cross-convert 1080i to 720p24 from P2

[Gary Adcock]

[Sean ONeil] “If it’s 1080 60i without any 3:2 pulldown, just add a deinterlace filter (essentiall making it 60p) and then throw it on a 720p 24 timeline and render. But if it does have 3:2 pulldown, it will be a chore to convert it.”

Sean —
got that backwards –if they shot with a pulldown that would mean the footage WAS originally shot at 24p and the popster would be able to do this easily

While running the “deinterlace” filter may pass in the SD world- in HDTV the converted footage would be very, very noticeable when placed in between other non converted footage, showing as much as 50-60% softer looking on an HD display. Mostly because you do not have the interlaced field order to hide detail in.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Chicago, IL

[Sean Oneil]

[gary adcock] “While running the “deinterlace” filter may pass in the SD world- in HDTV the converted footage would be very, very noticeable when placed in between other non converted footage, showing as much as 50-60% softer looking on an HD display. Mostly because you do not have the interlaced field order to hide detail in.”

Gary, I’m a bit confused. What do yo mean “you do not have the interlaced field order to hide detail in”. Could you elaborate on that a bit? It didn’t make sense to me.

All I know is that I’ve had 100% success doing this with HDV footage. It only works if the footage was shot at 30fps 60i. The reason is because this type of footage does not contain any pulldown pattern. A simple weave deinterlace will combine the fields back together perfectly and create a flawless 30p video image. No more fields, and no redundant frames. Thus, you are able to scale it, change the framerate – do whatever you want to it using simple tools (such as rendering it in a FCP sequence that has different settings). And the results are pristine.

What I was saying though is that this will not work if the footage was shot at 60i using a 24fps framerate – because a pulldown pattern is added to the video to achieve this. If this is the case, one has to first remove the pulldown using more complex tools (Cinema Tools, Natress, etc.) before scaling it or changing the framerate.

[Gary Adcock]

Sean

The original post was talking about footage shot 1080i60 and trying to load that into project timeline where most of the footage was shot as 720p24 from the HVX200.

The process of converting 60i footage to 24p is not easy or simple. The internal tools offer by most NLE’s are not sufficient to produce a “broadcast” quality conversion. Thats why hardware devices like Terranex, Ukon and others are created.
3rd Party software companies ( Nattress- Agolith) can produce quality results because the plugins rely on sheer CPU power to handle this content. The de-interlace filter in FCP (like most NLE’s) is really designed to handle still frame and motion conversions- not really raw video.

[Sean ONeil] “All I know is that I’ve had 100% success doing this with HDV footage. It only works if the footage was shot at 30fps 60i. The reason is because this type of footage does not contain any pulldown pattern”

But Sean if there is a pulldown the footage is already 24 frame and software like Cinema Tools and DVfilm can be used to extract the non dupe frames– applying a 60-24 frame conversion on content that is already 24 looks horrible.
FCP does not support native (captured over FW) 24p content in HDV today.

Please also tell me you are watching that HDV footage on a real HD monitor that can handle either HDSDI or Component HD signal — and both progressive and interlaced footage properly – Not a computer monitor, not digital preview in FCP, not on NTSC a real HD display.
In your workflow the footage would fall apart when inserted into the “correctly” shot 720p footarge

The last thing to note here- as an HDV shooter – The HVX200 does not interpolate between frames using Long GOP mpeg- every frame is compressed without regard to the surrounding frames – The exact opposite of your HDV camera, and because of that you are accustom to seeing the smearing that naturally comes from the Long GOP process ( where 2 frames out of every 30 contain around 50-60% of the information for all of the content in those 30 frames — so the other 28 frames a second, take up the rest of the info – or less than 2% of the total amount of compression is used for each of the remaining frames – resulting in a loss of detail.

In the case of the HVX200 every frame has 100% of the information contained in every single frame.
Which one is going to look better, the HDV frame that only has 2% of the total information or the HVX’s frame that has 100% of the information.

my 2cents.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows
Chicago, IL

[Sean Oneil]

??? I replied to this a few days ago and it’s gone.

Anyways, I think you’re just misunderstanding me. When the camera is set to 30fps (which Daryl could very well have used), there is no pulldown added. 60i, with every 2 fields making up a frame. So it only requires a simple deinterlace filter to make this kind of footage progressive-scan. At that point, you can scale it and lower the frame-rate using simple tools (FCP) without any side-effects.

But when you have 60i footage shot at 24fps (3:2 pulldown added), then of course a simple deinterlace filter will not work. As you and I both said, you need a Teranex in this case (or a lot of time and patience w/ Cinema Tools).

Both the HDX200 and the Z1U record 1080 60i but can be set to use a framerate of either 30fps or 24fps. So the the same concept applies for either camera. The fact that DVCProHD is far superior to HDV doesn’t have anything to do with this particular situation. In fact, 90% of what we shoot is on 720 Varicam, but a lot of B-roll is shot on 1080 HDV. This is how I figured out this workflow, and it does work.

And yes, I use a HD CRT monitor connected via component to a Blackmagic Multibridge (which is connected via HD-SDI to the Mac).

So again, if Daryl shot it at 30fps, all he has to do is throw a deinterlace filter on the clip, choose the right setting, and then place the clip on a 24fps 720p timeline and render. It works great with FCP 5.1. It does not “fall apart”. If you ‘d like to stop by I’d be happy to prove it to you.

Sean