Audio pitch shift due to Hz conversion

2005-06-24
2013-04-10
  • Kevin M. Dean

    Kevin M. Dean - 2005-06-24

    I've been noticing an issue with the latest greatest where audio is playing either pitched up or down. It seems there's something wrong with the audio filter chain.

    For instance when I see the following in the console the audio is pitched wrong:

    Checking audio filter chain for 48000Hz/2ch/s16be -> 48000Hz/2ch/s16be...
    AF_pre: 48000Hz/2ch/s16be
    AO: [macosx] 44100Hz 2ch floatbe (4 bps)
    Building audio filter chain for 48000Hz/2ch/s16be -> 44100Hz/2ch/floatbe...

    Note the last line which indicates 48000Hz -> 44100Hz which would account for the problem. Now if I stop the movie and then reopen it I usually get:

    Checking audio filter chain for 48000Hz/2ch/s16be -> 48000Hz/2ch/s16be...
    AF_pre: 48000Hz/2ch/s16be
    AO: [macosx] 48000Hz 2ch floatbe (4 bps)
    Building audio filter chain for 48000Hz/2ch/s16be -> 48000Hz/2ch/floatbe...

    Note that it's now 48000Hz -> 48000Hz and plays correctly. This changes between opening without me changing anything. It's really odd and hadn't happened before the latest version.

    The reverse (44100 -> 48000, then 44100 -> 44100) has also happened.

    I can't see why it would arbitrarily not work and then work properly without any difference between instances.

    Anybody else run across this or have any ideas.

    Thanks.

     
    • Dan Nolen

      Dan Nolen - 2005-08-25

      Yeah, I'm getting this too, but it doesn't correct itself in my case.

      Console says:

      Checking audio filter chain for 22050Hz/1ch/s16be -> 22050Hz/2ch/s16be...
      AF_pre: 22050Hz/1ch/s16be
      AO: [macosx] 48000Hz 1ch floatbe (4 bps)
      Building audio filter chain for 22050Hz/1ch/s16be -> 48000Hz/1ch/floatbe...
      Video: no video
      Starting playback..

       
      • Dan Nolen

        Dan Nolen - 2005-08-25

        This is on 10.4.2 with a PowerBook G4 1.5 GHz + 1 GB RAM. VLC plays the audio at normal speed. Neither plays the video in this .wmv file.

         
      • Kevin M. Dean

        Kevin M. Dean - 2005-09-02

        Since this version of mplayer is dead you should switch to the latest: http://www.macupdate.com/info.php/id/18580

        It solved any problems I had.

         

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