VP8GetCostLuma4   862 3rdparty/libwebp/enc/quant.c       rd_tmp.R = VP8GetCostLuma4(it, tmp_levels);
VP8GetCostLuma4   490 3rdparty/libwebp/enc/vp8enci.h int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]);