, 220 Mbps, 4:2:2 color space.

For almost everything I shoot the internal footage is good enough, but I've got several green screen projects coming up, so I'd like to be able to record at the highest possible quality for the purpose of "pulling a better key".

Is this the problem you're referring to?:

mattdavis.pro/2013/12/30/canon-c100-psf-the-fix/

ddixon wrote: Is this the problem you're referring to?:
mattdavis.pro/2013/12/30/canon-c100-psf-the-fix/

I read that article a few days ago. If you scroll all the way down I'm the last comment in the thread. Even though it's talking about changing interlaced footage to progressive, the article does't address my issue. When I follow his steps I do get an improvement in aliasing, but the interlacing is still not removed.

not know if your problem has been solved or not, but you can try some converter to switch mode between "Interlaced" abd "Progressive".