Some question about line_length in DT

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Orin
1

hi,
I run v4l2-ctl --all, then get some informations:

root@allen-desktop:/# v4l2-ctl --all
Driver Info:
	Driver name      : tegra-video
	Card type        : vi-output, z_ox05b3s_96717 30-0
	Bus info         : platform:tegra-capture-vi:0
	Driver version   : 5.10.104
	Capabilities     : 0x84200001
		Video Capture
		Streaming
		Extended Pix Format
		Device Capabilities
	Device Caps      : 0x04200001
		Video Capture
		Streaming
		Extended Pix Format
Media Driver Info:
	Driver name      : tegra-camrtc-ca
	Model            : NVIDIA Tegra Video Input Device
	Serial           : 
	Bus info         : 
	Media version    : 5.10.104
	Hardware revision: 0x00000003 (3)
	Driver version   : 5.10.104
Interface Info:
	ID               : 0x03000008
	Type             : V4L Video
Entity Info:
	ID               : 0x00000006 (6)
	Name             : vi-output, z_ox05b3s_96717 30-0
	Function         : V4L2 I/O
	Pad 0x01000007   : 0: Sink
	  Link 0x0200000c: from remote pad 0x1000003 of entity '13e40000.host1x:nvcsi@15a00000-': Data, Enabled
Priority: 2
Video input : 0 (Camera 0: ok)
Format Video Capture:
	Width/Height      : 2560/1944
	Pixel Format      : 'RG10' (10-bit Bayer RGRG/GBGB)
	Field             : None
	**Bytes per Line**    : 5120
	Size Image        : 9953280
	Colorspace        : sRGB
	Transfer Function : Default (maps to sRGB)
	YCbCr/HSV Encoding: Default (maps to ITU-R 601)
	Quantization      : Default (maps to Full Range)
	Flags             : 

Camera Controls

                    sensor_mode 0x009a2008 (int64)  : min=0 max=1 step=1 default=0 value=0 flags=slider
           sensor_configuration 0x009a2032 (u32)    : min=0 max=4294967295 step=1 default=0 [22] flags=read-only, volatile, has-payload
         sensor_mode_i2c_packet 0x009a2033 (u32)    : min=0 max=4294967295 step=1 default=0 [1026] flags=read-only, volatile, has-payload
      sensor_control_i2c_packet 0x009a2034 (u32)    : min=0 max=4294967295 step=1 default=0 [1026] flags=read-only, volatile, has-payload
                    bypass_mode 0x009a2064 (intmenu): min=0 max=1 default=0 value=0
				0: 0 (0x0)
				1: 1 (0x1)
                override_enable 0x009a2065 (intmenu): min=0 max=1 default=0 value=0
				0: 0 (0x0)
				1: 1 (0x1)
                   height_align 0x009a2066 (int)    : min=1 max=16 step=1 default=1 value=1
                     size_align 0x009a2067 (intmenu): min=0 max=2 default=0 value=0
				0: 1 (0x1)
				1: 65536 (0x10000)
				2: 131072 (0x20000)
               write_isp_format 0x009a2068 (int)    : min=1 max=1 step=1 default=1 value=1
       sensor_signal_properties 0x009a2069 (u32)    : min=0 max=4294967295 step=1 default=0 [30][18] flags=read-only, has-payload
        sensor_image_properties 0x009a206a (u32)    : min=0 max=4294967295 step=1 default=0 [30][16] flags=read-only, has-payload
      sensor_control_properties 0x009a206b (u32)    : min=0 max=4294967295 step=1 default=0 [30][36] flags=read-only, has-payload
              sensor_dv_timings 0x009a206c (u32)    : min=0 max=4294967295 step=1 default=0 [30][16] flags=read-only, has-payload
               low_latency_mode 0x009a206d (bool)   : default=0 value=0
               preferred_stride 0x009a206e (int)    : min=0 max=65535 step=1 default=0 value=0
                   sensor_modes 0x009a2082 (int)    : min=0 max=30 step=1 default=30 value=1 flags=read-only

I see “Bytes per Line : 5120”， but line_length = 2608. I think “Bytes per Line” should equal to 2608*2, right?

2

Hi,

For the camera basic functionality first needs to check the device and driver configuration.
You can reference to below program guide for the detailed information of device tree and driver implementation.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#sensor-software-driver-programming

Please refer to Applications Using V4L2 IOCTL Directly by using V4L2 IOCTL to verify basic camera functionality.
https://docs.nvidia.com/jetson/archives/r36.3/DeveloperGuide/SD/CameraDevelopment/SensorSoftwareDriverProgramming.html?highlight=programing#to-run-a-v4l2-ctl-test

Once confirm the configure and still failed below link help to get log and some information and some tips for debug.
https://elinux.org/Jetson/l4t/Camera_BringUp#Steps_to_enable_more_debug_messages

Thanks!

3

hi

I have already looked at these documents, and the answer I need is about the relationship between line_length and bytes per line

4

Because I now have an error message in trace that vi has either more or less pixels per line than expected. I don’t know if the line_length and active_w Settings are the problem？

6

The size more or less relative with the active_w/active_h.

7

Is Line_length important for Bayer mode? The resolution of the camera is 2592 to 1944, and the total width of each line is 2608, so line_length equals 2608, right?

8

The line_length relative to the sensor exposure time.
Please check with the sensor spec for the detail.

Thanks

10

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.