6 Replies Latest reply on Feb 23, 2012 8:30 AM by Arlo Ihrig

    Trouble Syncing P2 24p footage with 29.97 audio

    Arlo Ihrig Level 1

      Hi All,

       

      I'm having problems syncing Panasonic P2 format footage shot at 24p from an HPX-500, and externally recorded sound.  I'm using PPro CS5.5 on Win7.  I believe this is because the P2 format is actually 29.97fps with some pull-down (Remove Pull-Down setting checked for the clips) and the audio was recorded with a timecode of 23.976.

       

      So when I use the Synchronize feature it gets the clips close, but the audio lags just so slightly, less than a frame.  I can switch to audio time units and manually sync, but I have a completed short film with a ton of clips that I have to do this for and I think it would take the next ten years to manually sync ;-)

       

      If there are any solutions to this, I would be greatful for any suggestions on how to handle this.  The specs of the video and audio clips are below.

       

      Type: P2 Movie

      File Size: 1.5 GB

      Image Size: 1280 x 1080

      Frame Rate: 29.97 (24p)

      Source Audio Format: 48000 Hz - 16 bit - Mono

      Project Audio Format: 48000 Hz - 32 bit floating point - Mono

      Total Duration: 00:01:48:20

      Average Data Rate: 13.7 MB / second

      Pixel Aspect Ratio: 1.5

       

      Type: Windows WAVE audio file

      File Size: 15.3 MB

      Source Audio Format: 48000 Hz - 24 bit - Mono

      Project Audio Format: 48000 Hz - 32 bit floating point - Mono

      Total Duration: 00:01:51:05328

      Average Data Rate: 140 KB / second

      Sound Dev: 744T S#461007017005

      sSPEED=023.976-ND

      sTAKE=1

      sUBITS=$01151201

      sSWVER=2.67

      sPROJECT=

      sSCENE=15-2

      sFILENAME=15-2T001_2.WAV

      sTAPE=120115

      sTRK2=Track B

      sNOTE=

       

       

      Arlo

        • 1. Re: Trouble Syncing P2 24p footage with 29.97 audio
          Jim_Simon Level 8

          This sync issue happens a lot when using external recorders.  It seems camera makers have no trouble at all designing devices that record sound at exactly the same rate.  But for some reason, audio devices just can't seem to do the same.

           

          You'll have to adjust the speed of your audio so that it matches the video.  For my own device, it's off by a predictable amount, so I can adjust the speed of the audio clip to 100.04% and know it'll work.  You'll have to experiment with the audio from your device.

          1 person found this helpful
          • 2. Re: Trouble Syncing P2 24p footage with 29.97 audio
            Arlo Ihrig Level 1

            Hey Jim - thanks.

             

            I have a little bit of an update:

             

            I definitely seem to have something similar.  I figured out a work around based on your suggestion - I found the difference in samples using the audio display, and found that if I sync my clips using timecode, then nudge everything by +2200 samples the audio matches nicely - but I don't like having to do this.

             

            This is a real pain in the butt and I've now spent my whole weekend trying to get this to work.  I'm really hoping Adobe will have some insight into this and either a fix/suggestion or something.  Its added a couple steps to my workflow - and I'm just working on the dialog with 4 channels - glad I don't have more.

            • 3. Re: Trouble Syncing P2 24p footage with 29.97 audio
              Arlo Ihrig Level 1

              Ok, so I wasn't quite right on this - it does seem that the external audio is coming in just slightly smaller than the P2 media audio.  I've tried slowing it (the external audio) down by varying amounts, but can't get it to stay in sync for more than about 10 seconds.  Its a very small amount that it goes out by, like 2200 samples (audio is 48k), and probably not noticable by anyone but me.  But it's very frustrating and I have a lot of clips to adjust.

               

              I've got to think that Adobe knows something about this - there must be an explanation   Buhler?

              • 4. Re: Trouble Syncing P2 24p footage with 29.97 audio
                Arlo Ihrig Level 1

                Adobe: Could it be that I'm experiencing something similar to this thread?

                http://forums.adobe.com/message/3695369#3695369

                • 5. Re: Trouble Syncing P2 24p footage with 29.97 audio
                  Jim_Simon Level 8

                  there must be an explanation

                   

                  Already given.  While camera makes have no problem creating hardware that records audio at a consistent rate, audio device makers either can't or won't do the same.

                  • 6. Re: Trouble Syncing P2 24p footage with 29.97 audio
                    Arlo Ihrig Level 1

                    Already given.  While camera makes have no problem creating hardware that records audio at a consistent rate, audio device makers either can't or won't do the same.

                     

                    Hey Jim, sorry - I should have clarified that statement a bit more.  The slight differences can be understood by your comment for sure, unfortunately .  But the timecode should not be mismatched at all - there seems to be a bad calculation in PPro somewhere.  Other applications can read and match the timecodes without any problems (see below).

                     

                    I found some further info - I had my friend import the footage and audio at his studio with FCP and Avid and they both matched perfectly (he's also going to try Smoke).  I also downloaded the trial of Avid Media Composer 6 and the clips matched up perfectly also.

                     

                    As a test, on my system, I batch "converted" all my audio files using Audition - just saving them with all the same parameters as the originals.  Then I imported back into Premiere and guess what?  They matched much, much more closely.  Still faster by 9951 samples after 00:01:47:00 - so I don't know how noticable 1/48th of a second will be, and I suppose I can find some nice edit points to adjust at.  But also back to your suggestion on adjusting the speed of the audio, I may be able minimize that too.

                     

                    Thanks for your help.