Internal Dataflow Error

Tim Müller tim at
Mon Feb 3 22:35:35 CET 2014

On Mon, 2014-02-03 at 17:53 +0600, aft wrote:


> I'm Trying a simple pipeline which is not working :
> arif at dev:~/GS_samples/sample_media$gst-launch-0.10 filesrc
> location="M1F1-Alaw-AFsp.wav" ! alawdec ! autoaudiosink

> WARN <alawdec0> no input format set: not-negotiated
> What i'm doing wrong? I want to understand it conceptually.

alawdec is a decoder element, and it needs to know what the input caps
are in order to interpret and process the data properly. filesrc will
not set any caps whatsoever on the buffers, it will just read them and
push them downstream.

If alaw was a typefindable format, you could just add a 'typefind'
element between filesrc and alwadec, but it's not typefindable.

>From the filename I would guess that the file is in fact a WAV file,
which means you need to use a 'wavparse' element before the decoder, so
try e.g.:

 filesrc location=foo.wav ! wavparse ! alawdec ! audioconvert !

but you could also just use playbin2 or decodebin2:

 playbin2 uri=file:///path/to/foo.wav

 filesrc location=foo.wav ! decodebin2 ! audioconvert ! autoaudiosink


Tim Müller, Centricular Ltd -

More information about the gstreamer-devel mailing list