8 Replies Latest reply on Feb 9, 2012 7:14 AM by ronfya

    h.264 gamma shift or limited range levels ... again

    ronfya

      Hi there,

       

       

      First of all, sorry the length, but I don't see how I can explain this huge problem in a shorter way.

      I know I am not alone out here having troubles with h.264, gamma, and all the players around that make all your beautiful colors and tones look different.

      I am not talking here about the fact that the video looks different on different computers. That is unavoidable, we have to deal with it and that's why we calibrate our system. But on one given computer, how the hell is it that a given video can look sooo different depending on which software you use to view it ?

       

       

      I have a good grasp of color management for photos, but I am completely lost for videos, and I am sure we will be a quite a few here if some pros can answer the following.

       

       

      1.

      I made screen caps from a H.264 video from a Canon 7D.

       

      h264 problem comparison.jpg

       

       

      First row are what the video looks like in the Final Cut Pro X monitor and Premiere CS5.5

      Last column is the video straight out of cam viewed in VLC, MPlayer, Quicktime X and Quicktime 7

      Others are exports from FCPX and Premiere with the defaults H.264 settings and viewed in the same players.

       

       

      After a close comparison of the screen caps, switching on/off one over another, I grouped the matches in color groups to describe the problem :

      Green, yellow and red groups are nearly perfect match within groups. (and in the case of greens, it is probably 100% perfect because it's apple QT)

      A rough classification from dark and saturated to bright and desaturated would be : RED, BLUE, YELLOW, GREEN, PINK.

      [BLUE & YELLOW] are different but very close, [GREEN & PINK] as well. I can live with that. No problem.

       

       

      But RED is very different from  [BLUE & YELLOW] which are both very different from [GREEN & PINK]

      The strangest thing for me being the export from Premiere which displays differently in QT7 and QTX.

      Does somebody have an explanation for this or even better, a fix ?

       

       

      - I already tried the "fix" with the transparency layer in QT pro but it does not work at all http://www.videocopilot.net/blog/2008/06/fix-quicktime-gamma-shift/

      - I heard about x264 but Adobe Media Encoder refuses to work when using it and does not change anything when exporting through Compressor http://byteful.com/blog/2010/07/how-to-fix-the-h264-gamma-brightness-bug-in-quicktime/

      - I heard about the limited range of colors (16-235) of the Rec.709 HD standard http://terburg.home.xs4all.nl/Publications/601_709_RGB.pdf

      That limited range is also causing VLC to wash out colors on PC with nVidia graphic cards http://wiki.videolan.org/VSG:Video:Color_nVidia

      I am on a MacBook Pro, OSX Lion with nVidia GeForce GT 330M but there is no control panel for it.

      Maybe something to fix in my workflow in that regard ?

       

       

       

       

      2.

      How do the big studios like Dreamworks do to export consistent material ?

       

       

      3.

      What are your favorite codec and container for exporting high quality to web apart h.264 / mp4?

       

       

      4.

      What are your favorite codec and container for burning DVDs ?

       

       

      5.

      Can anyone provide a link to a comprehensive and accurate real world RECIPE BOOK for encoding/exporting  ?

      I mean, I am in urgent need of finding a way to export PROPERLY for web and DVDs before even taking the time to understand everything.

       

       

      Thank you so much everybody !

       

       

      R.

        • 1. Re: h.264 gamma shift or limited range levels ... again
          Jim_Simon Level 8

          how the hell is it that a given video can look sooo different depending on which software you use to view it ?

           

          Because software players are not standardized, do not have the same capabilities, have various settings which affect the image, etc.

           

          That's why you don't use software players to judge quality.  You use a properly calibrated external TV.

          • 2. Re: h.264 gamma shift or limited range levels ... again
            ronfya Level 1

            Let's put this another way.

            On a properly calibrated computer screen, which software player is more likely to replicate a properly calibrated external TV ?

             

            And what is your preset of choice for web export ?

            When exporting with that one, do your videos also look different when played in VLC and QT ?

             

            Thanks

            • 3. Re: h.264 gamma shift or limited range levels ... again
              Jim_Simon Level 8
              On a properly calibrated computer screen, which software player is more likely to replicate a properly calibrated external TV ?

               

              None.  That's why professionals always use a properly calibrated external TV.

              • 4. Re: h.264 gamma shift or limited range levels ... again
                ronfya Level 1

                So calibrating our computer screen is useless ? (Except for photography)

                 

                And still ...

                What is your preset of choice for web export ?

                When exporting with that one, do your videos also look different when played in VLC and QT ?

                 

                Thank you for answering the last two if you please.

                • 5. Re: h.264 gamma shift or limited range levels ... again
                  Harm Millaard Level 7

                  Calibrating your displays with an Elite Spyder3 or similar is very worthwhile, but can't match an external monitor.

                   

                  Everything played with QuiRcktime on a PC shows a gamma shift. They have earned this name.  VLC does not and shows the same picture as PR.

                  • 6. Re: h.264 gamma shift or limited range levels ... again
                    ronfya Level 1


                    Harm Millaard wrote:

                     

                    Calibrating your displays with an Elite Spyder3 or similar is very worthwhile,

                     

                     

                    Of course. And mine is calibrated.

                    I was just trying to take an extreme example to illustrate the fact that even though Jim Simon is only describing a reality, it does not mean that a good and consistent result (not necessary ideal) cannot be achieved otherwise, with less equipment. 

                     

                     

                    Harm Millaard wrote:

                     

                    but can't match an external monitor.

                     

                     

                    That part I don't understand though.

                    Is it not in contradiction with the first part of your sentence ? Why ?

                     

                     

                    Harm Millaard wrote:

                     

                     

                    Everything played with QuiRcktime on a PC shows a gamma shift. They have earned this name.  VLC does not and shows the same picture as PR.

                     

                    How does one grade his colors on FCPX then if it displays exactly what QTX displays (which is brighter and less saturated than VLC) ?

                     

                    Yeah I know, we're going in circles here ... but I would really love to find some kind of solution to this.

                     

                    • 7. Re: h.264 gamma shift or limited range levels ... again
                      shooternz Level 6

                      Using a calibrated monitor is all very well if you have some way of interfacing with it. (ie hardware)

                       

                      Maybe Jim and Harm can give you some details how they interface to "calibrated tvs"  from PPRO .....but facilities I use outside of my own ..use BM / AJA type cards  to reference monitors (Note: they are not actually interfacing with Premiere or FCP etc.)

                       

                       

                      As regards diferent looks on different displays.  Thats a fact of life and all you can do is work to the best standard and reference  you have or need for your purpose.  If you do broadcast work...go thru the pieline and calibrate to the BC standard. 

                       

                      The web and computer displays...well thats un controlleable because there is no standard for the displays.

                       

                      I am very satisfied with the results I get from my computer monitors (interfaced directly with PPRO) and I have checked IQ thruy my broadcast pipeline. ie source clips > edit> fx/grade >mastering > output and broadcast

                      • 8. Re: h.264 gamma shift or limited range levels ... again
                        ronfya Level 1

                        About the "need of a calibrated broadcast monitor for a good preview" ...

                         

                        Even though it is a requirement for broadcast, when the videos stay on internet and on computers, they are RGB, they will never see a TV set.

                        So I should be able to edit and view them in FCPX on a computer (with calibrated monitor) and make them look quite the same as they are exported to a computer (with calibrated monitor).

                         

                        By the way, I know we are on Adobe forums here but, since QTX is displaying wrong gamma and since QTX & FCPX are displaying the same thing, it is easy to notice that the monitor in FCPX is off. How can I make good grading then if I use FCPX ?