[Sugar-devel] Sugar-devel Digest, Vol 38, Issue 17

[James Cameron]

On Wed, Dec 07, 2011 at 01:07:46AM +0100, laurent bernabe wrote:
> 2011/12/7 James Cameron <quozl at laptop.org> wrote:
> > You might also try moving the setup of the gst stream to after the
> > initialisation of pygame.  Experiment, and let us know your results.
> 
> Sorry but I did not understand this sentence 

Sorry.  Try moving the "setup of the gst stream" to after the
"initialisation of pygame".

The "setup of the gst stream" are the lines:

	# grab a frame from camera to file
	pipeline = gst.parse_launch('v4l2src ! ffmpegcolorspace ! jpegenc !  filesink location=/tmp/pippypic.jpg')
	pipeline.set_state(gst.STATE_PLAYING)

The "initialisation of pygame" is the line:

	# start using pygame
	pygame.init()

Moving one beyond the other means to change the order in which these
operations occur.  I expect the result will be certain failure, which is
a useful result because it proves the timing is important.

--

Given your test results of success if more time is wasted, perhaps the
program should retry the read of the file until it works, like this:

# start using pygame
pygame.init()

# turn off cursor
pygame.mouse.set_visible(False)

# create the pygame window and return a Surface object for
# drawing in that window.
screen = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)

# grab a frame from camera to file
pipeline = gst.parse_launch('v4l2src ! ffmpegcolorspace ! jpegenc !
filesink location=/tmp/pippypic.jpg')
pipeline.set_state(gst.STATE_PLAYING)

while True:
    try:
        # load in the grabbed camera frame
        image = pygame.image.load('/tmp/pippypic.jpg')
        break
    except pygame.error:
        # pause to allow more time for the camera frame to be grabbed
        time.sleep(1)

...

-- 
James Cameron
http://quozl.linux.org.au/