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Exporting to / Compressing to DHxHD
Hi all,
I need to convert a 1080p25 ProResHQ file to DNxHQ (1080p25 185 10bit), so it can be laid off to tape from an Avid. (The decks in question are only connected to Avids.)I’m having trouble using FinalCutPro and Compressor to do this. After Effects seems to work but it’s a long render.
I made a Luma Ramp test footage to demonstrate the issues I’m getting with the actual file I’m trying to convert. The Luma Ramp originated in After Effects and was rendered to ProResHQ.
(1.) Here’s the original proreshq Luma Ramp imported to FCP:
(2.) Trying to export a sequence from FCP to DNxHQ using Export/Quicktime Movie causes FCP to crash with the following error:
FCP 7.02
QT 7.6.6
OS X 10.5.8
MacPro 2009 6GB RAM
Uncertain which version of AvidCodecLE I have installed.
(Yes, I’ll reinstall/upgrade to the current.)
There is no Avid NLE on this machine.(3.) Here’s the Luma Ramp converted to DNxHQ via After Effects and brought back into FCP:
Note the gamma shift. I’m not too concerned about that.
I am more concerned about the banding noise in the continuous tone ramp. Click the image to view full size.
(4.) Here’s the Luma Ramp converted to DNxHQ via Compressor and brought back into FCP:
Note the luma range is compressed to 10-92. Yikes!
And the banding noise in the continuous tone ramp is more severe.
Any thoughts?
I’m OK running the clip through AFX to get to DNxHD, but am curious what experience others have had trying to use FCP or Compressor to get to DNxHD.
FWIW I don’t have access to an Avid NLE.
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5 Replies
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[John Pilgrim] “(4.) Here’s the Luma Ramp converted to DNxHQ via Compressor and brought back into FCP:
Note the luma range is compressed to 10-92. Yikes!
And the banding noise in the continuous tone ramp is more severe.”
I guess that somewhere the AVID codec have a Full Range/Video Range option.
The AE graphic shows that has been exported “Full range” (0-1024) while the Compressor one seems to be exported “Video range” (64-940).Have a look at that and try again in Compressor setting the “Frame Control ON”.
rafael -
Thanks for the suggestion Rafael.
Alas, I already made Compressor presets for and tried both the Rec709 and RGB options.
On your suggestions I turned on frame controls for both Rec709 and RGB, but it didn’t make a difference.I upgraded to the latest Mac_AvidCodecsLE 2_3_2.zip from Avid here and re-exported for Compressor but the results were the same.
Interesting comment on the Avid download page (emphasis mine):
Color Levels
For all non-Avid QuickTime codecs, these options allow you to specify whether the file being imported has pixel values that are stored using computer RGB values (where the 0-700 mV (video black to video white) voltages are mapped using the full range of 0-255, 8-bit) or ITU-R BT.601/ITU-R BT.709 values (where the 0-700 mV voltages are mapped using the 601/709 standard range of 16-235, 8-bit).However, when importing movies compressed using any of the Avid QuickTime codecs, you should always set this option to 601/709, regardless of the color levels in the movie. This is because the Avid codecs internally encode the material using 601/709 color levels. You instead specify the QuickTime codec options in a third-party program whether the file you are creating or rendering contains a computer RGB or 601/709 mapping. Failure to do this with current versions of Avid editing applications results in a dramatically slow import and incorrect color levels in the imported element.
Seems the Apple apps don’t correctly interpret the color levels.
Deleting (with JES Extensifier) the quicktime gamma (gama) and color (nclc) atoms from the MOV files created by Compressor doesn’t remedy the problem.
So, maybe I’ll send a test file to an Avid NLE and see if it correctly interprets the color levels, even if FCP & QuickTime Player don’t.
Lastly, importing the original and the DNxHD files to After Effects and trying every probable footage interpretation and color management workflow setting can’t get the DNxHD to match the original.
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[John Pilgrim] “For all non-Avid QuickTime codecs, these options allow you to specify whether the file being imported has pixel values that are stored using computer RGB values (where the 0-700 mV (video black to video white) voltages are mapped using the full range of 0-255, 8-bit) or ITU-R BT.601/ITU-R BT.709 values (where the 0-700 mV voltages are mapped using the 601/709 standard range of 16-235, 8-bit).”
This is what I’ve been calling Full or Video Range.
I understand that this works only when transcoding RGB stuff, as happens with other codecs that offer this option (Sheer, AJA).Is clear that Compressor is not mapping properly the values.
I have no experience with the AVID codecs, so I have few doubts.
Is an 8b or 10b codec?
About the “banding” have you always rendered in 16 or 32b in AE?
Rafael -
My DNxHD settings were always 1080p25 185 10bit.
The Luma Ramps were rendered from a 32bit AFX project. -
Reading all this I am tempted to suggest you move to another codec. I know it is not ideal and it may degrade the picture somewhat, but I’d be curious to know what you get if you export to DVCPro HD from the ProRes and then import this into your Avid. Will you still get the banding?
I am sorry I can’t test this myself at the moment but thought it might help.
Patrice
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