How to Color Correct Clips from Mercalli Standalone

[Norman Black]

Can you describe this 601 to 709 conversion filter mentioned. What are the channel blend settings?

[Wayne Waag]

Can you describe this 601 to 709 conversion filter mentioned.

A little background. My interest in this stemmed from using Proshow Producer for slideshows where I export a high bit rate MPEG-2 for import into Vegas. A look at MediaInfo revealed the color primaries, transfer characteristics and matrix coefficients to be BT601, those used for Standard Definition video. My understanding is that, when Vegas decodes MPEG-2 files with a vertical resolution of 720 or greater, it assumes the file was encoded using BT709, the high definition set of coefficients, the result being, the colors are off. I found that applying a 601 to 709 conversion filter in Procoder fixed the problem and then began searching for a fix in Vegas. Eventually, I found this article https://www.personal-view.com/faqs/software/sony-vegas-pro, which referenced a thread at DVinfo https://www.dvinfo.net/forum/what-happens-vegas/115239-mixing-hd-709-sd-601-clips.html wherein the originator calculated the coefficients for such a conversion that could be applied in the Vegas Channel Blend Fx. Some slightly different coefficients were suggested by Glenn Chan, which I also tried but couldn’t see a difference.

What are the channel blend settings?

Here is a screen shot of the actual coefficients.

If you have Vegasaur, I can upload these presets to Dropbox which also include the conversion suggested by Glenn Chan as well as the reverse 709 to 601 conversion filter.

wwaag

[Graham Bernard]

Comment1: Love the Otter and the chuckling!

Comment2: Should ProDad be made aware and thence their option to work with SCS to make people aware and possibly a User friendly solution? Or am I thinking this around the wrong way?

Comment3: Could you do a YT on just how you pulled the Levers on Channel? Your trial and error and your reasoning, motivation to use the adjustments and approach would be great to hear and see. Having used Corel’s Channel Blend, I’ve used Channel Blend in Vegas to perform valuable CC. It would be valuable to see your approach.

Comment4: Outstanding work!

I “skim-read” the links you provided. Pretty dense material, but I kinda got it.

Wayne, thank you for your time and obvious wish to share your findings and abilities.

Grazie

Video Content Creator and Potter
PC 7 64-bit 16gb * Intel® Core™i7-2600k Quad Core 3.40GHz * 2GB NVIDIA GEFORCE GTX 560 Ti
Cameras: Canon XF300 + PowerShot SX50HS Bridge

[Wayne Waag]

[Grazie]

Comment1: Love the Otter and the chuckling! Around the house, my wife refers to me as the Happy Otter for reasons I can’t say. The “chuckling” came from a YT video of a baby otter and the photo from a screensaver site. No originality on my part.

Comment2: Should ProDad be made aware and thence their option to work with SCS to make people aware and possibly a User friendly solution? Or am I thinking this around the wrong way?

To my way of thinking, the best way to avoid problems is to use the Version 2 plug-in inside of Vegas. No problems of changing levels or colors. Since I can now batch process selected events on the timeline using scripts, there is no read to use the Standalone except in those instances requiring CMOS correction using Version 4. In Vegas, we’re used to doing everything manually when it comes to levels unlike other editors. Mercalli seems to be in the same camp as others in this regard. Hopefully collaboration with SCS will lead to new plug-in that enables batch processing from the timeline without the use of scripts. Their choice to use the SD 601 standards rather than HD 709 is a mystery to me. Having said that, there are others that will argue (notably Glenn Chan) that it really doesn’t make that much of a difference anyway. In other words, don’t worry about the lack of color accuracy. It’s really too bad that Mercalli dropped their AVI rendering option, since it was the only instance of maintaining complete color and levels accuracy. Sadly, most editors are probably unaware that these problems exist, which was really the whole point behind this exercise.

Comment3: Could you do a YT on just how you pulled the Levers on Channel? Your trial and error and your reasoning, motivation to use the adjustments and approach would be great to hear and see. Having used Corel’s Channel Blend, I’ve used Channel Blend in Vegas to perform valuable CC. It would be valuable to see your approach.

As far as use of Channel Blend filter, I simply plugged in the numbers for the conversion from the DVinfo thread. The underlying mathematics is beyond my pay grade. The only trial and error was finding a value for gamma correction for ProRes. In searching online, there seemed to be a consensus that a problem with gamma existed, so after applying the 601 to 709 conversion, I applied a levels filter and tried different gamma settings. For testing, I would simply “copy” the preview in Vegas, “paste” into a new file in Photoshop, and then use the eyedropper to determine the color values of the six primaries. Using this procedure, I arrived at a gamma correction value of .86. The first article I referenced has a suggested value of .88, which seems pretty close. I had actually forgotten about this article when I did the testing. Of note, the problem with gamma for ProRes seems to be a Vegas decoding issue. When opened directly in Photoshop, the colors were correctly displayed.

Comment4: Outstanding work!

I appreciate your kind words. It really does mean a lot, especially from someone who’s been a respected contributor to these forums over the years.

wwaag

[Norman Black]

Wayne: Thanks for the conversion settings. I do have Vegasaur but I think I can easily enter those values. I don’t think I need a 709 to 601, but I guess it couldn’t hurt to have it.

Grazie: The issue with 601 matrix being used is well known thing that can happen on with libavcodec/ffmpeg and certain encode conversion. t Prodad is using this code for encoding. That code defaults to 601 and you have to change to 709. Prodad is apparently running with default. The color shift is so small that they probably don’t realize it is happening.

[Wayne Waag]

[Norman]

Here’s the dropbox link. https://www.dropbox.com/s/zvb2tengg52rbcl/Channel%20Blend%20Presets.vpb?dl=0

wwaag

[Steve Rhoden]

Sorry, can never see the need for Mercalli standalone, going outside of
vegas for stabilization takes away precious edit times and efficiency.

Steve Rhoden (Cow Leader)
Film Maker & VFX Artist.
Owner of Filmex Creative Media.
Samples of my Work and Company can be seen here:
https://www.facebook.com/FilmexCreativeMedia

[Wayne Waag]

[Steve]

Sorry, can never see the need for Mercalli standalone

For once (lol), I have to disagree. Have a look at this 24 sec clip.

https://youtu.be/euclQi4GxPE

Original was filmed 600mm, handheld. Lots of shake. The second is using the Mercalli 2.0 plug-in. Lots of distortion, especially noticeable at the bottom. The 3rd and 4th, with CMOS correction using V4.0 SAL. Not that bad now. MY recommendation is to use V4.0 ONLY for those cases where CMOS correction is required. For one thing, it is very slow. Its biggest application is probably for very shaky GoPro footage. For all other instances, agreed, use the plug-in and save yourself the bother of color correction issues.

wwaag

[Norman Black]

One thing about Merc V4, is that is stabilizes with much less cropping of the source video than Merc V3. That is an additional advantage.

Vegas has a “Mercalli V2” plug-in built-in. The standard “sony” stabilizer is MercV2. It just has less control over options than the actual MercV2. The Vegas one also has unfortunate/misleading naming of the controls.

https://www.sonycreativesoftware.com/forums/ShowMessage.asp?ForumID=4&MessageID=888701

[Wayne Waag]

Just to make it clear, the V2 plug-in I refer to and used in the above YT demo is NOT the one that’s included inside of Vegas. The degree of control for the Mercalli V2 plug-in is pretty much the same as V4 except there is no CMOS distortion correction. I must admit that V3 which enabled batch processing did not seem worth the $40 upgrade cost at the time. Dropping the ability to render to an avi and only providing avc options seemed a step backward IMHO. But, the CMOS correction in V4 is really great and well worth the upgrade cost. Hopefully, there will be a V4 plug-in the the future, which will enable batch processing from the timeline.

wwaag