7 Replies Latest reply on Apr 2, 2010 8:39 AM by anonmous

    I-Frames in Premiere Pro CS4

    anonmous Level 1

      Hello, in the book 'Real World Video Compression', the author notes that within Final Cut Pro he "may tell Compressor to insert I-Frames at specific locations, which you do by inserting a compression marker." He says he might want to do this for footage which is 'particularly dynamic.' Is there a way within Premiere Pro CS4 to insert an I-Frame at a specific location?

       

      Thank you,

       

      Matt

        • 1. Re: I-Frames in Premiere Pro CS4
          Jeff Bellune Adobe Community Professional

          Encore chapter markers.

           

          -Jeff

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          • 2. Re: I-Frames in Premiere Pro CS4
            Pijetro Level 1

            Assuming you're talking about video for web, then no, this would be a function required within Adboe Media Encoder, since it's at the stage of compression (final output)..

            The timeline in Ppro is a utility that wasn't designed for this in mind...

            And although the Encore timeline allows for markers, i don't think it had "I frame" insertions in mind that dedicated compression programs give you for optimimum filesize/performance.


            Compression markers at output, and timeline markers are two different things...

            • 3. Re: I-Frames in Premiere Pro CS4
              anonmous Level 1

              Thanks to both who responded.  I'm stumped.  One response stated that placing an Encore chapter marker within Premiere would result in making the frame an I-frame, and the other response stated that I needed to mark frames as I-frames within AME.  In the Encore CS4 help it states that if the source is MPEG-2, then setting a chapter point will insert the chapter point at the nearest GOP header, but that if working with a .avi file, adding a chapter point will result in the frame being interpreted as a GOP header.  So,

               

              1. If my source within Premiere is anything other than MPEG-2, will adding an Encore chapter marker from within Premiere follow the rule as dictated by the Encore CS4 help?
              2. If my source within Premiere were MPEG-2, would I be able to add an Encore chapter marker from within Premiere only on existing GOP header frames as implied by the Encore CS4 help?
              3. The other poster mentioned setting I-frames within Adobe Media Encoder, but I don't see where this can be done.  Is AME able to do this?
              4. Is it correct to assume that if I used dynamic link to send a sequence from Premiere to Encore that the rules would stay the same?

               

              Thanks,

               

              Matt

               

              Message was edited by: anonmous to make the questions hopefully more concise

              • 4. Re: I-Frames in Premiere Pro CS4
                Jeff Bellune Adobe Community Professional
                1. Yes.
                2. No.  Exporting from Pr as MPEG2 DVD will force a re-encode and a new GOP will begin at each En Chapter Marker (as long as there is text in the Name field of the marker).
                3. I didn't test, but it seems the best you can do is to check "Automatic GOP Placement", which lets the AME decide where I-frames should go.  Auto placement isn't available for MPEG2 DVD, only for MPEG2.  That means you'd be responsible for making sure that all of your MPEG2 settings were fully DVD-compliant. 
                4. The rules for Pr sequences apply inside of En when a Pr sequence is added to the En project via Dynamic Link.

                 

                NB: If you don't want the audience to be able to skip to the chapter markers that are being used as compression markers, then export from Pr as MPEG2 DVD, and import the encoded file into En.  Once the encoded file is added to an En timeline, delete the compression chapter markers.  The I-frames that were created will remain in place.  If you dynamically-link the sequence from Pr to En, then transcode the sequence *before* you build the project by using File | Transcode Now.  Then delete the compression chapter markers as before.

                 

                -Jeff

                • 5. Re: I-Frames in Premiere Pro CS4
                  Pijetro Level 1

                  I think there's been a misinterpretation here...

                  I haven't read the book, but i'm sure the authour meant "dynamic range of type of footage", and not Dynamic linking from app to app..

                   

                  As far as compression for web output, you have advanced settings that allow for extra I frames to be added for footage that has high action, and you need to break the GOP's up, and want to keep the quality. This sort of overrides the universal settings of your project.

                  These are advanced options within advanced compression programs like Sorensen Squeeze..These options usually aren't available in NLE exports.

                   

                  As far as Dynamic footage, i think the authour meant Dynamic colours, and actions..Not Dynamic linking...

                   

                  But i've been wrong before...

                  • 6. Re: I-Frames in Premiere Pro CS4
                    anonmous Level 1

                    Jeff, thanks for the thorough and clear answers!

                     

                    Matt

                    • 7. Re: I-Frames in Premiere Pro CS4
                      Jeff Bellune Adobe Community Professional

                      You're welcome. 

                       

                      -Jeff