topic Re: iMX8MP - ISP Using V4L2 Interface in i.MX Processors

iMX8MP - ISP Using V4L2 Interface

khang_letruong — Sat, 02 Jul 2022 06:12:38 GMT

Dear NXP Teams,

In order to use the ISP V4L2 API of iMX8MP that is described in Chapter 3 - ISP Using V4L2 Interface of i.MX_8M_Plus_Camera_and_Display_Guide.pdf document, I was looking for its source code / implementation of which location indicated as following :

I looked in https://source.codeaurora.org/external/imx/isp-vvcam/ with associated branch (lf-5.10.52-2.1.0) but unable to find the location/folder mentioned in above document.

Could you help to clarify? Knowing that I am using LF-5.10.52.

Thanks in advance and best regards,
Khang

Re: iMX8MP - ISP Using V4L2 Interface

artsiomstaliaro — Sat, 02 Jul 2022 15:29:48 GMT

This is part of the isp-imx-4.2.2.16.0 package. You can find it in the Yocto build.

Re: iMX8MP - ISP Using V4L2 Interface

malik_cisse — Tue, 05 Jul 2022 08:13:51 GMT

Hi Khang,

What do you actually want to do?

as artsiomstaliaro said the v4L2 API examples are in isp-imx rather than isp-vvcam.

You will find a rather good example that does open V4L2 device, ISP process video, Downscale, configure ISP and render video on display using DRM. I tested it and it works great. Here is the full path:
isp-imx-4.***\appshell\v4l_drm_test\video_test.cpp

I did not find the folder mentioned in the doc either. I think NXP reused some docs from verisilicon without updating the path. It is hard to find the resources when following the pointers in the doc.

In order to configure the ISP dynamically (e.g set CCM Matrix, AWB, Gamma, etc.) you can use vvext example:
isp-imx-4.2.2.11.0\appshell\vvext\vvext.cpp
I used this successfully also. The only problem I had, is trying to compile this in a minimal self-contained environment.
I had to compile it within its original folder hierarchy.

Re: iMX8MP - ISP Using V4L2 Interface

khang_letruong — Tue, 05 Jul 2022 09:51:31 GMT

Hi @malik_cisse ,

Thanks for your reply.I know quite well about vvext.

The requirement of my client is that they would only use gst-launch for streaming and maybe v4l2-ctl for controlling the ISP parameters (which is WDR3 in my case).

Anyway, I found a work-around to do that in low level layer.

Regards,

Khang

Re: iMX8MP - ISP Using V4L2 Interface

jiangyaqiang — Wed, 26 Oct 2022 02:26:46 GMT

HI khang_letruong:

I'm also porting a camera IMX415 need to use ISP, could you show me how to use V4L2 to control it ?

Thank you very much.

Re: iMX8MP - ISP Using V4L2 Interface

malik_cisse — Wed, 26 Oct 2022 09:01:34 GMT

Hi jiangyaqiang

I would also like to know how Khang Letruong solve the issue.
Here is how I solved it.
The core processing is actually quite simple. For example enabling gamma correction is done as follows:

int viv_private_ioctl(const char *cmd, Json::Value& jsonRequest, Json::Value& jsonResponse) { if (!cmd) { ALOGE("cmd should not be null!"); return -1; } jsonRequest["id"] = cmd; jsonRequest["streamid"] = streamid; struct v4l2_ext_controls ecs; struct v4l2_ext_control ec; memset(&ecs, 0, sizeof(ecs)); memset(&ec, 0, sizeof(ec)); ec.string = new char[VIV_JSON_BUFFER_SIZE]; ec.id = V4L2_CID_VIV_EXTCTRL; ec.size = 0; ecs.controls = &ec; ecs.count = 1; ::ioctl(fd, VIDIOC_G_EXT_CTRLS, &ecs); strcpy(ec.string, jsonRequest.toStyledString().c_str()); int ret = ::ioctl(fd, VIDIOC_S_EXT_CTRLS, &ecs); if (ret != 0) { ALOGE("failed to set ext ctrl\n"); goto end; } else { ::ioctl(fd, VIDIOC_G_EXT_CTRLS, &ecs); Json::Reader reader; reader.parse(ec.string, jsonResponse, true); delete ec.string; ec.string = NULL; return jsonResponse["MC_RET"].asInt(); } end: delete ec.string; ec.string = NULL; return S_EXT_FLAG; } /*************************GAMMA**************************/ void enableGamma(bool enable) { strError = enable ? "GAMMA enabled": "GAMMA disabled"; Json::Value jRequest, jResponse; jRequest[GC_ENABLE_PARAMS] = enable; viv_private_ioctl(IF_GC_S_EN, jRequest, jResponse); }

It is all based on VIDIOC_S_EXT_CTRLS as described in " i.MX 8M Plus ISP Using V4L2 Interface User Guide" chap 2.5 Feature control API.

I could implement this using isp-imx-4.2.2.11.0\appshell\vvext\vvext.cpp as template. So far I was not able to compile this in a minimalistic environment only using v4l2 API and JSON library.

I am eager to see if Khang Letruong or someone else managed to do that before.
Full source code is in attachment.

Re: iMX8MP - ISP Using V4L2 Interface

jiangyaqiang — Wed, 26 Oct 2022 09:37:57 GMT

HI malik_cisse:

Thanks a lot.

I have impplemented my camera driver by reference to vvcam/v4l2/sensor/ov2775/ov2775_mipi_v3.c,

and I want to test it by command /opt/imx8-isp/bin/video_test or gst-launch, but both of them fail. gst-launch fail in vidioc_reqbufs( Failed to allocate required memory.).

video_test fail in :Get Caps Supports Failed.

maybe there is something wrong in my driver.

Re: iMX8MP - ISP Using V4L2 Interface

malik_cisse — Mon, 16 Jan 2023 10:09:16 GMT

Hi Khang,

When you say:

The requirement of my client is that they would only use gst-launch for streaming and maybe v4l2-ctl for controlling the ISP parameters (which is WDR3 in my case).

Anyway, I found a work-around to do that in low level layer.

How do you control WDR3 in this case not using vvext?
I am still struggling making the ISP API work outside of vvext.
Thank you

Re: iMX8MP - ISP Using V4L2 Interface

khang_letruong — Mon, 16 Jan 2023 10:17:38 GMT

Hi @malik_cisse ,

How do you control WDR3 in this case not using vvext?

I did not need to have WDR3 on so I hard-coded it to off in the driver.

I am still struggling making the ISP API work outside of vvext.

vvext is an example of using JSON request for controlling ISP parameters.

Regards,
Khang.