[Mike Most]

Since things like stabilizations and repositions/resizing are much better done in Resolve than Media Composer (the scaling engine is much, much better and cleaner) you might want to try a round trip workflow using AAF and a return AAF, as described in another post. Of course, that might be impractical if your clients expect to see a finished version of the piece during color correction (which is usually the case in longform work, which is why the roundtrip approach is rarely used for things like television series…).

[Mike Most]

While it is true that the i axis (it’s NOT “I-bar,” that is a term that whomever wrote that Apple document made up and a whole lot of other people obviously took as some kind of gospel) falls in the area of the display that flesh tones often fall into, one has little to do with the other. It is simply based on the limitations of bandwidth, and the desire when the NTSC system was first introduced to allow for more information in the orange/cyan axis than the purple/green axis, due primarily to the fact that human vision has more acuity in those colors. By skewing the color difference signals toward the orange/cyan axis (it’s actually 33 degrees rotated from the X/Y axis, so if you want to mark your own I-axis just rotate it -33 degrees with respect to Y) they created a situation where the purple/green axis could be more severely bandwidth restricted, since it was “less critical” in terms of the way the human visual system perceives images. In other words, the presence of the I axis and the location of common Caucasian flesh tones being in a similar area on a vectorscope is not completely a coincidence, But it is also the case that this wasn’t done to give some kind of flesh tone guide, it was done because that’s the way human vision works. And I would also point out that in the PAL color system – used in more than 80% of the world for over 50 years – the I and Q axes do not exist (they use the U and V axes, which correspond exactly the the X and Y axes). So an assumption that the I axis is there specifically for flesh tones – in particular Caucasian flesh tones – is incorrect, based on equally incorrect information printed in an Apple document.

There are truths and there are untruths. Just because Apple says something doesn’t make it true, even if they are the richest company in the world. And asking the Blackmagic engineers to put an axis on their vectorscope display that has no relation to anything other than standard definition NTSC video, simply because you happen to like seeing it, is essentially asking them to be incorrect in terms of engineering. If you want to see an I-axis, draw one and use it if you like. But you shouldn’t demand that engineers do things that are technically incorrect or effectively obsolete, as that is not their job. That’s all I’m going to post in this thread, because it’s clear that people are going to do and think whatever they want whether it makes any technical sense or not, and regardless of the facts.

[Mike Most]

If you believe that flesh tones should always look the same, or that they are not dependent on other aspects of the image, or that they’re not relative to the environment, or that they should always be in the exact same place on scopes, then what you’re describing ends up being a technical crutch that will often make your images look less natural, not more natural.

Everything in terms of color is relative to what’s around it. A flesh tone in perfect white light is quite different than the same flesh tone in a warmly lit room or in cool moonlight. It is different in a lit part of a room than it is in shadow in the same room. You don’t need a specific marked point on a vectorscope if you understand all of that, and you don’t need a specific marked axis if you understand what the vector display is telling you. Calibration – the purpose for which the I and Q axes were placed on a standard def vector display in the first place – is one thing. A confirmation of what’s in a real world image is another, and for that, you basically want the vectorscope to tell you relative values, and black and white balance. Flesh tones are going to land wherever they land depending on the scene lighting and the scene content. You don’t grade based on a vectorscope (except as an aid for balance, as I mentioned), you grade based on an accurate calibrated display, which is the only way to judge relative color. The best pure colorist I know (and I know most of the best in the industry) almost never looks at scopes. In fact, he often doesn’t even have them turned on. But his monitoring is checked and calibrated every day, sometimes multiple times during the day, to ensure that what he is seeing is accurate.

[Mike Most]

It’s not there because its only real purpose is to define where the subcarrier should be on a standard definition, NTSC video signal, along with another axis that is 90 degrees opposed to it (the Q axis). It has no relevance in an HD world, regardless of what people here seem to think it is. The notion that it’s some kind of “flesh tone indicator,” or that its actually called an “I-Bar” is something that people who have no idea what its real purpose was simply made up. The fact that people here are seriously discussing it in those terms is, frankly, a bit distressing.

[Mike Most]

True, of course (regarding the I and Q axes). In the PAL world, the U and V axes represent the same thing (they happen to be coincident with the X and Y axex, so this isn’t as obvious). But that fact likely won’t stop people here from coming up with their own explanations as to what those things represent.

[Mike Most]

Put the MXF files in a numbered folder under the Avid MediaFiles/MXF tree. Start Avid. Go into or create a project. Make a new bin. Go to the desktop and navigate to the numbered folder. You should find that Avid created a file that ends in “.mdb.” This is the database file. Drag it directly into the bin. The bin wil populate with master clips for every shot in the folder.

I’ve never understood why Avid doesn’t make this more obvious, as it’s by far the simplest way to incorporate new media into an Avid project. And BTW, you can add the media even while Media Composer is already running, because adding a new numbered folder into the directory tree will force a folder rescan by Media Composer and create (or re-create) the database file at any time.

[Mike Most]

Solid real time performance at resolutions as high as 4K and above require more than one processing box can likely provide. It is this fact that is one of the primary, if not THE primary reason, for the continued existence and support of the Linux version of Resolve. At this point in time, and for the foreseeable future, I would say that for true 4K work – and by that I mean any format, not just compressed Red files – the Linux platform is the logical choice. You can hack together something on Mac and Windows systems, but it will be limited by the single box requirement and can never really match the performance of a multi-chassis-Infiniband-connected Linux system. That’s just technical fact.

[Mike Most]

Sounds like whoever did the offline edit resized the clips. Try importing the XML and deselect “use sizing transforms,” or whatever that particular setting is in the load XML dialog box. Use fit to current format (the default setting, NOT “stretch to corners) and it should be fine. The black bars at the top and bottom have nothing to do with resolution and everything to do with aspect ratio. If the material was shot in a 2:1 aspect – common for Red material – it will be letterboxed because you’re fitting it into a 1920×1080 container.

[Mike Most]

That’s why most high end users work with and render to image sequences (DPX and the like). With an image sequence, each frame is its own file and can be individually replaced. This is not possible with wrapped movie formats like Quicktime and MXF. Unfortunately, Media Composer does not currently support image sequences for output. You would have to use either Avid DS, Autodesk Smoke, or perhaps Assimilate Scratch or Premiere Pro for that kind of support.

[Mike Most]

Buy the Tangent Element panel set and urge Blackmagic to map the Offset controls to the fourth trackball ;-D