just saw yesterday you answer, thank you! I got all the issues solved:
1) Font is not readable and overall picture quality is horrible:
this issue solved itself, I just opened NoMachine yesterday and it was working again. I did restart both machines several times the last time and the issue was reproducible so I suppose that it was a network issue.
2) If I close the client, the Linux hosts screen turns black and does not respond anymore:
I was able to reproduce this issue only once more the first time I closed the session, what happens is that the x-server gets overloaded and does not respond anymore for several minutes, all subsequent sessions could be closed without any issue. I have attached the logs but, since this did not happen again I do not want to waste your time.
3) Impossible to activate the H264 codecs:
copying as well swresample-1.dll did not work for me. I also tried installing “windows 7 codec pack” which does register the codecs on Windows (checked with <MSINFO32 command) but that did not work as well. Finally I just installed the AVC pack on the Windows client and that solved it.