Gamma shift with QT files

[Tom Daigon]

I can tell you that when I export to DNxHD 175 8 bit 23.976 I always select RGB instead of 709.

As a test I have reimported that clip back into PrP and compared it using both the scopes and using the “Difference” blend mode.

They are identical.

If I export as 709 I do notice a gamma shift. This was a source of concern until I started using RGB which seemed to fix it.

Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=DxPrG3WUyz8
(Best viewed at 1080P and full screen)
HP Z820 Dual 2687
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[Walter Biscardi]

I keep hearing about this but honestly, when we color grade anything via our AJA or BMD output devices to our Flanders Scientific monitors, what we see when we export H264 files is pretty much exactly what we see on our external monitors.

If you’re relying on your computer monitors to accurately show you what the final QT output will be when color grading, that seems to be where most folks have issues. There’s two seasons of our PBS Series “This American Land” up on YouTube and those QT files are pretty darn close to what we output for broadcast.

https://www.youtube.com/user/ThisAmericanLand?feature=watch

Walter Biscardi, Jr.
Editor, Colorist, Director, Writer, Consultant, Author, Chef.
HD Post and Production
Biscardi Creative Media

“This American Land” – our new PBS Series.

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[Walter Soyka]

Are you saying that imported QuickTime sources look wrong in Premiere, or exported QuickTime output from Premiere looks wrong in QuickTime Player?

What kind of footage, and how are you monitoring?

Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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[Ronaldo German]

Thank you all for your responses.
Good question Walter. Tha answer is: both!
Imported QuickTime sources look wrong in Premiere, when compared with the same files played (with the same monitor / conditions) in Vegas Pro 9 or 12 (that seemed OK).
I`ve made 2 export (render) tests from the same timeline (just GH2`s AVCHD files), one to DNXHD (709) and the other to MJPEGA.
When watched through the same (non-professional) monitor, both rendered files were very diferent from the original: DNXHD file was brighter (as more gamma) and MJPEGA darker (as less gamma – no RGB levels to choose).
Now I just tested the DNXHD render using Tom`s sugestion and he is right. Using RGB levels, the DNXHD export showed (by eye) the same image as the original files.
But it seems wrong that we can`t trust in a future result of a export using a so renowned (and expensive) sotware.
It brings a insecure feeling to the process.

[Tom Daigon]

Ronaldo, Im glad you found the workflow I suggested addresses the issue.

To tell you the truth, ever since I switched to the PC I have been avoiding using QuickTime as much as possible. There is the gamma problem you experienced as well as a slowdown when exporting from PrP due to the need for qt32server which acts as a bottleneck in the process, since Quicktime is not a 64 bit app yet. I dont see Apple giving a needed update any time soon.
I do use DNxHD for professional work. But Ive also started using MXF OP1a AVC-I 100 for mastering. It exports 2x as fast as QuickTime and there are no gamma issues.
I also switched to using the MP4 version of H.264 which also exports quickly and has no gamma issues.

Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=DxPrG3WUyz8
(Best viewed at 1080P and full screen)
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid

[Ronaldo German]

Thank you for your tips, Tom.
I also like and use DNXHD for mastering my (to be) broadcast work.
I also think is weird that AVI 1920X1080, uncompressed or not, not be possible to master (export) in PP6.
Regards

[Tom Daigon]

Actually in my exploration of exporting different codecs I have done it in AVI 1920 x 1080 uncompressed. The file is like 5 x bigger then DNxHD.

Here is the export screen setting I used.

Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=DxPrG3WUyz8
(Best viewed at 1080P and full screen)
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid

[Ronaldo German]

Thank you Tom.
I got full HD resolution when I put none choosing the codec.

[Ronaldo German]

Tom
I didn`t find the AVC-I 100 as a option to export.
Could you please let me know how you get it?
Thanks

[Tom Daigon]

Glad to hear it Ronaldo.

Tom Daigon
PrP / After Effects Editor
http://www.hdshotsandcuts.com
https://www.youtube.com/watch?v=DxPrG3WUyz8
(Best viewed at 1080P and full screen)
HP Z820 Dual 2687
64GB ram
Dulce DQg2 16TB raid