10 Replies Latest reply on Dec 2, 2011 12:06 AM by sp101010

    Safe Margins

    sp101010

      Hi,

       

      This will probably end up being a few questions....sorry!

       

      I capture live footage from an event into PP via a BMD SDI Card.

       

      I capture as SD. I then create a sequence using 'Use clip to create sequence'.

       

      The live footage is predominantly PowerPoint, with text and images using all of the slide, right out to the very far edges. The image is all visible in my Program monitor, but outside the safe margins.

       

      When i send it to Encore and create a DVD, i start losing edges of the image as it is outside the safe areas.

       

      I use the scale effect to reduce the size of the image slightly, and that works fine for getting all the image onto screen. The image however degrades significantly, the text becomes almost unreadable. Why is this? Is there any way to make the image smaller without the quality loss?

       

      The Safe margins are also slightly not correct for when i create a disc and it would be nice to alter the safe margin sizes. Is this possible?

       

      Last question... The SDI out of my BMD card show the 'Source Monitor'. How can i make it output the Program Monitor so it shows me what i am editing?

       

      Scott

        • 1. Re: Safe Margins
          Harm Millaard Level 7

          DVD is 720 x 480 NTSC or 720 x 576 PAL. If your source material does not adhere to these dimensions, there will be scaling and possibly quality loss.

          Safe margins have no relation to the final quality, it is only a visual aid during editing for display on analog TV's and are irrelevant for your workflow.  What is relevant is that Powerpoint slides are usually square pixels and DVD uses non-square pixels. So check your PAR carefully.

          • 2. Re: Safe Margins
            sp101010 Level 1

            Thanks Harm,

             

            The capture file and the sequence both are 720x576.

             

            The quality is fine, until i use the scale effect to make the entire image smaller. I need to make it smaller as it is too big when made into a DVD. Its all visible when editing, but not when i play it.


            SP

            • 3. Re: Safe Margins
              Harm Millaard Level 7

              The 720 x 576 dimension is correct for DVD. You need not make it smaller to fit a normal screen, on the contrary, that is a sure way to lower quality. What might be going on here is that the PAR of the source material is wrong. In that case you need to use interpret footage to set the correct PAR.

              • 4. Re: Safe Margins
                sp101010 Level 1

                OK, i used interpret footage and tried every PAR possible. It didnt help. Without being smart i didnt think it would but i couldnt come back without atleast trying it!

                 

                All PAR changes kept the full height image which is the problem, as some of the text is outside the safe margins and therefore disappear when burnt to DVD.

                 

                SP

                • 5. Re: Safe Margins
                  Harm Millaard Level 7

                  some of the text is outside the safe margins and therefore disappear when burnt to DVD.

                   

                  That is not correct. The text is still there, but whether it is shown when played back depends on the TV used. Older analog tube TV's have often large overscan areas and may display only 90% of the image but most flat screen TV's show almost the entire picture. Since you said the source material is Powerpoint slides, it makes sense to adjust the position of the text in the slides in Powerpoint to compensate for the display on older tube based TV's. I repeat that safe margins are nothing more than a visual aid to be aware that some analog TV's may not show the material outside those margins, but you will find that different analog TV's show more or less of the total picture, depending on the overscan used by that TV.

                   

                  When encoding, the whole picture is used and ends up on the DVD. It depends on the quality of the TV how much of that 100% picture is displayed.

                  • 6. Re: Safe Margins
                    Stephen_Spider Level 3

                    So you captured a powerpoint presentation through your BM card directly as a video clip? If the PPT presentation wasn't composed with broadcast safe margins in mind at all, there will need to be scaling done to fit in. That's why I usually get powerpoints as .bmps and process them in Photoshop.

                     

                    Most of the time shrinking the clip a little will not cause horrible degradation. It sounds like the image may already be marginal?

                     

                    Have you tried creating a custom sequence that is about 10% bigger on width and height, the drop your presentation clip into that?

                     

                    About your monitor problem, the program monitor should show whatever is  on the timeline when playing, scrubbing through the sequence or playing from the program monitor on the top right. If it doesn't, there are some hardware issues going on.

                    • 7. Re: Safe Margins
                      sp101010 Level 1

                      Hi Again,

                       

                      Completely agree, all the image is there but the issue is the overscan problem. Its lots of TV's though, including a 2 week old LED. Regardless of the TV age etc, the customer cant see the whole picture and I need to fix that.

                       

                      I tried using scale and that blurs the image.

                       

                      Yes, the PPT slides are the problem, we send them a template with margins, but if they ignore that advice and show up 10 minutes before they hit the stage, editing them is not a possibility. Everything (slides and live camera/s) is captured via SDI on a BMD Card.

                       

                      Importing the slides as images has a few issues: We quite often PiP the image with the live camera, the images still need to be scaled (and then blur!) and the timeframe really doesnt really allow it...

                       

                      I'll try the custom made sequence idea and see if that works. Theory says it should!

                       

                      I'll hassle BMD about the card issue as the SDI output is showing the 'Source' monitor, not the Program monitor.

                       

                      Thanks all!


                      SP

                      • 8. Re: Safe Margins
                        sp101010 Level 1

                        OK small update,

                         

                        Outputting of the timeline to the SDI Card was due to not using the BMD Sequence presets. Using these ensures the card responding correctly. Makes it a bit hard to create a sequence based on the properties of a clip or image.

                         

                        Using a BMD sequence made it output to a TV monitor, including the issues im having with the image becoming blurry after scaling the size down. Capturing the image as 1920x1080 and using a 1920x1080 sequence fixes all these issues on the monitor, overscan fixed and image is sharp and crisp. Until i burn to DVD, then it was blurry and crap again...

                         

                        Any ideas?

                         

                        SP

                        • 9. Re: Safe Margins
                          Stephen_Spider Level 3

                          HD vs SD?

                           

                          1920 X 1080

                          vs

                          720 X 480

                           

                          Have you tried watching the DVD on a SD monitor?

                          • 10. Re: Safe Margins
                            sp101010 Level 1

                            Yeah same problem, Overscans and Blurry...