quicktime photoJPEG 4:2:2 or 4:2:0? at DVinfo.net

Miguel Lopez · August 18th, 2005, 08:59 AM

Hello.
Is the quicktime photoJPEG compression (at 100%quality) 4:2:2 or 4:2:0?

thanks!

Graeme Nattress · August 18th, 2005, 11:52 AM

Neither, at 100% it's RGB 4:4:4

At 75% it's Y'CbCr 4:2:2

Graeme

Miguel Lopez · August 19th, 2005, 08:34 AM

Thanks!
Then, if at 100% it s 4.4.4 where does the compression came from? becasuse file sizes are considerably much smaller than uncompressed images.

Miguel Lopez · August 19th, 2005, 01:16 PM

And why is that when i render the same file from after effects, instead of vegas (with same settings), the file size is more than twice?

Graeme Nattress · August 19th, 2005, 01:19 PM

About Vegas / AE, I have no idea.

The compression comes from quantising the discrete cosine transform coeficients - that's how JPEG works, and how it gives variable compression amounts. PhotoJPEG is a superb codec for high quality and small (relatively) sizes.

Graeme

August 18th, 2005, 08:59 AM	#1
Miguel Lopez Regular Crew Join Date: Mar 2003 Location: Madrid, Spain Posts: 187	quicktime photoJPEG 4:2:2 or 4:2:0? Hello. Is the quicktime photoJPEG compression (at 100%quality) 4:2:2 or 4:2:0? thanks!

August 18th, 2005, 11:52 AM	#2
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	Neither, at 100% it's RGB 4:4:4 At 75% it's Y'CbCr 4:2:2 Graeme __________________ www.nattress.com - filters for FCP

August 19th, 2005, 01:19 PM	#5
Graeme Nattress RED Problem Solver Join Date: Sep 2003 Location: Ottawa, Canada Posts: 1,365	About Vegas / AE, I have no idea. The compression comes from quantising the discrete cosine transform coeficients - that's how JPEG works, and how it gives variable compression amounts. PhotoJPEG is a superb codec for high quality and small (relatively) sizes. Graeme __________________ www.nattress.com - filters for FCP

August 19th, 2005, 08:34 AM	#3
Miguel Lopez Regular Crew Join Date: Mar 2003 Location: Madrid, Spain Posts: 187	Thanks! Then, if at 100% it s 4.4.4 where does the compression came from? becasuse file sizes are considerably much smaller than uncompressed images.

August 19th, 2005, 01:16 PM	#4
Miguel Lopez Regular Crew Join Date: Mar 2003 Location: Madrid, Spain Posts: 187	And why is that when i render the same file from after effects, instead of vegas (with same settings), the file size is more than twice?