Tvheadend

Hi,

my tvheadend daemon seems not able to call ffmpeg via pipe (in URL field when adding Mux):
pipe:///usr/local/bin/ffmpeg -y -vsync 0 -hwaccel cuvid -c:v h264_cuvid -i http://xxxx:9981/play/stream/channel/yyyyyy -vf scale_cuda=1280:720 -preset slow -c:a copy -c:v h264_nvenc -maxrate 3M -f mpegts pipe:1

My syslog says:
tvheadend²⁷⁹⁷: spawn: /usr/local/bin/ffmpeg: error while loading shared libraries: libnppig.so.e: No such file or directory

In /etc/environment I've also set the library path so I'm able to run ffmpeg succesfully under 'hts' user with the same command, just differs by a output file for testing (succesful playback later):

1. sudo su hts
2. /usr/local/bin/ffmpeg -y -vsync 0 -hwaccel cuvid -c:v h264_cuvid -i http://xxxx:9981/play/stream/channel/yyyyyy -vf scale_cuda=1280:720 -preset slow -c:a copy -c:v h264_nvenc -maxrate 3M TEST.mp4

But still not able to call it via pipe in the web gui.
Ubuntu 16.04, Tvheadend 4.2.6-16~g42e737f
Any ideas ?