  This paper investigates the decoding energy and decoding time demand of
VTM-7.0 in relation to HM-16.20. We present the first detailed comparison of
two video codecs in terms of software decoder energy consumption. The
evaluation shows that the energy demand of the VTM decoder is increased
significantly compared to HM and that the increase depends on the coding
configuration. For the coding configuration randomaccess, we find that the
decoding energy is increased by over 80% at a decoding time increase of over
70%. Furthermore, results indicate that the energy demand increases by up to
207% when Single Instruction Multiple Data (SIMD) instructions are disabled,
which corresponds to the HM implementation style. By measurements, it is
revealed that the coding tools MIP, AMVR, TPM, LFNST, and MTS increase the
energy efficiency of the decoder. Furthermore, we propose a new coding
configuration based on our analysis, which reduces the energy demand of the VTM
decoder by over 17% on average.
