Changes between Initial Version and Version 1 of Docs/825gen2/Dev/Devices/USB/Webcams

Timestamp:

01/23/24 07:49:36 (10 months ago)

Author:

Don Wilson

Comment:

--

Docs/825gen2/Dev/Devices/USB/Webcams

@@ +1 @@
+= USB Web Cams =
+
+The 825gen2 has some support for USB cameras.
+
+After plugging a Logitech USB webcam into the 825 from a terminal type dmesg.
+
+{{{
+[ 7653.802688] usb 1-1.4: new high-speed USB device number 4 using xhci-hcd
+[ 7654.211992] usb 1-1.4: Found UVC 1.00 device <unnamed> (046d:0825)
+[ 7654.324569] input: UVC Camera (046d:0825) as /devices/platform/soc@0/38200000.usb/xhci-hcd.0.auto/usb1/1-1/1-1.4/1-1.4:1.0/input/input7
+[ 7654.325132] usbcore: registered new interface driver uvcvideo
+[ 7655.880687] usb 1-1.4: set resolution quirk: cval->res = 384
+[ 7655.881370] usbcore: registered new interface driver snd-usb-audio
+}}}
+
+Many webcams currently are UVC (USB Video Class). The 825gen2 has support for this. 
+
+Type **lsmod** to show loaded modules
+
+{{{
+card825gen2:~$ lsmod
+Module                  Size  Used by
+snd_usb_audio         294912  0
+snd_hwdep              20480  1 snd_usb_audio
+snd_usbmidi_lib        36864  1 snd_usb_audio
+uvcvideo              106496  0
+algif_hash             20480  1
+algif_skcipher         20480  1
+af_alg                 32768  6 algif_hash,algif_skcipher
+cardmnbdm              24576  0
+rpmsg_ctrl             16384  0
+…
+}}}
+
+From the terminal type the following command to capture a still image from the camera.
+
+{{{
+card825gen2:~$  gst-launch-1.0 v4l2src device=/dev/video2 num-buffers=1 ! jpegenc ! filesink location=/tmp/test.jpg
+Setting pipeline to PAUSED ...
+Pipeline is live and does not need PREROLL ...
+Pipeline is PREROLLED ...
+Setting pipeline to PLAYING ...
+New clock: GstSystemClock
+Redistribute latency...
+Got EOS from element "pipeline0".
+Execution ended after 0:00:02.385972216
+Setting pipeline to NULL ...
+Freeing pipeline ...
+}}}
+
+The file /tmp/test.jpg contains the image.
+
+To capture an image from an app a **system** call could be used to perform the above command line. However, it would be better to use the gstreamer library within the code. An example of this will be added to this page at a later date.
+
+