Tvheadend

Hello,
someone know why the 4.3-17 has less issue playing IPTV and faster zapping than 4.3-59.
To play mkv file I using the following script:

/usr/bin/ffmpeg -loglevel fatal -i "$1" -c:v libx264 -profile:v high -level 4.0 -b:v 2600k -preset:v ultrafast -c:a libfdk_aac -b:a 128k -metadata service_provider="$2" -metadata service_name="$3" -r 25.000 -f mpegts -tune film pipe:1

$1 = IPTV link;
$2 = Service provider;
$3 = Service name;

with version 4.3-17 is working perfectly;
with version 4.3-59, but I check also older vrsion ex. 4.3-34, I have no video but with sound.

I am missing some new setup introduced later that version 4.3-17?

Regards
Andrea