Update choose-camera.py

[gheaeckkseqrz]

Tested wih 2 Canon DSLR: 0: usb:001,009 Canon EOS 4000D 1: usb:001,010 Canon EOS 700D

[jim-easterbrook]

The camera list is reset after you choose a camera. The original script works when I have a Canon DSLR and a phone connected to my computer, your proposed change does not.

[gheaeckkseqrz]

We seem to have different behaviours on different computers then. Here is the output from the unmodified script :

➜  /tmp python choose-camera.py
0:  usb:001,016  Canon EOS 4000D
1:  usb:001,017  Canon EOS 700D
Please input number of chosen camera: 1
WARNING: gphoto2: (gp_libusb1_find_device_by_class_lib [libusb1.c:1465]) Invalid parameters: 'class' is NULL/FALSE.
WARNING: gphoto2: (gp_context_error) An error occurred in the io-library ('Bad parameters'): No error description available
Traceback (most recent call last):
  File "/tmp/choose-camera.py", line 91, in <module>
    sys.exit(main())
  File "/tmp/choose-camera.py", line 76, in main
    text = camera.get_summary()
gphoto2.GPhoto2Error: [-2] Bad parameters

And if I add a print as such

    # choose camera
    camera = gp.Camera()
    idx = port_info_list.lookup_path(addr)
    camera.set_port_info(port_info_list[idx])
    print("camera_list[0][0] ", camera_list[0][0])
    idx = abilities_list.lookup_model(camera_list[0][0])
    camera.set_abilities(abilities_list[idx])

I get :

➜  /tmp python choose-camera.py
0:  usb:001,016  Canon EOS 4000D
1:  usb:001,017  Canon EOS 700D
Please input number of chosen camera: 1
camera_list[0][0]  Canon EOS 4000D
WARNING: gphoto2: (gp_libusb1_find_device_by_class_lib [libusb1.c:1465]) Invalid parameters: 'class' is NULL/FALSE.
WARNING: gphoto2: (gp_context_error) An error occurred in the io-library ('Bad parameters'): No error description available
Traceback (most recent call last):
  File "/tmp/choose-camera.py", line 92, in <module>
    sys.exit(main())
  File "/tmp/choose-camera.py", line 77, in main
    text = camera.get_summary()
gphoto2.GPhoto2Error: [-2] Bad parameters

The script works as expected when selecting camera at index 0, but not at index 1.

What informations do you need in order to investigate this problem?

[gheaeckkseqrz]

Extra bit of information that may be relevant, the two cameras are connected on a usb hub, so they may be associated to the same port. This would mean that when running camera_list = abilities_list.detect(port_info_list), I get the CameraList * with two items, whereas someone having two cameras connected to differents usb ports on the motherboard would get only one.

[jim-easterbrook]

My mistake was to get the name from camera_list after resetting it - obviously the choice index is no more likely to be right than 0. Commit 502e2d3 is how I think I meant to do it, and works for me.

[gheaeckkseqrz]

The new version does works on my side too :) Thanks for looking into this, and thanks for developing this library and making it open source :)

[jim-easterbrook]

I've just done a further rework which I think gets closer to what I was trying to do in the first place.