Another non-unicode issue

[virtuald]

We fixed a problem similar to this previously.

https://www.chiefdelphi.com/t/trouble-running-the-python-example-code-with-wpilib-frcvision-raspberry-pi-image/342147/2

Would be good to identify the string in question and figure out the right way to convert it to unicode.

[auscompgeek]

We could decode non-UTF-8 strings as latin1. But then the question arises of what happens when a user tries to set the property to that value.

Would it even be possible to set non-UTF-8 string values? Is it possible to pass in bytes?

[virtuald]

I'm not sure what happens if we store bytes in pynetworktables (even though this is clearly what the C ntcore implementation must be doing). I think the python version will try to convert it to a string, which will fail.

[virtuald]

If anyone has a camera that causes this issue, to address this we first need to know what the bytes returned by the camera are. The best way to do this is to (a) identify what key is causing the issue (typically it's the camera name) and (b) get the bytes (using... some program? A good start would be the output of v4l2-ctl --all or some similar program).

[virtuald]

@PeterJohnson points out that we should give a better warning when a encoding/decoding error occurs. Perhaps something that mentions what key failed.

[oleitersdorf]

I'm encountering this problem using a Pi NoIR Camera (https://www.amazon.com/Arducam-Camera-Raspberry-Interchangeable-LS-2717CS/dp/B013JV4Z7K/ref=sr_1_4?ie=UTF8&qid=1548005788&sr=8-4&keywords=noir+camera+pi).

This is the result from running v412-ctl --all:

Driver Info (not using libv4l2):
    Driver name   : bm2835 mmal
    Card type     : mmal service 16.1
    Bus info      : platform:bcm2835-v4l2
    Driver version: 4.14.79
    Capabilities  : 0x85200005
        Video Capture
        Video Overlay
        Read/Write
        Streaming
        Extended Pix Format
        Device Capabilities
    Device Caps   : 0x05200005
        Video Capture
        Video Overlay
        Read/Write
        Streaming
        Extended Pix Format
Priority: 2
Video input : 0 (Camera 0: ok)
Format Video Capture:
    Width/Height      : 640/480
    Pixel Format      : 'MJPG'
    Field             : None
    Bytes per Line    : 0
    Size Image        : 307200
    Colorspace        : SMPTE 170M
    Transfer Function : Default
    YCbCr/HSV Encoding: Default
    Quantization      : Default
    Flags             : 
Format Video Overlay:
    Left/Top    : 150/50
    Width/Height: 1024/768
    Field       : None
    Chroma Key  : 0x00000000
    Global Alpha: 0xff
    Clip Count  : 0
    Clip Bitmap : No
Framebuffer Format:
    Capability    : Extern Overlay
            Global Alpha
    Flags         : Overlay Matches Capture/Output Size
    Width         : 640
    Height        : 480
    Pixel Format  : 'YU12'
Streaming Parameters Video Capture:
    Capabilities     : timeperframe
    Frames per second: 30.000 (30/1)
    Read buffers     : 1

User Controls

                     brightness (int)    : min=0 max=100 step=1 default=50 value=50 flags=slider
                       contrast (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                     saturation (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                    red_balance (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                   blue_balance (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                horizontal_flip (bool)   : default=0 value=0
                  vertical_flip (bool)   : default=0 value=0
           power_line_frequency (menu)   : min=0 max=3 default=1 value=1
                      sharpness (int)    : min=-100 max=100 step=1 default=0 value=0 flags=slider
                  color_effects (menu)   : min=0 max=15 default=0 value=0
                         rotate (int)    : min=0 max=360 step=90 default=0 value=0 flags=00000400
             color_effects_cbcr (int)    : min=0 max=65535 step=1 default=32896 value=32896

Codec Controls

             video_bitrate_mode (menu)   : min=0 max=1 default=0 value=0 flags=update
                  video_bitrate (int)    : min=25000 max=25000000 step=25000 default=10000000 value=10000000
         repeat_sequence_header (bool)   : default=0 value=0
            h264_i_frame_period (int)    : min=0 max=2147483647 step=1 default=60 value=60
                     h264_level (menu)   : min=0 max=11 default=11 value=11
                   h264_profile (menu)   : min=0 max=4 default=4 value=4

Camera Controls

                  auto_exposure (menu)   : min=0 max=3 default=0 value=0
         exposure_time_absolute (int)    : min=1 max=10000 step=1 default=1000 value=1
     exposure_dynamic_framerate (bool)   : default=0 value=0
             auto_exposure_bias (intmenu): min=0 max=24 default=12 value=12
      white_balance_auto_preset (menu)   : min=0 max=9 default=1 value=1
            image_stabilization (bool)   : default=0 value=0
                iso_sensitivity (intmenu): min=0 max=4 default=0 value=0
           iso_sensitivity_auto (menu)   : min=0 max=1 default=1 value=1
         exposure_metering_mode (menu)   : min=0 max=2 default=0 value=0
                     scene_mode (menu)   : min=0 max=13 default=0 value=0

JPEG Compression Controls

            compression_quality (int)    : min=1 max=100 step=1 default=30 value=30

Any other way in which I could help?

[PeterJohnson]

The problem is the intmenu's. cscore does the wrong thing when converting the enum value names. I opened a PR to fix this in wpilibsuite/allwpilib#1561.