UVC対応Webカメラの情報取得方法について、どうもLinuxでしか詳細情報が取れない。

Logicool製のWebカメラC270を接続して確認してみた。

> sudo apt-get install v4l-utils

接続されているカメラデバイス一覧

> sudo v4l2-ctl --list-devices
UVC Camera (046d:0825) (usb-0000:00:1d.0-1.6):
        /dev/video0

カメラ情報詳細

> sudo v4l2-ctl -d /dev/video0 --all
Driver Info (not using libv4l2):
        Driver name   : uvcvideo
        Card type     : UVC Camera (046d:0825)
        Bus info      : usb-0000:00:1d.0-1.6
        Driver version: 4.4.186
        Capabilities  : 0x84200001
                Video Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps   : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
        Width/Height      : 640/480
        Pixel Format      : 'YUYV'
        Field             : None
        Bytes per Line    : 1280
        Size Image        : 614400
        Colorspace        : sRGB
        Transfer Function : Default
        YCbCr Encoding    : Default
        Quantization      : Default
        Flags             :
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 640, Height 480
        Default     : Left 0, Top 0, Width 640, Height 480
        Pixel Aspect: 1/1
Selection: crop_default, Left 0, Top 0, Width 640, Height 480
Selection: crop_bounds, Left 0, Top 0, Width 640, Height 480
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 30.000 (30/1)
        Read buffers     : 0
                     brightness (int)    : min=0 max=255 step=1 default=128 value=128
                       contrast (int)    : min=0 max=255 step=1 default=32 value=32
                     saturation (int)    : min=0 max=255 step=1 default=32 value=32
 white_balance_temperature_auto (bool)   : default=1 value=1
                           gain (int)    : min=0 max=255 step=1 default=64 value=64
           power_line_frequency (menu)   : min=0 max=2 default=2 value=2
      white_balance_temperature (int)    : min=0 max=10000 step=10 default=4000 value=4000 flags=inactive
                      sharpness (int)    : min=0 max=255 step=1 default=24 value=24
         backlight_compensation (int)    : min=0 max=1 step=1 default=0 value=0
                  exposure_auto (menu)   : min=0 max=3 default=3 value=3
              exposure_absolute (int)    : min=1 max=10000 step=1 default=166 value=166 flags=inactive
         exposure_auto_priority (bool)   : default=0 value=1

対応フォーマット一覧

> sudo v4l2-ctl -d /dev/video0 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
        Index       : 0
        Type        : Video Capture
        Pixel Format: 'YUYV'
        Name        : YUYV 4:2:2
                Size: Discrete 640x480
                        Interval: Discrete 0.033s (30.000 fps)
                        Interval: Discrete 0.040s (25.000 fps)
                        Interval: Discrete 0.050s (20.000 fps)
                        Interval: Discrete 0.067s (15.000 fps)
                        Interval: Discrete 0.100s (10.000 fps)
                        Interval: Discrete 0.200s (5.000 fps)
                Size: Discrete 160x120
                        Interval: Discrete 0.033s (30.000 fps)
                        Interval: Discrete 0.040s (25.000 fps)
                        Interval: Discrete 0.050s (20.000 fps)
                        Interval: Discrete 0.067s (15.000 fps)

:

        Index       : 1
        Type        : Video Capture
        Pixel Format: 'MJPG' (compressed)
        Name        : Motion-JPEG
                Size: Discrete 640x480
                        Interval: Discrete 0.033s (30.000 fps)
                        Interval: Discrete 0.040s (25.000 fps)
                        Interval: Discrete 0.050s (20.000 fps)
                        Interval: Discrete 0.067s (15.000 fps)
                        Interval: Discrete 0.100s (10.000 fps)
                        Interval: Discrete 0.200s (5.000 fps)
                Size: Discrete 160x120
                        Interval: Discrete 0.033s (30.000 fps)
                        Interval: Discrete 0.040s (25.000 fps)
                        Interval: Discrete 0.050s (20.000 fps)
                        Interval: Discrete 0.067s (15.000 fps)

コマンド一覧

> sudo v4l2-ctl -d /dev/video0 --list-ctrls-menu
                     brightness (int)    : min=0 max=255 step=1 default=128 value=128
                       contrast (int)    : min=0 max=255 step=1 default=32 value=32
                     saturation (int)    : min=0 max=255 step=1 default=32 value=32
 white_balance_temperature_auto (bool)   : default=1 value=1
                           gain (int)    : min=0 max=255 step=1 default=64 value=64
           power_line_frequency (menu)   : min=0 max=2 default=2 value=2
                                0: Disabled
                                1: 50 Hz
                                2: 60 Hz
      white_balance_temperature (int)    : min=0 max=10000 step=10 default=4000 value=4000 flags=inactive
                      sharpness (int)    : min=0 max=255 step=1 default=24 value=24
         backlight_compensation (int)    : min=0 max=1 step=1 default=0 value=0
                  exposure_auto (menu)   : min=0 max=3 default=3 value=3
                                1: Manual Mode
                                3: Aperture Priority Mode
              exposure_absolute (int)    : min=1 max=10000 step=1 default=166 value=166 flags=inactive
         exposure_auto_priority (bool)   : default=0 value=1

ベンチマーク(速度検証)

> sudo v4l2-ctl -d /dev/video0 --list-formats-ext
        Index       : 0
        Type        : Video Capture
        Pixel Format: 'YUYV'
        :
        Index       : 1
        Type        : Video Capture
        Pixel Format: 'MJPG' (compressed)

# pixelformatに上記のIndexを指定する
# YUYV
> sudo  v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=0
> sudo v4l2-ctl --stream-mmap=3 --stream-count=300
<<<<<<<<<<<<<<<< 14.28 fps
<<<<<<<<<<<<<< 14.28 fps
<<<<<<<<<<<<<< 14.28 fps

# MJPG
> sudo  v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=1
> sudo v4l2-ctl --stream-mmap=3 --stream-count=300
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 30.00 fps
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 29.85 fps
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< 29.80 fps

# illigal format
> sudo  v4l2-ctl --set-fmt-video=width=640,height=480,pixelformat=3
VIDIOC_ENUM_FMT: failed: Invalid argument