I responded to this yesterday but the reply didn't seem to get through. These delays on replies to L2 posts seem to be happening a lot for me lately.
I had some time to test 8.5.2 yesterday and there is a difference in the project/color space setup from 8.3.1. IIRC in 8.3.1 when creating a new project there was an entire laundry list of project choices that included a listing of the color space. In 8.5.2 the color space is a different setting from the project type. Perhaps on 8.3.1 you could also change the color space after you created the project but I'm not near an 8.3.1 system to refresh my memory. I also found that there is also a color space setting in the video output more tab. There I could select RGB Full Range and the output on the scope would reflect a full range from about -50mV to 750ishmV. That control is separate from the project color space or it can be set to follow the project color space.
I'm beginning to think much of my confusion is centered around Avid's use of RGB to denote Full Range/Full Swing signal levels and as you point out the change from 422 to 444 when switching to an RGB project. I find with my HDSDI NitrisDX output anything other than a YCbCr project color space yields whacky displays of all greeny video and a whacked vector display. I assume this is par for the course given HDSDI is a YUV signal for my scope and program monitor. There is no component in on my Reference Prgm monitor but I was able to connect to the client monitor which is a samsung consumer LED. Once I set the component output to True P not Psf I could see the output of the Nitris component and switched it from RGB to component signal type as the monitor want YPbPr. I did notice if I turned on cross convert to 59.94i both the HDSDI and the Component out go dark for some reason. This has worked on my 6.5.4.7 system with the same NitrisDX. I use it all the time out of habit because the monitor wouldn't accept Psf I would just toggle to cross convert 59.94 to see an image on it, that was before Avid added the True P vs. Psf setting. Now the cross convert to 59.94i seems to not work.
Dave why do you run in RGB projects? Is it based on your source material. I'm pretty sure if I had 444 material that was Full Range levels if I ama linked to it and didn't tell the source settngs to scale to legal the resulting Avid media if I transcode would have Full Swing levels. It would just be hard for me to scope it as the levels would look completely illegal in my 709 infrastructue. I haven't looked into it but I know monitors in the past have had RGB setting etc... to handle different signal types. Are there external scopes out there that can handle all the varying color spaces and display them in a manner that looks legal on their display. You mention how Resolve works in Full Swing internally and there scopes show 100 percent for Full Swing then on baking out Avid media it scales to legal what they call video levels so the essence of those baked out files are 709 levels. You mention that your "RGB" project gives you extra bit depth and resolution as it's 444 instead of 422 what is it that mandates your RGB project choice. Given all my work is broadcast based I've yet to work in an RGB project.
I have downloaded the Avid High Res Workflow .pdf so hopefully when I get a chance it will enlighten me on these myriad of new choices in color space.
Dave Hogan
May 7 1:04 AM
I work on a daily basis using "RGB" project settings in the AVID (Currently in v8.3.1). To be clear, and many probably already know this, the AVID project setting for RGB vs YRB is only about bit resolution of each channel. AVID still functions ONLY in 601/709 colorspace INSIDE the AVID.
Clipster uses a terminology of FULL vs HEADSPACE, to indicate that in the former, you have black at zero and white at max. In 8 bit that would be 0 and 255. In 10 bit it.s 0 and 1027.
So there are two different kinds of RGB when discussing the AVID. When you set your colorspace in the project settings to RGB, you still have headroom on black and white, it's just that you have 3 full channels of full range and 10 bit resolution (Red, Green & Blue). In this setting we have only two resolutions in 1080p, DNxHD 440 and Uncompressed. Both are 10 bit only.
When switching to YRB (4:2:2) you have both of your color difference channels half sampled, and all but your max DNX resolution are 8 bit, and you have a choice on uncompressed of 8 or 10 bit. (the unmarked one being 8 bit).
Now I have run into MANY inconsistencies when trying to create full range RGB QuickTimes. The AVID is consistently inconsistent in this manner. I have done exports with the same settings, and had them work right sometimes and wrong others.
Michael Phillips has tackled this problem in two ways, in the following post. First he recommends creating exports using the MXF OP1a export, to get reliable exports of AVID resolution you require. To get full range, you just apply a color lut to the timeline you are exporting, and it will bump the levels to full range.
I don't know how far back these features go, or if you have access to a current version of MC for your exports, but this is a simple and reliable way to export from the AVID, and get full range levels.
Hope this is of some assistance,
Dave Hogan
Burbank, CA
|
John Moore Barking Trout Productions Studio City, CA bigfish@pacbell.net
__._,_.___
Posted by: John Moore <bigfish@pacbell.net>
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a New Topic | • | Messages in this topic (23) |
this is the Avid-L2
.
__,_._,___
No comments:
Post a Comment