UV4L and v4l2rtspserver

Question

I am trying to stream with uv4l over v4l2rtspserver

This is what I do:

1. Start /dev/video0

 $ uv4l -nopreview --auto-video_nr --driver raspicam --encoding h264
 [core] Trying to loading driver 'raspicam' from built-in drivers...
 [core] Loading driver 'raspicam' from external plug-in's...
 [driver] Dual Raspicam & TC358743 Video4Linux2 Driver v1.9.63 built Oct  6 2018
 [driver] Detected camera ov5647, 2592x1944
 [driver] Selected format: 1920x1080, encoding: h264, H264 Video Compression
 [driver] Framerate max. 30 fps
 [driver] H264 costant bitrate: 8000000
 [core] Device detected!
 [core] Registering device node /dev/video0

2. Try to stream over v4l2rtspstream:

 $ sudo v4l2rtspserver /dev/video0 -r -W 1920 -H 1080 -F 30
log level:500

[NOTICE] /home/v4l2rtspserver/src/main.cpp:594
        Create V4L2 Source.../dev/video0
[NOTICE] src/V4l2Device.cpp:117
        driver:raspicam capabilities:5000001 mandatory:1000001
[NOTICE] src/V4l2Device.cpp:120
        /dev/video0 support capture
[NOTICE] src/V4l2Device.cpp:122
        /dev/video0 support read/write
[NOTICE] src/V4l2Device.cpp:123
        /dev/video0 support streaming
[NOTICE] src/V4l2Device.cpp:147
        /dev/video0:H264 size:1920x1080
[NOTICE] src/V4l2Device.cpp:229
        fps:1/30
[NOTICE] src/V4l2Device.cpp:230
        nbBuffer:5
[NOTICE] /home/v4l2rtspserver/src/main.cpp:617
        Create Source .../dev/video0
[NOTICE] /home/v4l2rtspserver/src/DeviceSource.cpp:93
        begin thread
[NOTICE] /home/v4l2rtspserver/src/main.cpp:150
        Play this stream using the URL "rtsp://ip:8554/unicast"
[NOTICE] /home/v4l2rtspserver/src/DeviceSource.cpp:202
        V4L2DeviceSource::getNextFrame errno:16 Device or resource busy
[ERROR] /home/v4l2rtspserver/src/DeviceSource.cpp:107
        error:Device or resource busy
[NOTICE] /home/v4l2rtspserver/src/DeviceSource.cpp:118

even if device is not busy it always shows

[ERROR] /home/v4l2rtspserver/src/DeviceSource.cpp:107 V4L2DeviceSource::getNextFrame errno:16 Device or resource busy

 $ sudo fuser /dev/video0 returns nothing...

I am already confused here and it seems I can't get it work normally. Any advice would be good. Thanks in advance.

Answer 1

It seems uv4l needs to preload its library (see https://www.linux-projects.org/documentation/uv4l-core/) Something like :

export LD_PRELOAD=/usr/lib/uv4l/uv4lext/armv6l/libuv4lext.so

An alternative is to use the standard raspicam v4l2 driver

sudo modprobe -v bcm2835-v4l2