Hello hackers!
I am trying my luck with a pipeline that receives audio and/or video contained in mpeg-ts over SRT. The audio and video will then be relayed to via RTP using the rtpbin.
The idea is to handle different types of codecs (right now h.264/h.265 and aac) dynamically. So when pad appears on the tsdemux we check the caps and decide how to build rest of the pipeline.
demux.connect_pad_added(move |_, pad| {
// When new pad appears:
// 1. Check caps
// 2. Create appropriate processing branch
// 3. Link to rtpbin
});
And in the method called from the callback to link rtpbin we then connect to the pad-added of the rtpbin giving us a pipeline sort of like:
[srtsrc]
|
[queue]
|
[tsdemux]
/ \ <- on pad-added
| \--------
V V
[queue] [queue]
| |
[capsfilter] [capsfilter]
| |
[parser] [parser]
| |
[capsfilter] [capsfilter]
| ___|
\ /
[rtpbin]
/ | \ <- on pad-aded
/ | \
[udpsink_rtp1] [udpsink_rtcp1]
[udpsink_rtp2] [udpsink_rtcp2]
This works quite well … most of the time … I occasionally get errors saying the pipeline is not linked … and sometimes get strange freezes, so I think I am not being careful enough. I would like some guidence here …
Is all this fine todo in the pad-added callbacks or do I need to use blocking probes at some stage to make this safe? Or is it ok to wait for pad-added on rtpbin and have the pipeline flowing?
I also wonder when I add elements dynamically to this pipeline at what stages I need to do the sync_state_with_parent calls to make sure the pipeline is in playing …
The error in log I get from time to time is:
{}"timestamp":"2025-02-07T14:02:22.914727Z","level":"INFO","message":"New demux pad detected","pad":"audio_1_0042"}
{"timestamp":"2025-02-07T14:02:22.914816Z","level":"INFO","message":"Detected incoming media","srt_stream_id":"ingestion-node-static-1","caps":"Caps(audio/mpeg(memory:SystemMemory) { mpegversion: (gint) 4, stream-format: (gchararray) \"adts\" })"}
{"timestamp":"2025-02-07T14:02:22.914913Z","level":"INFO","message":"Identified incoming audio stream","srt_stream_id":"ingestion-node-static-1","codec":"Mp4aLatm"}
{"timestamp":"2025-02-07T14:02:22.915431Z","level":"INFO","message":"End of stream","srt_stream_id":"ingestion-node-static-1","span":{"stream":"ingestion-node-static-1","name":"pipeline"}}
0:00:31.255691907 915410 0x7f5ae4000f60 WARN basesrc gstbasesrc.c:3177:gst_base_src_loop:<src> error: Internal data stream error.
0:00:31.255735328 915410 0x7f5ae4000f60 WARN basesrc gstbasesrc.c:3177:gst_base_src_loop:<src> error: streaming stopped, reason not-linked (-1)
0:00:31.255858947 915410 0x7f5ae4000f60 WARN queue gstqueue.c:1040:gst_queue_handle_sink_event:<srt_queue> error: Internal data stream error.
0:00:31.255878583 915410 0x7f5ae4000f60 WARN queue gstqueue.c:1040:gst_queue_handle_sink_event:<srt_queue> error: streaming stopped, reason not-linked (-1)
All help and guidance welcome!
Jonas