Null src caps in pad_added for hsldemux2

[Flash]

Hi!
I am trying to reproduce part of uridecodebin3 pipeline. Something like
souphttp => typefind => hlsdemux => multiqueue => %some_decoders%

 When I call current_caps() in pad_add handler (like in Basic tutorial #3),
the response always is null.
Part of debug output:
0:00:03.780275220  9547 0x7fddd86411e0 INFO        GST_ELEMENT_PADS
gstelement.c:758:gst_element_add_pad:<hlsdemux2> adding pad 'video_00'
0:00:03.780281654  9547 0x7fddd86411e0 DEBUG        GST_REFCOUNTING
gstobject.c:708:gst_object_set_parent:<'':video_00> set parent (ref and
sink)
0:00:03.780292735  9547 0x7fddd86411e0 DEBUG               GST_PADS
gstpad.c:1103:gst_pad_set_active:<hlsdemux2:video_00> activating pad from
none
0:00:03.780298194  9547 0x7fddd86411e0 DEBUG               GST_PADS
gstpad.c:1008:pre_activate:<hlsdemux2:video_00> setting pad into push mode,
unset flushing
0:00:03.803780278  9547 0x7fddd86411e0 DEBUG               GST_PADS
gstpad.c:1231:activate_mode_internal:<hlsdemux2:video_00> activated in push
mode
0:00:03.803821999  9547 0x7fddd86411e0 DEBUG               GST_CAPS
gstpad.c:2742:gst_pad_get_current_caps:<hlsdemux2:video_00> get current pad
caps (NULL)

The pads do successfully link, however.
But to understand which decoder (h264? hevc? aac?) to use, I need to know
what the output of the demuxer pads is. How to get these caps?

In the handler for uridecodebin, caps return normally.
Gstreamer version: 1.22.0
Language: rust

Is there some kind of magic here? Or am I just doing something wrong?

--

Regards
Flashick
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20230301/609a3714/attachment.htm>