gst-launch error handling

[Tim-Philipp Müller]

On Wed, 2011-12-14 at 12:42 +0100, Florian Lindner wrote:

> I plan to use gst-launch in a simple python script that mass converts
> flac to mp3 files. I would use it like that:
> 
> gst-launch-0.10 filesrc location=accept.flac ! decodebin !
> audioconvert ! lamemp3enc ! xingmux ! id3v2mux ! filesink
> location=out.mp3
> 
> How can I do error handling if any of the pipeline modules produce an
> error? e.g. I've modified the flac file to be invalid, that produces
> that output:
> ...
> Returncode is 0. How to detect an error? Parse output for ERROR?
> 
> I know that gst-launch is not intended for applications, but in my
> simple case using the python interface with the event loop and all
> that stuff seems to be a bit too much. Or have I mistaken the API
> docs?

If you have a python script, you should probably just use the gstreamer
python bindings and use pipeline = gst.parse_launch("....") and then
check for error message on the pipeline's bus (or EOS), either in a
blocking way (timed_pop) or asynchronously (running a main loop).

 Cheers
  -Tim