View Full Version : 4K/50i? 4K/60i
Tom Lowe
07-10-2007, 08:23 PM
I can't remember seeing anything about interlaced shooting. Sorry if this thread is redundant.
Just wondering: Could the RED possibly shoot 4k/50i or 60i to onboard media, so those of us who want to overcrank shots could then de-interlace the footage and slow it down in post?
Would this work? Is it even viable?
Jeff Kilgroe
07-10-2007, 08:28 PM
I don't think it's possible. The sensor is progressive scanning, so if you wanted 60i, it would still have to operate the full sensor area at 60Hz and deal with that data in-camera. It would seem to me that you would have to do an in-camera vertical down-rez and compress on each frame and alternate tossing even lines vs. odd lines every frame. Then let the codec reconstruct each condensed 4096x1150 frame into even or odd fields of a 4096x2300 frame. Not sure what we would be gaining there, except possibly smoother motion at the expense of resolution.
Graeme Nattress
07-10-2007, 09:53 PM
Interlace is inherently evil :-)
Poi Boy
07-10-2007, 10:17 PM
good answer !
-A
Tom Lowe
07-10-2007, 11:21 PM
Interlace is inherently evil :-)
Okay, Mr Smartypants, how else can we get 4K overcranked on board? :)
Justin Anderson
07-11-2007, 12:20 AM
Okay, Mr Smartypants, how else can we get 4K overcranked on board? :)
Send Graeme a check for $10000 and you may or may not get an answer.
Noah Kadner
07-11-2007, 12:36 AM
Send Graeme a check for $10000 and you may or may not get an answer.
Um no- send the $10K to me. Graeme's too busy to answer easy questions. Hint- your answer is here:
http://www.red.com/formatoptions.shtml
Noah
Jeremy Hughes
07-11-2007, 05:44 AM
I see what you mean, Tom. I think a 4:3 aspect ratio for 4K would be better. Then you could put an anamorphic lens onto it.
What resolution would be equivelent to open gate 35mm anyway?
laguun
07-11-2007, 06:19 AM
Interlace is inherently evil :-)
isnīt it:
evil
more evil
interlace
interlace df?
however
most of the world broadcast the huge mayority in interlace.
however, -all- interlace formats are at maximum 1080p.
so, with red, shoot fullres P - from there you can easily go to interlace in a much higher quality. the workflow is slower, however, without i.
Okay, Mr Smartypants, how else can we get 4K overcranked on board? :)
I'd like to get the answer to that one too!
From what I understand on the website, you simply cannot get 60fps @4K recorded on an onboard media.
But why is that exactly? Is it only because 4K@60fps would be too much datarate or is there something about that being too much processing to actually create the redcode raw ?
I wish 4K@60fps would become available with some future fast enough CF cards... Is it an option?
To put it simply: Where is the limitation?
And also: Why couldn't you record 120FPS in 720p using 35mm when you can do it when using 16mm ??? (that's also what I get from the format options board)
Jeff Kilgroe
07-11-2007, 06:48 AM
4K @ 60fps is too much for the internal processors to handle. It has nothing to do with the recording media, the camera simply can't process that much data onboard... for now.
You can't shoot 120fps using the 35mm sensor size because the sensor can't scan the full surface area at 120Hz. It can only do the s16mm sensor area at the full 120Hz. Once again that's too much data to handle internally by the onboard processors, but it can cope with a down-rez and encode to RGB. So we should be able to get 720p 4:4:4 RGB at 120fps onboard. We should be able to get 720p and 1080p @ 60fps from the s35mm sensor area at 4:4:4 RGB onboard. ...Once all those RGB functions are enabled.
Graeme Nattress
07-11-2007, 07:01 AM
Think of interlace as a form of compression. It compresses, say, traditionally 60p into 60i or 50p into 50i. However, for long enough, it was never properly decompressed, the CRT display using phosphor decay coupled to your persistance of vision (and heavy interlace filtering to avoid twitter) to make it work.
Would you, in modern times, use a compression system, ie interlace, where the decode side of the problem, ie, decompression, is a problem that is yet to be properly solved. Extracting 60p back out of 60i is not easy, slow (and I'd hate to see how slow on 4k) and never quite works right anway. Everyone has their own methods of getting the progressive signal back out through de-interlacing, but there are as many methods as there are engineers, and they range from quick and dirty through to slow and nice, but even the "nice" have problems when the optical flow systems lead to bubbling or boiling of edges under certain circumstances.
Stephen Webb
07-11-2007, 07:06 AM
Going off on a tangent (sorry to hijack the thread) but if the camera can do 4K@60p, why only 2K@120p? Is that just a limit of how fast the data can be read off the sensor?
4K @ 60fps is too much for the internal processors to handle. It has nothing to do with the recording media, the camera simply can't process that much data onboard... for now.
For now? Does that mean that this could become possible in the near future?
And then, if it became possible, would we have any storage option fast enough to record it? Because that would make about 2*27=52MB datarate to record... Are there any CF cards fast enough for that, for exemple?
Otherwise...
It's true that I use a lot the interlaced mode on the HVX200 to make slow mo out of it... But with interlaced, you get half the definition which, in many case was ok enough... Here, with the red, my only option would be to shoot 1080p for those slow-mo shots, but then that's 1/4 of the definition which will become much more noticeable I think.
Tom Lowe
07-11-2007, 08:48 AM
CK, I believe it has been stated that the processor onboard the RED can possibly be upgraded in the future to allow for higher 4K REDCODE RAW framerates. With the brisk pace of processor speed enhancements, this gives me hope.
So if interlaced video is half the res of 4K, that's still a lot more resolution than 1080RGB, right? Because 1080RGB is what most of us are going to be forced to shoot for overcranking.
JasonAvalos
07-11-2007, 09:25 AM
So there is no way to under/over crank in the 4k or 2k format? i am confused.
CK, I believe it has been stated that the processor onboard the RED can possibly be upgraded in the future to allow for higher 4K REDCODE RAW framerates. With the brisk pace of processor speed enhancements, this gives me hope.
I ordered mine about a week ago. Does anybody here thinks there's a chance I could get one of the hypothetic newer processors by the time I get it (some time in 2008)?
So if interlaced video is half the res of 4K, that's still a lot more resolution than 1080RGB, right? Because 1080RGB is what most of us are going to be forced to shoot for overcranking.
That's right.
But interlaced video is already an old story I guess...