[antpoli]

ciao,
sto provando a sviluppare un OSD (OnScreenDisplay) utilizzando il modulo "picamera" di python e durante l'esecuzione del parametro "update" per aggiornare il render ricevo un errore di no buffers available: Resource temporarily unavailable; try again later ed in particolare la sfilza di seguito

Traceback (most recent call last):
File "_ctypes/callbacks.c", line 314, in 'calling callback function'
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1227, in wrapper
self._pool.send_buffer(block=False)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1931, in send_buffer
super(MMALPortPool, self).send_buffer(port, block, timeout)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1881, in send_buffer
raise PiCameraMMALError(mmal.MMAL_EAGAIN, 'no buffers available')
picamera.exc.PiCameraMMALError: no buffers available: Resource temporarily unavailable; try again later
Traceback (most recent call last):
File "_ctypes/callbacks.c", line 314, in 'calling callback function'
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1227, in wrapper
self._pool.send_buffer(block=False)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1931, in send_buffer
super(MMALPortPool, self).send_buffer(port, block, timeout)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1881, in send_buffer
raise PiCameraMMALError(mmal.MMAL_EAGAIN, 'no buffers available')
picamera.exc.PiCameraMMALError: no buffers available: Resource temporarily unavailable; try again later
Traceback (most recent call last):
File "_ctypes/callbacks.c", line 314, in 'calling callback function'
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1227, in wrapper
self._pool.send_buffer(block=False)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1931, in send_buffer
super(MMALPortPool, self).send_buffer(port, block, timeout)
File "/usr/lib/python2.7/dist-packages/picamera/mmalobj.py", line 1881, in send_buffer
raise PiCameraMMALError(mmal.MMAL_EAGAIN, 'no buffers available')
picamera.exc.PiCameraMMALError: no buffers available: Resource temporarily unavailable; try again later

il codice che origina il problema è il seguente:

try:
        while True:
            text = time.strftime('%H:%M:%S', time.gmtime())
            img = crossHair.copy()
            draw = ImageDraw.Draw(img)
            draw.font = ImageFont.truetype("/usr/share/fonts/truetype/freefont/FreeSerif.ttf", 50)
            draw.text((10, 10), text, (255, 255, 255))

            overlay.update(img.tostring())

            time.sleep(1)
    finally:
        camera.remove_overlay(overlay)

quando arriva all'esecuzione del comando overlay.

Ovviamente non ho problemi di memoria, come si può vedere dallo screenshot dell'output del comando "free -m"


Proprio non riesco a capire come mai        
Qualcuno mi può aiutare?

grazie