[maemo-developers] GStreamer pipeline with live and non-live sources

[From: Henrik Hedberg]

    Hi,

    We have a strange problem with our dear JamMo application. It uses 
GStreamer to provide karaoke-like singing game for children.

    The following (simplified) pipeline used to work before PR1.1.1 update:

gst-launch-0.10 filesrc location=/home/user/MyDocs/test.mp3 ! decodebin! 
pulsesink pulsesrc ! wavenc ! filesink 
location=/home/user/MyDocs/recording.wav

Since PR1.1.1 there are audible scratches or even worse: the sound 
disappears totally. It is because the sink has to slave its clock to the 
pipeline clock, which is the one provided by the live source [1], and 
there is probably not enough processing power available.

    However, it used to work!

    The difference is at least the GStreamer version, which was upgraded 
to 10.0.25 in PR1.1.1. It was 10.0.23 in PR1.1. (In addition, there were 
synchronisation issues with PR1.0, so the only working version was 
PR1.1. with GStreamer 0.10.23). Actually, the same happens in desktop 
environment too when comparing different GStreamer versions.

    It is extremely important to be able to have playback and recording 
in sync. Thus, I have tried different buffering and latency parameters, 
but have not found a solution.

    Does anyone know, how the pipeline above could be optimized to work 
decently in N900?

    Thank you in advance!

    BR,

    Henrik

[1] 
http://sourceforge.net/mailarchive/message.php?msg_name=1284472222.2407.9.camel%40metal

-- 
    Henrik Hedberg  -  http://www.henrikhedberg.net/