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1 Using Camera on Linux (MIPI Camera OV13850 & OV4689, and webcam logitect C920)

Hardware Setting: The Camera module can be connected to a MIPI port:

FriendlyELEC provides some scripts use to test a camera's functions. You can run it in a commandline to test picture taking and video recording.
You may try update this script to the lastest version by using the following commands:

cd /tmp/
git clone https://github.com/friendlyarm/gst-camera-sh.git
sudo cp gst-camera-sh/*.sh /usr/bin/

There are three scripts:
gst-camera.sh: preview, photo and video of a single camera
dual-camera.sh: preview two cameras
stop-gst-camera.sh: stop preview

1.1 Options in "gst-camera.sh"

Options Comment
--index or -i Camera's index, it can be either 0 or 1. When two cameras are connected to a board you need to specify 1 to access the second camera.
--action or -a Specify an action, it can be "preview" to preview, "photo" to take a picture or "video" to record video
--output or -o Specify an output file to save a picture when taking a picture or video file when recording video
--verbose or -v If it is specified as "yes" it will output the complete command when "gst-launch-1.0" is called
-x Using the rkximagesink plugin, the preview image will be output to the X11 window for the FriendlyDesktop and Lubuntu systems
-g Using the glimagesink plugin, the preview image will be output to the X11 window for the FriendlyDesktop and Lubuntu systems
-k Using the kmssink plugin, the preview image will be output directly to the screen for the FriendlyCore system

The script gst-camera.sh will automatically recognize OV13850, OV4689 and C920 camera, and then pass the appropriate parameters to gst-launch-1.0.

1.2 Usage of gst-camera.sh

  • Preview
gst-camera.sh --action preview
  • Picture Taking

You can run the following command to take a picture and save it as a "1.jpg" file,

gst-camera.sh -a photo -o 1.jpg
  • Preview and Record

You can run the following command to record video and save your video to a "1.ts" file. Hardware encoding is activated when it is recording video.

gst-camera.sh --action video -output 1.ts

  • Show Complete Command

If you add the "--verbose yes" option it will show a complete gsteamer command.

gst-camera.sh --action video --output 1.ts --verbose yes

Here is the complete gsteamer command you will see:

gst-launch-1.0 rkisp num-buffers=512 device=/dev/video0 io-mode=1 ! \
    video/x-raw,format=NV12,width=1280,height=720,framerate=30/1 ! \
        mpph264enc ! queue ! h264parse ! mpegtsmux ! \
        filesink location=/tmp/camera-record.ts
  • Preview dual camera

Connect two mipi cameras, or one mipi camera and one usb camera (tested only: Logitech C920 pro), call the following command:


Note: It is recommended to test this on FriendlyDesktop.

1.3 gst-launch-1.0 parameter description

Preview camera on FriendlyDesktop:

gst-launch-1.0 rkisp device=/dev/video1 io-mode=4 ! video/x-raw,format=NV12,width=1280,height=720,framerate=30/1 ! rkximagesink

Important parameters

parameter description
device preview device(selfpath): /dev/video1 and /dev/video5, picture device(mainpath): /dev/video0 and /dev/video4, webcam device: /dev/video8
io-mode 1: memory map, 4:dmabuf
rkximagesink/glimagesink/kmssink rkximagesink for FriendlyDesktop, kmssink for FriendlyCore, glimagesink for webcam on FriendlyDesktop

1.4 Access the camera in OpenCV

MIPI camera:

cv.VideoCapture('rkisp device=/dev/video1 io-mode=4 ! video/x-raw,format=NV12,width=640,height=480,framerate=30/1 ! videoconvert ! appsink', cv.CAP_GSTREAMER)

USB camera:

cv.VideoCapture('rkisp device=/dev/video8 io-mode=4 ! videoconvert ! video/x-raw,format=NV12,width=640,height=480,framerate=30/1 ! videoconvert ! appsink', cv.CAP_GSTREAMER)

Please refer to the sample code here for details:https://github.com/friendlyarm/install-opencv-on-friendlycore/tree/rk3399/examples

1.5 Camera application tutorial: Push video stream

Please refre this guide: How to setup RTMP server on NanoPC-T4

1.6 Reference resource

http://blog.iotwrt.com/media/2017/10/01/camera/ http://www.360doc.com/content/16/1019/17/496343_599664458.shtml