7 Replies Latest reply on Mar 12, 2012 8:56 PM by cgidude

    Rec601 / broadcast safe colors

    cgidude

      using premiere pro CS5.5 or TMPGEnc+ i'm exporting MPEG2 files for PAL broadcast.  i'm able to create an MPEG2 file which i'm pretty sure will meet all specs of the digital delivery service, however as i'm new to broadcast delivery i'm unsure of the quickest way to comply with Rec601 levels.  

      apologies in advance for noobness of my post but does Rec601 basically mean restricting luminance between 16-235...?  that's easy enough to level but what about color saturation...?

      i understand there are good tools out there for this like Color Finesse, but this a very low budget project & at this stage i just need a fast solution. 

      any info much appreciated.

       

      kind rgds,

      -paul

        • 1. Re: Rec601 / broadcast safe colors
          shooternz Level 6

          Heres a quick and dirty explanation and solution ( because I do not know your BC specs)

           

          You need to limit Luma and Chroma Levels.

           

          It is "content dependent" so you need to look closely at what is in the clips ( in the timeline) before you export to your delivery media.

           

          Content dependent means video and graphics at any frame in the timeline and what the levels are... combined and separately

           

          Eg a black clip may be o.k until your peak white graphic is overlayed on top of it.

           

          Therefore legalise all the clips and graphics.

           

          How:

           

          Open all the scopes and look for clipping and excess in Luma and Chroma. ie where the peaks go flat or above.

           

          Simple solution: Get the levels down so they dont clip or exceed.

           

          Different content requires application of different Effects ( controls).  Its a bit trial and error but LEVELS is a good start point. Curves is another. R,G,B Channel Curves is another.  Set a video Luma Limiter eg. 95% High and 5% Low  may work.

           

          I usually need more than one effect on a clip.

           

          Its a fiddle in PPRO but very doable ...(and its a bit easier in Resolve where there are functions such as Soft Clip and precision WFMs)

           

          Tip: Any Peak white graphic will always be ilegal so sort it out before importing or creating one. 90% opacity on a white graphic is a quick and dirty fix but White Levels is better.

          1 person found this helpful
          • 2. Re: Rec601 / broadcast safe colors
            cgidude Level 1

            thanks heaps for that quick reply, it all made sense.  as per your sugesstion by setting white & black levels its quite easy to legalise clips' Luma. 

            Chroma i'm a little uncertain but basically when looking at the vectorscope, if the graph data hits the outer edges of the circle its clipping..?  i have one such clip with very saturated yellows, editing RGB curves & dragging down the RG seemed to fix it.

            btw i'm in NZ too   my delivery provider is eBus, spec below:

             

            File Chroma Encoding: 4:2:0 (or 4:2:2 by request)   (this setting can be specified in TMPGEnc+ but not in prem...?)

            MPEG Encoding Bitrate: 15Mbit/sec

            MPEG Encoding GOP: 12     (still have to research this one a bit lol)

            MPEG Encoding Type: Interlaced TFF

            Video Standard: PAL

            Aspect Ratio: 16/9 FHA or 4x3 as specified by broadcaster

            Frame Size: 720(H) x 576(V) pixels

            Frame Rate: 25.00 fps

            Picture Scan Type: Interlaced TFF or Progressive

            Picture Levels: Video Rec601 Levels

            • 3. Re: Rec601 / broadcast safe colors
              Jim_Simon Level 8

              In the tab under Effects>Video there is a Broadcast effect for this purpose.

              • 4. Re: Rec601 / broadcast safe colors
                shooternz Level 6

                Broadcast Effect goes no where near far enough for critical broadcast legalising.  Its kind of global and one needs to drill into different parts of the image and use other effects as well.

                 

                 

                @cgidude

                 

                The vectorscope is only part of the story. Use the Parades as well.  They effectively show what color is clipping at the top (flat lines).

                 

                A few transient peaks are o.k but sustained chroma cliping will get a Rejection Slip.

                 

                It is usually only one color that chroma clips but as I say..."content dependent".

                 

                You will be amazed how much you can legalise a color and it shows no visual difference

                 

                I have less issues at the Black level butg I do keep an eye on that.

                 

                White graphics need care and attention.

                 

                If you get a chance and for your own education...see if you can run a source clip or master clip thru' Ultrascope'.

                 

                All my work passes thru this at the facilty where I master.  (Digital Post).  It is enlightening to see how critical the BC legal rules are and how theruy are applied by the dleviverers ( eg eBus)

                • 5. Re: Rec601 / broadcast safe colors
                  cgidude Level 1

                  after looking at parades it appears most of my content has some clipping at 100% lol... what are the actual legal limits in the RGB parade for example.... nothing above 90-95%...?

                  • 6. Re: Rec601 / broadcast safe colors
                    shooternz Level 6

                    90- 95% is a good target .  I just mainly ensure I have no sustained clipping.

                    • 7. Re: Rec601 / broadcast safe colors
                      cgidude Level 1

                      all good.  i fount out about GOP so that's another issue sorted.

                      going OT slightly in the specs i listed a few posts back it gives two requirements for interlaced or progressive... MPEG Encoding Type & Picture Scan Type... in all software i've used there's only one option to choose interlaced or progressive when encoding so i'm not sure why its mentioned twice....?