There are 4 entropy tables to select for initial entropy table,
depending on the frame base q-index. The entropy tables are
trained with derf, yt, and stdhd sets. About 0.2% gain on
the following test sets:
derflr 0.227%
yt 0.277%
stdhd 0.233%
hevclr 0.221%
hevcmr 0.155%
hevchr 0.182%
Change-Id: I3fde846c47fc020e80c814897690b4cda1da569c
Change-Id: I460408372586c823974f945ed9fd8dcb0360fbaf
