i.MX Processors中的主题 HDR problem in IMX8MP

HDR problem in IMX8MP

fengyus — Fri, 06 Sep 2024 01:45:13 GMT

i have implement OV2740 with ISP in IMX8MP. but i can't use the HDR function.

the OV2740 supports two modes of HDR: HDR-lite and staggered HDR. i put the details here:

and about the staggered HDR, i have confirmed that VC0 and VC1 are output simultaneously with their MIPI line signals interlaced. it's not frame interlaced. it's line interlaced.

so does the ISP of IMX8MP support this two HDR mode?

if support, how should i enable the HDR? i have tried the staggered HDR. but i failed. here is my edit to my source codes about the HDR:

in isp-imx source codes:

in isp-vvcam source codes:

i find the static struct vvcam_mode_info_s pov2740_mode_info[]; in vvcam/v4l2/sensor/ov2740/ov2740_mipi_v3.c. and in its mode1, i set

.hdr_mode = SENSOR_MODE_HDR_STITCH,
.stitching_mode = SENSOR_STITCHING_L_AND_S,

then i compile and flash into my board. when i run Gstreamer command, i can't see any error logs. but i can't display the video streaming. the HDMI screen just shows the desktop without any video display.

Re: HDR problem in IMX8MP

joanxie — Tue, 10 Sep 2024 02:03:29 GMT

refer to the reference manual

High Dynamic Range (HDR)
• Native HDR sensor with compand output and max 14-bit compressed input
• 2-exposure and 3-exposure line-interleaved (staggered) HDR
• Full resolution for multiple exposures is output by the image sensor, and the
sensor outputs are interleaved on a per-line basis. No impact to vertical
resolution, but frame rate is reduced by a factor of 2 (for 2-exposure HDR)
or 3 (for 3-exposure HDR).
• Referred to as DOL-HDR (Digital Overlap High Dynamic Range) and as
Staggered HDR (12-bit x3)
• A separate Dewarp engine is also supported to adjust an image (i.e. fisheye lens) at a
resolution up to the max resolution supported by the ISP.

so the ISP can support staggered HDR, but couldn't support 2-exposure line-interleaved HDR

Re: HDR problem in IMX8MP

fengyus — Tue, 10 Sep 2024 02:40:44 GMT

thanks a lot for your reply.

so in my case, the ISP supports OV2740's staggered HDR mode but doesn't support OV2740's HDR-lite mode?

i am also using the OV2740's staggered HDR and i am sure the MIPI signal of OV2740 has changed to the staggered HDR mode after my i2c settings to the sensor. but i failed to output images with the ISP. can you give some advise about how to edit the source codes to make the ISP adapt to the OV2740's staggered HDR mode? you can see my edit above in this topic.

by the way, the MIPI signal of OV2740 is RAW10 format. and please note again, in the staggered HDR mode, it's multi-VC. VC0 and VC1 are line-interlaced. it doesn't matter, right?

Re: HDR problem in IMX8MP

joanxie — Tue, 10 Sep 2024 10:13:52 GMT

so in my case, the ISP supports OV2740's staggered HDR mode but doesn't support OV2740's HDR-lite mode?

>refer to the RM, only 2-exposure line-interleaved HDR isn't supported by ISP

can you give some advise about how to edit the source codes to make the ISP adapt to the OV2740's staggered HDR mode? you can see my edit above in this topic.

>I got a patch before to test this, I sent to you by mail, you can try to test it firstly

Re: HDR problem in IMX8MP

fengyus — Thu, 12 Sep 2024 04:08:22 GMT

thanks a lot for your patch file.

i have tried the patch file. unfortunately, it doesn't work. i still can't display the video stream when set to staggered HDR mode.

i find the register (which you set in the patch file) instruction from the manuals as below:

it shows you set it as 0x3,and it's reserved. are you sure to set it as 0x3?

both 0x2 and 0x3 are all reserved. i think they should have actual meaning. they are just not released to customer. do you know their actual meaning? can you tell me?