4:4:4 12-bit Uncompressed DVX100

[Thomas Smet]

Combustion 3 from Discreet could be a good editor to use if you are into visual effects work or just high end color control. Combustion 3 has a basic editor built in while supporting uncompressed files in a 16 bit color space. This will allow you to do some really high quality color correction and compositing effects while also editing your project. There are two codecs out there that I know of right now that will allow 16 bit quicktime files to be created. You could convert your captured tiff sequences along with audio tracks to one of these codecs. You could then have full FX, editing, and audio inside of Combustion 3. You can also just load the Tiff sequences into Combustion 3 if you would like. I am not sure if Combustion 3 will load EDL files. Does anybody know if this works? If it does load EDL files or another type of editing project file then you could edit your dv version of the video in any program and export a edl file. The edl file could then load your actual raw tiff video into Combustion 3 once the editing is done for color timing/correction and effects work.

[John Alton Disciple]

Can we get a video file sample so we can test which editors are best suited for editing, correction, speed, ability to accuruately monitor the image, etc?

Thanks.

[Aaron Shaw]

Yes that would be a good idea. I use After Effects with the Color Finess plugin (well its now built in - vs 6.5) and would hate to pay for combustion too.

based off what i know about juan's mod, it seems like there is a very simple and relatively user-friendly solution to the editing/finishing paradigm...

edit offline (in 23.98 fps) using the 24pa, 4:1:1, 25Mbps footage that is laid to tape. this of course will be hassle-free, as long as you use a slate or something for synching later on. then once you have picture lock, you take note of the used takes/shots. locate those tiff sequences and load them into 16-bit software, such as aftereffects or combustion. batch render them out to 23.98 fps movies, using a 16-bit lossless codec.

import those new 16-bit movies into your same FCP/avid project. don't worry that the image size is bigger than 720x480. then manually synch them up to their DV shot equivalent. this labor of synching is going to be necessary if you intend to use the camera audio, anyway (or you could greatly simplify and quicken the whole synching process by making sure to capture your DV tape clips with the frame of the slate making visual contact as your first frame, then when you import the tiff sequences into AE/combustion, just trim the clips so that this is the first frame of the rendered 16-bit clips, then open your FCP/avid project and simply reconnect/replace the DV clips in the timeline to the new 16-bit movies).

then from FCP/avid, you would create an EDL (using automatic duck if you're using FCP) to port the complete edit into aftereffects or combustion. open it up and your final edit is neatly laid out for you, with each individual trimmed shot as its own layer, ready for color grading.

trying to edit the actual 16-bit footage is going to either require one helluva expensive workstation for realtime playback, or significantly hinder your ability to edit creatively and quickly. editing offline-to-online is a lot less headachey than it used to be.

hope this helps,
jaan

[John Alton Disciple]

Juan,

Since most of the comments on how to edit the footage (and they make sense) is to edit the dv footage and then sync up the uncompressed files, would it not make sense to have a timecode-in hookup on the mod for SMPTE timecode? For film out use, it's pretty normal to record tracks of audio on another device that's receiving the same time code as the camera (sourced from a timecode transmitter) and then match the timecodes in post when you're onlining the production. Would this add too much to the cost of the mod?

[Juan P. Pertierra]

Well, i still have a but of confusion as to what the difficulty in synching the video to the audio is...i've done it several times and it works pretty much as it does with film, but easier, because the audio is linked to the DV video.

I've shot both DV and RAW at the same time, the only thing needed is some reference to synch up two frames. Remember that you get 24fps in both RAW and DV, so once they are both aligned, you are done. The DV video has the audio also, so as long as you remember to move the entire DV footage(with audio) in your software, you'll be fine.

I've been using something pretty dumb, a stopwatch. I just start it up, and move it across the screen. This allows for a large margin of error and it makes it extremely easy to find two corresponding frames.

Another thing I should note, is that I have actually edited RAW uncompressed video using just the TIFF frames in FCP on my 1.33Ghz powerbook, and it works fine. The sequence was only over a minute long, but it worked just fine. I wouldn't be surprised if on a fast system such as a dual G5, you could get away with not even using DV footage at all.

For color correction you can use anything...in fact, i'm no photoshop genius but I bet that once you figure out the corrections for one section of frames, you could use some batch/script in photoshop to process the rest of the files.

On the pixel shift:
~~~~~~~~~~~
I'm still trying to figure out how to take advantage of this. I have confirmed that the green CCD is indeed shifted slightly along the Z axis such that it captures detail which lies in between pixels on the R and B channels.

The problem is that since only the green channel is shifted, the result is not a complete mosaic, but rather a pattern in which R and B coincide, there is solo G information for other pixels, and then there are locations where there is no actual information.

Now, i'm sure there's a way of de-mosaicing this somehow, i just haven't figured it out...shifting the green CCD seems to be common practice, anyone have any ideas?

Juan

regarding green pixel shift... juan i have some ideas that might be a possible solution to the green shift, though it'll be a lot easier to spend five minutes trying it, instead of fifteen minutes trying to type out specific instructions. it also uses some software and plugins that you may not already own. can you post a recent frame?

[Juan M. M. Fiebelkorn]

Well, in fact that Green CCD pixel shift has a clear explanation:
That is because every color column of a 4:2:2 image is placed between two columns of green.
So instead or doing (R1+R2)/2 and a (B1+B2)/2 you just shift the green CCD half pixel and you are ready.
So take note that it won't be exactly the same situation as a Bayer mosaic.
Anyway that doesn't avoid we can use it to increase resolution a little....


If you want, send me a couple of images (TIF or RAW format if more than 8 bit 16 bit per pixel) and a clear description of relative spatial position of pixels and/or the mosaic pattern it gives and I'll see what I can do....I guess I have an idea and a working demosaic that could just needs to be tweaked for that special case...

morsa a t morsa d o t net d o t ar

[Juan P. Pertierra]

The whole thing(including my DVX ;) ) is torn apart right now so I am going to re-run some of the raw files I have and upload a PSD file without any resizing.

BTW, i'm also looking for a second DVX100 so we can install the device on it and lend it for demo. If anyone has an old standard DVX100 lying around and want to sell it, let me know. It doesn't matter how banged up it is. :)

Juan

[Anders Holck Petersen]

<<<-- Originally posted by Juan P. Pertierra : Well, i still have a but of confusion as to what the difficulty in synching the video to the audio is...i've done it several times and it works pretty much as it does with film, but easier, because the audio is linked to the DV video.>>>

Would it be possible to grab the DV timecode from the Firewire connector and embed it into the current filename? Don't know if the DVX outputs timecode when in cameramode but some cameras do. Should be a walk in the park to de-embed it from the DV stream right :)

[Juan P. Pertierra]

It's not hard to do, IF you have DV connected over firewire. however, what i've been doing is recording RAW to the computer and DV at the same time to regular tape. In this case, the timecode is on the tape itself, so the computer cannot really synch the RAW to the DV timecode. Maybe the computer could handle the DV stream on firewire and the RAW stream on USB2.0, but i think that's pushing it.

Since the DV tape is transfered later, the computer has no reference to synch the RAW with the DV footage, unless the use steps in and does it.

Another option would be to have a piece of software somehow compare the first RAW frame to the DV footage, and figure out which two frames are equal. Statistically this can be done but it might take a while, doing it in an efficient manner might be trickier. Synching the RAW footage to the DV footage is not hard at all and takes about 10 seconds at the most, i don't think it's a big deal.

Juan

[Anders Holck Petersen]

Ok, that's right you would have to process the entire DV stream in order to obtain the timecode information.

Too bad the DVX does not have a TC Lcd as the PD100 had, could be easy to intercept the driver bus.

BTW. How do you start/stop the recording? Have you thought about using the tally light as a start stop for the computer RAW capture?

[Juan P. Pertierra]

For those of you asking for an un-resized raw image for the shift de-mosaiqing: I ran an old file through the software again...i think this was shot with the anamorphic adapter at 10-bit RGB.

It is a PSD file with three layers, R,G,B and there is no color correction whatsoever, the only thing I did was flip the blue channel horizontally and nudge the layers so they are more or less aligned.

Please note like I said before, that the Red and Blue layers seem to line up perfectly while the green channel is one pixel wider and taller, and seems to capture detail in between R/B pixel elements.

http://expert.cc.purdue.edu/~pertierr/shift_work.psd

Juan,

Quick question, off topic a bit. Is it possible to adjust the minimal gain on the DVX's chips? Some say that the gain is to high on the DVX's even at 0db, would it be possible to change that 0db to like a -3db or -6db? Would the camera then be able to acheive less noisy images even though an increase in light would be necessary during shooting? Thanks.

[Brett Erskine]

Juan will your system ALSO have some of the great features found in traditional HDR like:

10 sec prerecorded RAM video for antishock and so you never miss a shot?

Firewire option for situation when you want to use it like a traditional HDR and just hook it up to any DV camera thru firewire and record the standard compressed DV stream?

If so your product will serve double duty and open yourself up to a much wider market.