How flvdemux and other plugins are linked together in Gstreamer?

[406769249]

Hello.I try to use Gstreamer in python. I just want the pipeline like RTMP source → flvdemux → fakesink.But it doesn’t work.
This is the output

Creating Pipeline 
 
Creating Source And other 
 
Adding elements to Pipeline 

Linking elements in the Pipeline 

Starting pipeline 

0:00:03.159383897 16325   0x55af55fb20 WARN                 basesrc gstbasesrc.c:3055:gst_base_src_loop:<rtmp-source> error: Internal data stream error.
0:00:03.159478234 16325   0x55af55fb20 WARN                 basesrc gstbasesrc.c:3055:gst_base_src_loop:<rtmp-source> error: streaming stopped, reason not-linked (-1)
Error: gst-stream-error-quark: Internal data stream error. (1): gstbasesrc.c(3055): gst_base_src_loop (): /GstPipeline:pipeline0/GstRTMPSrc:rtmp-source:
streaming stopped, reason not-linked (-1)

This my code

import sys
sys.path.append('../')
import gi
gi.require_version('Gst', '1.0')
from gi.repository import GObject, Gst
from common.bus_call import bus_call
import os
os.environ["GST_DEBUG_DUMP_DOT_DIR"] = "/tmp"
os.putenv('GST_DEBUG_DUMP_DIR_DIR', '/tmp')

def main(args):

    GObject.threads_init()
    Gst.init(None)

    print("Creating Pipeline \n ")
    pipeline = Gst.Pipeline()
    if not pipeline:
        sys.stderr.write(" Unable to create Pipeline \n")

    print("Creating Source And other \n ")
    source = Gst.ElementFactory.make("rtmpsrc", "rtmp-source")
    if not source:
        sys.stderr.write(" Unable to create Source \n")
    flvdemux1 = Gst.ElementFactory.make("flvdemux", "flv-demux")
    if not flvdemux1:
        sys.stderr.write(" Unable to create flvdemux \n")
    fakesink = Gst.ElementFactory.make("fakesink", "fake-sink")
    if not fakesink:
        sys.stderr.write(" Unable to create fake sink \n")

    source.set_property('location', 'rtmp://121.43.126.231:12966/live/28de595627d6d45cc11e4d17cbf021ee4c947bbb8ba8ddbc live=1')
    
    print("Adding elements to Pipeline \n")
    pipeline.add(source)
    pipeline.add(flvdemux1)
    pipeline.add(fakesink)
    
    print("Linking elements in the Pipeline \n")
    source.link(flvdemux1)
    flvdemux1.link(fakesink)
    
    # create an event loop and feed gstreamer bus mesages to it
    loop = GObject.MainLoop()
    bus = pipeline.get_bus()
    bus.add_signal_watch()
    bus.connect("message", bus_call, loop)

    Gst.debug_bin_to_dot_file(pipeline, Gst.DebugGraphDetails.ALL, "pipeline")

    # start play back and listen to events
    print("Starting pipeline \n")
    pipeline.set_state(Gst.State.PLAYING)
    try:
        loop.run()
    except:
        pass
    # cleanup
    pipeline.set_state(Gst.State.NULL)

if __name__ == '__main__':
    print(sys.argv)
    sys.exit(main(sys.argv))

And my pipeline.png tell me that the flvdemux doesn’t link to fakesink.Please help me.

[406769249]

This is my gst command’s pipeline png. The flvdemux has “video” part

Why my code can’t gei it?Please help me .

[406769249]

Gstreamer of python's gst.LinkError problem

I found this, i think maybe it’s the same problem.But it’s a long time away from now, can someone tell me how to do?

[DaneLLL]

Hi,
You would need to link the pad dynamically as mentioned in this discussion thread:
c - Gstreamer:dynamically link realize - Stack Overflow

Suggest try it in C code first to have a working C sample, and then apply to python.

[406769249]

I only use python…I know the discussion says, but i don’t know how to apply to python.Any other example?

[DaneLLL]

Hi,
Found a sample with qtdemux. Please take a look and give it a try:
python - Seamless video loop in gstreamer - Stack Overflow

[406769249]

THANKS!! Problem solved