Python GStreamer src element

[Glenn Pierce]

Looking again I suspect I have to use python struct like
http://www.google.com/codesearch#r6HeTJTZfuY/old/somasrc.py&q=file:%5C.py%20BaseSrc%20do_create&type=cs&l=45

I will experiment and post the results.

On 16 January 2012 15:09, Glenn Pierce <glennpierce at gmail.com> wrote:
> I didn't want to high jack the thread from Mahendra about writing a
> src plugin in Python. However, I sure it would help him as well.
>
> I am also trying to create an element src in Python. I have found the
> following code at
> http://lists.freedesktop.org/archives/gstreamer-devel/2011-July/032110.html
> This seems to work when placed into a pipeline with a fake sink.
>
> To extend this example and learn more I have decided to try to play a
> sine wave.  (Ultimately I wan't to pass data from a text to speech
> engine)
>
> I cant seem to find any good examples of what's need to be done in do_create.
> What I have at the moment is
>
> def do_create(self, offset, length):
>       data = [str(math.sin(a)*255.0) for a in numpy.arange(0.0,
> 2*math.pi, 0.01)]  ? # How am I meant to populate data ?
>       buf = gst.Buffer(data)
>       caps = gst.caps_from_string('audio/x-raw-float, rate=44100,
> channels=1, width=8')
>       buf.set_caps(caps)
>       buf.timestamp = 0 * gst.SECOND
>       buf.duration = 4 * gst.SECOND
>       return gst.FLOW_OK, buf
>
>
> I basically need to know how I can populate the Buffer object with
> audio data as a string.
> Everything I try results in
>
> error: Internal data flow error.
>
> I am using to with the following pipeline to playback.
>
> 'acapelasrc ! audioconvert ! audioresample ! autoaudiosink'
>
> Any pointers would be greatly appreciated.
>
> Thanks