add optional perspective transform

Author: floe

gst_helpers.py

@@ -123,7 +123,7 @@ def connect_bus(msgtype, callback, *args):
     bus.connect(msgtype, callback, *args)
 
 # test sources as stream placeholders
-def add_test_sources(frontdev="",surfdev="",fake=False,bgcol=0xFF00FF00,wave="ticks"):
+def add_test_sources(frontdev="",surfdev="",fake=False,bgcol=0xFF00FF00,wave="ticks",perspective=None):
 
     if fake:
         frontsrc = "videotestsrc is-live=true pattern=smpte ! timeoverlay" if frontdev == "" else frontdev
@@ -136,6 +136,9 @@ def add_test_sources(frontdev="",surfdev="",fake=False,bgcol=0xFF00FF00,wave="ti
         surfsrc  = "v4l2src do-timestamp=true device="+surfdev+"  ! videorate ! videoconvert" 
         audiosrc = "alsasrc do-timestamp=true" # "audiorate ! audioconvert"
 
+    # FIXME still a bit hackish, maybe solveable without double videoconvert?
+    vc = None if perspective == None else new_element("videoconvert")
+
     logging.debug("  Front Source: "+frontsrc)
     logging.debug("Surface Source: "+surfsrc)
     logging.debug("  Audio Source: "+audiosrc)
@@ -145,7 +148,7 @@ def add_test_sources(frontdev="",surfdev="",fake=False,bgcol=0xFF00FF00,wave="ti
         new_element("tee",{"allow-not-linked":True},"fronttestsource")
     ])
 
-    add_and_link([ Gst.parse_bin_from_description( surfsrc, True ),
+    add_and_link([ Gst.parse_bin_from_description( surfsrc, True ), perspective, vc, # <-- NOTE
         new_element("capsfilter",{"caps":Gst.Caps.from_string("video/x-raw,format=YV12,width=1280,height=720,framerate=15/1")}),
         new_element("tee",{"allow-not-linked":True},"surfacetestsource")
     ])

webrtc_client.py

@@ -64,6 +64,7 @@ def on_element_added(thebin, element):
 parser.add_argument("-t","--target", help="server to connect to (%(default)s)", default="127.0.0.1")
 parser.add_argument("-f","--front",  help="front image source   (device or pipeline)",default=""   )
 parser.add_argument("-s","--surface",help="surface image source (device or pipeline)",default=""   )
+parser.add_argument("-p","--perspective",help="perspective (9 floats: \"1,0,0,...\")",default=""   )
 
 args = parser.parse_args()
 print("Option",args,"\n")
@@ -74,7 +75,13 @@ def on_element_added(thebin, element):
 if not args.fake and (args.front == "" or args.surface == ""):
     logging.warning("Need to either specify --fake for test sources, or -f/-s for source devices/pipelines.")
 
-add_test_sources(args.front,args.surface,args.fake)
+if args.perspective != "":
+    params = [ float(f) for f in args.perspective.split(",") ]
+    pt = new_element("perspective",{"matrix":params})
+else:
+    pt = None
+
+add_test_sources(args.front,args.surface,args.fake,perspective=pt)
 
 session = Soup.Session()
 session.set_property("ssl-strict", False)