Custom Gst.Element in GTK3

[Manuel]

Hi,

it's me again.
I just used the wrong PadTemplate-names.
Now it works! :)

Here is the working code: http://pastebin.com/GdiYhxzf

Thank you all.

Best regards



Am 17.07.2014 23:50, schrieb Manuel:
> Hi,
> 
> thanks for pointing me in the right direction.
> VideoFilter might be what I was looking for. Is there any simple example
> code available?
> 
> Because this short snippet does not work: http://pastebin.com/GdiYhxzf
> 
> My do_transform_frame_ip method is never called.
> I read in the BaseTransform-docs that BaseTransform provides already a
> sinkpad and sourcepad. Or do I have to specify the sink- and src-pads by
> myself? Because the sinkpad field is None.
> Or do I have to override some of BaseTransform do_* methods?
> What am I missing? :)
> 
> Best regards
> 
> 
> 17.07.2014 12:39 AM, Jan Alexander Steffens:
>> BaseTransform is in GstBase, not Gst. VideoFilter is in GstVideo.
>>
>> On Thu, Jul 17, 2014 at 12:24 PM, Manuel <manuel at wenns-um-email-geht.de> wrote:
>>> Hey,
>>>
>>> it seems that Gst 1.0 shipped with Ubuntu 14.04 does not include the
>>> BaseTransform/VideoFilter classes:
>>>         AttributeError: 'gi.repository.Gst' object has no attribute 'BaseTransform'
>>>
>>> It would be nice if I could stick with the Gst-code/version shipped with
>>> Ubuntu :)
>>>
>>> Is there some documentation about the pool negotiation in python?
>>> As mentioned I just need to get the timestamp of the buffers, for
>>> example to show the current position in a label and show some text using
>>> textoverlay (like subtitles). And then the buffers should just be
>>> forwarded to the next element in the pipeline. I don't need to modify
>>> buffers etc..
>>> Maybe I don't even need to implement my own Gst.Element. :) I just need
>>> the "ticks" to show the subtitles as soon as possible as the video
>>> reaches say position 00:04.140 . Any ideas? :)
>>>
>>> Best regards
>>>
>>>
>>> 17.07.2014 11:37 AM, Thibault Saunier:
>>>> Hello,
>>>>
>>>> I tried the example. But it seems to be broken. For example it uses
>>>>> set_chain_function, which IMHO should be set_chain_function_full.
>>>>> (According to
>>>>>
>>>>> http://lazka.github.io/pgi-docs/Gst-1.0/classes/Pad.html#Gst.Pad.set_chain_function_full
>>>>> ).
>>>>>
>>>>
>>>> It is overriden:
>>>> http://cgit.freedesktop.org/gstreamer/gst-python/tree/gi/overrides/Gst.py#n109
>>>> it can thus be used like it is in the example (this override has not been
>>>> released yet)
>>>>
>>>>
>>>> It looks like you should use Gst.BaseTransform (maybe Gst.VideoFilter)
>>>> instead of using Gst.Element as a baseclass for your element, it would
>>>> handle more things for you (and I guess pool negotation is one of those
>>>> things).
>>>>
>>>> Regards,
>>>>
>>>> Thibault
>>>>
>>>>
>>>> But I noticed two things:
>>>>> 1.
>>>>> When changing the function names to set_chain_function_full and
>>>>> set_event_function_full and adding a source-pad it almost looks like my
>>>>> TestFilter-class.
>>>>>
>>>>> One difference:
>>>>> In my code the chain-function tries to push the buffer to the next
>>>>> element (self.srcpad.push(buffer)). The example instead just returns
>>>>> Gst.FlowReturn.OK. This is where my code produces the error ("We don't
>>>>> have a bufferpool negotiated") and the example doesn't. Do I have to do
>>>>> something more to be able to push the buffer to the next element?
>>>>>
>>>>
>>>> Why don't you implement
>>>>
>>>>
>>>>> 2.
>>>>> In my last email I mentioned that I even didn't get it (my GTK3-example)
>>>>> playing with textoverlay and autovideosink in the Bin (without my custom
>>>>> element).
>>>>> But when I change the GhostPad's name in my GTK3-example to 'sink'
>>>>> (instead of 'video_sink' like in my GTK2-example) and remove the
>>>>> TestFilter from the Bin then the video is playing fine. I updated the
>>>>> example at pastebin. Now I just need to get my filter to work :)
>>>>>
>>>>> Best regards
>>>>>
>>>>>
>>>>> 17.07.2014 09:29 AM, Thibault Saunier:
>>>>>> Hello,
>>>>>>
>>>>>> I think when you say Gtk3 you mean GStreamer 1.0 with PyGObject.
>>>>>>
>>>>>> Do you have gst-python installed? It is necessary to be able to create
>>>>>> GstElement subclasses.
>>>>>>
>>>>>> You can have a look at that example:
>>>>>>
>>>>> http://cgit.freedesktop.org/gstreamer/gst-python/tree/examples/plugins/python/sinkelement.py
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>> Thibault Saunier
>>>>>>
>>>>>>
>>>>>> On Thu, Jul 17, 2014 at 12:07 AM, Manuel <manuel at wenns-um-email-geht.de>
>>>>>> wrote:
>>>>>>
>>>>>>> Custom Gst.Element in GTK3
>>>>>>> --------------------------
>>>>>>> Hi all,
>>>>>>>
>>>>>>> I wrote a gst.Element (GTK2), which is a simple filter that just
>>>>>>> forwards all buffers it receives on the sink-pad to the src-pad. Later I
>>>>>>> will grab some information from the buffer before forwarding it. (More
>>>>>>> precisely I will grab the timestamps and show some text based on the
>>>>>>> time, like subtitles). The GTK2-version works fine.
>>>>>>>
>>>>>>> Today I tried to change my code so that it uses the GTK3
>>>>>>> gi.repository-package.
>>>>>>> Although the new class looks almost the same it doesn't work.
>>>>>>>
>>>>>>> This is the error printed on the console:
>>>>>>> Error: Internal error: can't allocate images xvimagesink.c(979):
>>>>>>> gst_xvimagesink_show_frame ():
>>>>>>>
>>>>>>>
>>>>> /GstPlayBin:MultimediaPlayer/GstPlaySink:playsink/GstBin:vbin/GstBin:timed-video-bin/GstAutoVideoSink:autovideosink0/GstXvImageSink:autovideosink0-actual-sink-xvimage:
>>>>>>> We don't have a bufferpool negotiated
>>>>>>>
>>>>>>> Here is my GTK2-version: http://pastebin.com/J2gHfvS4
>>>>>>> And here the GTK3-version: http://pastebin.com/9u8zzcTk
>>>>>>>
>>>>>>> This is a scenario:
>>>>>>> A video-file is played using playbin. The playbin's video-sink is set to
>>>>>>> a Gtk.Bin that combines my own Gst.Element with textoverlay and an
>>>>>>> autovideosink.
>>>>>>>
>>>>>>> NOTE: If you remove the textoverlay from the GTK3 example then at least
>>>>>>> the audio is playing ;)
>>>>>>>
>>>>>>> I would be very grateful for your help. :)
>>>>>>>
>>>>>>> Best Regards
>>>>>>> _______________________________________________
>>>>>>> gstreamer-devel mailing list
>>>>>>> gstreamer-devel at lists.freedesktop.org
>>>>>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> gstreamer-devel mailing list
>>>>>> gstreamer-devel at lists.freedesktop.org
>>>>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> gstreamer-devel mailing list
>>>>> gstreamer-devel at lists.freedesktop.org
>>>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> gstreamer-devel mailing list
>>>> gstreamer-devel at lists.freedesktop.org
>>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>>>
>>>
>>> _______________________________________________
>>> gstreamer-devel mailing list
>>> gstreamer-devel at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>> _______________________________________________
>> gstreamer-devel mailing list
>> gstreamer-devel at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>>
> 
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>