udp videostreaming in gstreamer mit python

Question

All dies geschieht in demselben Computer. Ich möchte einen Videostream von Gstreamer mit der GST unter Verwendung Python erhalten. Zuerst werde ich gstreamer Pipeline

gst-launch-1.0 v4l2src ! video/x-raw,width=640,height=480 ! timeoverlay ! tee name="local" ! queue ! autovideosink local. ! queue ! jpegenc! rtpjpegpay ! udpsink host=127.0.0.1 port= 5000 

dann wollen stelle ich mit einem Skript in Python zur Ausgabe in opencv

import sys 
from gi.repository import Gst 
import cv2 
import numpy 

Gst.init(None) 


image_arr = None 

def gst_to_opencv(sample): 
    buf = sample.get_buffer() 
    caps = sample.get_caps() 
    print caps.get_structure(0).get_value('format') 
    print caps.get_structure(0).get_value('height') 
    print caps.get_structure(0).get_value('width') 

    print buf.get_size() 

    arr = numpy.ndarray(
     (caps.get_structure(0).get_value('height'), 
     caps.get_structure(0).get_value('width'), 
     3), 
     buffer=buf.extract_dup(0, buf.get_size()), 
     dtype=numpy.uint8) 
    return arr 

def new_buffer(sink, data): 
    global image_arr 
    sample = sink.emit("pull-sample") 
    buf = sample.get_buffer() 
    print "Timestamp: ", buf.pts 
    arr = gst_to_opencv(sample) 
    image_arr = arr 
    return Gst.FlowReturn.OK 

# Create the elements 
source = Gst.ElementFactory.make("udpsrc", None) 
depay = Gst.ElementFactory.make("rtpjpegdepay", None) 
decoder = Gst.ElementFactory.make("jpegdec", None) 
sink = Gst.ElementFactory.make("appsink", None) 



# Create the empty pipeline111 
pipeline = Gst.Pipeline.new("test-pipeline") 

if not pipeline: 
    print("Not all elements could be created.") 
    exit(-1) 


sink.set_property("emit-signals", True) 
#sink.set_property("max-buffers", 2) 
# # sink.set_property("drop", True) 
# # sink.set_property("sync", False) 

#caps = Gst.caps_from_string("application/x-rtp, encoding name=JPEG, payload=26, width=640, height=480; video/x-bayer,format=(string){rggb,bggr,grbg,gbrg}") 
caps = Gst.caps_from_string(" application/x-rtp, encoding-name=JPEG, payload=26, format=(string)[]{rggb,bggr,grbg,gbrg}") 
sink.set_property("caps", caps) 


sink.connect("new-sample", new_buffer, sink) 

# Build the pipeline 
pipeline.add(source) 
pipeline.add(depay) 
pipeline.add(decoder) 
pipeline.add(sink) 
if not Gst.Element.link(source, depay): 
    print("Elements could not be linked.") 
    exit(-1) 
if not Gst.Element.link(depay, decoder): 
    print("Elements could not be linked.") 
    exit(-1) 
if not Gst.Element.link(decoder, sink): 
    print("Elements could not be linked.") 
    exit(-1) 

# Modify the source's properties 
source.set_property("port", 5000) 

# Start playing 
ret = pipeline.set_state(Gst.State.PLAYING) 
if ret == Gst.StateChangeReturn.FAILURE: 
    print("Unable to set the pipeline to the playing state.") 
    exit(-1) 

# Wait until error or EOS 
bus = pipeline.get_bus() 


# Parse message 
while True: 
    message = bus.timed_pop_filtered(10000, Gst.MessageType.ANY) 
    # print "image_arr: ", image_arr 
    if image_arr is not None: 
     cv2.imshow("appsink image arr", image_arr) 
     cv2.waitKey(1) 
    if message: 
     if message.type == Gst.MessageType.ERROR: 
      err, debug = message.parse_error() 
      print("Error received from element %s: %s" % (
       message.src.get_name(), err)) 
      print("Debugging information: %s" % debug) 
      break 
     elif message.type == Gst.MessageType.EOS: 
      print("End-Of-Stream reached.") 
      break 
     elif message.type == Gst.MessageType.STATE_CHANGED: 
      if isinstance(message.src, Gst.Pipeline): 
       old_state, new_state, pending_state = message.parse_state_changed() 
       print("Pipeline state changed from %s to %s." % 
         (old_state.value_nick, new_state.value_nick)) 
     else: 
      print("Unexpected message received.") 

# Free resources 
pipeline.set_state(Gst.State.NULL) 

Ich sehe diesen Fehler

Pipeline state changed from null to ready. 
Unexpected message received. 
Pipeline state changed from ready to paused. 
Unexpected message received. 
Unexpected message received. 
Unexpected message received. 
Error received from element rtpjpegdepay0: No RTP format was negotiated. 
Debugging information: gstrtpbasedepayload.c(373): gst_rtp_base_depayload_chain(): /GstPipeline:test-pipeline/GstRtpJPEGDepay:rtpjpegdepay0: 
Input buffers need to have RTP caps set on them. This is usually achieved by setting the 'caps' property of the upstream source element (often udpsrc or appsrc), or by putting a capsfilter element before the depayloader and setting the 'caps' property on that. Also see http://cgit.freedesktop.org/gstreamer/gst-plugins-good/tree/gst/rtp/README 

einen Video-Stream von GStreamer erhalten Wie man es repariert?

Empfänger gstreamer Pipeline

gst-launch-1.0 udpsrc port=5000 ! application/x-rtp, encoding-name=JPEG,payload=26 ! rtpjpegdepay ! jpegdec ! autovideosink 

Answer 1

Sie haben Kappen zu verhandeln auf udpsrc wie

gst-launch-1.0 udpsrc port=9090 caps=application/x-rtp,media=video,encoding-name=MP2T 

Wie Sie die Daten senden, basierend auf, dass diese Kappen variieren. Sie müssen das RTP-Format aushandeln, da Sie vor dem Editieren ein rtp-Bezahlelement verwendet haben.