# Leopard Imaging LI-M021C-MIPI Stereo-Optic Cameras

## Cameras setup
The camera sensors should be conencted to a ConnectTech's Elroy board.

## Features

* V4L2 Kernel Driver Version 2.0 supported on L4T32.2.1
* V4l2 controls
  * test pattern
  * individual gains
  * vertical/horizontal flip
  * flash control
* LibArgus and nvarguscamerasrc
* Resolution supported: 1280x720 @ 60fps
* Gain, exposure, and framerate controls
* Camera synchronization

## Capture Tests

### Frame-rate Tests

* Set the framerate to 60fps and the driver will configure the sensor:
```
gst-launch-1.0 nvarguscamerasrc sensor-id=0 aelock=true awblock=true ! 'video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12,framerate=(fraction)60/1' ! fakesink
```

* Set the framerate to 45fps and the driver will configure the sensor:
```
gst-launch-1.0 nvarguscamerasrc sensor-id=0 aelock=true awblock=true ! 'video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12,framerate=(fraction)45/1' ! fakesink
```

### UDP Streaming Test
#### Sender Endpoint
```
gst-launch-1.0 nvarguscamerasrc ! 'video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12,framerate=(fraction)30/1' ! omxh264enc control-rate=2 bitrate=8000000 ! 'video/x-h264, stream-format=(string)byte-stream' ! h264parse ! rtph264pay mtu=1400 ! udpsink host=$HOST_IP port=5000 sync=false async=false
```

#### Receiver Endpoint
```
gst-launch-1.0 udpsrc port=5000 ! "application/x-rtp,media=(string)video,payload=(int)96,clock-rate=(int)90000,encoding-name=(string)H264" ! rtph264depay ! queue ! avdec_h264 ! xvimagesink sync=true async=false
```

### Set Controls Test
Run a pipeline, then set gain and exposure controls using v4l2-ctl:
```
v4l2-ctl -d /dev/video1 -c exposure=14000
v4l2-ctl -d /dev/video1 -c gain=100
```

### Dual Synchronized Capture Test
First run the master pipeline and then the slave pipeline:

#### Master Pipeline
```
gst-launch-1.0 nvarguscamerasrc sensor-id=0 aelock=true awblock=true ! 'video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12,framerate=(fraction)60/1' ! fakesink
```

#### Slave Pipeline
```
gst-launch-1.0 nvarguscamerasrc sensor-id=1 aelock=true awblock=true ! 'video/x-raw(memory:NVMM), width=(int)1280, height=(int)720, format=(string)NV12,framerate=(fraction)60/1' ! fakesink
```

It is not recommended to start both streams at the same time, because nvarguscamerasrc will fail if no buffers arrive on a defined timeout.

### V4l2 Capture Test
#### Master
```
v4l2-ctl -d /dev/video0 --set-fmt-video=width=1280,height=720,pixelformat=RG12 --set-ctrl bypass_mode=0 --stream-mmap
```

#### Slave
```
v4l2-ctl -d /dev/video01 --set-fmt-video=width=1280,height=720,pixelformat=RG12 --set-ctrl bypass_mode=0 --stream-mmap
```

## Appends

#### Kernel Changes

The Driver for the MT9M021 cameras consists on the following structure, that adds the DTB and Kernel sources, along with its Makefiles that lead its portability to a Kernel source.
```bash
. 
├── hardware
│   └── nvidia-spiri
│       └── platform
│           └── t18x
│               ├── common
│               │   └── kernel-dts
│               │       └── t18x-common-platforms
│               │           ├── tegra186-tx2-spiri-camera-base.dtsi
│               │           └── tegra186-tx2-spiri-camera.dtsi
│               └── quill
│                   └── kernel-dts
│                       ├── Makefile
│                       ├── tegra186-tx2-spiri-base.dts
│                       ├── tegra186-tx2-spiri-mPCIe.dts
│                       ├── tegra186-tx2-spiri-revF+.dts
│                       └── tegra186-tx2-spiri-USB3.dts
├── kernel
│   ├── kernel-4.9
│   │   └── arch
│   │       └── arm64
│   │           └── configs
│   │               └── tegra_defconfig
│   └── nvidia-spiri
│       ├── drivers
│       │   └── media
│       │       ├── i2c
│       │       │   ├── Kconfig
│       │       │   ├── Makefile
│       │       │   ├── mt9m021.c
│       │       │   └── mt9m021_mode_tbls.h
│       └── include
│           └── media
│               └── mt9m021.h
└── README.md
```
In order to add the Driver to the Kernel, the following reference Kernel files are patched for adding custom controls that the camera implements.

* kernel/nvidia/drivers/media/platform/tegra/camera/camera_common.c
* kernel/nvidia/drivers/media/platform/tegra/camera/tegracam_ctrls.c
* kernel/nvidia/include/media/camera_common.h
* kernel/nvidia/include/media/tegra-v4l2-camera.h


#### Documentation
* <a href="https://nextcloud.spirirobotics.com/f/3369">CSI2 adapter board guide</a>
* <a href="https://nextcloud.spirirobotics.com/f/3382">Camera module data sheet</a>
* <a href="https://nextcloud.spirirobotics.com/f/3392">Camera sensor data sheet</a>
* <a href="https://nextcloud.spirirobotics.com/f/3396">Camera sensor development guide</a>
* <a href="https://nextcloud.spirirobotics.com/f/3386">MIPI bridge</a>