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Alexandre Brandt
Compression quality issue
on Sep 5, 2014 at 3:53:35 pm

Hello folks,

I've been using Adobe Media Encoder for about two years now and I'm having an issue I never had before. I've compressed a 2 minute video in h264 at 6000kbps 1920x1080 and the quality is terrible...I've check the movie inspector in quicktime and the data rate is at 8.25 Mbit/sec. The total file size is 225MB for a 2min video.

I've uploaded two screen shots to show you:
http://imageshack.com/a/img902/2252/sFLJqy.jpg
http://imageshack.com/a/img538/6626/rPNcRA.jpg

The original footage is perfect, resolution of 1920x1080, shot on C300 and converted in Apple Pro Res 422 for postproduction. I just compressed the video with MPEGstreamclip and it works fine so its not the original file thats acting up.Hello folks,

What is wrong with Adobe Media Encoder ?

motion pictures + storytelling = ?
-> FILMMAKING !

Producer | Filmmaker
http://www.alexandrebrandt.com


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Ryan Holmes
Re: Compression quality issue
on Sep 5, 2014 at 6:07:57 pm

[Alexandre Brandt] "What is wrong with Adobe Media Encoder ?"

That does look abnormally soft in the sky, edges, and trees. Well there's a lot to the encoding process (not letting Adobe off the hook here). But things we don't know about your settings - CBR, 1 Pass, 2 Pass? Keyframe interval? Is there motion in the clip (camera pan or the a breeze blowing the trees)?

All of the above, combined with the data rate will impact the video quality on the way out the door. Now I'm not familiar with your encoding background or what goals you're trying to reach with this final product, but 6,000kbps is not terribly high for a 1080p video. The scene could very easily fall apart on you in multiple software packages. Commonly accepted data rates for 1080p video range from 8,000kbps-50,000kbps (see compression guides for Vimeo and YouTube).

So one solution - up your data rate. Another solution lower your keyframe rate. Another solution move to CBR encoding away from 1/2 pass encoding. And yet one more solution do all the above! :-)

Ryan Holmes
http://www.ryanholmes.me
@CutColorPost


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Alexandre Brandt
Re: Compression quality issue
on Sep 9, 2014 at 8:42:33 pm

Hello,

Thanks for your quick responses.

The settings I'm using are the same I've been using for a couple years with no issue at all. Its not a lack of kbps issue at all. I compressed at 6000kbps on MPEG stream clip and the output looks fine. This is a screenshot of it http://imageshack.com/a/img673/1668/evVFJd.jpg

I'm using CS5. I'm compressing to H.264 via "Format: QuickTime" and then selecting H.264 in the drop down menu. There is no setting for CBR. Regarding keyframes its automatic. There is practically no motion in the clip.

Alexandre

motion pictures + storytelling = ?
-> FILMMAKING !

Producer | Filmmaker
http://www.alexandrebrandt.com


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Walter Soyka
Re: Compression quality issue
on Sep 5, 2014 at 6:34:28 pm

Are you encoding to H.264 via the H.264 format, or via the QuickTime format?

If you are running Media Encoder CC 2014, have you installed the very latest updates? There was a bug in the initial release that could cause softening of H.264 encodes.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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