Hi all,
I've got some weird behaviour with my little python app. It opens up a video
device and streams the images to pyGTK window.
It basically works OK but occasionally has issues when stopping the stream. It
appears to get stuck in a while loop whilst waiting for a signal to clear.
So questions:
1) is waiting for a signal to clear in this manner the best approach.
2) is there a way to debug what is really happening in the various threads?
A code snippet is:
--
class pyv4l2_grabber(threading.Thread):
--
def stop_stream(self):
if self.active == 1:
self.event_stop_stream.set()
self.active = 0
while self.event_stop_stream.isSet():
time.sleep(0.1)
print "stopped capture, frame rate was ",
(self.frame_count /(self.end_time - self.start_time))
--
It appears that when 'stop' fails I can wait as long as I want, but when ever I
press control-C it reports:
--
CTraceback (most recent call last):
File "./pyDataMatrixScanner.py", line 329, in button2_clicked
self.videodevice.stop_stream()
File "./pyDataMatrixScanner.py", line 170, in stop_stream
time.sleep(0.1)
KeyboardInterrupt
--
The code which actually draws the image to the screen/gtk-pixmap is surrounded
by:
--
gtk.gdk.threads_enter()
...
gtk.gdk.threads_leave()
--
which seem to be required for speed. If these are removed (or the drawing to
screen is disabled) the lockup does not occur.... very strange.
Any suggestions?
Simon.
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