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James Hilton
QuickTime
on Feb 26, 2010 at 10:53:09 pm

Hi, a quick technical question that searching on here for previous posts hasn't found a conclusive answer too.

If I encode a video using QuickTime Pro with the built in H.264 codec using quality = 100% (best) with multipass, what colour sampling will it use?

Is it going to be 4:4:4, 4:2:2 or 4:2:0 or something else?

Thanks in advance,
James



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Daniel Low
Re: QuickTime
on Feb 26, 2010 at 11:16:57 pm

4:2:0.

Apple sees H.264 as a delivery codec (quite rightly) and as such 4:2:0 is perfectly suitable.

Apple has ProRes 4:2:2 & 4:4:4 for a 'work' codec

http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC
http://images.apple.com/quicktime/pdf/H264_Technology_Brief.pdf
http://images.apple.com/finalcutstudio/docs/Apple_ProRes_White_Paper_July_2...

Obviously you'd only want to work with the colour subsample of the source you have, no point in going from 4:2:2 to 4:4:4 unless you love compositing.

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James Hilton
Re: QuickTime
on Feb 27, 2010 at 12:50:33 pm

Thanks for the info Daniel.

I did wonder, so far I have been quite impressed with H.264 from QuickTime and seems like a good option for sending files to clients who have file size limits etc.

I have done a test encode on a video here, that has a lot of vibrant colour, and comparing an encode (using QuickTime) at Photo-JEPG @95% and H.264 at 100%, there is no obvious difference, except for file size (for a c20s clip the H.264 is about 160MB smaller). The original colour has been retained well to my eyes with this non scentific experiment.

I was under the impression that Photo-JEPG @95% was 4:2:2, hence my interest to know what H.264 @ 100% actually was.


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Daniel Low
Re: QuickTime
on Feb 27, 2010 at 1:21:31 pm

PhotoJPEG is a great intermediate codec as well as a handy delivery codec in certain situations.

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