comment here

src/interface.jl

@@ -41,9 +41,11 @@ vecToDict(vec::Vector{UInt8}) = copy(JSON3.read(String(vec)))
     _, frame_1 = webcam.read()      # julia's PythonCall python-obj numpy array
     # frame_1 = cv.imread("20.jpg")     
 
-    _, buffer = cv.imencode(".jpg", frame_1)
+    # compress image data formats in order to make network transfer easier.
+    _, buffer = cv.imencode(".jpg", frame_1)    
+
     jpg_as_pyStr = base64.b64encode(buffer).decode("utf-8")
-    jpg_as_juliaStr = pyconvert(String, jpg_as_pyStr)
+    jpg_as_juliaStr = pyconvert(String, jpg_as_pyStr)   # for base64, python string or julia string is the same
     juliaDict = Dict("img"=> jpg_as_juliaStr)
     publish(mqttClient, "sometopic", JSON3.write(juliaDict))    # mqtt publish
     
@@ -52,7 +54,7 @@ vecToDict(vec::Vector{UInt8}) = copy(JSON3.read(String(vec)))
     #                            server - receive image                            #
     # ---------------------------------------------------------------------------- #
     img_str = payload["img"]    # payload received thru mqtt
-    buf = base64.b64decode(juliaDict["img"])
+    buf = base64.b64decode(img_str)
     buffer = np.frombuffer(buf, dtype=np.uint8)
     frame_1 = cv.imdecode(buffer, 1)
     frame_1_julia = pyconvert(Array, frame_1);