diff --git a/edgetpuvision/apps.py b/edgetpuvision/apps.py
new file mode 100644
index 0000000..3aa052c
--- /dev/null
+++ b/edgetpuvision/apps.py
@@ -0,0 +1,55 @@
+import argparse
+import logging
+import signal
+
+from .camera import make_camera
+from .gstreamer import Display, run_gen
+from .streaming.server import StreamingServer
+
+from . import svg
+
+EMPTY_SVG = str(svg.Svg())
+
+def run_server(add_render_gen_args, render_gen):
+    logging.basicConfig(level=logging.INFO)
+
+    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    parser.add_argument('--source',
+                        help='/dev/videoN:FMT:WxH:N/D or .mp4 file or image file',
+                        default='/dev/video0:YUY2:1280x720:30/1')
+    parser.add_argument('--bitrate', type=int, default=1000000,
+                        help='Video streaming bitrate (bit/s)')
+
+    add_render_gen_args(parser)
+    args = parser.parse_args()
+
+    gen = render_gen(args)
+    camera = make_camera(args.source, next(gen))
+    assert camera is not None
+
+    with StreamingServer(camera, args.bitrate) as server:
+        def render_overlay(tensor, layout, command):
+            overlay = gen.send((tensor, layout, command))
+            server.send_overlay(overlay if overlay else EMPTY_SVG)
+
+        camera.render_overlay = render_overlay
+        signal.pause()
+
+
+def run_app(add_render_gen_args, render_gen):
+    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    parser.add_argument('--source',
+                        help='/dev/videoN:FMT:WxH:N/D or .mp4 file or image file',
+                        default='/dev/video0:YUY2:1280x720:30/1')
+    parser.add_argument('--downscale', type=float, default=2.0,
+                        help='Downscale factor for .mp4 file rendering')
+    parser.add_argument('--display', type=Display, choices=Display, default=Display.FULLSCREEN,
+                        help='Display mode')
+    add_render_gen_args(parser)
+    args = parser.parse_args()
+
+    if not run_gen(render_gen(args),
+                   source=args.source,
+                   downscale=args.downscale,
+                   display=args.display):
+        print('Invalid source argument:', args.source)
diff --git a/edgetpuvision/camera.py b/edgetpuvision/camera.py
index a588425..4b1c914 100644
--- a/edgetpuvision/camera.py
+++ b/edgetpuvision/camera.py
@@ -1,8 +1,6 @@
 import os
 import threading
 
-import numpy as np
-
 from . import gstreamer
 from . import pipelines
 
@@ -10,12 +8,11 @@
 
 class Camera:
     def __init__(self, render_size, inference_size):
-        self._layout = gstreamer.make_layout(Size(*inference_size), Size(*render_size))
+        self._layout = gstreamer.make_layout(inference_size, render_size)
 
         self._loop = gstreamer.loop()
         self._thread = None
-
-        self.on_image = None
+        self.render_overlay = None
 
     @property
     def resolution(self):
@@ -28,19 +25,19 @@
         def on_buffer(data, _):
             obj.write(data)
 
-        def on_image(data, _):
-            if self.on_image:
-                self.on_image(np.frombuffer(data, dtype=np.uint8), self._layout)
+        def render_overlay(tensor, layout, command):
+            if self.render_overlay:
+                self.render_overlay(tensor, layout, command)
+            return None
 
         signals = {
           'h264sink': {'new-sample': gstreamer.new_sample_callback(on_buffer)},
-          'appsink': {'new-sample': gstreamer.new_sample_callback(on_image)},
         }
 
         pipeline = self.make_pipeline(format, profile, inline_headers, bitrate, intra_period)
 
-        self._thread = threading.Thread(target=gstreamer.run_pipeline,
-                                        args=(self._loop, pipeline, signals))
+        self._thread = threading.Thread(target=gstreamer.run_loop,
+                                        args=(self._loop, pipeline, self._layout, render_overlay, signals))
         self._thread.start()
 
     def stop_recording(self):
diff --git a/edgetpuvision/classify.py b/edgetpuvision/classify.py
index 8ca2f55..88e6147 100644
--- a/edgetpuvision/classify.py
+++ b/edgetpuvision/classify.py
@@ -14,8 +14,8 @@
 from edgetpu.classification.engine import ClassificationEngine
 
 from . import svg
+from .apps import run_app
 from .utils import load_labels, input_image_size, same_input_image_sizes, avg_fps_counter
-from .gstreamer import Display, run_gen
 
 
 CSS_STYLES = str(svg.CssStyle({'.txt': svg.Style(fill='white'),
@@ -114,22 +114,7 @@
                         help='Print inference results')
 
 def main():
-    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
-    parser.add_argument('--source',
-                        help='/dev/videoN:FMT:WxH:N/D or .mp4 file or image file',
-                        default='/dev/video0:YUY2:1280x720:30/1')
-    parser.add_argument('--downscale', type=float, default=2.0,
-                        help='Downscale factor for .mp4 file rendering')
-    parser.add_argument('--display', type=Display, choices=Display, default=Display.FULLSCREEN,
-                        help='Display mode')
-    add_render_gen_args(parser)
-    args = parser.parse_args()
-
-    if not run_gen(render_gen(args),
-                   source=args.source,
-                   downscale=args.downscale,
-                   display=args.display):
-        print('Invalid source argument:', args.source)
+    run_app(add_render_gen_args, render_gen)
 
 if __name__ == '__main__':
     main()
diff --git a/edgetpuvision/classify_server.py b/edgetpuvision/classify_server.py
index e5c9f97..c505fa0 100644
--- a/edgetpuvision/classify_server.py
+++ b/edgetpuvision/classify_server.py
@@ -6,11 +6,11 @@
 #   --model ${TEST_DATA}/mobilenet_v2_1.0_224_inat_bird_quant.tflite \
 #   --labels ${TEST_DATA}/inat_bird_labels.txt
 
+from .apps import run_server
 from .classify import add_render_gen_args, render_gen
-from .server import run
 
 def main():
-    run(add_render_gen_args, render_gen)
+    run_server(add_render_gen_args, render_gen)
 
 if __name__ == '__main__':
     main()
diff --git a/edgetpuvision/detect.py b/edgetpuvision/detect.py
index 7b73166..7ea68e2 100644
--- a/edgetpuvision/detect.py
+++ b/edgetpuvision/detect.py
@@ -20,8 +20,8 @@
 from edgetpu.detection.engine import DetectionEngine
 
 from . import svg
+from .apps import run_app
 from .utils import load_labels, input_image_size, same_input_image_sizes, avg_fps_counter
-from .gstreamer import Display, run_gen
 
 CSS_STYLES = str(svg.CssStyle({'.txt': svg.Style(fill='white'),
                                '.shd': svg.Style(fill='black', fill_opacity=0.6),
@@ -145,23 +145,7 @@
                         help='Print inference results')
 
 def main():
-    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
-    parser.add_argument('--source',
-                        help='/dev/videoN:FMT:WxH:N/D or .mp4 file or image file',
-                        default='/dev/video0:YUY2:1280x720:30/1')
-    parser.add_argument('--downscale', type=float, default=2.0,
-                        help='Downscale factor for video/image file rendering')
-    parser.add_argument('--display', type=Display, choices=Display, default=Display.FULLSCREEN,
-                        help='Display mode')
-    add_render_gen_args(parser)
-    args = parser.parse_args()
-
-    if not run_gen(render_gen(args),
-                   source=args.source,
-                   downscale=args.downscale,
-                   display=args.display):
-        print('Invalid source argument:', args.source)
-
+    run_app(add_render_gen_args, render_gen)
 
 if __name__ == '__main__':
     main()
diff --git a/edgetpuvision/detect_server.py b/edgetpuvision/detect_server.py
index f711ba2..1babc37 100644
--- a/edgetpuvision/detect_server.py
+++ b/edgetpuvision/detect_server.py
@@ -11,11 +11,11 @@
 #   --model ${TEST_DATA}/mobilenet_ssd_v2_coco_quant_postprocess_edgetpu.tflite \
 #   --labels ${TEST_DATA}/coco_labels.txt
 
+from .apps import run_server
 from .detect import add_render_gen_args, render_gen
-from .server import run
 
 def main():
-    run(add_render_gen_args, render_gen)
+    run_server(add_render_gen_args, render_gen)
 
 if __name__ == '__main__':
     main()
diff --git a/edgetpuvision/gstreamer.py b/edgetpuvision/gstreamer.py
index 874cecf..cc561ca 100644
--- a/edgetpuvision/gstreamer.py
+++ b/edgetpuvision/gstreamer.py
@@ -100,6 +100,8 @@
 Layout = collections.namedtuple('Layout', ('size', 'window', 'inference_size', 'render_size'))
 
 def make_layout(inference_size, render_size):
+    inference_size = Size(*inference_size)
+    render_size = Size(*render_size)
     size = min_outer_size(inference_size, render_size)
     window = center_inside(render_size, size)
     return Layout(size=size, window=window,
@@ -120,7 +122,7 @@
     return streams[0]
 
 def loop():
-    return GLib.MainLoop.new(None, False)
+    return GLib.MainLoop()
 
 @contextlib.contextmanager
 def pull_sample(sink):
@@ -228,13 +230,12 @@
     result = get_pipeline(source, inference_size, downscale, display)
     if result:
         layout, pipeline = result
-        run_loop(pipeline, layout, render_overlay)
+        run_loop(loop(), pipeline, layout, render_overlay)
         return True
 
     return False
 
 def get_pipeline(source, inference_size, downscale, display):
-    inference_size = Size(*inference_size)
     fmt = parse_format(source)
     if fmt:
         layout = make_layout(inference_size, fmt.size)
@@ -245,7 +246,7 @@
         info = get_video_info(filename)
         render_size = Size(info.get_width(), info.get_height()) / downscale
         layout = make_layout(inference_size, render_size)
-        return layout, file_pipline(filename, info, layout, display)
+        return layout, file_pipline(info.is_image(), filename, layout, display)
 
     return None
 
@@ -255,21 +256,21 @@
     else:
         return camera_display_pipeline(fmt, layout, display is Display.FULLSCREEN)
 
-def file_pipline(filename, info, layout, display):
+def file_pipline(is_image, filename, layout, display):
     if display is Display.NONE:
-        if info.is_image():
+        if is_image:
             return image_headless_pipeline(filename, layout)
         else:
             return video_headless_pipeline(filename, layout)
     else:
         fullscreen = display is Display.FULLSCREEN
-        if info.is_image():
+        if is_image:
             return image_display_pipeline(filename, layout, fullscreen)
         else:
             return video_display_pipeline(filename, layout, fullscreen)
 
-def run_loop(pipeline, layout, render_overlay):
-    loop = GLib.MainLoop()
+def run_loop(loop, pipeline, layout, render_overlay, signals=None):
+    signals = signals or {}
     commands = queue.Queue()
 
     with contextlib.ExitStack() as stack:
@@ -280,10 +281,11 @@
             GLib.io_add_watch(sys.stdin.fileno(), GLib.IO_IN, on_keypress, commands)
             stack.enter_context(term_raw_mode(sys.stdin.fileno()))
 
-        run_pipeline(loop, pipeline, {'appsink': {'new-sample':
-            functools.partial(on_new_sample,
+        run_pipeline(loop, pipeline, {'appsink':
+            {'new-sample': functools.partial(on_new_sample,
                 render_overlay=functools.partial(render_overlay, layout=layout),
                 layout=layout,
                 images=images,
-                commands=commands)}
+                commands=commands)},
+            **signals
         })
diff --git a/edgetpuvision/server.py b/edgetpuvision/server.py
deleted file mode 100644
index bb3c0aa..0000000
--- a/edgetpuvision/server.py
+++ /dev/null
@@ -1,31 +0,0 @@
-import argparse
-import logging
-import signal
-
-from .camera import make_camera
-from .streaming.server import StreamingServer
-
-def run(add_render_gen_args, render_gen):
-    logging.basicConfig(level=logging.INFO)
-
-    parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
-    parser.add_argument('--bitrate', type=int, default=1000000,
-                        help='Video streaming bitrate (bit/s)')
-
-    parser.add_argument('--source',
-                        help='/dev/videoN:FMT:WxH:N/D or .mp4 file or image file',
-                        default='/dev/video0:YUY2:1280x720:30/1')
-    add_render_gen_args(parser)
-    args = parser.parse_args()
-
-    gen = render_gen(args)
-    camera = make_camera(args.source, next(gen))
-    assert camera is not None
-
-    with StreamingServer(camera, args.bitrate) as server:
-        def on_image(tensor, layout):
-            overlay = gen.send((tensor, layout, None))
-            server.send_overlay(overlay)
-
-        camera.on_image = on_image
-        signal.pause()