all video processing samples use camera as default source (and fallback to synth…

all video processing samples use camera as default source (and fallback to synth in case of capture error)

samples/python2/camshift.py

@@ -98,7 +98,7 @@ class App(object):
 if __name__ == '__main__':
     import sys
     try: video_src = sys.argv[1]
-    except: video_src = video.presets['chess']
+    except: video_src = 0
     print help_message
     App(video_src).run()
 

samples/python2/color_histogram.py

@@ -23,8 +23,8 @@ if __name__ == '__main__':
     cv2.createTrackbar('scale', 'hist', hist_scale, 32, set_scale)
 
     try: fn = sys.argv[1]
-    except: fn = 'synth:bg=../cpp/baboon.jpg:class=chess:noise=0.05'
-    cam = video.create_capture(fn)
+    except: fn = 0
+    cam = video.create_capture(fn, fallback='synth:bg=../cpp/baboon.jpg:class=chess:noise=0.05')
 
     while True:
         flag, frame = cam.read()

samples/python2/edge.py

@@ -4,7 +4,7 @@ import sys
 
 if __name__ == '__main__':
     try: fn = sys.argv[1]
-    except: fn = video.presets['chess']
+    except: fn = 0
 
     def nothing(*arg):
         pass

samples/python2/facedetect.py

@@ -25,7 +25,7 @@ if __name__ == '__main__':
     
     args, video_src = getopt.getopt(sys.argv[1:], '', ['cascade=', 'nested-cascade='])
     try: video_src = video_src[0]
-    except: video_src = 'synth:bg=../cpp/lena.jpg:noise=0.05'
+    except: video_src = 0
     args = dict(args)
     cascade_fn = args.get('--cascade', "../../data/haarcascades/haarcascade_frontalface_alt.xml")
     nested_fn  = args.get('--nested-cascade', "../../data/haarcascades/haarcascade_eye.xml")
@@ -33,7 +33,7 @@ if __name__ == '__main__':
     cascade = cv2.CascadeClassifier(cascade_fn)
     nested = cv2.CascadeClassifier(nested_fn)
 
-    cam = create_capture(video_src)
+    cam = create_capture(video_src, fallback='synth:bg=../cpp/lena.jpg:noise=0.05')
 
     while True:
         ret, img = cam.read()

samples/python2/lk_track.py

@@ -77,7 +77,7 @@ class App:
 def main():
     import sys
     try: video_src = sys.argv[1]
-    except: video_src = video.presets['chess']
+    except: video_src = 0
 
     print help_message
     App(video_src).run()

samples/python2/motempl.py

@@ -12,21 +12,21 @@ def draw_motion_comp(vis, (x, y, w, h), angle, color):
     cv2.rectangle(vis, (x, y), (x+w, y+h), (0, 255, 0))
     r = min(w/2, h/2)
     cx, cy = x+w/2, y+h/2
-    angle = angle*3.1415926/180
+    angle = angle*np.pi/180
     cv2.circle(vis, (cx, cy), r, color, 3)
     cv2.line(vis, (cx, cy), (int(cx+np.cos(angle)*r), int(cy+np.sin(angle)*r)), color, 3)
 
 if __name__ == '__main__':
     import sys
     try: video_src = sys.argv[1]
-    except: video_src = 'synth:class=chess:bg=../cpp/lena.jpg:noise=0.01'
+    except: video_src = 0
 
     cv2.namedWindow('motempl')
     visuals = ['input', 'frame_diff', 'motion_hist', 'grad_orient']
     cv2.createTrackbar('visual', 'motempl', 2, len(visuals)-1, nothing)
     cv2.createTrackbar('threshold', 'motempl', DEFAULT_THRESHOLD, 255, nothing)
 
-    cam = video.create_capture(video_src)
+    cam = video.create_capture(video_src, fallback='synth:class=chess:bg=../cpp/lena.jpg:noise=0.01')
     ret, frame = cam.read()
     h, w = frame.shape[:2]
     prev_frame = frame.copy()

samples/python2/opt_flow.py

@@ -47,7 +47,7 @@ if __name__ == '__main__':
     import sys
     print help_message
     try: fn = sys.argv[1]
-    except: fn = video.presets['chess']
+    except: fn = 0
 
     cam = video.create_capture(fn)
     ret, prev = cam.read()

samples/python2/video.py

@@ -39,6 +39,9 @@ class VideoSynthBase(object):
             buf = cv2.add(buf, noise, dtype=cv2.CV_8UC3)
         return True, buf
 
+    def isOpened(self):
+        return True
+
 class Chess(VideoSynthBase):
     def __init__(self, **kw):
         super(Chess, self).__init__(**kw)
@@ -87,33 +90,40 @@ class Chess(VideoSynthBase):
         self.draw_quads(dst, self.black_quads, (10, 10, 10))
 
 
-
 classes = dict(chess=Chess)
 
-def create_capture(source):
+presets = dict(
+    empty = 'synth:',
+    lena = 'synth:bg=../cpp/lena.jpg:noise=0.1',
+    chess = 'synth:class=chess:bg=../cpp/lena.jpg:noise=0.1:size=640x480'
+)
+
+
+def create_capture(source = 0, fallback = presets['chess']):
     '''
       source: <int> or '<int>' or '<filename>' or 'synth:<params>'
     '''
+    cap = None
     try: source = int(source)
     except ValueError: pass
     else:
-        return cv2.VideoCapture(source)
-    source = str(source).strip()
-    if source.startswith('synth'):
-        ss = filter(None, source.split(':'))
-        params = dict( s.split('=') for s in ss[1:] )
-        try: Class = classes[params['class']]
-        except: Class = VideoSynthBase
-
-        return Class(**params)
-    return cv2.VideoCapture(source)
-
-
-presets = dict(
-    empty = 'synth:',
-    lena = 'synth:bg=../cpp/lena.jpg:noise=0.1',
-    chess = 'synth:class=chess:bg=../cpp/lena.jpg:noise=0.1:size=640x480'
-)
+        cap = cv2.VideoCapture(source)
+    if cap is None:
+        source = str(source).strip()
+        if source.startswith('synth'):
+            ss = filter(None, source.split(':'))
+            params = dict( s.split('=') for s in ss[1:] )
+            try: Class = classes[params['class']]
+            except: Class = VideoSynthBase
+            try: cap = Class(**params)
+            except: pass
+    if cap is None:
+        cap = cv2.VideoCapture(source)
+    if not cap.isOpened():
+        print 'Warning: unable to open video source: ', source
+        if fallback is not None:
+            return create_capture(fallback, None)
+    return cap
 
 if __name__ == '__main__':
     import sys
@@ -127,7 +137,7 @@ if __name__ == '__main__':
     args = dict(args)
     shotdir = args.get('--shotdir', '.')
     if len(sources) == 0:
-        sources = [ presets['chess'] ]
+        sources = [ 0 ]
 
     print 'Press SPACE to save current frame'