[gst-devel] gst-python problem: refcount for gst.Buffer too big?

[Артём Попов]

Hi all,

I'm trying to write a gst element in python, based on
GstBaseTransform. The core of such an element would be "transform" and
"transform_ip" methods, with receive GstBuffer arguments. Both of
these methods don't work for me, due to too large reference count of
Buffers passed to them. By the way, the "transform" method requires
"get_unit_size" virtual method to be implemented, the patch is here:

http://bugzilla.gnome.org/show_bug.cgi?id=339248

in "transform_ip", buffer refcount is 3, and that makes the buffer unwritable
in "transform", both buffer refcounts are 2, what makes output buffer
unwritable as well...

def transform_ip (self, outbuf):
    print outbuf.__grefcount__ # always prints 3
    return gst.FLOW_OK

def transform (self, inbuf, outbuf):
    print inbuf.__grefcount__ # always prints 2
    print outbuf.__grefcount__ # always prints 2
    return gst.FLOW_OK

"gst_buffer_is_writable" checks, that the buffer refcount should be 1,
and gst-python uses just that to enable or disable data writing to the
buffer. So, how can I solve (or maybe workaround) this problem?
Thanks. --Artem