Playback of MP4 file on 2 different Macs/Quicktime versions look different

Question

Level 1

0 points

Playback of MP4 file on 2 different Macs/Quicktime versions look different

I created a MP4 file from a Motion project (the project has been transferred between my MacBook Pro on Leopard and my iMac which has Snow Leopard).

On my iMac the file shows 156MB, and I use Quicktime Pro 10.X (its at home so not sure of what version) and the file comes up at 1280x720 as intended.

I then copy the file to my MacBook Pro which has Quicktime Pro 7.6.6 (I thought installing FCP included latest QT Pro Player??). The file size shows up as 149MB, and when i play the file back it comes up squashed, as in it's squashed at the top and bottom. So a circle looks oval now.

When i try and export on my MacBook Pro - i get the squashed image straight away.

I dont understand how this is possible? Can anyone shed light on whats going on? Is it the different QuickTime Pro versions?

iMac 27" i7, Mac OS X (10.6.3)

Posted on May 19, 2010 8:39 PM

Reply

Answer 1

Jon Walker

Level 6

19,489 points

May 22, 2010 4:17 AM in response to kmxe

I dont understand how this is possible? Can anyone shed light on whats going on? Is it the different QuickTime Pro versions?

Sounds like what you are seeing basic difference in the way the two versions of the QT Player display the aspect ratio. Beginning with iMovie '08 thru iMovie '09 and on into QT Player X, the display dimensions are determined by the by the pixel aspect ratio setting and not the the "Current Size" setting data embedded in your file. QT 7, on the other hand, relies on the "Current Size" sitting to display the movie. When these settings equate to different dimension, your movie will display differently depending on which player you are using at any given time. The easiest way to corrent this problem in your case, is to simply open the movie in QT 7.6.6 Pro, reset the display scale to 1280x720 in the Video Track "Visual Settings" tab in the "Properties" window, and then save these changes. Thereafter, the movie should play correctly in either QT Player. If things had been reversed and it was the pixel aspect ratio setting that had been erroneous, then you would have had to re-compress the file embed the correct aspect ratio. This is also why your QT v7.6.6 attempted exports reproduce the error since it is passing the incorrect scale dimension on to the new file you are creating unless you manually modify the output dimensions.

Reply