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johnt53984649
johnt53984649
Inspiring
June 2, 2017
Answered

Minimize Compression Artifacts in Dark Areas?

  • June 2, 2017
  • 1 reply
  • 13745 views

Example Compression Artifacts - YouTube

Between 6 and 20 seconds of this video, notice that the very bottom left corner of the video suffers some small, although noticeable, issues with compression artifacts (you may have to watch full-screen in 1080p to notice).  When performing a RAM preview in After Effects, absolutely none of the artifacts are visible.  So this tells me that these artifacts must be a result of the compression codec I've chosen to use.  Of course, I know that YouTube re-compresses uploaded footage, and there's absolutely no way around that, but those artifacts you see there are also just as visible as they are in the file that's directly exported out of After Effects.

So here were my export settings:

MXF OP1a, AVC-Intra Class100 1080, RGB (Millions of Colors), "Best" Quality, 1920x1080, 59.94 FPS.

So, directly out of After Effects, this MXF file displays very noticeable artifacts in the lower left corner when either played in Premiere Pro or in VLC media player.  That fact that I end up converting it to a lower-quality MP4 (h.264 at 30 CBR) and uploading it to YouTube just for you to see is not the only reason for these artifacts.

So, here's my question: What should I do to minimize the visibility of these artifacts in the file directly output from After Effects?  Are there other codecs you recommend?  Should I just avoid dark areas altogether in my videos?  Do I need to work in higher color depth and find a codec that supports it?  I'm just trying to maximize the quality of my archival versions of these videos.

[Edited to correct link]

This topic has been closed for replies.
Correct answer Rick Gerard

If the artifacts are in the original footage you can help hide them by adding some noise or grain to the footage. If you are going to re-compress and suspect that compression is causing problem then you have three options if you know what your doing inside compression settings or just one, adding noise or grain to hide artifacts. The other two options are to 1, increase the data rate to the maximum acceptable, and 2, enable multi pass rendering. Both can be applied but if you send the video to YouTube or Vimeo or about any other streaming service, it will be re-compressed by their system anyway so there's only so much you can do. As long as you are working with 8 bit footage your options for reducing artifacts and banding are very limited. Noise and grain are the best options to hide the problems.

1 reply

Dave_LaRonde
Dave_LaRonde
Inspiring
June 2, 2017

Well, an old adage comes to mind -- "You get what you pay for."

You can either repair the video, live with it, or download stuff that doesn't have the bejeezus compressed out of it... which may involve some investment.

R
Community Expert
Rick GerardCommunity ExpertCorrect answer
Community Expert
June 2, 2017

If the artifacts are in the original footage you can help hide them by adding some noise or grain to the footage. If you are going to re-compress and suspect that compression is causing problem then you have three options if you know what your doing inside compression settings or just one, adding noise or grain to hide artifacts. The other two options are to 1, increase the data rate to the maximum acceptable, and 2, enable multi pass rendering. Both can be applied but if you send the video to YouTube or Vimeo or about any other streaming service, it will be re-compressed by their system anyway so there's only so much you can do. As long as you are working with 8 bit footage your options for reducing artifacts and banding are very limited. Noise and grain are the best options to hide the problems.

johnt53984649
johnt53984649Author
Inspiring
July 18, 2017

Changing the project to 16 or 32 bit may help. If you decide to do that then render a visually lossless intermediate using a suitable production format and then render your deliverable using the Adobe Media Encoder.  There is little or no gain when you set the project to 32 bit and render directly in the AME.

Accurately color grading the project is also a great help. Animated still images can be the source of the problem if the color values are not within spec. Without details or examples it's hard to give you more help than that.


I was actually able to notice a significant visual difference in my render when simply changing the project to use 32 bit.  I appreciate the help!

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