4:4:4 12-bit Uncompressed DVX100

[Thomas Smet]

I know this isn't related to the dvx100a but going back to the XL2. Even if we can only get 960 x 480 with a mod that is a 2:1 aspect ratio. If we want a 2.35:1 cinematic aspect ratio we now would only need to crop 72 pixels from the resolution. That would be 36 from the top and 36 from the bottom. This gives us 960 x 408 or a 2.35 x 1 aspect ratio. This would be great if we plan on going to film with that type of aspect ratio because we keep most of the resolution without cropping to 720 x 272 like we would with regular 4x3 DV.

[Nick Hiltgen]

Thomas I get the idea of what you're saying but I think there might be a slight problem with your math, er... your formula.

I think that the pixels are not exactly 1x1 but 1x.9 which means that when you shoot in 4:3 mode you're shooting in 480x720 which gives an effective resolution of 480x (720x.9) or 480 x 648 (approx. 640) which reduces way the heck down to 4x3 (or 4:3)

Now, do the same math with 480x960 you get 480x(960x.9) or 480x864 which is 1X 1.8 which is almost 16x9 (16x9 being 480x853 which is 1x 1.77)

So in order to get cinema scope (1x2.35) or cinema flat (1x1.85) you'd have to remove 112 pixels from the top (864/2.35= 368 and 480-368=112) for scope and 13 pixels for cinema flat (864/1.85=467 and 480-467=13)

That being said it's still interesting because the dv format can't hold anymore then 720x480 (or 648x480) so in order for the xl2 to record it on to minidv tape then there must be some sort of algorithm that compresses the footage on to the tape and effectively (we hope) perserves the total image quality. However, if someone were to capture the entire CCD image (or at least the ones that are firing in the xl2's case) without using ANY compression or algorithms, they would be super duper cool, and would hopefully finish up with this silly dvx100 business and get onto working on one for the xl2, before everyone decides to go HDV and we need a RAID array to capture uncompressed information off the chips.

I hope that wasn't too technical, and more so I hope that my math was right, if anyone else want's to correct me please do.

[Frank Roberts]

I'll correct you. The business with the DVX100 isn't silly. He's working his tail off and a lot of us appreciate it. I don't own an XL2.

[Nick Hiltgen]

Frank is right, it's not silly, just an attempt at humor, I'd venture to say that there are VERY few of us that own an XL2 right now as well.

[Frank Roberts]

Sorry, I think I overreacted. You know what's crazy, it's funny how sometimes we all get so overwhelmed that we can't even sense when someone is just trying to be humorous. Nick, keep up the humor bro, its me who should be corrected. Best- Frank

[Thomas Smet]

going down to 368 is still much better than going down to 272. Also the 864 rez from the XL2 would be pure pixels and not stretched from an anamorphic 720x480 so it would look much better when blown up. If you have a 720x480 image that is anamorphic and correct it your 864x480 image is interpolated. Even though it looks good a raw 864x480 image would still look better.

[Nick Hiltgen]

Thomas, yeah, I agree it's still better then the previous option and a raw image would definitely be better. I wonder if another option might be to use a P+S technic with anamorphic lenses, and then expand it further in post?

[Juan P. Pertierra]

It seems like there might be different versions of this device, with SDI/DVI, etc.

As far as the editing goes, the best way is to just treat it like film. Use the DV footage for editing, and create an EDL which renders the final product using the RAW frames. The RAW frames can be color corrected in your favorite program.

Juan

[Thomas Smet]

Or once everything is captured you could render the raw frames and the audio track into one of the 16 bit video codecs that were discussed on this forum and then you would have a video file of raw frames and audio to work with. If you use the microcosm codec for this purpose you could even get lossless compression to save some space. Once you convert everything you could then delete the raw frames and the dv video and save a lot space.

[Nick Hiltgen]

Juan, does that mean you'll be including a SMPTE time code, for the EDL's?

[Phil Rhodes]

Hi,

Signed up specifically to ask this question - from the way you're doing this modification, the timecode data isn't readily available to you. However, it's pretty much an absolute requirement to be able to work with this stuff in postproduction. The simplest and most generic way to do it would be to insert the timecode into the filename of each frame as a frame count; this is the way film scanners tend to do it. This way you could roll tape in the camera as well and use that as your offline. This would save a lot of messing about processing offline versions of the 12-bit data.

Also, I don't get the purpose of SDI. You want to modify a 3K camera so it needs a deck costing 15 to record? Hard disk and DVI for monitoring if possible would be fine by me.

Phil

[Luis Caffesse]

"Also, I don't get the purpose of SDI. You want to modify a 3K camera so it needs a deck costing 15 to record? Hard disk and DVI for monitoring if possible would be fine by me."


The purpose for SDI is ease of use for many people.

SDI is an industry standard. Also, it allows for the use of a deck
which is an advantage for some who feel more comfortable
with their footage on a tape than on a hard drive.

Secondly, a deck is not necessary, as many capture cards are
available that utilize SDI. Blackmagic Design makes an SDI
capture card for under three hunderd dollars.

Lastly, SDI allows for the easy capture of uncompressed 10 bit
4:2:2 video footage as opposed to 4:4:4 RAW frames. It would
be easier to work with, and would take up much less space.
This would make it much more feasible for long form projects,
like feature work.


Either way, from what Juan has said, it is not a zero sum game.
There is no reason we can't have SDI as well as the other
ptions. So, there is no reason to use the option, but it would
be great to have the option.

-Luis

PS.
The cheapest Digibeta camera on B&H costs 44K.
So I think it's worth modifying a 3k camera to get the
image of a 44K camera.

[Ben Syverson]

Secondly, a deck is not necessary, as many capture cards are
available that utilize SDI.

Great, just what we need, an interface that requires an expensive capture card. How do you expect to capture in the field? Please, Gigabit Ethernet or Firewire 800. They're built-in to many computers these days and easy/cheap to add to older computers.

- ben

[Luis Caffesse]

"Great, just what we need, an interface that requires an expensive capture card"


Again, it is an interface that allows you to use industry standards if you choose to. Many people already have equipment with SDI.

And, once again, it is an option that you do not have to use.

I don't think anyone has suggested that SDI should replace the use of FW800 or anything else.

Much like the silly 'film grain' function included on the new XL2, don't use it if you don't like it.

-Luis

[Phil Rhodes]

Hi,

> SDI is an industry standard.

Yes, I'm aware, I use it weekly.

> Secondly, a deck is not necessary, as many capture cards are
> available that utilize SDI. Blackmagic Design makes an SDI
> capture card for under three hunderd dollars.

Hang on. You want to overlook the drive on the camera and lug an entire computer around with you, to record the image data on its.... hard drive?

> The cheapest Digibeta camera on B&H costs 44K.
> So I think it's worth modifying a 3k camera to get the
> image of a 44K camera.

Yaright, okay, you're one of those people! I really don't have time to list the differences between the DVX-100 and the DVW-790, but suffice to say that no matter what you do to a DVX-100, it will never be a 790.

Phil