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Best sizing methods

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Chris Blair
Best sizing methods
on Apr 28, 2009 at 1:34:32 am

We use VelocityQ editing systems, which have a wide range of export options, but like a lot of NLE systems, many of it's functions are "dumbed down" or basic in nature.

So we often export to a high-quality intermediate format before final encoding in a dedicated compression app. My question:

Is is better to re-size to your final dimensions before going into the dedicated compression app, or better to output at the original size, frame-rate etc. and let the compression software do the rest?

My assumption has always been it's best to let the encoding app do the sizing, frame-rate adjustment etc., but some of our tests have showed the opposite is true, especially with older but still widely used codecs like On2's VP6 and VP7 codecs, which a lot of clients still ask for. Sizing in the NLE before transoding to On2 files looks much better than letting the compression software do it (have tried both CarbonCoder or ProCoder). With other codecs/formats, we get better results letting the compression software do all the size, rate conversions. It would just be nice to find one workflow rather than having a different set of steps depending on the codec.

Any evidence beyond anecdotal or theoretical discussions that shows one way is definitely better than the other? Or reasons why with some codecs it works better doing it a certain way than others?



Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


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Daniel Low
Re: Best sizing methods
on Apr 28, 2009 at 11:49:08 am

[Chris Blair] "Is is better to re-size to your final dimensions before going into the dedicated compression app, or better to output at the original size, frame-rate etc. and let the compression software do the rest?"

I ALWAYS let the transcoder application do the resizing, unless I'm coming out of something like After Effects or Shake.

[Chris Blair] "but some of our tests have showed the opposite is true, especially with older but still widely used codecs like On2's VP6 and VP7 codecs"

Remember that it is the host application, not the CODEC that does the resizing and frame rate conversion in most cases. These are generally part of the pre-process, but not always, depending on the app. Apps like Flix muddy the waters between the application and the codec of course.

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Chris Blair
Re: Best sizing methods
on Apr 28, 2009 at 9:13:26 pm

Thanks Daniel...that helps explain why we see inconsistent results depending on what and how we're compressing.

I didn't realize the host app was the one that always handled the resizing. That explains a lot.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


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