[wdmaudiodev] Re: Audio Video Sincronization

  • From: Bipin Mistry <bpnmistry@xxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Wed, 1 Feb 2006 23:34:06 +0530


I agre with inserting the Audio or droping the video Frame can server the
But my issue is row data of the conference is created initially using

1. Windows Media Encoder for Video without sound.
2. 3rd Party Dll provides me the Audio files for individual users in the
    (I do not have any control over Audio at the Run time)

Now when STOP is triggered
1. I have to mix all the WAV files generated by DLL and then
2. mix it with Video file I have created using Windows Media encoder and
create FINAL VIDEO file.

In such case I can not get all users audio syncronized with video file as
for example
User A audio Play time is 5:00 minutes
User B audio Play time is 4:57 minutes
User C audio Play time is 4:53 minutes
User D audio Play time is 4:55 minutes

Then in the MIX file I can here A till 5:00 B till 4:57, C till 4:53 & D
till 4:55 in 5:00 minutes of MIX audio file.
Where my problem resides.... if this is solved then my all worries are

So if group members can throw some lights on this front then it will be

Bipin Mistry.

On 2/1/06, Tim Roberts <timr@xxxxxxxxx> wrote:
> Bipin Mistry wrote:
> >
> > This would have helped me if I was recording the Audio...
> Why does that make a difference?  You're going to have to run the whole
> file through whatever stretching algorithm you choose.  Robert's
> suggestion has some merit; inserting a few bytes of silence when the
> audio is quiet might be an easy solution, if the audio generally has
> quiet spots.
> Just slowing down an audio file is not difficult.  For a 3% stretch, for
> example, you can just duplicate every 33rd sample in the file.  The
> downside is that you'll hear the pitch go down.  A true audio stretching
> algorithm that maintains the pitch is very hard, like master's thesis
> hard.  Google will serve you better than this list.
> > But here seen is I am using 3rd party dll provided by end user which
> > gives me audio files as output... (no source code or any document on
> > architeacture for this dll is available)
> >
> > So I have to play my game on the output files generated for every user
> > by 3rd party dll.
> > And that too once 3rd party dll has completed his task.
> So, you're saying that these audio files were not generated from the
> same source as the video you're syncing to?  What kind of audio files
> are they?  If it is music, you could just start over from the
> beginning.  If it's a voice narration or a sound effect, you could just
> insert a bit of silence at the beginning and end.
> --
> Tim Roberts, timr@xxxxxxxxx
> Providenza & Boekelheide, Inc.
> ******************

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