我有一个Raspberry Pi相机v2.1版本，可以拍摄分辨率为3280x2464的照片。
我已经使用raspistill命令进行了测试，似乎一切正常：
raspistill -o 8mp.png -w 3280 -h 2464
返回信息：
8mp.png JPEG 3280x2464 3280x2464+0+0 8-bit sRGB 4.524MB 0.010u 0:00.010
然而，当我使用Python代码拍照时，它会拒绝。这是我正在使用的代码：
#!/usr/bin/python
import picamera
camera = picamera.PiCamera()
camera.resolution = (3280,2464)
camera.capture("test.png")
camera.close()
这是错误信息：
mmal: mmal_vc_port_enable: failed to enable port vc.ril.image_encode:out:0(PNG ): ENOSPC
mmal: mmal_port_enable: failed to enable port vc.ril.image_encode:out:0(PNG )(0x700090) (ENOSPC)
Traceback (most recent call last):
File "pic.py", line 6, in <module>
camera.capture("test.png")
File "/usr/local/lib/python2.7/dist-packages/picamera/camera.py", line 1383, in capture
encoder.start(output)
File "/usr/local/lib/python2.7/dist-packages/picamera/encoders.py", line 1024, in start
super(PiCookedOneImageEncoder, self).start(output)
File "/usr/local/lib/python2.7/dist-packages/picamera/encoders.py", line 394, in start
self.output_port.enable(self._callback)
File "/usr/local/lib/python2.7/dist-packages/picamera/mmalobj.py", line 813, in enable
prefix="Unable to enable port %s" % self.name)
File "/usr/local/lib/python2.7/dist-packages/picamera/exc.py", line 157, in mmal_check
raise PiCameraMMALError(status, prefix)
picamera.exc.PiCameraMMALError: Unable to enable port vc.ril.image_encode:out:0(PNG ): Out of resources (other than memory)
我注意到使用 .jpg 而不是 .png 可以正常工作。这对我来说有点奇怪，因为文档中说它应该可以工作，而且 raspistill 命令也可以在 .png 上使用此分辨率。有任何想法吗？