Template:DebianBullseyeDesktop-XFCE-HDMIIN

How to test HDMI-IN

The node of HDMI-IN device is: /dev/video0, which can be operated by the v4l2-ctl command.

• Obtain device information

pi@NanoPC-T6:~$ v4l2-ctl -d /dev/video0  -V -D
Driver Info:
	Driver name      : rk_hdmirx
	Card type        : rk_hdmirx
	Bus info         : fdee0000.hdmirx-controller
	Driver version   : 5.10.110
	Capabilities     : 0x84201000
		Video Capture Multiplanar
		Streaming
		Extended Pix Format
		Device Capabilities
	Device Caps      : 0x04201000
		Video Capture Multiplanar
		Streaming
		Extended Pix Format
Format Video Capture Multiplanar:
	Width/Height      : 3840/2160
	Pixel Format      : 'NV12' (Y/CbCr 4:2:0)
	Field             : None
	Number of planes  : 1
	Flags             : premultiplied-alpha, 0x000000fe
	Colorspace        : Unknown (0x11507070)
	Transfer Function : Unknown (0x000000b8)
	YCbCr/HSV Encoding: Unknown (0x000000ff)
	Quantization      : Default
	Plane 0           :
	   Bytes per Line : 3840
	   Size Image     : 12441600

• View the resolution and image format of the currently connected device

pi@NanoPC-T6:~$ v4l2-ctl -d /dev/video0 --get-fmt-video
Format Video Capture Multiplanar:
	Width/Height      : 3840/2160
	Pixel Format      : 'NV12' (Y/CbCr 4:2:0)
	Field             : None
	Number of planes  : 1
	Flags             : premultiplied-alpha, 0x000000fe
	Colorspace        : Unknown (0x1193b008)
	Transfer Function : Unknown (0x000000b8)
	YCbCr/HSV Encoding: Unknown (0x000000ff)
	Quantization      : Default
	Plane 0           :
	   Bytes per Line : 3840
	   Size Image     : 12441600

• Capture a frame

pi@NanoPC-T6:~$ v4l2-ctl  -d /dev/video0 --set-fmt-video=width=3840,height=2160,pixelformat='NV12' \
    --stream-mmap=4 --stream-skip=10  --stream-to=/home/pi/4k_nv12.yuv --stream-count=1 \
    --stream-poll

• Preview on computer (Linux/Mac)

ffplay -f rawvideo -video_size 3840x2160 -pixel_format nv12 4k_nv12.yuv

• Preview HDMI-In frames in the GUI

Click "Multimedia" -> "Qt V4L2 test Utility"，and then "Start Capturing" icon on the toolbar，the configuration interface is shown below：

• View HDMI-IN audio device

pi@NanoPC-T6:~$ cat /proc/asound/card*
 0 [rockchipdp0    ]: rockchip_dp0 - rockchip,dp0
                      rockchip,dp0
 1 [rockchiphdmi0  ]: rockchip_hdmi0 - rockchip,hdmi0
                      rockchip,hdmi0
 2 [realtekrt5616co]: realtek_rt5616- - realtek,rt5616-codec
                      realtek,rt5616-codec
 3 [rockchiphdmi1  ]: rockchip_hdmi1 - rockchip,hdmi1
                      rockchip,hdmi1
 4 [rockchiphdmiin ]: rockchip_hdmiin - rockchip,hdmiin
                      rockchip,hdmiin

As you can see, the sound card number of HDMI-IN is 4.

• Recording audio (recording 10 seconds)

pi@NanoPC-T6:~$ arecord -D hw:4,0 -f cd test.wav -d 10

• Playback recorded audio (output to HDMI0)

pi@NanoPC-T6:~$ aplay test.wav -D 'hw:rockchiphdmi0'