NoMachine software on the user's computer (i.e. NoMachine used as a client or Enterprise Client) supports the H.264 hardware decoding on Windows and Mac hosts with hardware accelerated video cards (GPUs). No further action is required. Note that if the screen resolution is bigger than 1920x1080, NoMachine falls back to VP8 by default. It's possible to override this behavior (see: https://www.nomachine.com/FR09L02830).
On Linux hosts or when the Windows/Mac computer doesn't have a GPU, it's possible to use the H.264 software decoding. To do that, it's necessary to have a H.264 decoder on the client: just install FFmpeg from the repository of your Linux distribution or install a Windows or Mac build from one of the sites providing it.
For example, you can download the package for Linux, Windows or Mac from https://www.ffmpeg.org/download.html.
rename the avcodec and avutil libraries into: libavcodec.so and libavutil.so
and place them in:
On Mac OS X
rename the avcodec and avutil libraries into: libavcodec.dylib and libavutil.dylib
and place them in:
Download the 32-bit shared build and place at least the following libraries:
There's no need to rename the libraries.
Verify that H.264 codec is used
To verify if the H.264 codec is used, run the NoMachine menu panel (ctrl+alt+0 or click on the page peel on top right of the window) in the session window. Click on Display -> Change Setting: the codec in use should be written on the bottom page on the left.
Alternatives to manual procedures
If you want to avoid the manual procedure for adding H.264 libraries to client and server host machines, you may acquire a NoMachine AVC Pack for each of your NoMachine hosts. The NoMachine AVC Pack provides all the necessary libraries necessary to make your NoMachine Client or Server use the H.264 codec. NoMachine AVC Pack is available for here https://www.nomachine.com/buyonline.
More about the AVC Pack is here: https://www.nomachine.com/AR10K00706
Support for H.264 on the server side
if you are a customer with a valid license, it's enough to install any of the server package for production you can download from your Customer Area.
If you are an evaluation user you may build the libx264 by following these instructions:
for v. 5 https://www.nomachine.com/AR09M00863
for v. 4 https://www.nomachine.com/AR10K00695