webrtcbin create-answer returns unknown SDP type

[Matthew Waters]

Looks like you are looking for python3-gst-1.0:
https://packages.ubuntu.com/search?suite=default&section=all&arch=any&keywords=python3-gst&searchon=names
<https://packages.ubuntu.com/search?suite=default&section=all&arch=any&keywords=python3-gst&searchon=names>.

I don't know how exactly the python bindings operate so cannot give you
that information.  Others on this list may be able to point you in the
right direction.

On 5/7/22 23:19, Alexei Golovko wrote:
> I have installed python3-gi package from apt repository, version
> 3.42.0-3build1.
> Yes, value for the enum changes each run.
> Could you give advice on how to check if this is a python binding
> problem or lower-level one?
>
> вт, 5 июл. 2022 г. в 16:02, Matthew Waters <ystreet00 at gmail.com>:
>
>     Please keep the list in CC so others searching for the same issue
>     might find a solution.
>
>     PyGObject is not gst-python.  gst-python provides some convenience
>     API on top of PyGObject and may be required in this case.
>
>     That log is expected for your case (no existing transceiver or pad).
>
>     The value for the enum is different from your last run.  This
>     points to uninitialized/random memory being accessed.  You would
>     need to figure out if that's in the python translation layer or not.
>
>     Cheers
>     -Matt
>
>     On 5/7/22 22:41, Alexei Golovko wrote:
>>     Here is the log with GST_DEBUG=3,*webrtc*:7 —
>>     https://pastebin.com/RshtnqQx
>>     I use PyGObject 3.42.1.
>>
>>     I see in logs following lines:
>>     2022-07-05 15:15:57.949 jord ERROR| 0:00:01.214992971     9
>>     0x55e2cbd19980 DEBUG              webrtcbin
>>     gstwebrtcbin.c:1874:_find_codec_preferences:<webrtctransceiver0>
>>     Could not find caps for mline 0
>>     2022-07-05 15:15:57.949 jord ERROR| 0:00:01.215007126     9
>>     0x55e2cbd19980 TRACE              webrtcbin
>>     gstwebrtcbin.c:4071:_create_answer_task:<wrb> trying to compare
>>     application/x-rtp, media=(string)video, payload=(int)96,
>>     clock-rate=(int)90000, encoding-name=(string)H264,
>>     profile-level-id=(string)42e01f, packetization-mode=(string)1,
>>     rtcp-fb-nack=(boolean)true, rtcp-fb-nack-pli=(boolean)true,
>>     rtcp-fb-goog-remb=(boolean)true; application/x-rtp,
>>     media=(string)video, payload=(int)97, clock-rate=(int)90000,
>>     encoding-name=(string)RTX, apt=(string)96 and (NULL)
>>
>>     Maybe they are related to the problem, though I am not sure.
>>
>>     вт, 5 июл. 2022 г. в 15:12, Matthew Waters <ystreet00 at gmail.com>:
>>
>>         Hi,
>>
>>         That SDP doesn't actually exist as a valid value.  You can enable
>>         GStreamer debugging with GST_DEBUG=3,*webrtc*:7 and that may show
>>         something interesting.
>>
>>         Otherwise, one has to figure out if the python bindings are doing
>>         something weird here.  I assume you have a relevant gst-python
>>         installation available and in use.
>>
>>         Cheers
>>         -Matt
>>
>>         On 5/7/22 02:44, Alexei Golovko via gstreamer-devel wrote:
>>         > Hi,
>>         > I try to use webrtcbin with Janus.
>>         > I've found examples like
>>         >
>>         https://github.com/centricular/gstwebrtc-demos/blob/master/janus/janusvideoroom.py,
>>         >
>>         https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/blob/master/tests/examples/webrtc/webrtcrenego.c,
>>         >
>>         https://github.com/centricular/gstwebrtc-demos/blob/master/sendrecv/gst-rust/src/main.rs,
>>         >
>>         https://gitlab.freedesktop.org/gstreamer/gst-examples/-/blob/master/webrtc/sendrecv/gst/webrtc_sendrecv.py.
>>         >
>>         > They tend to create an offer locally, send it to Janus,
>>         receive an
>>         > answer and set it as a remote description. I would like to
>>         mimic
>>         > behaviour, which we used to use with python's aiortc: get
>>         an offer
>>         > from Janus, generate an answer and send it back.
>>         >
>>         > I set SDP offer from Janus with set-remote-description,
>>         then emit
>>         > create-answer; but I get an answer WebRTCSessionDescription
>>         with an
>>         > empty SDP and a very strange WebRTCSDPType=-43384639
>>         (non-existing enum?).
>>         >
>>         > What am I doing wrong and how to fix this?
>>         >
>>         > The python script used is here: https://pastebin.com/WGPcF64m
>>         > Module dvr_processor.dvr_processor.janus contains
>>         communication with
>>         > Janus: https://pastebin.com/KAhTv8Lq
>>         > Logs are here: https://pastebin.com/QVegDhRZ
>>         >
>>         > It is gstreamer 1.20.1 on ubuntu-22.04 based image.
>>         >
>>         > Regards,
>>         > Alexei Golovko.
>>
>
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