Sticky suggestion: h.264 Gamma Shift and how to fix it

#1

I have seen a lot of question regarding the gamma shift issue when encoding into h.264 quick time movies.

Wouldn’t it be nice to stick a thread on top of this forum containing a solution?

After rendering into a QuickTime/h.264 file, open it up in QuickTime and select “Show Movie Properties.” Highlight the video track then click on the “Visual Settings” tab.
Towards the bottom left you should see “Transparency” with a drop-down box next to it.
Select “Blend” from the menu then move the “Transparency Level” slider to 100%. Choose “Straight Alpha” from the same drop-down and close the properties window and finally “Save.”

requires QuickTime Pro
regards to mitchgates for the original posting

#2

http://www.geoff3d.com/blog/labels/h.264.html

#3

So does the above solution work… or not?

#4

I have used the motion jpeg -> h.264 trick and it works for me. No gamma shift.

#5

this definitely works… here is what i did and the quality is 100% after encoding and fixing the gamma.

  1. Export from AFX as Quicktime >> Animation with Best settings

  2. Original file size was 1.3GB for a 2min compositon

  3. Open in Quicktime Pro and export as “Quicktime Movie” with H.264 encoding and Best settings.

  4. New file size will be 38MB with loss of visual quality and poor gamma.

  5. Do the gamma trick and save. 100% and lossless visual quality and 38.1MB Final Size.

#6

has anyone tried setting the projects color management?

#7

I’ve ran into this issue a couple times. Looking at the solutions, one has to wonder, does this issue appear on software not using Apple’s Quicktime for decoding the video data?

It seems like a playback problem with Apple’s software more than anything, especially based on the fixes: the first one alters the file’s alpha channel parameters without re-encoding, and suddenly the file should look normal?

What both fixes have in common is using QT Pro to deliver the final file. Obviously it does something ‘right’, which – I guess – must be writing something to a header of the file, that makes Quicktime to decode the file properly. Comparing headers of the files with correct and incorrect encoding might reveal something.

If I remember correctly, AE CS3 uses it’s own Media Core engine to decode Quicktime files, so it could be used to check if the whole gamma shifting is just a decoding issue with decoders using Apple’s Quicktime. CS2 used Quicktime for decoding, so it should suffer from the same issue. If the Media Core engine decodes the files according to Apple’s specifications, though, the files might also appear washed out inside CS3.

#8

Sticky this baby!

#9

When I apply this workaround, my files don’t stream anymore. Does anyone of you know if this is a common problem?

Or that there is another workaround in the meanwhile (after this workaround was posted).

#10

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