IMX CSI
Testing our MIPI cameras
Before you start any of below pipeline make sure you have camera connected. IMX family of processor uses gstreamer as multimedia framework. Please refer to https://gstreamer.freedesktop.org/
Camera Probe
Run below command to see if you have got the camera detected
# v4l2-ctl --list-devices
This should output below
i.MX6S_CSI (platform:30710000.csi):
/dev/video1
pxp (pxp_v4l2_out):
/dev/video0
As you can see above i.MX6S_CSI (platform:30710000.csi): is camera and pxp (pxp_v4l2_out): pixel procesing engine for overlay on display
How to check whether I have the right camera stack / gstreamer plugin installed on my filesystem ?
Checking whether you have got the imx platform plugins installed on your filesystem: Run below command to check whether you have the IMX platform specific gstreamer plugin installed or not.
# gst-inspect-1.0 | grep "imx" imxpxp: imxpxpvideotransform: Freescale PxP video transform imxpxp: imxpxpvideosink: Freescale PxP video sink imxv4l2videosrc: imxv4l2videosrc: V4L2 CSI Video Source imxaudio: imxmp3audioenc: Freescale i.MX MP3 encoder imxaudio: imxuniaudiodec: Freescale i.MX uniaudio decoder
- imxv4l2videosrc: is the IMX family CSI camera v4l2 community plugin. Currently devkits only supports OV5640 as YUV input.
where sensor process incoming light and converts it to YUV 4:2:2 format data. MIPI data is captured by the MIPI CSI input of the devkit. Bayer processing not supported.
Testing Camera Loopback / Camera Preview on Display
The below pipelines are suitable for the fslc based Yocto releases for the VAR-SOM-MX7 (Yocto Morty and newer).
- For 640x480@30fps:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=0 ! imxpxpvideosink
- For 720x480@30fps:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=1 ! imxpxpvideosink
- For 1280x720@30fps :
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=2 ! imxpxpvideosink
- For 1920x1080@30fps:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=3 ! imxpxpvideosink
- For 2592x1944@15fps:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=4 ! imxpxpvideosink
Testing Camera JPEG Snapshot / Taking Single Picture
To Capture JPEG snapshot run any of below pipeline depending upon the resolution you want to take picture.
- For 640x480:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=0 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
- NTSC 720x480:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=1 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
- 720P 1280x720:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=2 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
- For 1080P:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=3 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
- For QSXGA 2592x1944:
# gst-launch-1.0 imxv4l2videosrc device=/dev/video1 imx-capture-mode=4 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
Please note : jpegenc is opensource software based jpeg encoder. This gets executed on CPU not using JPEG hardware acceleration.
To see your recently taken picture, transfer /tmp/test.jpg to your PC via scp or winscp and see whether you got correct snapshot or not.
References
You can find more examples in the GStreamer section.
Please note: IMX7 has different multimedia capabilities than IMX6. All the references mentioned above for GStreamer section should only be considered as examples. The pipelines may not work on IMX7 software stack.
For detailed camera training for IMX family refer to : http://cache.freescale.com/files/training/doc/ftf/2014/FTF-CON-F0119.pdf