8 Replies Latest reply on Mar 12, 2009 2:33 PM by LudaDave

    Repeated frames when time remapping AVCHD clips in AE

    LudaDave
      I will try to explain the best I can. Keep in mind I am a novice and by no means highly technical. First some background: I edit sports video for college bound athletes. I put together highlight videos for them. When I am filming I start/stop the camera at the beginning/end of a play so I can easily identify/edit "clips". I have imported 10 AVCHD "clips" from my Sony HDR-SR11 to a Premiere Pro CS4 project. I am using the "AVCHD 1080i anamorphic/29.97fps" sequence setting as my output for this project will be a 1440x1080 mepeg2 file. So I get my clips in the timeline add some transitions, no major edits, render the work area and playback. Everything looks fine, all clips play smooth. Now here's the rub. I want to freeze play, highlight an athlete then continue play. To do this I am using AFTER EFFECTS (NOTE I have done this with HDV footage off my Canon HV20 camera with no problems) so anyway with the new CS4 edition I can right click on a clip in my timeline and choose "replace with after effects composition"....I do and the clip migrates to AE into a a composition ready for me to work my magic. So my method for freezing play is select the "clip" in the composition, Ctrl-Alt-T for time remapping. I add 5 seconds to the duration of the composition since I am going to add time when I freeze the clip. I find the point in the clip where I want to freeze it. I place a "time remap" keyframe at that point. I then drag my mouse to highlight the keyframe I just placed and the keyframe at the end of the clip......I drag them to the right 2 seconds, then cut/paste the keyframe I added which is placed by the CTI (which is still at the original point). Now I have a 2 second freeze in play. I add a white solid and do some masking to highlight the athlete during that freeze. And that's it.....I press "O" then "N" to define the work area then I choose "trim comp to work area" from the composition menu. I repeat this process to all my clips and here is where I see the problem. I go back to my timeline in PP and I play the clips......I see my freeze/highlight edits from AE just fine but on SOME clips......2 out of 5 for example.....I get jittery playback. So I decided to scrub thru the clip frame by frame to see what is going on. So within 29 frames this is what I see. Girl is getting ready to serve a volleyball....Frame 1-15....she steps forward to serve THEN at frame 18 she pops back to the starting point...IT LOOKS LIKE FRAMES 1-12 ARE BEING REPEATED. I scrub the rest of the clip and this happens at random points....a small block of frames gets repeated throughout the clip which in the end looks like "jitter" or "jumpy" motion. I follow the same workflow in AE for each clip BUT this "jitter" does not happen on every clip...only some. So is my workflow at fault or is AE/PP/Adobe still buggy when it comes to working with AVCHD codec?? Anyone else experience this, if so do you have a fix?
        • 1. Re: Repeated frames when time remapping AVCHD clips in AE
          Andrew Yoole MVP & Adobe Community Professional
          Your workflow sounds fine. It sounds to me like there may be some kind of bug with AVCHD and AE. Any long-GOP format like AVCHD is very complex for a program like AE to deal with, because the format doesn't contain individual discreet frames of vision.

          To test the theory, try converting one of your problem pieces of footage to a lossless codec such as Quicktime Animation (100% quality, no keyframes) or even Uncompressed. Then take the original AE project and replace the AVCHD footage with the new lossless copy.

          If the error continues to occur, we have more to discuss. If the error is gone, my guess is that there is some processing error in the AVCHD codec causing the problem, which may not be fixable besides working around it as mentioned above.
          • 2. Re: Repeated frames when time remapping AVCHD clips in AE
            LudaDave Level 1
            Andrew thanks for the feedback. Just to clarify when you say take a "problem piece and convert" do you mean take the clip that I have applied the AE to or the original clip before I have added any effects? Export that clip to a "lossless" format and then drop it in the comp to replace the .mts file?
            • 3. Re: Repeated frames when time remapping AVCHD clips in AE
              Andrew Yoole MVP & Adobe Community Professional
              I mean the original captured footage, before you take it to AE. Once it's converted (in Quicktime Pro or any other conversion utility you might have) then take it into AE.

              The point is to determine if the AVCHD format/codec is causing the problem or not.
              • 4. Re: Repeated frames when time remapping AVCHD clips in AE
                LudaDave Level 1
                I haven't tested your theory yet Andrew but I did do this. In trying to track down exactly where these repeated frames are occurring. In AE I redid one clip that was repeating frames. I went frame by frame in AE and see no repeated frames. These changes should occur automatically in PP since the AE comp is still dynamically linked to my PP timeline. So I scrubbed the "source" (AE comp) file from the PP project panel frame by frame. And low and behold there are repeated frames, so it appears the problem is the handoff from AE to PP Sooooooo, ok I deleted the source file in the PP project panel and reimport it via dynamic link. Open the clip in the source monitor and yes...repeated frames at same point....recheck the comp in AE....no repeated frames. Delete the clip from PP project panel and this time import the clip directly instead of dynamic link.....repeated frames still there. So how about rendering the clip in AE the old fashion way then import to PP. AE Render Queue best settings - lossless.....blah blah blah. I ended up with an .avi file with no repeated frames. So to me the problem is the handoff between AE & PP. So rendering my AVCHD comps in AE first is my work around for now. Andrew...thanks! I will try your theory of converting the clip prior to the comp asap...right now I am trying to meet a deadline.
                • 5. Re: Repeated frames when time remapping AVCHD clips in AE
                  LudaDave Level 1
                  I guess that does rule out the AVCHD format as the problem (well sort of...it's a problem for Adobe)......seems to me the problem is with AE handing off a non-rendered comp to PP....yes? no?
                  • 6. Re: Repeated frames when time remapping AVCHD clips in AE
                    Andrew Yoole MVP & Adobe Community Professional
                    Sounds like you have the problem identified, at least! All I'd observe is taht, if the original footage (not Dynamic Linked) viewed in PPro also exhibits the problem, sounds like its PPro not coping with AVCHD.
                    • 7. Re: Repeated frames when time remapping AVCHD clips in AE
                      Level 1
                      I've found that if I want to do any kind of manipulation of time with AVCHD clips I first need to convert them to another codec. The MPEG GOP scheme gives a bunch of problems. I usually just convert the clips to Motion JPG files, then after the tweaking is complete I can send them to any format I wish.

                      I also have found that AVCHD clips will occasionally come in at the wrong frame rate. The format is kind of an odd duck still.
                      • 8. Re: Repeated frames when time remapping AVCHD clips in AE
                        LudaDave Level 1
                        Yes! odd duck it is. So much for saving time "capturing" :) BUT I look forward to when AVCHD shares a peaceful co-existance with Adobe's suite of production tools. Thanks guys.