[gst-devel] Changing play rate in a GnlFileSource element

[Edward Hervey]

On Tue, 2009-05-26 at 19:18 +0200, Andoni Morales wrote:
> I want to extract a video segment of a stream and encode it into a new
> file at a different play rate.
> 
> I am wondering if it's possible to change the play rate of the stream
> obtained from the GnlComposition element by setting the "duration"
> property of the GnlFileSource element X time longer than the
> "media-duration" property, for example:
> 
> start=0;
> duration=10,
> media-start=10;
> media-duration=15;

  That will make the output playback at (15/10=) 1.5 times the normal
playback speed.

  The 'media_duration' is how much will be taken from the contained
stream,
  The 'duration' is for how long it will be played back.

  If you want the file to playback at half speed, you'll need to make
the duration twice as long as the media-duration (thereby playing back X
seconds in 2*X seconds).

> 
> Does this paramaters sets the "rate" property of the GnlFileSource to
> 1/2 or do I rather have to use a GnlOperation element with the
> videorate element?

  It will set the rate of the outgoing segment but will not modify the
timestamps/frequency of the buffers.
  You will need to add the following on the output of your gnlfilesource
in order for the timestamps/newsegment to be transformed accordingly:

  gnlfilesource ! identity single-segment=True ! videorate !
yourencoder ...


    Edward

> 
> Andoni
> 
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