Tool/software: Linux
Support,
I am trying to use guvcview to get a Logitech webcam working. I am using Debian distribution since it has apt-get for installing different applications. I have been running into several problems. Can you help?
If not with Debian, i can use the TI SDK.
Regards,
Marc
Hi Marc,
You can use yavta to validate the video capture. It's file based application, so basically will write the captured video in file. You can view the content offline on host machine using any YUV viewer tool. Below example command that captures 60 frames of 800x600 resolution in yuyv format and stores in in vout_800x600_yuyv.yuv file.
#yavta -c60 -fYUYV -Fvout_800x600_yuyv.yuv -s800x600 /dev/video1
Once USB video capture is validated, the next work I foresee is to modify USB UVC driver to allocate memory from contiguous location. By default, it allocates the memory from vmalloc which does not guarantee memory from contiguous pool. For USB capture to share its buffer tilcdc driver for display, it needs to produce the video in contiguous memory location as tilcdc driver expects so. Attached patch which enabled this functionality in 2016 LTS but is broken in 2017/2018 LTS. This needs to be taken care for 2017/2018 LTS kernel version. Attached patch that worked on 2016 LTS kernel version.
https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/791/usb_5F00_capture.txt.patch
After this is taken care, then you can use gstreamer pipeline using v4l2src and waylandsink plugin to quickly validate the capture-display functionality. Since end application needs to use video analytics, I would suggest to stay away with gstreamer and wayland windows manager. Better to program the capture and display using direct v4l2 and drm APIs respectively. You can refer to dual camera demo (loopback.c file) for same.
Please note that LCD controller on AM335x doesn't have inbuilt scaler or color format conversion engine and hence the captured image needs to be converted to the RGB format accepted by the LCD controller as well the image is scaled to the display resolution.
If there's more need on image processing on top of capture + display, AM437x may be a better choice of processor as it's Display Sub System (DSS) is more powerful then LCD controller. It can do on the fly scaling and color format conversion of input image, leaving the A9 to do other image processing.
You can run out of box dual-camera-demo packaged in AM437x Processor SDK Linux to demonstrate capture and display on AM437x GP EVM/SK EVM. This demo also integrates QT for some user interface. For capture + display only demo, you can use kmscature application. This demo is not packaged with processor SDK but can be built using Yocto.
Source code can be found here.
Yocto build recipe is -
MACHINE=am437x-evm bitbake kms++
Yocto build procedure -
