Tvheadend

Hello everybody,
I've met with problem when HD channels are pixelated so much. I saw it when I used Kodi + HTS plugin, Showtime(Movian), VLC + HTSP Plugin.
It happens only with HD channels. Also if video stream was transcoded to resolution lower than Full HD (i.a. 1280*720) image is fine, but I don't have so much CPU resources to transcode 3-4 streams simultaneously.

These software version were used:
- Debian Jessie
- TVHeadend 4.1-680~g29a610f
- Kodi - 15.1
- Kodi-hts plugin - 2.1.18
- Showtime - 4.99.215
- vlc - 2.2.1

Also please look at the example of pixelised images.

P.S. I've also tried to watch HD channels via TVHclient + VLC on android and it's look fine.

Could you advice me something?

With regards,
Mike