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16x9 QT's squished to 4x3 with a 16x9 preset. Why?

Posted by clay 
16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 10:57AM
OK, I have this issue that I've seen before, but am not sure how to address it. I'm working with some 720p DVCPRO HD content. I output a self-contained QT from FCP 6.0.6 that looks great when played in Quicktime X. Send it through a compressor preset that I've setup for Youtube upload (high quality 16x9 h264), and it comes back as a 4x3 squished Quicktime (everything else looks right). If I try another custom Compressor preset that I have setup as 16x9 h264 (different pixel dimensions and data rate), and aspect ratio is fine.

Now, I've used this exact same Compressor preset (the original Youtube HQ one) many times on many different source files, and never had this issue. I have seen this aspect ratio glitch before on a couple DVCPROHD files that I used compressor to convert, but it seemed random, because several other files in the same batch came out just fine.

Is there some sort of Aspect ratio flag in the files in question that's somehow been corrupted or ignored by compressor? Any ideas you folks have would be appreciated.
Re: 16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 11:15AM
an update:

I restarted the computer, and first tried encoding one of the files using the Youtube HQ preset without using Qmaster cluster. It came through and looked fine, though it took a freaking long time :-( Ran the same file again through compressor/same preset, but this time, I used the Qmaster cluster. 4x3 squashed output. So, for the time being, I'm re-encoding without Qmaster to get these files out the door.

Still not sure why I'm having this issue... Maybe a re-install of FCP on the Qmaster cluster machine would help? Just did that recently on my main machine to address another Qmaster issue.
Re: 16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 11:38AM
should have also noted that the file that made use of qmaster resulted in about a 2% larger file in terms of filesize (93mb vs 91mb)
Re: 16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 12:26PM
clay Wrote:
-------------------------------------------------------
> Is there some sort of Aspect ratio flag in the
> files in question that's somehow been corrupted or
> ignored by compressor?

There is an aspect ratio tag stored in the vmhd atom.

Download Dumpster from here:
[discussions.apple.com]

Then open the file in Dumpster and navigate to moov > trak > mdia > minf > vmhd. A value of 1 for "flags" means it's anamorphic, 0 means it isn't.

My software:
Pro Maintenance Tools - Tools to keep Final Cut Studio, Final Cut Pro X, Avid Media Composer and Adobe Premiere Pro running smoothly and fix problems when they arise
Pro Media Tools - Edit QuickTime chapters and metadata, detect gamma shifts, edit markers, watch renders and more
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Re: 16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 12:36PM
You can launch the clip in QT7, hit apple J for movie properties and set aperture to clean, then save the movie.

>Send it through a compressor preset that I've setup for Youtube upload (high quality 16x9 h264)

I usually like to resize to square pixels for web as some equipment along the line may not read the tags properly and mess up your aspect ratio.



www.strypesinpost.com
Re: 16x9 QT's squished to 4x3 with a 16x9 preset. Why?
July 06, 2011 01:18PM
Jon Chappell Wrote:
-------------------------------------------------------
> clay Wrote:
> --------------------------------------------------
> -----
> > Is there some sort of Aspect ratio flag in the
> > files in question that's somehow been corrupted
> or
> > ignored by compressor?
>
> There is an aspect ratio tag stored in the vmhd
> atom.
>
> Download Dumpster from here:
> [discussions.apple.com]
> =0&tstart=0
>
> Then open the file in Dumpster and navigate to
> moov > trak > mdia > minf > vmhd. A value of 1 for
> "flags" means it's anamorphic, 0 means it isn't.

The flag on both the original and both versions of the encoded file (qmaster and non qmaster) is showing up as "1". Hmmm.
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