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Activity Forums Compression Techniques 640×480, any drop in quality?

  • 640×480, any drop in quality?

    Posted by Romeo Rubio on August 18, 2011 at 10:43 pm

    I’ve been encoding video content from DVDs (mostly letterboxed 16×9 fit into a 4×3) using mpeg streamclip. I’m making them into prores files to edit in FCP. If I choose 720×480, streamclip says no scaling will be performed. If I choose 640×480 it says scaling will be performed. In reality isn’t there actually no “scaling” involved, just the rectangle pixels being translated into square ones, right? Is there any information being tossed out as compared to just doing a straight 720×480 encode? I’ve done extensive comparisons and it doesn’t seem like it. I just want to make sure.

    I guess it’s best to explain in detail why I’m encoding to 640 instead of 720. I’m trying to keep the workflow as simple as I can for the individual I’m preparing the clips for. With him starting with 640×480 he just has to export as Quicktime Movie and then bring that into streamclip and convert to h.264 for the web. So he doesn’t have to fiddle with any pixel aspect ratio business anytime he is working with the stuff.

    Now most of these are destined for the web. But I was curious to see how they would look if taken all the way to a burned DVD. I thought it would be complicated and would have to manually change pixel ratios/resolutions. To my surprise, all I had to do was export as Quicktime movie from FCP, put it in compressor, added one of the DVD droplets, and burned it in DVD studio pro. The quality seemed to hold well and the aspect ratios stayed correct. My question at this point is is there any quality advantage when you get to the DVD stage and you started with 640×480 stuff as opposed to 720×480?

    That explanation is probably going to confusing but all the questions really boil down to this: is there any quality loss going from 720×480 (non-square pixel ratio, or ntsc) to 640×480 and vice versa?

    Jeff Greenberg replied 14 years, 8 months ago 2 Members · 1 Reply
  • 1 Reply
  • Jeff Greenberg

    August 19, 2011 at 2:49 pm

    No scaling will be performed because it’s stored at 720×480. Transfer as that, edit as that, finish as that and THEN convert at the end.

    There is no ADVANTAGE but there certainly is disadvantage to scaling it to 640×480.

    Best,

    Jeff G

    Apple Master Trainer | Avid Cert. Instructor DS/MC | Adobe Cert. Instructor
    ————
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