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Topics - TKez

#1
Raw Video / Recording Raw on a DJI Gimbal
March 10, 2024, 10:28:09 PM
It seems whenever anything is plugged into the mini USB camera control port, raw recording throws a bunch or errors on the screen and the files are corrupt.

Are there any workarounds for this?

Such a shame not not be able to record raw on a gimbal.
#2
Recently I shot a bunch of stuff with some lights, and exposed both by 'eyeballing' the LCD and checking the histogram.
Bringing MLVs into MLVApp, everything looks really blown out. Highlights are obliterated.
Exporting as cDNG, I started to freak a bit when I realised I couldn't even recover the highlights in Resolve.

Back in MLVApp I discovered If I set the White Level to maximum, it looks roughly as it did on the LCD when shooting. I could rest a bit easier.
I've seen mention of these levels come up on the forum, but before switching from MLVFS to MLVApp, I've never had access to them, not had any need to.

So then,

A. How are these values set?
B. What should I investage if they are wrong? The camera? The ML version in use? or the software doing the conversion?
C. Is there anything wrong with selecting all the MLVs I just shot, and setting all their White Levels to maximum to try salvage my footage?

Sorry if this information exists somewhere on the forum, but I can't find it.

White Level according to MLVApp is set to 6000, but nothing looks even close to correct unless its set to somewhere in the 12,000 - 16,000 range.


EDIT: I can see now in some other posts that white level should be 16200 or even max 16383 for 5D Mk3. So why would it be set to 6000 in my files?


#3
I've been overjoyed at the performance of my 70D raw recording capabilities with the newest experimental branches.
With 11bit lossless I can record continuous RAW now at near-enough-to-HD rez, and that's been a game changer.

But the thorn in the side on 70D is the moire, it constantly ruins good shots when color grading and I decided it's time to say goodbye to moire and get a 5D mk iii.

All is well and good except when I tested the SD card for RAW. With the same settings as continuous on 70D, I can get max 6 seconds on the 5D.
Where I live, a Sandisk Extreme CF card is exactly 4x price of a Sandisk Extreme SD for the same size. They're also about 6x the price of an SSD that are used in other cameras.
I realise this is economies of scale at play, but my question is....

If the 70D can do it, why not the 5D mk iii?

Can the 70D sd slot really be faster than then 5D mk iii SD slot?
#4
I shot some stuff the other day for a project using a Blackmagic Cinema Camera and a 70D for the second cam.
My well thought out plan was that If I brought the 70D Raw footage into Resolve , set the colourspace to BMDFilm and set the white balance to the same as the BMCC camera was set to, the shots should match.
But even with the exposure tweaked to match, the color and tonality is very different.
When I cut the footage from the 2 cams together and drop a BMD Film > Rec709 LUT over the sequence, the shots from the Canon look more contrasty and saturated than the BMCC footage.
The BMCC footage also seems to have a pretty strong green cast compared to the Canon

Has anyone had experience matching footage like this?
Is there a recommended workflow for this or just a matter of matching things manually?

Thanks in advance
#5
Feature is there for standard video recording, but can't seem to do it for RAW.

On the cameras with limited SD bandwidth, in my use case I'm often just reading to continually restart, gaps aren't that important.

Any way? LUA maybe?
#6
Testing different ways to deal with Moire and being that blurring and upsampling are visually similar, am I giving up one of the reasons for shooting raw in the first place (444, I know the bit depth is still there).

#7
As I understand it, for cameras that can record Log natively, it can provide most of the dynamic range benefits or RAW, whilst keeping the convenience of single file clips and space conservation of [barely] compressed formats like Prores. (From here on in 'Prores' is interchangeable with your intermediate codec of choice)

But being that ML users must shoot RAW to get these benefits, by the time we get MLVs into a usable format, we've already had to deal with (to varying degrees deepening on model) space/time/res limitations and extra workflow steps involved with shooting RAW. So as we're not really able to cash in on a lot of the conveniences that a true cam->NLE log workflow provides, I'm interested to know why the people that are using things like VisionLog / Cinelog-C in their workflows choose to do so.

I assume some people would like to go Log-Prores to keep dynamic range available whilst maintaining the playback/scrub speed of Prores in NLEs like FCP.
If so do you....?

1. Drop a Log->Rec709 LUT on your Log clips (or output/timeline) by default so you're viewing as Rec.709, and do cc/grading before the LUT in the chain?
   This would obviously have the benefit of allowing clipped areas to be recovered if needed, but should otherwise look like the Log step never happened. Other than that, is there also a specific benefit to applying color correction while in the Log colourspace as opposed to filming 'flat' (contrast/saturation reduced) Rec709? Another way to say this is: If I'm displaying Log footage through a Rec.709 LUT, but adjusting curves before that LUT, the function curve is affecting a very different set of values than if it were after the LUT. Do people use this to advantage? What the theory?

2. Drop a "Film Look" type LUT on the log footage that has the Log->Rec709 transfer built in?
   Since I've been playing with Log and thinking about it, this should effectively give the LUT access to values that lie outside the range of rec.709 and presumably the opportunity to map those values into more a pleasing highlight rolloff. In testing though I can't say such a subltle difference justifies the extra steps and CPU load.

3. Begin grading directly from the Log footage, working contrast and saturation back in manually?
I hear a lot that log is just an intermediate step for maintaining DR, and not intended for output. But I swear a lot of new TV series with flat look resemble Log footage with the blacks pulled down and some sat in the mids. Is this the case or am I just misinterpreting a stylistically flat, but not necessarily log grade.
#8
Decided to start another thread as the forum suggested it, but it's really an extension of this thread.

http://www.magiclantern.fm/forum/index.php?topic=8389.0

Appologies If someone's gone here already but I couldn't find it.

Anyhow I couldn't come to a conclusion about what Prores format suits best, and it seems opinions vary.
Do we use 422 and not care about chroma resolution loss as the difference with be negligible?
Or keep all the data and use 4444, possibly wasting space as we don't need alpha?

Well I did a test by bringing in a DNG sequence into AE and using 'Set Matte' to create some alpha.

RGBA -> Prores 4444 = 140.2MB
RGB -> Prores 4444 = 78.4MB     
RGB -> Prores 422(HQ) = 66.1MB 
RGB -> Prores 422 = 49.4MB

RGB-4444 %55 the size of the RGBA, but RGB-4444 is only %18 larger than it's RGB-422HQ counterpart.

So my conclusion is. the lossless compression of the alpha channel is not wasting space.
May as well be safe and use 4444 as the size difference is only marginal over HQ.





#9
Just wanted to share the little headphone amp I wired up.
Cheap, portable, easy to solder, and decent quality components so it sounds great.

What you need:

1.$10  http://www.ebay.com.au/itm/2-X-150-mW-Class-AB-Headphone-Amplifier-Board-LM4881-150mW-Stereo-HP-Amp-/121155320773?pt=AU_Bedroom_Furniture&hash=item1c356b7bc5
2. 9V battery clip (a few cents)
3. Canon AV cable.
4. Suitable enclosure of your choice. Sweets tins are good.

I had a spare AV cable so I chose to butcher it and keep it simple but you could easily wire up RCA sockets. I also chose not to use terminal blocks but they're probably a good idea.

There's only a dip switch for low and high gain but I've found the default setting to be the perfect level as is.
You could easily attenuate the input with a pot but I find the ML headphone volume control is enough (devs: a couple a negative gain options might be handy)




Now just need a on/off switch and suitable pocket sized case that could be optionally velcro'd to the tripod.

Specs are not bad either.

Size:76.2 mm (L) x 50.8 mm (W) x 12.1 mm(H) ± 0.2mm
Thermal shutdown protection circuitry
Adjustable gain
Wide power supply range: 8V-24V
Audiophile Quality Sound:
0.025% THD+N @120mWrms 16Ω
0.02% THD+N @75mWrms 32Ω







#10
I realise that DNG is the best way to go for MLV but for the scope of what I'd like to do, the 1000s of files and disk space is overkill.

I really just want as much sensor info as possible, squeezed into a tidy Prores4444 file that is easy to work with, doesn't suffer the drawbacks of H.264 compression, and allows me some extra headroom for compressing highlights in a more aesthetically pleasing way.

I also realise that full manual grading is the ultimate, but for my needs, I'd like to start with some film stock emulation LUTs in Resolve and tweak from there.
I'd like to be able to use the Resolve film emulation, and/or the ones found here http://juanmelara.com.au/print-film-emulation-luts-for-download/

Does anyone have any recommendations for the best way to do this with regard to tone mapping / log gamma etc?

There seems to be a lot of options between exporting from MLRawViewer and input and output LUTs in Resolve, and the naming convention doesn't seem universal.

Some examples:
MLRawview -> Prores Linear -> Resolve -> input LUT 'Linear to DCI' - > output LUT 'DCI-P3 Kodak2383'
MLRawview -> Prores rec709 -> Resolve -> input LUT 'none' - > output LUT 'Rec709 Kodak2383'

Now the LUTs linked above say the only requirement is that the input be in 'LOG' format, but there are so many LOGs!

Eg.
MLRawview -> Prores Log -> Resolve -> input LUT 'none' - > output LUT 'LC3DL_Kodak 2383' ... the gamma is way too high, so 'log' from MLRawView is obviously not the Log he is talking about (by the screenshots I think its from RED).

If I instead use his input LUT (Video2Log_HR_150) like this, 

MLRawview -> Prores sRGB -> Resolve -> input LUT 'Video2Log_HR_150' - > output LUT 'LC3DL_Kodak 2383 ...

...the gamma looks about right, but going through LUT transfers 3 times doesn't seem very purist :)

To try and understand conventions better, how do the curves relate?

MLRawViewer has things like, Log, HDR, sLog, sLog2, C.Log, Log.C etc
Resolve has things like DCI, 'Canon Log', Cineon etc.

There's also the visionLog LUT which seems like it would be a good choice to squeeze MLV into prores, but how does that fit into the workflow via MLRawViewer and Resolve?

Anyone gone down this path already with some insight?