speed up camera_pi mjpeg stream

raspberry/roberto/__init__.py

@@ -23,7 +23,7 @@ login = LoginManager()
 login.login_view = "users.login"
 socketio = SocketIO()
 if platform == 'raspberry':
-    from roberto.camera.camera_pi import Camera
+    from roberto.camera.camera_pi_new import Camera
 else:
     from roberto.camera.camera_opencv import Camera
 camera = Camera()

raspberry/roberto/camera/camera_pi_new.py

@@ -0,0 +1,46 @@
+import io
+import time
+import picamera
+from .base_camera import BaseCamera
+
+from threading import Condition
+
+class StreamingOutput(object):
+    def __init__(self):
+        self.frame = None
+        self.buffer = io.BytesIO()
+        self.condition = Condition()
+
+    def write(self, buf):
+        if buf.startswith(b'\xff\xd8'):
+            # New frame, copy the existing buffer's content and notify all
+            # clients it's available
+            self.buffer.truncate()
+            with self.condition:
+                self.frame = self.buffer.getvalue()
+                self.condition.notify_all()
+            self.buffer.seek(0)
+        return self.buffer.write(buf)
+
+
+class Camera(BaseCamera):
+    @staticmethod
+    def frames():
+        with picamera.PiCamera() as camera:
+            camera.resolution = (640, 480)
+            camera.exposure_mode = 'sports'
+            camera.framerate = 15
+            camera.rotation = 180
+            # let camera warm up
+            time.sleep(2)
+
+            output = StreamingOutput()
+            camera.start_recording(output, format='mjpeg')
+
+            while True:
+                with output.condition:
+                    output.condition.wait()
+                    frame = output.frame
+                #yield b'--FRAME\r\n'
+                yield frame
+                #yield b'\r\n'