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Date Rate or Overall Size?

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Rich Sims
Date Rate or Overall Size?
on Feb 16, 2006 at 4:12:45 pm

Hello All,

I know this may be a foolish question to some but here goes. I've been compressing a slew of programming over the last bunch of years but have not had to do so in the last year. Of course much has changed.

I'm in the process of compressing a bunch of commercial spots as well as cut down documentary pieces for use on the web. I am using Cleaner along with Sorenson video 3. It seems I can get great results with this combo.

Here's the question.

When I up the data rate to limit at 1500 kbits/sec and peak at 3000 kbits/sec my 1:40 sec piece is around 20 megs in size. It looks great but on DSL, Satelite and cable hookups it catches up to itself.

When I lower the date rate to limit at 1200 kbits/sec and peak at 2400 kbits/sec the same piece drops to 15 megs. I lose a little qualtiy but almost imperceptable when viewing.

Many have told me not to go over 800-900 kbits/sec I'm just not happy with the results at this level.

So, is it the overall size of the piece 15megs vs. 20 megs or the data rates I have set?


Sorry for the long wind up to the questions but wanted to give the background.

Take care and thanks,
Rich


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Charles Simonson
Re: Date Rate or Overall Size?
on Feb 17, 2006 at 1:28:31 am

Its the data rate, which lends itself to the overall final size that is causing this. I don't know what resolution you are encoding at, but I will let you know that I often encode to 368x208 at 900kbps, and my encodes look fantastic. I use Compression Master's MPEG-4 Part 2 encoder, but you should be able to get very similar results with Sorenson Video 3, if you have the Pro version and are doing a 2-pass VBR, which it sounds like you are. The one tip I have is, instead of doubling your rate for the peak, set that lower to something like 1800-2000 for a 1100-1200 target encode. At 900, I use a peak of 1600, which gives enough bits to the scenes that need it with out taking away too much from the scenes that don't.



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Rich Sims
Re: Date Rate or Overall Size?
on Feb 17, 2006 at 6:34:39 pm

Thank you Charles,

I'm going to be trying your suggestion over the weekend.

Take care,
Rich


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