[Motion-user] Cannot get image from UV4L USB Cam on Raspberry Pi

[Oli v. <oli...@gm...>]

Hi there, 

I’m trying to setup a USB camera in Motion (and MotionEye) but as soon as I add the camera to Motion, I get this message.

[1:ml1:Camera1] [ERR] [VID] v4l2_mmap_set: Error mapping buffer 0 mmap: No such device
[1:ml1:Camera1] [ERR] [VID] vid_start: V4L2 device failed to open
[1:ml1:Camera1] [WRN] [ALL] motion_init: Could not fetch initial image from camera
[1:ml1:Camera1] [WRN] [ALL] motion_init: Motion continues using width and height from config file(s)

I configured the camera as follow:
- Camera Type: `Local V4L2 Camera` 
- Camera: H264 USB Camera

Streaming does work when I watch it from UV4L streaming server and I take pictures with fswebcam.

I tried to setup the camera in a network camera with the MJPEG stream from UV4L server. I do see the video but I can’t get more than 2-4 frames/s. Even after I recompiled ffmpeg and Motion. https://github.com/ccrisan/motioneye/issues/930 <https://github.com/ccrisan/motioneye/issues/930>. 
Settings : 75% quality,  1280x720, no streaming, Recording on motion on H264/OMX.
If I try the same stream on mobile phone in VLC, the stream is perfectly fluid.

Anyway, I would like to make it work with Local V4L2 camera:

Configuration:
Raspberry Pi 3 (first one) - Raspbian Buster.
Ethernet, no WiFi
ffmpeg version 4.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 8 (Raspbian 8.3.0-6+rpi1)
  configuration: --enable-mmal --enable-omx --enable-omx-rpi --extra-cflags=-I/opt/vc/include/IL
Camera: 
	ELP-USBFHD04H-KRL170
	Max. Resolution: 1920X1080
	Picture format: H.264,MJPEG or YUY2
	USB2.0 HS/FS, USB1.1 FS
	USB Video Class(UVC)1.1
	1920 (H) x 1080 (V) pixels H.264 30fps MJPEG 30fps
	1280 (H) x 720 (V) pixels H.264 30fps MJPEG 30fps


Thank you