turning parts of pipeline on/off

[Alexey Fisher]

> > I have a simple pipeline (actually it's generated according to
> > configuration and much more complicated, but it allways ends up
> after
> > something that gives x-video/raw-yuv, like "decodebin" shown below):
> > 
> >  souphttpsrc location="someurl" ! decodebin ! my_app_sink
> > 
> > and I would like to be able to get jpeg snapshots from time to time.
> > Since "my_app_sink" needs raw yuv input, I splitted the pipeline
> with
> > tee:
> > 
> >  souphttpsrc location="someurl" ! decodebin ! tee name=t  !
> > my_app_sink t. ! queue ! jpegenc ! my_jpeg_appsink
> > 
> > or in crude ascii art:
> > 
> >  souphttpsrc -> decodebin -> tee ----------> my_app_sink
> >                               \-> jpegenc -> my_jpeg_appsink
> > 
> > 
> > it works, but "jpegenc" is running all the time, consuming CPU power
> > and in "my_jpeg_appsink" I'm just "throwing jpegs away" most of the
> > time, since I need the jpeg only once in a while - less than one per
> > minute (while my input stream has usualy more than 10fps).
> > 
> > Now comes my question - is there any way to "turn off" the
> > "my_jpeg_appsink" part of the pipeline when I don't need jpegs and
> > only turn it on when I need one without disturbing the "my_app_sink"
> > part?
> > 
> > If my description is confusing, please tell me and I'll try again.
> 
> Can't you just dynamically add jpegenc and your jpeg_appsink when
> needed
> and remove them immediately after each snapshot? Is that possible
> without disturbing my_app_sink ie while the pipeline is in state
> PLAYING?
> 
> I really hope that is possible because I want to do something sort of
> similar with a DVB application, with a dvbbasebin or dvbsrc source.
> While one programme is being recorded, a user might want to start
> watching the same programme "live", or record or watch another
> programme
> from the same transport stream, and these extra sinks need to be
> stopped
> and started without interrupting any other recording or live
> streaming/playback using the same source.

You can use:
 vlave - to drop packets.
 tee - allocate new pad, not sure about destroing pad.
 output-selector - but i think it will switch between sinks
-- 
Regards,
        Alexey