How to set the exposure and gain of the camera？

[Joshua2]

Hi,

I'm using imx8mp-evk,
camera previews the video stream normally, but I don't know what commands to use to control other parameters such as exposure, gain, brightness, contrast, etc.
I tried using "v4l2-ctl" but the prompt failed.

imx8mpevk:~# v4l2-ctl -d 3 -c exposure_absolute=100
unknown control 'exposure_absolute'

Can you share usage examples or documentation?

Thanks,

Joshua

[joanxie]

did you use ISI or ISP? for V4L2 support, maybe you can refer to the link as below

https://community.nxp.com/t5/i-MX-Processors/v4l2-ctl-no-control-available-no-brightness-no-exposure...

[Joshua2]

Hi joanxie,

    Thank you for your reply, we used the ISP, the access is RAW10 format sensor, the ISP is running normally.
The kernel version is: Linux imx8mpevk 6.1.55 g770c5fe2c1d1.

The isp-vvcam is: https://github.com/nxp-imx/isp-vvcam.git, branch: lf-6.1.55_2.2.0，based on this branch, we added the driver for sensor.

rootimx8mpevk:~# v4l2-compliance -d 3

v4l2-compliance 1.22.1, 64 bits, 64-bit time_t

Compliance test for viv_v4l2_device device /dev/video3:

Driver Info:

Driver name      : viv_v4l2_device

Card type        : VIV

Bus info         : platform:viv1

Driver version   : 6.1.55

Capabilities     : 0x84201001

Video Capture

Video Capture Multiplanar

Streaming

Extended Pix Format

Device Capabilities

Device Caps      : 0x04200001

Video Capture

Streaming

Extended Pix Format

Media Driver Info:

Driver name      : vvcam-video

Model            : viv_media

Serial           : 

Bus info         : platform:vvcam-video.0

Media version    : 6.1.55

Hardware revision: 0x00000000 (0)

Driver version   : 6.1.55

Interface Info:

ID               : 0x03000012

Type             : V4L Video

Entity Info:

ID               : 0x00000010 (16)

Name             : viv_v4l21

Function         : V4L2 I/O

Pad 0x01000011   : 0: Sink, Must Connect

  Link 0x0200001f: from remote pad 0x1000015 of entity 'vvcam-dwe.1' (V4L2 I/O): Data, Enabled

Required ioctls:

test MC information (see 'Media Driver Info' above): OK

warn: v4l2-compliance.cpp(642): media bus_info 'platform:vvcam-video.0' differs from V4L2 bus_info 'platform:viv1'

test VIDIOC_QUERYCAP: OK

test invalid ioctls: OK

Allow for multiple opens:

test second /dev/video3 open: OK

warn: v4l2-compliance.cpp(642): media bus_info 'platform:vvcam-video.0' differs from V4L2 bus_info 'platform:viv1'

test VIDIOC_QUERYCAP: OK

test VIDIOC_G/S_PRIORITY: OK

test for unlimited opens: OK

Debug ioctls:

test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)

test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:

test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)

test VIDIOC_G/S_FREQUENCY: OK (Not Supported)

test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)

test VIDIOC_ENUMAUDIO: OK (Not Supported)

test VIDIOC_G/S/ENUMINPUT: OK

test VIDIOC_G/S_AUDIO: OK (Not Supported)

Inputs: 1 Audio Inputs: 0 Tuners: 0

Output ioctls:

test VIDIOC_G/S_MODULATOR: OK (Not Supported)

test VIDIOC_G/S_FREQUENCY: OK (Not Supported)

test VIDIOC_ENUMAUDOUT: OK (Not Supported)

test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)

test VIDIOC_G/S_AUDOUT: OK (Not Supported)

Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:

test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)

test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)

test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)

test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls (Input 0):

test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK

test VIDIOC_QUERYCTRL: OK

test VIDIOC_G/S_CTRL: OK

test VIDIOC_G/S/TRY_EXT_CTRLS: OK

test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK

test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)

Standard Controls: 1 Private Controls: 1

Format ioctls (Input 0):

fail: v4l2-test-formats.cpp(263): fmtdesc.description mismatch: was 'Y/UV 4:2:0', expected 'Y/CbCr 4:2:0'

test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: FAIL

test VIDIOC_G/S_PARM: OK

test VIDIOC_G_FBUF: OK (Not Supported)

fail: v4l2-test-formats.cpp(460): pixelformat 3231564e (NV12) for buftype 1 not reported by ENUM_FMT

test VIDIOC_G_FMT: FAIL

fail: v4l2-test-formats.cpp(460): pixelformat 3231564e (NV12) for buftype 1 not reported by ENUM_FMT

test VIDIOC_TRY_FMT: FAIL

fail: v4l2-test-formats.cpp(452): expected EINVAL, but got 16 when getting format for buftype 1

test VIDIOC_S_FMT: FAIL

test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)

test Cropping: OK

test Composing: OK

fail: v4l2-test-formats.cpp(1806): doioctl(node, VIDIOC_S_FMT, &fmt)

fail: v4l2-test-formats.cpp(1954): testBasicScaling(node, fmt)

test Scaling: FAIL

Codec ioctls (Input 0):

test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)

test VIDIOC_G_ENC_INDEX: OK (Not Supported)

test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls (Input 0):

fail: v4l2-test-buffers.cpp(573): ret && ret != EINVAL (got 16)

test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: FAIL

fail: v4l2-test-buffers.cpp(783): VIDIOC_EXPBUF is supported, but the V4L2_MEMORY_MMAP support is missing or malfunctioning.

fail: v4l2-test-buffers.cpp(784): VIDIOC_EXPBUF is supported, but the V4L2_MEMORY_MMAP support is missing, probably due to earlier failing format tests.

test VIDIOC_EXPBUF: OK (Not Supported)

test Requests: OK (Not Supported)

Total for viv_v4l2_device device /dev/video3: 46, Succeeded: 40, Failed: 6, Warnings: 2

Thanks,

Joshua

[joanxie]

if you use ISP, try to use vvext tool to set, which is under /opt/imx8-isp/bin, the usage is 

./vvext <video_id> "window name" "param string",  you can use  ./vvext <video_id> to find the prompt window, then choose what you need 

[Joshua2]

Could you share the document? I don't know how to set it.

[joanxie]

this just a simple tool, I send the steps to you before, you can just test firstly, go to /opt/imx8-isp/bin, if your camera is video0, just use  ./vvext 0 0 or ./vvext 0, you should find prompt windows like , you also can use ./vvext --help to get further parameter information

[Joshua2]

Okay, thank you very much!