If you link to media using the AMA process and the clip does not match the aspect ratio and frame size set in your Format tab, then Media Composer will allow you to change the way it is displayed at any time.
An important note from Avid technology:
If you are working in an Interplay environment, do not change the Reformat attribute from the Stretch setting. If you use a different setting, and you then use 'Interplay Transcode' or 'Send to Playback,' the results might not be what you expect.
Below are the steps to display the AMA file's image as desired:
Set your bin to be displayed in Text View from the Bin Display menu in the lower left of your bin.
You're going to display the Reformat column. Start by going to the Bin menu and selecting Choose Columns.
In the Bin Column Selection window choose Reformat.
Click on OK to close the window.
Select the clip(s) in your bin for which you want to Reformat the display.
In the Reformat column of the selected clip(s), click to reveal, and also choose, the alternate display options. If multiple clips are selected, you can change the Reformat setting for one of the selected clips and have that setting applied to all of the selected clips.
Note that if you loaded the clip into the Source Window, you will see the Reformat display change occur. Whatever you set here will be applied to the clip when it is edited into your sequence. However, if you have already edited the clip into a sequence, the version in the sequence will continue to display in the manner that it was set in when it was first edited into the sequence. This is to prevent changes being applied to the sequences that are considered complete and ready to export or master to tape. If you want to update all the instances of the clip in your sequence to use the new Reformat setting, this can be done without having to re-edit the clip(s). Follow the next set of steps:
Select the sequence(s) in the bin.
Right-click on the selected sequence(s).
Choose Refresh Sequence.
From the submenu select Reformatting Options. See the next section for details.
Pillarbox/Letterbox: This feature scales the image as large as possible within the currently set aspect ratio that you've set for your Project's display. If the Project is set to display 4:3, then a 16:9 image will be letterboxed (black bars on the top and bottom). If the Project is set to display 16:9, then a 4:3 image will be Pillarboxed (black columns on the left and right-hand side of the screen).
Center Crop: No scaling occurs in this option. If the project is set to display 4:3, then a 16:9 image will have the left and right hand side portions of the image cropped. If the project is set to display 16:9, then a 4:3 image will have the top and bottom portions cropped.
Center Keep Size: If the image is larger, when it is centered in the window, portions of the image on all the sides may be cropped. If the image is smaller, then its native size will be displayed and black color will appear around it.
Changing the project's aspect ratio display
Method 1: Project Window | Format tab | Aspect Ratio menu.
Method 2: Right-click in either the Source Window or the Record Window and select Project Aspect Ratio, and then select the desired display from the submenu.