[gst-devel] playbin and videodrop [was: Some questions]

Diego Essaya dessaya at gmail.com
Mon Feb 21 11:54:07 CET 2005


On Sun, 06 Feb 2005 11:18:46 +0100, Ronald S. Bultje wrote:

> > 3)Is there a way to get/set the playback rate of both the audio and video
> > streams?
> 
> Like 'play at twice normal speed'? Or 'play at 25 fps and 44,1 kHz'? As
> for the first, yes, we have elements for that, btu they're not part of
> playbin. You can create a bin (with a ghost pad) containing the actual
> video/audiosink and the speed-changing element for this, and set that
> element as video-sink or audio-sink property in playbin. The
> audio-element is called 'speed', the video-element is called 'videodrop'
> (although that appears to be deprecated in favour of 'videorate', which
> again cannot do this, so this may not work at all in the end). For
> forcing frame/samplerates, see audioscale and videorate. Audioscale is
> part of playbin.

Hi. I'm bringing this thread up again because I want to do exactly
what is discussed here. I want to play a video 'twice or half normal
speed'.

First I tried using 'decodebin'. But after looking at the Totem
source, now I want to try using 'playbin', for two main reasons: 1)
with 'decodebin' I didn't know how to get audio and video
synchronized; and 2) I didn't know how to keep the current video frame
shown in the app window when in paused state.

I tried the solution of using a custom bin for playbin's 'video-sink'
('videodrop' -> 'xvimagesink') and it works, except for the sound. The
problem is, I tried using the same technique for sound (ie, creating a
bin with 'speed' -> 'alsasink'), but it just didn't work. Then,
someone at #gstreamer told me that the 'speed' element is broken in
the stable release.

So, what I would like to do is to enable sound only when playing at
normal speed. Is there a way to disable sound with playbin? I tried
setting 'audio-sink' to a 'fakesink', but I'm getting crashes because
I'm changing the 'audio-sink' while in paused state.

Any other solutions are also welcome :)

Thanks in advance,

-- 
======= Diego Essaya =========---- -- - -  -           *
 e-mail:  dessaya at fi.uba.ar                                *
 jid: dessaya at jabber.org.uk                       *
===============================-- -- - -  -              *




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