Hardware implementations of codecs can be made that perform encode at low power if a certain level of quality/efficiency can be given up.

This is already the case for AVC/HEVC on mobile devices where storage and power considerations overwhelm the possible quality and coding efficiency advances that could be available from a highly-intensive, highly-tunable CPU-based encode.

In comparison, if you look at digital cinema, video is dumped as raw, unencoded pixels onto high-speed, high-power SSDs without any compression; this way, the original image can be manipulated losslessly before going through an intensive encode process for an optimal quality/space balance for end-user media delivery.