4 Replies Latest reply on Aug 14, 2009 8:13 AM by the_wine_snob

    Waveform gets out of sync

    MrMazda

      Hi all,

       

      I often take an audio track from a PAL source (25fps) and add it to an NTSC (23.976fps) sequence so I use the "Rate Stretch Tool" a lot!

       

      I've done so many... I lost count!

      It works perfectly BUT I never can rely on the "Waveform Display" once the duration of the audio clip is changed.

      I seems as if PP was not adjusting the display according to the new speed.  The sync between the actual audio and the waveform is totaly off.

      Every clip is conformed, all PEK files are there

      You can see on the picture I attached:

       

      Both tracks use the same wav file, but the one on the top was stretched just a little.

      Both waveforms still look the same! They are not 100% identical but it's quite obvious they should be different.

       

      When totaly zoomed out... Il looks like PP is displaying the stretched track properly... zoom in and everything is off!

       

      Like I said... The playback is perfect. This is only a display thing but it makes the waveform display totaly useless!

       

      A simple "render workspace" doesn't change anything but If I do a "render and replace".... The "new" rendered track displays perfectly at any zoom level.

       

      This can be reproduced using any kind of audio source (wav, mp3, ac3) as long as the clip's duration is not too short.

      Tried on CS3 3.0 and 3.2 on Win XP.

       

      Any ideas?

      Thanks

        • 1. Re: Waveform gets out of sync
          Jim_Simon Level 8

          Any ideas?

           

          So long as the sound works, don't worry about the 'picture' of the sound.

          • 2. Re: Waveform gets out of sync
            MrMazda Level 1

            To properly sync to the new video, I often have to make some razor cuts and to change the duration of the subclips...

            Being able to visually place the CTI right in a very short silence part would be very usefull.

            I'm 100% sure I'm not the only one who has noticed that behavior...

            I'v lived without it for a long time but it would be nice if it worked!

             

            Maybe someone has a solution to get it working properly...

            Thanks

            • 3. Re: Waveform gets out of sync
              Jim_Simon Level 8

              I'm 100% sure I'm not the only one who has noticed that behavior.

               

              I don't know.  I adjust the speed of audio clips all the time (damn digital records can't keep accurate time), and the waveform display moves right along with it.

              • 4. Re: Waveform gets out of sync
                the_wine_snob Level 9

                Hm-m, maybe I just never noticed. I use the Rate-Stretch a fair amount, but then I am seldom going back in to do fine edits later. I look upon the PEK (Waveform Display) as a bit of an emulation. Now, with non Rate-Stretch material, I've found it pretty accurate, but maybe have just not encountered its foibles.

                 

                Wonder if doing a Render of that section of the Timeline (using the WAB), would allow the Waveform to redraw to better reflect the change?

                 

                Wonder if zooming in either/or horizontally, or vertically would cause the Waveform to redraw more accurately? Maybe a zoon in on both?

                 

                I'll pay especially close attention to this next time and let you know if it is more accurate for me. As is, I probably just never noticed the change, or lack thereof.

                 

                Good luck,

                 

                Hunt, off to Stretch some Audio...

                 

                 

                 

                PS, I never bothered to notice, but does PrPro regenerate CFA's and PEK's, when the Rate-Stretch Tool is used? If so, it happens so quickly on my machine, that I have never noticed the little blue bar. Might be there, but go by to quickly to call attention to itself.

                 

                Message was edited by: the_wine_snob Added PS