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rohal
rohal
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I am trying to lower the time to capture a still image from the Pi camera (I have a V2 and HQ). To this end, I have found my way to the PiCamera 1.13 docs, specifically chapter 16 dealing with the MMAL object. I tried following the example code given between 16.1.1 and 16.1.7, which seems to be a basic set-up and capture. I reduced the code to the minimum I thought would work; there is a lot of input and output confirmation I removed. Here is the code:

from picamera import mmal, mmalobj as mo import io def image_callback(port, buf): output.write(buf.data) return bool(buf.flags & mmal.MMAL_BUFFER_HEADER_FLAG_FRAME_END) camera = mo.MMALCamera() preview = mo.MMALRenderer() camera.outputs[2].format = mmal.MMAL_ENCODING_RGB24 camera.outputs[2].framesize = (640, 480) camera.outputs[2].commit() camera.outputs[2] camera.outputs[2].enable() camera.outputs[2].disable() output = io.open('image.data', 'wb') camera.outputs[2].enable(image_callback) output.tell() camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

This code runs without error from a file, cam_test.py, but produces the file image.data of size 0 bytes. However, when the code is run interactively from the Python console, as the examples do, the desired file is created properly only when the code is entered in parts. That is, I can paste the code up to the first output.tell(), then copy & paste the remaining code (the image capture) into the console and have success. This tells me I have the code to create the image file; why does it not work from a Python file? I have checked Python versions in both cases is the same (3.7.3) and use a Python virtual environment. Thanks in advance for any input.

Edit: The second part of the code is the last 5 lines

camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

I had tried a 1 second delay between the two parts (in the .py file); still image.data file of 0 bytes.

I am trying to lower the time to capture a still image from the Pi camera (I have a V2 and HQ). To this end, I have found my way to the PiCamera 1.13 docs, specifically chapter 16 dealing with the MMAL object. I tried following the example code given between 16.1.1 and 16.1.7, which seems to be a basic set-up and capture. I reduced the code to the minimum I thought would work; there is a lot of input and output confirmation I removed. Here is the code:

from picamera import mmal, mmalobj as mo import io def image_callback(port, buf): output.write(buf.data) return bool(buf.flags & mmal.MMAL_BUFFER_HEADER_FLAG_FRAME_END) camera = mo.MMALCamera() preview = mo.MMALRenderer() camera.outputs[2].format = mmal.MMAL_ENCODING_RGB24 camera.outputs[2].framesize = (640, 480) camera.outputs[2].commit() camera.outputs[2] camera.outputs[2].enable() camera.outputs[2].disable() output = io.open('image.data', 'wb') camera.outputs[2].enable(image_callback) output.tell() camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

This code runs without error from a file, cam_test.py, but produces the file image.data of size 0 bytes. However, when the code is run interactively from the Python console, as the examples do, the desired file is created properly only when the code is entered in parts. That is, I can paste the code up to the first output.tell(), then copy & paste the remaining code (the image capture) into the console and have success. This tells me I have the code to create the image file; why does it not work from a Python file? I have checked Python versions in both cases is the same (3.7.3) and use a Python virtual environment. Thanks in advance for any input.

I am trying to lower the time to capture a still image from the Pi camera (I have a V2 and HQ). To this end, I have found my way to the PiCamera 1.13 docs, specifically chapter 16 dealing with the MMAL object. I tried following the example code given between 16.1.1 and 16.1.7, which seems to be a basic set-up and capture. I reduced the code to the minimum I thought would work; there is a lot of input and output confirmation I removed. Here is the code:

from picamera import mmal, mmalobj as mo import io def image_callback(port, buf): output.write(buf.data) return bool(buf.flags & mmal.MMAL_BUFFER_HEADER_FLAG_FRAME_END) camera = mo.MMALCamera() preview = mo.MMALRenderer() camera.outputs[2].format = mmal.MMAL_ENCODING_RGB24 camera.outputs[2].framesize = (640, 480) camera.outputs[2].commit() camera.outputs[2] camera.outputs[2].enable() camera.outputs[2].disable() output = io.open('image.data', 'wb') camera.outputs[2].enable(image_callback) output.tell() camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

This code runs without error from a file, cam_test.py, but produces the file image.data of size 0 bytes. However, when the code is run interactively from the Python console, as the examples do, the desired file is created properly only when the code is entered in parts. That is, I can paste the code up to the first output.tell(), then copy & paste the remaining code (the image capture) into the console and have success. This tells me I have the code to create the image file; why does it not work from a Python file? I have checked Python versions in both cases is the same (3.7.3) and use a Python virtual environment. Thanks in advance for any input.

Edit: The second part of the code is the last 5 lines

camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

I had tried a 1 second delay between the two parts (in the .py file); still image.data file of 0 bytes.

Source Link
rohal
rohal
  • 21
  • 5

PiCamera 1.13 docs MMAL example problem

I am trying to lower the time to capture a still image from the Pi camera (I have a V2 and HQ). To this end, I have found my way to the PiCamera 1.13 docs, specifically chapter 16 dealing with the MMAL object. I tried following the example code given between 16.1.1 and 16.1.7, which seems to be a basic set-up and capture. I reduced the code to the minimum I thought would work; there is a lot of input and output confirmation I removed. Here is the code:

from picamera import mmal, mmalobj as mo import io def image_callback(port, buf): output.write(buf.data) return bool(buf.flags & mmal.MMAL_BUFFER_HEADER_FLAG_FRAME_END) camera = mo.MMALCamera() preview = mo.MMALRenderer() camera.outputs[2].format = mmal.MMAL_ENCODING_RGB24 camera.outputs[2].framesize = (640, 480) camera.outputs[2].commit() camera.outputs[2] camera.outputs[2].enable() camera.outputs[2].disable() output = io.open('image.data', 'wb') camera.outputs[2].enable(image_callback) output.tell() camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = True camera.outputs[2].params[mmal.MMAL_PARAMETER_CAPTURE] = False output.tell() camera.outputs[2].disable() output.close()

This code runs without error from a file, cam_test.py, but produces the file image.data of size 0 bytes. However, when the code is run interactively from the Python console, as the examples do, the desired file is created properly only when the code is entered in parts. That is, I can paste the code up to the first output.tell(), then copy & paste the remaining code (the image capture) into the console and have success. This tells me I have the code to create the image file; why does it not work from a Python file? I have checked Python versions in both cases is the same (3.7.3) and use a Python virtual environment. Thanks in advance for any input.