deadlock after seek

[Patrick Fischer]

Hello List

I have a problem with seek.
Occasionally it happens that I have a deadlock when I try to reverse. Happens every 5-20 times.

I have had this problem for several years now.
It is a mobile app on Android and iOS. So far the problem is only known to occur on Android, but that doesn't mean it can't occur on iOS.

The structure of my pipeline
httpsoupsrc -> src-queue -> typefind -> demux -> audioqueue -> aacparse -> capsfilter -> appsink
                                                     (so from demux) -> videoqueue -> h264parse -> capsfilter -> appsink


For the implementation of the Seek function I tried different approaches. My current implementation looks like this:

static void
seek_to_time(CustomData *customData,
             gint64 seekToPos)
{
    if (!GST_CLOCK_TIME_IS_VALID (customData->duration)) {
        LOGW ("Seek failed! Invalid duration\n");
    }
    LOGI ("seek_to_time to %" G_GINT64_FORMAT "\n", seekToPos);
    if(!gst_element_seek_simple(customData->pipeline, GST_FORMAT_TIME, (GstSeekFlags)(GST_SEEK_FLAG_FLUSH | GST_SEEK_FLAG_KEY_UNIT),seekToPos))
    {
        LOGW ("Seek failed!\n");
    }
    g_usleep(500); // just to test, no change with or without
    LOGI ("seek_to_time to %" G_GINT64_FORMAT " done\n", seekToPos);

    GstState current, pending;
    GstStateChangeReturn stateChange = gst_element_get_state(customData->pipeline, &current, &pending, 0*GST_SECOND);

    gst_element_set_state (GST_ELEMENT (customData->pipeline), GST_STATE_PLAYING);
}

With the debugger I can see that it hangs at gst_element_get_state.
There it never comes back. I also did it with a timeout it didn't change anything unfortunately.


When I look into the logfile, I see that I often get the following log output:
16:49:22.216 W ../gst/gstpad.c:4677:gst_pad_push_data:<ts-demuxer:audio_0_04da> Got data flow before segment event
16:49:22.216 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<AACqueue1:sink> Got data flow before segment event
16:49:22.216 W ../gst/gstpad.c:4677:gst_pad_push_data:<AACqueue1:src> Got data flow before segment event
16:49:22.216 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<AACparse1:sink> Got data flow before segment event
16:49:22.258 W ../gst/gstpad.c:4677:gst_pad_push_data:<ts-demuxer:video_0_04d9> Got data flow before segment event
16:49:22.258 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<H264queue0:sink> Got data flow before segment event
16:49:22.258 W ../gst/gstpad.c:4677:gst_pad_push_data:<H264queue0:src> Got data flow before segment event
16:49:22.258 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<H264parse0:sink> Got data flow before segment event
16:49:22.261 W ../gst/gstpad.c:4677:gst_pad_push_data:<H264parse0:src> Got data flow before segment event
16:49:22.261 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<H264capsfilter0:sink> Got data flow before segment event
16:49:22.261 W ../gst/gstpad.c:4677:gst_pad_push_data:<H264capsfilter0:src> Got data flow before segment event
16:49:22.261 W ../gst/gstpad.c:4416:gst_pad_chain_data_unchecked:<H264appsink0:sink> Got data flow before segment event

This one worries me, but it also sometimes occurs when there is no deadlock.
Could the "Got data flow before segment event" problem have something to do with the hang?
I just can't figure out the problem.
Does anyone have any ideas what I can investigate further?

Regards
Patrick

Patrick Fischer
Software Developer
o: 
+49 4307 8358 0
patrick.fischer at vitec.com
www.vitec.com


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