Drag the file directly into Media Encoder ( standalone) and choose MPEG-2 to "re encode it".
The file size will be a trial and error process.
The quality could be "awful" also.
The project was created in Premiere and exported to 1440 X 1080 mpeg2 file, can I export it to a NTSC 720 x480 custom preset with losing too much quality?
>losing too much quality
Going from HD to SD always means a loss of quality... how much is too much is up to you... test and find out what happens with different settings
If you can tell us your intentions it will be easier to suggest a solution. What is the intended purpose of this new file? If for computer viewing, then outputting at 720x480 might be an issue since most players are going to show that file as 4:3 rather than the intended 16:9, since it would be "anamorphic widescreen".
You might need to export at 854x480 using square pixels (1.0 PAR) to get proper display on playback. But again, tell us your goals and we can narrow the suggestions
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