LOG or Rec.709 for VFX Assets

Currently, ActionVFX delivers files mostly in Rec.709/BT.1886. But, we have had some people ask why we don’t deliver in the native LOG such as the Log3G10/REDWideGammaRGB from RED. One reason we haven’t delivered in LOG is because of ease of use that comes with Rec.709. For most people, LOG requires at least one extra step of either using a LUT or an input transform when bringing assets into a project.

I’m curious to hear what your preference is! Would you prefer the ease of use and simplicity that comes with Rec.709 or would you prefer the extra capabilities of LOG such as better integration into HDR projects and being able to choose your own Highlight Rolloff and Contrast with the LUTs that RED provides?

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Personally I feel Rec.709 is fine for like 99% or use cases. I’ve never had an issue pulling the needed dynamic range from the elements in comp and feel that Rec.709 is perfectly fine.

I could see the appeal of Log/linear files for things where the dynamic range is important (fire, muzzles etc) but then as long as nothing is clipping in the Rec.709 file it really shouldn’t be an issue In my opinion. I haven’t had to do any specifically HDR work yet so maybe for other use cases it will vary but for Film/TV its never been a problem for me! :grinning:

p.s. I feel like providing these would have an astronomical effect on filesize and download time haha!

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Thanks Will! Glad to hear your thoughts on this. What software do you work in most often? I’m curious how you think working with LOG assets would affect your ability to work fast. Wild there be extra steps that would slow you down or would it be a simple process for you?

As far as file size, if we were to deliver LOG files, it most likely would not be in conjunction with Rec.709 but would be in place of it so the files should be the same size. Does this change your thoughts any on which you would prefer?

Im a Nuke Compositor Zac, and my main thought was just that the rec.709 is a default colourspace in almost all softwares Ive used. While things like REDWideGammaRGB are options in nuke I believe (dont quote me here this is off the top of my head) that it would require the nukeproject to be set in a different colour space. It may only save a couple of seconds but having in Rec.709 from my point of view could save some potential headaches!

Also the filesize thing was just an afterthought and if it would be no real difference to the Rec.709 in filesize theres no issue! :slight_smile:

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I understand. Thank you for sharing some more details on that!

For major feature films using rec709 isn’t a very good choice for storing VFX assets.
With rec709 you limit yourself in the color range right from the beginning. Especially for fire, muzzle flashes etc.

VFX studios will most of the times convert every downloaded asset into a linear EXR sequence anyways and most of the recent projects will use ACES workflow.
As a VFX studio a good choice is linear EXR with ACEScg since that matches most of the pipeline when integration CG elements.

Providing the RAW source data (log) or linearized format, would be the best fit for the clients.

I mean the obvious solution would be to offer both, but I understand that’s file space on your servers.

The way I see it, you have two segments of client base, which I will (slightly incorrectly) parse as “Studio” and “Indie.”

“Studio” users are preparing work for television/film work and are the most likely to be using high end cinema cameras, shoot RAW, and really need the grading flexibility of LOG footage. These are your working artists who have to get the look right as their job. (I used to be in this group)

“Indie” users are, of course, everyone else. The vlogger/hobbiest/group of aspiring friends making films for fun. There’s usually no money involved and include the people who think it’s ridiculous that their VFX heavy, 5 minute short might take a few hours to render. This group, in general, is very interested in working fast, because no money is involved and they want to finish so they can go catch up on Netflix.(No insult intended, I’m in this group)

Studio guys absolutely want LOG most of the time. Indies will want REC. 709 most of the time, and many (most) aren’t familiar with LOG and might wonder why everything is so flat looking?

So, having both download options available caters to both groups. Of course that’s using extra server space at the ActionVFX end.

The cold-and-logical answer is to follow the money. Are you making most of your income from Studio or Indie users? ActionVFX is a great group of people who want to make reasonably priced, high quality elements available to all, but it’s still a business and you have to make money to live, keep your office, shoot more elements and storefront what you have. Catering to the market segment buying the most makes sense on paper.

But, of course, ActionVFX is a company with heart, and that calculus of income is cold. Now the, “heart” thing to do is provide the highest quality files - LOG - and make sure you kick out some tutorials on coloring.

As someone who bridges between Studio and Indie users I’d take the LOG. At minimum I could save a preset to the Curves effect of my software to expand your LOG elements to full (rec 709) range. Now I have a drag and drop preset to set me up for the next grading steps…

I guess that’s a long post to vote for LOG?

A wildcard option might, MIGHT, be to offer REC 709 on the storefront, but LOG on the drive. It’s going to be Studio users buying drives, and they’re the ones most likely to want LOG. I have no idea on how much extra effort that requires at the ACTIONVFX end, but it’s a thought.

@triem23 nice summary! I agree :slight_smile:

I don’t know how many people actually use LOG?
As mentioned before VFX studios will convert everything to linear. So providing linear EXRs avoids that everybody has to convert from log-to-lin again in-house and saves everybody a lot of render time.

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@jonas So based on that, Rec 709 and EXR is the optimal combination, maybe?

Yes, sounds right! :slight_smile:

Linear EXR (ACEScg preferred)
ProRes4444 with rec709

Thanks for sharing your thoughts @jonas and @triem23! The hardest part about delivering EXRs is the file size. It can quickly add up and make delivery more difficult and time-consuming. ACES is something I have been keeping up with as well. It certainly has its benefits and I am excited that more productions are taking advantage of it!

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Yeah, it’s the balance between file size and quality that has to be an eternal question at your end. If space were half the cost you’d just host rec 709, log AND EXR for everything.

I am a huge fan of logarithmic JPEGs. You can achieve up to 1/10th of the file size of an EXR sequence while keeping 98% of the quality for live action shots. No idea why this is not used more often?!

Combining this with new compression algorithms like AV1 Image File Format (AVIF) if definitely worth looking into!

Simply take your linear EXR (e.g. 16bit) and perform a simple lin2log. Render out a JPEG sequence (quality 96%, sub-sampling 4:4:4 ) As a viewer LUT use log2lin.
Since you don’t use an ARRI Alexa you shouldn’t run into the negative values issue.

I noticed today that the iPhone also already uses new image formats.
HEIC (also known as HEIF) and HEVC for video.

Hey there! I’m also a Nuke compositor that has worked on many feature film projects for many years. I just wanted to agree with Jonas about using exrs. Any kind of log space is useful for compositing. In Nuke, we use a linear workflow. So if we’re given an asset in log we’ll have all of that color data to work with which is essential. Theres been too many times where I had to fight the color on assets because they’re clamped or the color highlights is so tight together its difficult to control. Someone mentioned before this is helpful for muzzle flashes, explosions, etc. I try and manipulate muzzle flashes to go in a log colorspace when color correcting almost every time. Take care!

Awesome, thanks for sharing this with us @jonas!

Thanks for your input @GregoryHarrington. That is good to know!

Also, welcome to the community!! :wave: