17 Replies Latest reply on Mar 2, 2010 5:45 PM by Phil Griffith

    Multi Camera Sync Question




      Premiere Pro CS4




      Sony HDR-SR12

      Flip Ultra HD





      I did a multi camera shoot that lasted about 40 minutes.  In editing, I synced the video clips from the cameras above around the beginning of the clips, and at the end of the clips, the Contour is about 11 frames off and the Flip is about 1 frame off, both being compared to the Sony.  What is the best way to fix this?  Is there something that can be done to make this not happen in the future, or is it just the nature of the beast?

        • 1. Re: Multi Camera Sync Question
          Harm Millaard Level 7

          Flip and Contour are troublesome to edit. Either convert the material to something editable or use other software, like WMM.

          • 2. Re: Multi Camera Sync Question
            gamzu07 Level 1



            Thanks for the quick reply.  I'm not sure what you mean by "convert the material to something editable" because the video is definitely in an editable format, I'm just not sure what is the best approach to fix the frame sync issue.  Also, I'm assuming by "WMM" you are referring to Windows Movie Maker, and I don't see why using a less capable product would fix the problem.


            I see you have a lot of posts and are most likely way more knowledgeable than me, but maybe you should make more quality posts so it can benefit us noobs better.

            • 3. Re: Multi Camera Sync Question
              Phil Griffith Level 2

              I would say that if they were in an editable format, they would stay synched! I

              • 4. Re: Multi Camera Sync Question
                gamzu07 Level 1



                So you're saying my video is currently un-editable and there's nothing I can do with it, all hope is lost and my multi camera shoot was a complete waste of time, and that I can't use a program that edits video clips to edit my videos to fix the issue because apparently they are completely corrupted and un-editable?

                • 5. Re: Multi Camera Sync Question
                  Phil Griffith Level 2

                  No, I'm not saying that. But basically, the contour and the ultra are basically meant to watched and not edited. IMO, convert them to the same  media if you want them to sync. Or not. You get to decide.

                  • 6. Re: Multi Camera Sync Question
                    Harm Millaard Level 7

                    PR is built on the premise that Pro video editors use standard (Pro) video cameras to edit their material. It is just a fact of life that there are so many different formats around, that no single program can handle them all. Consumer programs like WMM (Windows Movie Maker) handle more different formats, even ones that were never intended to be edited. PR does limit itself to specific formats, under the adagio: Do what you are good at. Don't turn into a Jack-of-all-trades.


                    Flip and Contour use, at least from PR's point-of-view, non-standard formats. Those formats are not easily edited, but programs like WMM can handle these much easier. Hence my remark.


                    For optimal use of PR, which is intended for semi-pro users or prosumers, not for the occasional student or dilettante, one would use a semi-pro or prosumer or professional camera, not a Flip, Aitek or Contour toy. Sorry if you don't like that term, but be real, these cameras are toys in comparison to P2, XDCAM or RED cameras. If you use an iPhone to record videos, who in his right mind would want to edit that crap, let alone with a professional tool like PR?


                    If you want to do multicam with PR, at least make sure you don't have garbage as a source, because then the GIGO law applies.

                    • 7. Re: Multi Camera Sync Question
                      gamzu07 Level 1



                      I don't even know where to begin.  You are completely missing the point.  I haven't been on this forum very long, and it appears that I don't fit in, but what I would do when someone asks a question is to ANSWER THE QUESTION!


                      I don't need you to tell me that my equipment isn't worth thousands of dollars.  I don't need you to suggest inferior software that can't even do what I want to do.  I don't need you to ramble on what you think PR should be used for.


                      What I want is for you to answer the question:


                      What would you do if you had two video clips (doesn't matter where they came from) that were synced at the beginning, and by the end of the clips, one was off by 11 frames?


                      From what I've read, this can even happen to higher-end cameras.  One solution I thought of would be to cut the clip that gets out of sync by 11 frames into 11 parts, and re-sync each part to the master clip, and then not use those frames that were lost when editing in multi-cam.

                      • 8. Re: Multi Camera Sync Question
                        Harm Millaard Level 7

                        Reread # 1. There is the answer.


                        If you then ask for more explanations to help a noob and you consider that rambling, bad luck.


                        Editable material does not go OOS (out-of-sync) on it's own volition. OOS happens because the material is not suitable for editing due to the format used (Flip, Contour) or because of OE.


                        EOS. (End of story).

                        • 9. Re: Multi Camera Sync Question
                          gamzu07 Level 1

                          Hopefully that is your last story.

                          • 10. Re: Multi Camera Sync Question
                            Curt Wrigley Level 4

                            I have no experience with the Ultra Flip and how it encodes.  But if you have it's cousin the Flip HD; it plays quite nicely with Pr CS4.




                            Do you know what the Ultra records to (what format, codec, frame size, frame rate...?)

                            • 11. Re: Multi Camera Sync Question
                              gamzu07 Level 1

                              I have the Flip Ultra HD (which is what I think you are referring to), which does play nicely with Pr CS4, and it and the ContourHD and the Sony HDR-SR12 all use the H.264 format.


                              This page has all the info you requested: http://store.theflip.com/en-us/products/UltraHD.aspx

                              • 12. Re: Multi Camera Sync Question
                                Curt Wrigley Level 4

                                If they all use the same encodg; then note the preset you should be using in the blog I quoted.

                                • 13. Re: Multi Camera Sync Question

                                  I am sorry so many responses to your reasonable question have been answered with such arrogance.  Here's my shot at a straight answer.


                                  There are many reasons why multiple long video segments can drift out of sync with each other, so it is difficult to tell which problem you may be facing, but here are some places to look:


                                  - The original cameras were not gen-locked together.

                                  Even $100,000 cameras will not stay in sync forever.  Pro cameras use a feed from a sync generator (or sometimes black burst, a composite video signal or even a word clock) that is fed to a special "gen-lock" input on pro cameras.  None of your cameras have this feature however.


                                  - You were powering the cameras from battery instead from an AC source.

                                  In the absence of a gen-lock signal, most cameras (including many prosumer and consumer models) will look to the 59.94 AC circuit (in the US) and will try to clock out the frames in sync with this power source.  If all cameras are powered by AC, then this is a "poor man's" gen-lock.  Note that this does NOT guarantee lipsync however, but it often keeps you closer.  On battery power, this clocking signal is unavailable and cameras tend to drift out of sync more easily.


                                  - You dropped frames during recording or capture.

                                  This is a VERY common way to lose sync over long periods of time, particularly when ingesting from tape.  Premiere often fails to detect glitchs or drop-outs, and this can be a real frustration in a multi-camera shoot.  When I have a sync problem in a long shoot, I often have to spot check the multi-cam sync every 5 minutes of so on the timeline to narrow drop where a drop-out occured.  There is often a freeze frame, a picture tear, or a color screen, but sometimes they are hard to spot.  When you find one, use the cut tool to turn the original clip into two clips and then slide the second one back into sync.


                                  - You used different CODEC's or frame rates on each camera.

                                  Every time a computer processes the video or audio, it has to "think" about what it is doing, and this processing (both in the camera and in your editing computer) sometimes results in slightly different different timings between HDV, AVCHD, Quicktime, MPEG2, etc.  It SHOULDN'T be different, but it sometimes is.  Sync is also frequently lost when going between a shooting codec and an editing one.  Try to be consistent in your signal processing.  (And look out for 29.97 vs 30 - they are NOT the same and clips will drift WAY out sync in an hour))


                                  - Audio is no longer in sync with video or timecode

                                  Audio is a different codec than video, and sometimes the picture is in sync, but the audio is not (or the timecode).  Even pro's use heads and tails visual slates with a "clapper" or a flash and sometimes even a timecode display to head them put video, audio and timecode back where it all belongs.  So buying a "pro" camera guarantees nothing......


                                  So, how do you fix it?


                                  1)  Re-capture if from tape and make sure you handle all clips the same way.

                                  2)  Drop all of the clips into sync at the beginning of the clips and then march through the quad split display to see when they begin to fall out of sync.  (You can also sometimes compare the 4 audio tracks and see EXACTLY which clip is the "odd man out")

                                  3)  When you find an error, cut the clip and slide it to fix.

                                  4)  Repeat until you are done.


                                  I do NOT recommend doing a time warp to fix things by speeding up up or slowing down a clip.  This will introduce picture quality errors, audio issues and other bad things.


                                  I hope that helps...


                                  Mike Fayette

                                  • 14. Re: Multi Camera Sync Question
                                    gamzu07 Level 1



                                    Thanks for the quality post, I learned a lot, and I'm sure future readers will to.  I knew someone on this forum had to have some knowledge with common sense to go with it.  I was hoping for an "easy button" solution, but it looks like I'll just have to check the sync every few minutes, until I get crazy expensive gear, which will probably be never.

                                    • 15. Re: Multi Camera Sync Question
                                      Curt Wrigley Level 4

                                      Mike, I think you missed the fact that he is using tapeless cameras.


                                      Did you check that you are using the proper sequence preset?   If you are there will be no colored line over the clips.

                                      • 16. Re: Multi Camera Sync Question
                                        gamzu07 Level 1



                                        Mike was listing across the board reasons for syncing issues and assumed I would use common sense and only look at the ones that pertained to me.  I'm assuming he also listed tapeless information for future readers that may not be under the exact same circumstances.


                                        And yes, I have the correct sequence preset, but the one camera is still off a little.

                                        • 17. Re: Multi Camera Sync Question
                                          Phil Griffith Level 2


                                          Here's my take on your responces.

                                          1.- The original cameras were not gen-locked together  



                                              I use 2 Sony digital cameras and a Panasonic analog camera and they all sync up to each other in Premiere just fine. For over 2 hrs they stay synced. All the time. No, I dont tether the cameras to a time source  while I use them.



                                          2. You were powering the cameras from battery instead from an AC source


                                               I always use battery on my cameras. Kinda hard to move around tied to a power cord.\


                                          3. You dropped frames during recording or capture


                                             Yes, this could cause sync problems. But op never mentions lost frames. and my experience with Premiere has been that it will tell you if even one frame is skipped. You can even tell it to stop capturing if it skips frames.




                                          5.  Audio is no longer in sync with video or timecode


                                          Well, you should be able to tell if that's happening before you do a multicam setup. Are the clips playing ok by themselves?


                                          All this leads to your "fixes"


                                          Go back and capture in the same format for all three cameras. Supposedly, the op says that they are the same format. So what's next?
                                          Perhaps change them from H264 to something else? Perhaps that might work and that's what I suggested from the start.. So did the other arrogant person. Convert your video to a good format that Premiere likes.  Do a search on the forums and see just how many times that's been said!


                                          If giving answers and suggestions that someone doesn't like, then I guess I'm arrogant.

                                          On the other hand, comin to the forum and asking for advice then basically saying you don't know what you're talking about, Isn't that kinda arrogant too?

                                          Don't mean to get in to a tif here, but I kinda resent being called arrogant here.

                                          Just my two cents. Life goes on.



                                          PS.  Sorry bout the underlines. Couldn't turn the underline off


                                          Edit:  I took the underlines off for you. (Curt)