Pipeline changing to PAUSED when adding many branches or crashes

Mon Dec 27 15:36:14 UTC 2021

Hello,

I am writing an application where I dynamically add many branches to the adder element. In each branch I wait for the first buffer on the src pad using pad probes. When that happens I try to link branch's bin to the adder. That means that bin.link(adder) is being called from multiple streaming threads in parallel. The problem is that when linking is being called from the streaming threads, it seems that adder is confused when it comes to the pads. It tries to link the same pad multiple times with different branches and finally reports an error which suggests a bug.

Moreover, sometimes pipeline is automatically changing state to PAUSED and never goes back to PLAYING, even if I set state.

If I do this in the main thread, the error dissapears but still it still sometimes stays in PAUSED.

1. Is that safe to link adder's branches dynamically from the streaming thread should I do this in the main thread?
2. What are the conditions under which the pipeline can automatically go and stay stuck in PAUSED? I add only sources, not sinks.
3. Does the warning below really indicate a bug or am I doing something incorrectly?

This is definitely sort of race condition, if I add exactly the same branches but slowly everything works fine.

Logs:

0:00:15.636019000 5427 0x7f850c06b800 INFO structure gststructure.c:2842:gst_structure_get_valist: Expected field 'channel-mask' in structure: audio/x-raw, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ];
0:00:15.636026000 5427 0x7f850c06b240 INFO GST_ELEMENT_PADS gstutils.c:1819:gst_element_link_pads_full: trying to link element stream3:(any) to element adder:(any)
0:00:15.636018000 5427 0x7f850c062b00 INFO GST_ELEMENT_PADS gstutils.c:1819:gst_element_link_pads_full: trying to link element stream:(any) to element adder:(any)
0:00:15.636189000 5427 0x7f850c06b240 INFO structure gststructure.c:2842:gst_structure_get_valist: Expected field 'channel-mask' in structure: audio/x-raw, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ];
0:00:15.636219000 5427 0x7f850c06b800 INFO GST_PADS gstutils.c:1633:prepare_link_maybe_ghosting: stream4 and adder in same bin, no need for ghost pads
0:00:15.636225000 5427 0x7f850c062b00 INFO structure gststructure.c:2842:gst_structure_get_valist: Expected field 'channel-mask' in structure: audio/x-raw, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ];
0:00:15.636236000 5427 0x7f850c06b800 INFO GST_PADS gstpad.c:2383:gst_pad_link_prepare: trying to link stream4:src and adder:sink_5
0:00:15.636270000 5427 0x7f850c06b240 INFO GST_ELEMENT_PADS gstelement.c:753:gst_element_add_pad:<adder> adding pad 'sink_6'
0:00:15.636362000 5427 0x7f850c06b800 INFO GST_PADS gstpad.c:2423:gst_pad_link_prepare: sink adder:sink_5 was already linked to stream2:src
0:00:15.636067000 5427 0x7f850c06b0c0 INFO GST_PADS gstpad.c:2591:gst_pad_link_full: linked stream2:src and adder:sink_5, successful

0:00:15.636382000 5427 0x7f850c06b0c0 INFO GST_EVENT gstevent.c:1610:gst_event_new_reconfigure: creating reconfigure event
0:00:15.636431000 5427 0x7f850c06b240 INFO GST_PADS gstutils.c:1633:prepare_link_maybe_ghosting: stream3 and adder in same bin, no need for ghost pads
0:00:15.636446000 5427 0x7f850c06b240 INFO GST_PADS gstpad.c:2383:gst_pad_link_prepare: trying to link stream3:src and adder:sink_6
0:00:15.636451000 5427 0x7f850c06b800 INFO GST_PADS gstpad.c:2534:gst_pad_link_full: link between stream4:src and adder:sink_5 failed: was linked

0:00:15.636366000 5427 0x7f850c062b00 INFO GST_ELEMENT_PADS gstelement.c:753:gst_element_add_pad:<adder> adding pad 'sink_7'
0:00:15.636493000 5427 0x7f850c06b240 INFO structure gststructure.c:2842:gst_structure_get_valist: Expected field 'channel-mask' in structure: audio/x-raw, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ];
0:00:15.636501000 5427 0x7f850a05aaa0 INFO basetransform gstbasetransform.c:1325:gst_base_transform_setcaps:<converter> reuse caps
0:00:15.636479000 5427 0x7f850c06b800 INFO GST_ELEMENT_PADS gstelement.c:869:gst_element_remove_pad:<adder> removing pad 'sink_5'

0:00:15.636605000 5427 0x7f85090e5400 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec7> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)191712, bitrate=(uint)191988;
0:00:15.636655000 5427 0x7f850c06b800 INFO GST_ELEMENT_PADS gstpad.c:2139:gst_pad_unlink: unlinking stream2:src(0x7f850c060ef0) and adder:sink_5(0x7f850c88db00)
0:00:15.636695000 5427 0x7f850a05aaa0 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec4> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)191712, bitrate=(uint)191988;
0:00:15.636781000 5427 0x7f850a05ab00 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec6> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)191712, bitrate=(uint)191988;
0:00:15.636850000 5427 0x7f85090e5400 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec7> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)192018, bitrate=(uint)191990;
0:00:15.636951000 5427 0x7f850a05ab60 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec5> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)191712, bitrate=(uint)191988;
0:00:15.636957000 5427 0x7f850a05ab00 INFO audiodecoder gstaudiodecoder.c:2522:gst_audio_decoder_sink_eventfunc:<atdec6> upstream stream tags: taglist, organization=(string)"no\ name", has-crc=(boolean)false, channel-mode=(string)joint-stereo, audio-codec=(string)"MPEG-1\ Layer\ 3\ \(MP3\)", nominal-bitrate=(uint)192000, minimum-bitrate=(uint)191712, maximum-bitrate=(uint)192018, bitrate=(uint)191990;

(radiokit-stream:5427): GStreamer-WARNING **: 16:00:49.856: pad adder:sink_5 has no event handler, file a bug.

Using 1.18.5 on Mac OS X.

Thanks,

Marcin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20211227/4443fc0d/attachment-0001.htm>