2. Camera¶

2.1. Camera Low-Level Debugging¶

V4L2 interface operation for MIPI-CSI cameras

Find camera nodes

$ grep '' /sys/class/video4linux/video*/name
/sys/class/video4linux/video0/name:stream_cif_mipi_id0
/sys/class/video4linux/video1/name:stream_cif_mipi_id1
/sys/class/video4linux/video10/name:rkcif_tools_id2
/sys/class/video4linux/video11/name:rkisp_mainpath
/sys/class/video4linux/video12/name:rkisp_selfpath
/sys/class/video4linux/video13/name:rkisp_iqtool
/sys/class/video4linux/video14/name:rkisp_rawrd0_m
/sys/class/video4linux/video15/name:rkisp_rawrd2_s
/sys/class/video4linux/video16/name:rkisp-statistics
/sys/class/video4linux/video17/name:rkisp-input-params
/sys/class/video4linux/video18/name:rkisp-pdaf
/sys/class/video4linux/video19/name:rkvpss-offline
/sys/class/video4linux/video2/name:stream_cif_mipi_id2
/sys/class/video4linux/video20/name:rkvpss_scale0
/sys/class/video4linux/video21/name:rkvpss_scale1
/sys/class/video4linux/video22/name:rkvpss_scale2
/sys/class/video4linux/video23/name:rkvpss_scale3
/sys/class/video4linux/video24/name:rkvpss_scale4
/sys/class/video4linux/video25/name:rkvpss_scale5
/sys/class/video4linux/video3/name:stream_cif_mipi_id3
/sys/class/video4linux/video4/name:rkcif_scale_ch0
/sys/class/video4linux/video5/name:rkcif_scale_ch1
/sys/class/video4linux/video6/name:rkcif_scale_ch2
/sys/class/video4linux/video7/name:rkcif_scale_ch3
/sys/class/video4linux/video8/name:rkcif_tools_id0
/sys/class/video4linux/video9/name:rkcif_tools_id1

Identifying the node to capture

For cameras using RKISP, such as the SC3336, you need to capture the video node corresponding to rkisp_mainpath. Based on the output information above, rkisp_mainpath corresponds to video11.

If using the IMX415 camera, use v4l2-ctl to capture camera data frames and save them to /data/out.yuv.
```
v4l2-ctl --verbose -d /dev/video11 --set-fmt-video=width=1920,height=1080,pixelformat='NV12' --stream-mmap=3 --stream-skip=3 --stream-to=/data/out.yuv
```
Copy the out.yuv file and view it using Ubuntu.
```
ffplay -f rawvideo -video_size 1920x1080 -pix_fmt nv12 out.yuv
```

2.2. PHY Introduction¶

The RV1126B chip has two DPHYs, which can operate in two modes: full mode and split mode.

Simply put, if using a monocular camera, we can configure it in full mode; if using a stereo camera, we can configure it in split mode.

The hardware design determines the software path, configured as follows:

csi2_dphy0 -> csi0(rx0) clk0 + 4 lane

csi2_dphy1 -> csi0(rx0) clk0 + 2 lane 0/1

csi2_dphy2 -> csi0(rx0) clk1 + 2 lane 2/3

csi2_dphy3 -> csi1(rx1) clk0 + 4 lane

csi2_dphy4 -> csi1(rx1) clk0 + 2 lane 0/1

csi2_dphy5 -> csi1(rx1) clk1 + 2 lane 2/3

2.3. Full Mode¶

The configuration link is as follows:

csi2_dphy0 –> mipi0_csi2 –> rkcif_mipi_lvds

csi2_dphy3 –> mipi2_csi2 –> rkcif_mipi_lvds2

Please see the device tree for details:

rv1126b-firefly-aio-1126bjd4-csi0-imx415.dtsi

rv1126b-firefly-aio-1126bjd4-csi1-imx415.dtsi

2.4. Split Mode¶

The configuration link is as follows:

csi2_dphy1 –> mipi0_csi2 –> rkcif_mipi_lvds

csi2_dphy2 –> mipi0_csi2 –> rkcif_mipi_lvds

csi2_dphy4 –> mipi2_csi2 –> rkcif_mipi_lvds2

csi2_dphy5 –> mipi2_csi2 –> rkcif_mipi_lvds2

Please see the device tree for details:

rv1126b-evb-dual-cam-csi0.dtsi

rv1126b-evb-dual-cam-csi1.dtsi

2.5. Previewing the Camera on a Linux System¶

The camera feed can be previewed using ffmedia. For ffmedia installation instructions, please click here: ffmedia Tutorial

After installing ffmedia, select the video node corresponding to rkisp_mainpath as described above to perform RTSP streaming. Assuming rkisp_mainpath corresponds to the video11 node, the following command uses video11 for RTSP streaming:

./demo /dev/video11 -e h264 --port 8554  --push_type rtsp --push_path /live/test

On your PC, use VLC media player to open the following RTSP stream link for preview:

rtsp://<device IP>:8554/live/test