FORUMS: list search recent posts

JPEG quality

COW Forums : Adobe Photoshop

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Zvi Twersky
JPEG quality
on May 5, 2014 at 1:12:42 pm

I was always told that if you keep importing and exporting the same JPEG image, every time you export, it's compressed some more so the quality decreases. What I'm doing now is fixing some lens dust spots on a video by importing the video into AE, exporting a JPEG seq, importing the JPEG seq into AE, and using a tracking script that allows the spot to be spot-healed in a PS script. PS exports new healed JPEGS. After one spot is removed, the new healed JPEGs are brought into AE as a new JPEG sequence and the process is repeated for each spot. There is one video that I did this process 11 times - so technically, the JPEGS were re-exported 11 times. But when I import the final clip that was fixed onto a video timeline in my NLE, and compare the original with the healed version, the quality doesn't seem to have changed at all - besides a few pixels (I check with a difference filter). How is this so? Thanks!



Return to posts index

Jon Doughtie
Re: JPEG quality
on May 5, 2014 at 2:04:29 pm

Quite a few different "flavors" of JPEG exist. A Google search for "lossless JPEG" provides some reading you may find interesting.

It is true that when JPEG was first introduced (after originally being a classified technology used by the military) it was a lossy compression format.

But if your difference matte shows no difference, well. . . sounds like a lossless/near-lossless version of JPEG.


Return to posts index

Zvi Twersky
Re: JPEG quality
on May 5, 2014 at 2:37:45 pm
Last Edited By Zvi Twersky on May 5, 2014 at 2:38:01 pm

Yes, I knew that there is a lossless JPEG but since PS only lets you choose the quality (until 12) I assumed that PS exported the regular lossy JPEG. It would be interesting to research if all of PS JPEG exports are lossless since there is no option of lossy\lossless in PS.



Return to posts index


Atiqur Sumon
Re: JPEG quality
on May 7, 2014 at 9:10:43 am

Use this command File+save the web and then select JPEG format


Return to posts index

Ivan Myles
Re: JPEG quality
on May 8, 2014 at 1:54:31 am

Consider using JPG2000 at max quality for lossless image sequences in 8-bit RGB. I prefer 10-bit DPX to minimize RGB-to-YCC artifacts.


Return to posts index

Shumi cps
Re: JPEG quality
on May 28, 2014 at 9:35:09 am

I guess you have used the most flexible process to keep your JPG image quality intact.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]