8 Replies Latest reply on Jul 10, 2011 9:33 PM by unkachuck

    PE9 audio-video sync on AVCHD imported from Droid-2

    unkachuck

      Hi-

       

      Haven't been able to find existing answers for this one...

       

      I shoot HD video using a Mototrola Droid 2, then import the files to PE9.  The files are in .3gp format.  When played in QT the audio and video synch properly, but once imported into PE9 the video drifts relative to the sound.  That is, the synch varies, not just a fixed offset.  This persisits in both preview and in rendered output. (mpeg, FLV output)  Audio seems perfect.

       

      Details:

      • PE9, fully up to date on Win 7.  QT is also up to date.
      • Video shot on a Motorola Droid 2.
      • File format is 3gp
      • 3gp file contains:
        • audio codec: mp4a: MPEG-4 AAC LC, 44100Hz 96 kb/s tot , stereo (2/0)
        • video codec avc1 H.264/MPEG-4 AVC.
      • The video has square pixels (but the header apparently says 0.9091 aspect ratio- Droid 2 bug?)
      • Source and Project Audio both indicate 44.1 KHz stereo (from clip properties) (source is compressed, project is 32-bit)
      • Image size 720x480 (from clip properties)
      • Video appears to have variable frame rate, and each clip reports a different number
      • Projects have a single clip plus some titles.

       

      I have tried a variety of settings.

      • For import I've tried both AVCHD LITE 720p24 and AVCHD LITE 720p30.  Although both specify square pixels, PE9->Interpret Footage identifies the file as having D1/DV NTSC (0.9091 aspect ratio).  I use Interpret Footage to force square pixels.  Also tried Full 1080i HD import setting, exact same behavior.
      • No matter what settings I use the Timeline shows a red bar indicating some mismatch
      • Using Interpret Footage I have tried framerates of 24, 25, 30, 20.975, "use from file" with no change
      • Not affected by "Display Format" in project settings

       

      Example:

       

      Am I using the wrong settings?  Is there a better codec that matches QT?  Do I have to prefilter the clips somehow?  My inputs are good.  Help!

       

      VERY frustrating, this should all work at the touch of a button.

       

      Thanks,

      Chuck

        • 1. Re: PE9 audio-video sync on AVCHD imported from Droid-2
          the_wine_snob Level 9

          Several Adobe programs have issues when working with muxed MPEG (several different CODEC's) files, and OOS (Out Of Sync) can be one of them.

           

          My recomendation is to do a test. Rip the Audio stream from the muxed AV file, with an audio-editing program. I use Adobe Audition, but the free Audacity works fine too. Once ripped, just Save the Audio as a PCM/WAV @ 48KHz 16-bit, and Import that. Wait a moment, while that Conforms to 32-bit floating point for editing (should be but moments), and then drag that WAV file to a free Audio Track, aligning it with the beginning of the Clip, from which it was ripped. In Audio Mixer (Window>Audio Mixer), just Mute the muxed Audio Stream's Audio Track, and test.

           

          How does that work?

           

          Good luck,

           

          Hunt

          • 2. Re: PE9 audio-video sync on AVCHD imported from Droid-2
            John T Smith Adobe Community Professional & MVP

            Go to Camera and Codec List http://forums.adobe.com/thread/862070?tstart=0 and open the linked text file

             

            There is a link inside that text file leading to a 3gp discussion

            • 3. Re: PE9 audio-video sync on AVCHD imported from Droid-2
              unkachuck Level 1

              Hi Hunt-

               

              Thanks for responding.  I've downloaded & configured Audacity, ripped the track and tried it.  The extracted audio is indistinguishable from the muxed audio track.  The problem appears to be with the video encoding.

               

              Chuck

              • 4. Re: PE9 audio-video sync on AVCHD imported from Droid-2
                unkachuck Level 1

                John-

                 

                Thanks.  Looks ;like the 3gp conversation referenced in there was me trying to track down why my 3gp Droid2 videos were getting truncated; turned out to be a PE9 bug related to variable frame rate, for which there was a patch.  You'd think there would be more users encountering this!

                 

                 

                This problem, too, is smelling to me like an incorrect interpretation of the variable frame rate compressed video, while the fixed-rate audio portion is fine. Realizing there are ample ways for this to be a matter of configuration I think we're simply seeing bad decoding.  This has been very frustrating, something this fundamental should just work.  I recently processed & posted more than 75 videos which now look like garbage...sigh...

                 

                Chuck

                • 5. Re: PE9 audio-video sync on AVCHD imported from Droid-2
                  John T Smith Adobe Community Professional & MVP

                  The thing is (I don't work for Adobe, but I do read most messages) that no flavor of Premiere is designed to work with cellphone video, which is often (mostly or always?) some oddball variation of a HIGHLY compressed codec

                   

                  Video from a real camera works much better

                   

                  I think you need to work on finding a convertion program to convert that 3gp into something that is actually designed to be edited

                   

                  The first place I would look is the cellphone web site, to see if they have software designed to edit their files

                  1 person found this helpful
                  • 6. Re: PE9 audio-video sync on AVCHD imported from Droid-2
                    unkachuck Level 1

                    What target format would you recommend for editing?  I'll find a converter to get me there and experiment.

                     

                    Lots of crappy editors out there.  I need the capabilities of PE, and they sure advertise 3gp as one of the supported import formats...sigh...

                    • 7. Re: PE9 audio-video sync on AVCHD imported from Droid-2
                      unkachuck Level 1

                      Okay, latest update.  I tried several video transcoders, I liked Free Video Converter (available at http://www.koyotesoft.com/indexEn.html) which is quite fast and flexible.  Then I took the original 3gp file (AVCHD) and converted it to an mp4 using their MPEG-4 codec.  The varying time-sync problem was still there when I imported the file to PE9, although it played fine on QT as did the original.

                       

                      Next, I used  Free Video Converter to convert the AVCHD file to avi using their MS-Mpeg4-V2 codec.  This seems to display video that matches the audio once imported into PE9.  I'm playing around with settings (mainly bitrate) to see if I can improve the video quality.  It appears that setting the bitrate to the original makes roughly the same size file and I cannot see any improvement with higher bit rate.  There is some loss of quality in a very challenging video environment (dark, flashing lights) but not too bad.

                       

                      BTW, Windows Live Movie Maker did not have the codec time-sync issues, but the tool is so limited that it doesn't adress anything I want to do.

                       

                      This path is imperfect but the results are much better.  Thanks for the help.

                      • 8. Re: PE9 audio-video sync on AVCHD imported from Droid-2
                        unkachuck Level 1

                        But wait...while time synch on the preview is now perfect, the rendered output (Flash video) still has varying time-sync problems, especially in the first minute of the video.

                         

                        I've tried transcoding to 30.0 fps and to 29.97 fps with the same results.

                         

                        Stumped again.