From http://forums.adobe.com/message/5696699#5696699 ATR is running QT 7.7.4 in Windows 8.0, 64-bit, so I would also expect it to run under 8.1.
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If this post or another user's post resolves the original issue, please mark the posts as correct and/or helpful accordingly. This helps other users with similar trouble get answers to their questions quicker. Thanks.
As Neale says, Quicktime is certainly compatible with Windows 8.1.
I have Premiere Elements 10, 11, and 12 running in Windows 8.1 64 bit with QuickTime 7.7.4 (the existing 32 bit application) successfully installed. QuickTime install is essential for obtaining the necessary QuickTime functions of Premiere Elements. There is no QuickTime 64 bit application from all reports.
The above holds true when Premiere Elements 10, 11, and 12 were run on Windows 8.0 64 bit before I moved to Windows 8.1 64 bit.
I suspect that you may have been confused by the Apple description of QuickTime
which includes "QuickTime 7.7.4 for Windows XP, Windows Vista or Windows 7"
As an aside, I also have iTunes installed on this same computer. It is version 22.214.171.124 and is a 64 bit application.
Please do not hesitate to ask if you need clarification on anything that I have written.
Yes, Quicktime is succesfully installed.
And yes, it bothers me greatly to install an application that is not conceived and tested for Windows 8 just for codecs.
But it works for now.
Thank you all.
Thanks for the follow up and the good news that you are moving forward with your Premiere Elements projects.
That "....it works.. " sounded good.
Again, please do not hesitate to ask if you have any question about your Premiere Elements workflows. We look forward to the opportunity to help if needed.