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Ref file brightness issues

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Matt JonesRef file brightness issues
by on Oct 10, 2008 at 7:37:23 pm

I'm using an exported reference file as the source for video compressions and having some issues with shifts in brightness. The source video was HDV digitized as M100HD 8-bit, assembled in M100HD v 12.7.1. Playing back on the m100 timeline, the video looks perfect on the NTSC monitor and on the subsampler on the Apple LCD.

As the program is exported as a reference file, it renders the graphics and creates a new file. Overall, the video looks washed out (grey blacks, etc.) except where a semi-transparent overlay graphic has been rendered. During the overlay, the video looks normal (black blacks). Once the overlay finishes, it's back to washed out video.

I'm rendering the graphics as M100HD 8 bit, same as the video.

What's going on? I'm guessing if I rendered the entire program as a self-contained file, it wouldn't shift, but I don't really want to render the whole 13 min program, just to recompress it again.

I've been doing this for years with m100 8.2.3 with no problems. There must be some check box I'm missing?

You can see the results here:

Check out about 40 sec in to see the shift when the lower-third comes in.

Thanks Bovines!

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Wickham StrubRe: Ref file brightness issues
by on Oct 10, 2008 at 9:16:49 pm

Hi Matt,

I just tried this myself and couldn't reproduce it. I then ran it by the engineer in charge of this area of the app and it doesn't make sense to him.

Are you absolutely sure that your "Render" codec is the same as the acquired media?

You're coming in HDV, can we assume you're capturing it at HD frame size?

If you play the By-Ref export in QT Player, does it look "bad" in QT Player?

Do you get a different result if you A: export Self-contained? or B: Export as "Other > QuickTime..."?


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Floh PetersRe: Ref file brightness issues
by on Oct 11, 2008 at 12:08:56 pm

It definitely sounds as if you are rendering into a different codec (e.g. Apple ProRes or Uncompressed 8 bit), which would explain your problems. If you are working with by ref or self contained clips you need to make sure that all of your material is in the same codec (in Media 100 i only one codec was supported, so you never could get into this problem).

If you are not sure if all your material is in the same codec, do a QuickTime export into a codec of your choice, and (for most purposes, e.g. if you want to use Compressor, iDVD or similar) set the color range to 0-255

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Matt JonesRe: Ref file brightness issues
by on Oct 13, 2008 at 3:08:54 pm

Thanks guys,

That was my problem. Although I had originally had everything set to M100 8 bit, I reset the codec to Prores422HQ in another project and didn't reset it it in the original project before I rendered and exported the ref file.

Now I need to re-render 100 or so GX in my timeline from ProRes to M100-8 bit. I tried using the find media, deleted them and now they don't render at all. I guess I'll have to re import the original PSDs and replace each one manually.

Any ideas on automating re-rendering of already rendered graphics?

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Floh PetersRe: Ref file brightness issues
by on Oct 13, 2008 at 3:12:01 pm

[Matt Jones] "Any ideas on automating re-rendering of already rendered graphics? "

Like graphics on a video composition track (V1 and up)? Yes, you could select them all, then do a "Unrender Selected Clips" from the Media Menu, and then a "Render all". If they don´t render because they are realtime graphics, do a "Render…" command (from the Media Menu), and select Force Render All.

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