17 Replies Latest reply on Jul 5, 2009 12:46 PM by Bob Ramage

    Slow mo jitter

    rmkmail

      When I add slow motion (or fast motion) to a SD PAL clip it looks fine when playing from the timeline but when rendered as Mpeg2 ready for dvd burning the clip jitters. I try to keep the speed control to whole ratios of the 50i frame rate. Any thoughts?

       

      Richard Knight

        • 1. Re: Slow mo jitter
          Ann Bens Adobe Community Professional & MVP

          When adding slomo always deinterlace the clip. (field options)

          Also reverse the field dominance when not on Matrox.

          • 2. Re: Slow mo jitter
            Bob Ramage Level 1

            I have also experienced this problem since the 4.1 update. Same footage. Same editing methods. My opinion is that the 4.1 update did something to frame blending which has worsened it noticeably.

            • 3. Re: Slow mo jitter
              pradamedia

              Have to agree with Ann on this.  Deinterlacing is the only way I can get it looking ok.  I also switch out frame blending.  I also have problems with progressive filter changes in a scene.  Introducing a gaussian blur over time, for example, was stuttery and unusable.  Remove frame blending and it works better, although I think it softens it too.

               

              I wonder if it's time for adobe to release a communique comparing CS3 and CS4 media handling characteristics - so you could see immediately how to modify workflow to get the same or better results than the previous software version.  It would save a lot of posts.  Of course that would mean them looking at their product through editor's eyes.

              • 4. Re: Slow mo jitter
                Bob Ramage Level 1

                All of my footage was deinterlaced. Prior to the 4.1 update slow motion with a moving camera looked beautiful. Now it produces a stuttery effect instead of the former smoothness. Either something was done to Premiere's frame blending which worsened it, or the AME is causing a problem.

                • 5. Re: Slow mo jitter
                  Jeff Bellune Adobe Community Professional

                  Bob,

                   

                  I know you've probably checked a dozen times already, but is there any chance that Frame Blending was accidentally turned off for the clips in question?  Because I get beautifully smooth slo-mo here (using Time Remapping) with 4.1.

                   

                  -Jeff

                  • 6. Re: Slow mo jitter
                    Bob Ramage Level 1

                    I checked the clips Jeff, and frame blending was enabled. The slow motion looks okay if the camera is stationary, but with any camera motion (e.g. pan, tilt, truck, dolly) there is a noticeable shudder and slight blurring. I didn't get this prior to the 4.1 update, and it manifests itself with 60i, 24p and 30p EX1 footage, regardless of output format and with the "max quality" switch enabled in the AME. I went back and looked again at some older edited slow motion footage and the difference in quality is very noticeable.

                    • 7. Re: Slow mo jitter
                      Jeff Bellune Adobe Community Professional

                      One other thing to check is that the sequence that you are exporting is

                      set to Maximum Render Quality - not just the AME.

                       

                      Other than that, I don't know what to tell you.  I've got lots of SD

                      footage with camera motion, but all of my HD footage uses a stationary

                      camera.  FWIW, my SD footage doesn't exhibit the issue.

                       

                      -Jeff

                      • 8. Re: Slow mo jitter
                        Colin Brougham Level 6
                        One other thing to check is that the sequence that you are exporting is

                        set to Maximum Render Quality - not just the AME.

                        Jeff,

                         

                        Just out of curiousity--because I'm really not sure--I was under the impression that the "Maximum Render Quality" option in the sequence settings only pertained to rendered preview files, and didn't have anything to do with exporting (unless, of course, you were using the "Use Preview Files" option in AME). Just curious...

                        • 9. Re: Slow mo jitter
                          Bob Ramage Level 1

                          The sequence is set to max render quality. As I said, this problem only appeared with the 4.1 update. Just to make sure I wasn't imaging things, I looked at three earlier projects edited with 4.01. In every one of them the slo-mo output quality is significantly better. All of my projects over the past year have been shot using the EX1. The output difference manifests itself in output to DVD, Blu-ray and H264. I have noticed the problem now in three separate projects. The only thing which has changed is the update to PPro and the AME.

                          • 10. Re: Slow mo jitter
                            Jeff Bellune Adobe Community Professional

                            Colin,

                             

                            You are most likely correct, and the layout of the sequence settings

                            dialog does suggest that.  However, I have seen enough variation in

                            export time and quality depending on whether a sequence is nested, or

                            whether Dynamic Link is in use, to be very careful with how I set that

                            option.  So I explicitly set it on every object that is involved in the

                            export, including the main sequence and any nested sequences.

                             

                            For example: below are the times for a 1+49 sequence when going from HD

                            1080i to SD 480i, using 2-pass VBR MPEG2-DVD encoding:

                             

                            A. Export the HD sequence, no MRQ anywhere: 3+57

                            B. Export the HD sequence, MRQ on for the HD sequence and the AME: 15+19

                            C. Nesting the HD sequence in an SD sequence and exporting the SD

                            sequence, MRQ on everywhere: 37+50

                             

                            Quality is noticeably better with each increase in render time. 

                            Theoretically, there should be no difference in time or quality between

                            B and C.  But there is.  And so I am very careful when I set up my exports.

                             

                            -Jeff

                            • 11. Re: Slow mo jitter
                              Colin Brougham Level 6

                              Thanks for that info, Jeff--this is pertinent as I'm moments away from beginning a 90-minute, three-camera DVCPROHD 720/24pN, with color correction and reframing "fixes" export to 24p DVD. I'm starting it today, with hopes that it'll finish up over the weekend. A preview render for my client at single-pass CBR without any of the MRQ options set took over 6 hours, and that's on a dual dual-core 2.33GHz Xeon. I hope I don't kill my computer.

                               

                              Apologies to the OP for going off-topic!

                              • 12. Re: Slow mo jitter
                                Bob Ramage Level 1

                                I've submitted a bug report to Adobe. In the meantime, much as I hate to do it, I will probably revert to 4.01.

                                • 13. Re: Slow mo jitter
                                  Jeff Bellune Adobe Community Professional

                                  Bob Ramage wrote:

                                   

                                  I've submitted a bug report to Adobe. In the meantime, much as I hate to do it, I will probably revert to 4.01.

                                  Bob,

                                   

                                  If/When you do revert, please process some footage in the reverted version and let us know the results.  Thanks.

                                   

                                  -Jeff

                                  • 14. Re: Slow mo jitter
                                    Bob Ramage Level 1

                                    I reverted to 4.01 and the jittery slo-mo was fixed. Clearly something changed in 4.1. I encoded the same selection of timeline in both 4.01 and 4.1. in 4.1 the jittery slo-motion appears. It is very noticeable and annoying. The image does appear slightly sharper during these moves, leading me to believe that a change was made to the frame-blending algorithm favouring sharpness at the expense of smooth motion. I used the previous version of the AME for both encodes to verify whether the problem was caused by it or Premiere. Looks like Premiere was the culprit.

                                    • 15. Re: Slow mo jitter
                                      tclark513 Level 3

                                      Bob Ramage wrote:

                                       

                                      I reverted to 4.01 and the jittery slo-mo was fixed. Clearly something changed in 4.1. I encoded the same selection of timeline in both 4.01 and 4.1. in 4.1 the jittery slo-motion appears. It is very noticeable and annoying. The image does appear slightly sharper during these moves, leading me to believe that a change was made to the frame-blending algorithm favouring sharpness at the expense of smooth motion. I used the previous version of the AME for both encodes to verify whether the problem was caused by it or Premiere. Looks like Premiere was the culprit.

                                       

                                      Bob,

                                       

                                      Did you happen to try the "Time Warp Filter" instead of the time remapping?  It has better results!  I am curious if that yields the same problem.  I don't have the right footage to try.

                                      • 16. Re: Slow mo jitter
                                        Bob Ramage Level 1

                                        I  just did a simple speed change to 50% on each clip. No filters applied. Frame blending on by default. I'll give the time warp filter a whirl and have a look. Thanks for the suggestion.

                                        • 17. Re: Slow mo jitter
                                          Bob Ramage Level 1

                                          Tried the time warp filter, and I have to say it certainly does produce some breathtaking slow motion. Takes a looooonnnnggg time to render, though. Still, it's a preferable solution to going back to 4.01. The only problem I had with time warp was strange jello-like artifacting in the entire frame whenever a still camera flash went off. Switching from pixel motion to frame mix on effected clips resolved this (although the resulting slow-motion wasn't quite as nice).

                                           

                                          I'd still like to see an improvement of basic frame-blending to the same smoothness as existed prior to the 4.1 update.