Understanding Bins and Ghost_pads

[Ian Davidson]

Thanks, Tim,

It shows ogg-demuxer as the source of the message.  I have done a debug 
trace which I now have the joy of wading through :-).

I notice that the helloworld program links the demuxer with the convert 
when it is notified that a dynamic pad has been added.  Is there a 
possibility that my code raises such a signal from more than one place?  
The program does not check which pad has been added.

Ian

On 01/01/2013 23:56, Tim-Philipp Müller wrote:
> On Tue, 2013-01-01 at 17:56 +0000, Ian Davidson wrote:
>
> Hi,
>
>> Question 1.
>> I can see the line(s) which outputs the message, but I don't know what
>> generates the message.  I tried to use gst_message_src_name - but I
>> did not get the usage right.  I thought it would give me a string, but
>> evidently not.  I could not get it to compile.  How can I print the
>> source of the message?  What line should I write?
> It's GST_MESSAGE_SRC_NAME(msg) in upper case (it's a an accessor macro,
> which is by convention in upper case), see:
> http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/gstreamer-GstMessage.html#GST-MESSAGE-SRC-NAME:CAPS
>
> Though it should be noted that the element posting the message (e.g. a
> soruce or demuxer) is not necessarily the element where the error
> occured, if it happened further downstream.
>
> a GST_DEBUG=*:3 log might shed some light (once you find the place where
> it's posted from, run with GST_DEBUG=*:6 and look at the lines before
> that.
>
>> Question 2
>> I add source and demuxer into bin1.  Then, later, I link source and
>> demuxer.  I am assuming that source and demuxer can only be in one
>> place - and that therefore, it is the only copies that are being
>> linked.
> That was a question? :)
>
> Well, you hold pointers to the elements, and there are only two, and
> both are in the same bin, so it should be fine.
>
>   
>> Question 3
>> I suspect that I have not linked my Ghost Pads.  How/where should I do
>> that?
> They should get linked via the gst_element_link (bin1, bin2); as far as
> I can tell.
>
> Cheers
>   -Tim
>
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