Vlcj本机发现在Raspberry Pi3 B +上失败

Question

I have java code that needs to use the Vlcj library on a Raspberry Pi 3 B+ with Raspbian. But when starting up with the NativeDiscovery.discover(), i get a "no vlc library found" message. I have tried to use addSearchPath() on "/usr/bin/" with no success.

How can I solve my issue? Thanks

Answer 1

Your JVM needs to know where to find libvlc.so and the VLC plugins.

They are not in "/usr/bin".

There is more than one way to try and resolve this, the simplest perhaps is to use LD_LIBRARY_PATH.

Once you have found the directory containing libvlc.so, you can specify the LD_LIBRARY_PATH environment variable when you start your app.

On my Pi, libvlc.so is in /usr/lib/arm-linux-gnueabihf, so something like (the given jar files in the classpath are just examples):

LD_LIBRARY_PATH=/usr/lib/arm-linux-gnueabihf java -cp vlcj.jar:jna.jar:jna-platform.jar:your-app.jar

This might be enough to make it work, it might not. LibVlc might complain about not being able to find its plugins.

If so, find where the plugins are installed (there should be a directory named "plugins" under the directory where you found libvlc.so).

On my Pi these are in /usr/lib/arm-linux-gnueabihf/vlc/plugins.

Now you set the VLC_PLUGIN_PATH to point to that directory:

LD_LIBRARY_PATH=/usr/lib/arm-linux-gnueabihf VLC_PLUGIN_PATH=/usr/lib/arm-linux-gnueabihf/vlc/plugins java -cp vlcj.jar:jna.jar:jna-platform.jar:your-app.jar

You can set those environment variables in your profile or whatever instead of specifying on the command line if you want.

vlcj's native discovery mechanism generally tries to resolve all of this nastiness for you, but it doesn't (currently) know about Raspberry Pi so you have to do it yourself.

The next major version of vlcj (which will be 4.0.0) has an improved native discovery mechanism. I tested an early development version of this on my Pi and it just worked straight away without any of the above.