If you’re using Premiere Pro CS5 or CS5.5 on the PC with Matrox MXO2 hardware, there’s some important information we’d like you to be aware of to get the best DVD export quality. This info only pertains to exporting "MPEG-2 for DVD" from a Matrox NTSC sequence – if you’re using a Matrox HD or Matrox PAL sequence, the cropping does not apply and you may disregard these instructions.
With the CS4 drivers for MXO2, a Matrox NTSC project was 720x480, but starting with CS5, Matrox changed this to 720x486. Since DVD uses 720x480 resolution, the 6 extra lines need to be cropped at export to get the proper 720x480 size for DVD. If you don’t crop these lines, the entire image will be scaled down, resulting in a quality loss. Also, it’s very important to crop a specific number of lines from the top and bottom, as choosing the wrong top and bottom numbers will soften the output quality.
With CS5, you need to crop 5 Top, 1 Bottom. With CS5.5, there are two cropping options to consider. If using the "Export" button to begin the encoding, choose 4,2. If using the "Queue" button that sends the job to Adobe Media Encoder, you must use 3,3. If you are working with a Matrox 486p sequence, use 6,0 for CS5, and 4,2 for CS5.5 (using either export method).
To set cropping, first set up all the parameters for the DVD export as you normally would. Next, at the top left of the Export window, select the SOURCE tab and click the cropping icon at the top left to make the crop settings active. Click on the "0" to the right of "Top" and then enter a number from the keyboard. Next, click the "0" to the right of "Bottom" and enter the other number. Do NOT hit the "Enter" key – this will launch the export immediately! Just click in another area of the export window to deselect the crop settings.
Now, you can toggle between the SOURCE and OUTPUT tabs to see the "before and after" results of the cropping. The image shown under the OUTPUT tab should fill the screen with no black borders. After double-checking that you entered the correct cropping numbers and that the output image looks correct, you can proceed with the encoding.
For more information, CS5 and CS5.5 users can reference pages 82 and 88 of their respective Matrox user guides. The above instructions are only for export to DVD; when exporting to a Matrox .avi file, CS5 and CS5.5 users should refer to pages 79 and 84 of their respective user guides for cropping charts.
Source article: http://www.sharbor.com/tutorials/2164.html