bufferless videocapture

scripts/snapchat_server.py

@@ -11,7 +11,7 @@
 from os import listdir
 from os.path import isfile, join
 import rospkg
-
+import Queue
 
 import dlib
 #import imutils
@@ -23,6 +23,32 @@
 from std_msgs.msg import String
 
 
+# bufferless VideoCapture
+class VideoCapture:
+
+ def __init__(self, name):
+ self.cap = cv2.VideoCapture(name)
+ self.q = Queue.Queue()
+ t = Thread(target=self._reader)
+ t.daemon = True
+ t.start()
+
+ # read frames as soon as they are available, keeping only most recent one
+ def _reader(self):
+ while True:
+ ret, frame = self.cap.read()
+ if not ret:
+ break
+ if not self.q.empty():
+ try:
+ self.q.get_nowait() # discard previous (unprocessed) frame
+ except Queue.Empty:
+ pass
+ self.q.put(frame)
+
+ def read(self):
+ return self.q.get()
+
 def handleRequest(req):
  print ("Chosen filter: "+req.name)
 
@@ -185,11 +211,9 @@ def cvloop():
  dir_ = spr+"flyes/"
  flies = [f for f in listdir(dir_) if isfile(join(dir_, f))] #image of flies to make the "animation"
  i = 0
- video_capture = cv2.VideoCapture(-1) #read from webcam
- print(video_capture.get(cv2.CAP_PROP_BUFFERSIZE))
- video_capture.set(cv2.CAP_PROP_BUFFERSIZE, 0)
- #video_capture.set(cv2.CAP_PROP_FPS, 10.0)
- print(video_capture.get(cv2.CAP_PROP_FPS))
+ video_capture = VideoCapture(-1) #read from webcam
+ # video_capture.set(cv2.CAP_PROP_FPS, 1.0)
+ # print(video_capture.get(cv2.CAP_PROP_FPS))
  (x,y,w,h) = (0,0,10,10) #whatever initial values
 
  #Filters path
@@ -205,7 +229,7 @@ def cvloop():
  while True:
  if flash:
  print("flashed")
- #ledscolor.publish("white")
+ ledscolor.publish("white")
  save = True
  flash_timestamp = time.time()
  flash = False
@@ -214,8 +238,8 @@ def cvloop():
  # print("turned off flash")
  # ledscolor.publish("black")
  # time.sleep(1.5)
- print("reading")
- ret, image = video_capture.read()
+ # print("reading")
+ image = video_capture.read()
 
  #image = imutils.resize(image, width=3000)
  # image = image[0:376, 0:500]
@@ -379,7 +403,7 @@ def cvloop():
  # OpenCV represents image as BGR; PIL but RGB, we need to change the chanel order
  # image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
  # if save:
- if save and time.time() - flash_timestamp > 2:
+ if save and time.time() - flash_timestamp > 0.2:
  print("saved img")
  cv2.imwrite('test.jpeg', image)
  ledscolor.publish("black")