9 Replies Latest reply on Sep 30, 2008 1:48 PM by (brohaugh_erik)

    audio / video sync problem

      i am having an issue with the audio being about 2.5 frames before the corresponding video in all of my .mp4 files taken with my sanyo xacti.

      i have discovered that it is not an issue with the camera as it plays fine on the camera and it also plays perfectly on the VLC media player. yet in adobe premiere elements 4 and in quicktime, i experience the problem described above.

      i am using windows vista with an intel duo processor (2.0 Ghz) and 2.0 Gb of RAM.

      thanks for any help that you can give me!!

      erik
        • 1. Re: audio / video sync problem
          the_wine_snob Level 9
          Erik,

          First thing I'd explore would be doing a file conversion to DV-AVI, before you Import into PE.

          Otherwise, if the OOS (out of sync) is constant, say your mentioned 2.5 sec., you can Alt-click on just the Audio (turn Snapping off) and slide it to sync.

          If the sync creeps, then either the initial file conversion, or cutting up the Clip into smaller Clips and manually adjusting the sync (tedious and seldom perfect for the entire Duration) would be an option.

          Good luck,

          Hunt
          • 2. Re: audio / video sync problem
            Level 1
            Hunt,

            Thanks for the advice. I have been doing something similar to what you say about sliding the audio over to line up, but it is tedious and not nearly as exact as the video is when played in VLC player.

            Are there free programs that will convert the file to dv-avi? Why would this make a difference? (not arguing, just don't understand)

            Thanks,
            Erik
            • 3. Re: audio / video sync problem
              (Dai_Jimpkins) Level 1
              Erik

              The reason Bill Hunt suggested converting to dv-avi (in my opinion) is that Premiere Elements is a dv-avi editor.
              Whatever you may import to it, it will convert it to a dv-avi internally.
              It sometimes has problems with this, so the best thing is often to give it a dv-avi file to start with

              Dai
              • 4. Re: audio / video sync problem
                the_wine_snob Level 9
                Erik,

                You are correct about the tedium of re-syncing more than a few Clips. In a good world, the OSS will be constant, so a re-sync, prior to cutting up the Clips is much easier. However, if the Clips are already cut, then you can speed things up a bit, by doing the first, and looking at the little number (will be a +, or - frames) in the upper left of the Audio Clip. This will tell you how far to jog the rest. If it's not constant, then each one needs to be done by hand, ear and eye.

                I try to find some obvious sound in the Audio Waveform and locate the visual for that (like a slate when shooting Audio & Video separately, but in sync). Only complaint that I have is that when one drags the Audio, the danged Waveform disappears! Same way in Pro. What I do is place my cursor on the spot in the Waveform, knowing that my visual reference will disappear, then drag my cursor to the visual clue. It still might take a few one frame moves, but is easier. I also like to expand the height of my Audio Track to see the Waveform better. Not sure if PE allows for this, as I do most of my work in Pro.

                As far as any software to automatically sync up Audio and Video, I'm not aware of any, but would love to hear of some, if anyone has recs.

                Dai is 100% correct on why I suggest doing the conversions before Import. Often, this will eliminate many sync problems, and will usually greatly speed up the editing in Premiere, as well.

                Good luck,

                Hunt
                • 5. Re: audio / video sync problem
                  Level 1
                  Thanks Hunt and Dai!

                  What software would you recommend for the conversion to dv-avi??

                  Also, Hunt, the shifting doesn't seem to line up exactly on a frame (it's something like +2.5 (frames)). Is that doable or do I need to do something extra like slow down a single frame to 50% and put that in the mix somehow?

                  Erik
                  • 6. Re: audio / video sync problem
                    the_wine_snob Level 9
                    Erik,

                    I use Digital Media Converter (Deskshare), and it has been very good over the years. Seems that it is ~US$49. I have a copy of it on all three of my machines. It does not have any built-in CODECs, so one would need any odd CODECs installed to convert from/to. With the adequate CODECs it is about 95% - 98% and does batch processing, plus you can set it's temp file, or "scratch disk," to other HDDs for quicker work. If you end up with something that it cannot convert, G-Spot (freeware) can be used to find out which CODEC you need.

                    Now, for the syncing issue. One half of a frame is only visible to one who knows the Audio and Video by heart. You can basically only align frame to frame. For 1/2 of a frame, I cannot imagine that anyone would notice. An NTSC frame is 0.033 sec. and 1/2 frame is 0.0167 sec. Gotta' have a sharp, frame-filling close-up to spot that. I always zoom in, so that I have a frame x frame view. I will add a Marker to the Video Track at the point that the sound should appear, i.e. a slap, an explosion, a noticeable vowel spoken, and then find that in the Audio. I will roughly get the Audio in alignment, and then place the cursor onto the peak for that sound. I drag this to align with my marker and release it. Then I check by scrubbing back and forth.

                    I've also changed the time to Audio Units for finer alignment. Might want to try that, if PE allows the Units to be changed. Now, I wish that I could move the CTI to my Video point, and then mark my Audio - press a button and have the Audio mark move to the CTI. That would be neat!

                    Hunt

                    Hunt
                    • 7. Re: audio / video sync problem
                      (Dai_Jimpkins) Level 1
                      I don't believe you can change the time ruler in PE. You are (unless I have missed it) stuck with hours:mins:secs:frames
                      You can adjust the size of the audio tracks so you can see the waveforms better.
                      I usually do this when synchronising multiple cameras or cameras and a separate minidisc sound recording.

                      Dai
                      • 8. Re: audio / video sync problem
                        the_wine_snob Level 9
                        Dai,

                        Thanks. This was one I did not know. In Pro, you have several choices for units of time measurment. Makes sense that it would be less useful in PE. I appreciate the clarification.

                        Hunt
                        • 9. Re: audio / video sync problem
                          Level 1
                          Bill and Dai,

                          Believe it or not, I am still stuck on this same problem.

                          I've found two 'solutions' neither of which is a solution:

                          1. When I install an old version of quicktime (6.5) the video plays in sync, but yet PE won't allow me to add the file to a project, saying something like unsupported file format. It will accept the videos when I have a slightly newer version (7.1), but then they are out of sync.

                          2. I can get the videos perfectly in sync using a program called mp4cam2avi (http://mp4cam2avi.sourceforge.net/) by adjusting the audio delay etc. Yet this time, when I try to add the converted avi files to the project, PE refuses and says unsupported audio rate in file.

                          I have gone to great lengths (including wiping out my whole computer to factory settings) to try to solve this problem, but keep coming up short of a solution. What I really don't understand is why this developed in the last few months - it never was a problem before.

                          Any suggestions???

                          Thanks,
                          Erik