These are the changes made to the Proximus unit (where the customer was not happy with the PQ in HEVC). I am still trying to find out what they do.

# Specific Telstra optimizations for 1080i HEVC
nex.useIntraSearchBr=0 # for perceptual optimization
nex.numTilesX=1 # be careful of perf => for this we can release ME using LHQ on B frame 
nex.ME_typeP=3 # improve P ME
nex.ME_typeBRef=3 # improve P ME

# Specific Telstra optimizations for 1080i H.264
# To disable in case of CPU problem
xec.iptv_hd.CabacBitsEstimator=3 # activate cabac bits estimator needed for decisionTypeI and decisionTypeP
xec.iptv_hd.decisionTypeI=3 #improve I best mode decision
xec.iptv_hd.decisionTypeP=3 # improve P best mode decisions
xec.iptv_hd.decisionPartInterP=3 #improve P partionning
xec.iptv_hd.transformMode=4 # improve T4x4 / T8x8 decisions


# Specific Telstra optimizations for SD H.264
# To disable in case of CPU problem
xec.iptv_sd.CabacBitsEstimator=3
xec.iptv_sd.decisionTypeI=3
xec.iptv_sd.decisionTypeP=3
xec.iptv_sd.decisionPartInterP=3
xec.iptv_sd.transformMode=4 # improve T4x4 / T8x8 decisions