Adjust mv_ratio_accumulator threshold.
Adjust mv_ratio_accumulator threshold.

This threshold effectively limits the amount of motion
from one end of a GF/ARF group to the other.
This patch makes the threshold depend on image size.

Change-Id: Id45d1d7bced815f86ddd037be53164894b00b82f

thdav/aom,WebRTC-Labs/libvpx,shyamalschandra/libvpx,VTCSecureLLC/libvpx,abwiz0086/webm.libvpx,zofuthan/libvpx,Acidburn0zzz/webm.libvpx,smarter/aom,altogother/webm.libvpx,kalli123/webm.libvpx,jdm/libvpx,shareefalis/libvpx,shacklettbp/aom,felipebetancur/libvpx,turbulenz/libvpx,ShiftMediaProject/libvpx,shareefalis/libvpx,altogother/webm.libvpx,running770/libvpx,reimaginemedia/webm.libvpx,iniwf/webm.libvpx,luctrudeau/aom,smarter/aom,matanbs/webm.libvpx,luctrudeau/aom,mwgoldsmith/vpx,kleopatra999/webm.libvpx,shareefalis/libvpx,smarter/aom,VTCSecureLLC/libvpx,GrokImageCompression/aom,mbebenita/aom,shacklettbp/aom,GrokImageCompression/aom,cinema6/libvpx,ittiamvpx/libvpx-1,hsueceumd/test_hui,matanbs/vp982,Distrotech/libvpx,kalli123/webm.libvpx,Laknot/libvpx,matanbs/vp982,stewnorriss/libvpx,liqianggao/libvpx,Maria1099/webm.libvpx,thdav/aom,vasilvv/esvp8,jdm/libvpx,openpeer/libvpx_new,liqianggao/libvpx,n4t/libvpx,mwgoldsmith/libvpx,felipebetancur/libvpx,GrokImageCompression/aom,running770/libvpx,abwiz0086/webm.libvpx,stewnorriss/libvpx,lyx2014/libvpx_c,kim42083/webm.libvpx,VTCSecureLLC/libvpx,thdav/aom,felipebetancur/libvpx,pcwalton/libvpx,mbebenita/aom,WebRTC-Labs/libvpx,Acidburn0zzz/webm.libvpx,jmvalin/aom,zofuthan/libvpx,jacklicn/webm.libvpx,Acidburn0zzz/webm.libvpx,iniwf/webm.libvpx,zofuthan/libvpx,Distrotech/libvpx,matanbs/webm.libvpx,shyamalschandra/libvpx,Suvarna1488/webm.libvpx,running770/libvpx,lyx2014/libvpx_c,Laknot/libvpx,matanbs/vp982,ittiamvpx/libvpx-1,ShiftMediaProject/libvpx,smarter/aom,kalli123/webm.libvpx,jmvalin/aom,ShiftMediaProject/libvpx,Suvarna1488/webm.libvpx,altogother/webm.libvpx,cinema6/libvpx,Distrotech/libvpx,iniwf/webm.libvpx,shacklettbp/aom,cinema6/libvpx,mwgoldsmith/libvpx,ittiamvpx/libvpx,GrokImageCompression/aom,jacklicn/webm.libvpx,Maria1099/webm.libvpx,iniwf/webm.libvpx,VTCSecureLLC/libvpx,zofuthan/libvpx,n4t/libvpx,gshORTON/webm.libvpx,matanbs/webm.libvpx,kim42083/webm.libvpx,felipebetancur/libvpx,webmproject/libvpx,webmproject/libvpx,openpeer/libvpx_new,goodleixiao/vpx,matanbs/vp982,hsueceumd/test_hui,mwgoldsmith/vpx,pcwalton/libvpx,kalli123/webm.libvpx,abwiz0086/webm.libvpx,turbulenz/libvpx,pcwalton/libvpx,gshORTON/webm.libvpx,jmvalin/aom,Maria1099/webm.libvpx,vasilvv/esvp8,jacklicn/webm.libvpx,zofuthan/libvpx,vasilvv/esvp8,shyamalschandra/libvpx,charup/https---github.com-webmproject-libvpx-,Distrotech/libvpx,jmvalin/aom,sanyaade-teachings/libvpx,luctrudeau/aom,mwgoldsmith/vpx,mwgoldsmith/vpx,goodleixiao/vpx,mbebenita/aom,ittiamvpx/libvpx,gshORTON/webm.libvpx,Laknot/libvpx,abwiz0086/webm.libvpx,kleopatra999/webm.libvpx,kim42083/webm.libvpx,Topopiccione/libvpx,running770/libvpx,Acidburn0zzz/webm.libvpx,mwgoldsmith/libvpx,lyx2014/libvpx_c,openpeer/libvpx_new,luctrudeau/aom,ittiamvpx/libvpx,liqianggao/libvpx,pcwalton/libvpx,kleopatra999/webm.libvpx,shyamalschandra/libvpx,hsueceumd/test_hui,jdm/libvpx,jacklicn/webm.libvpx,pcwalton/libvpx,stewnorriss/libvpx,jmvalin/aom,Maria1099/webm.libvpx,ittiamvpx/libvpx,ittiamvpx/libvpx-1,smarter/aom,goodleixiao/vpx,Laknot/libvpx,turbulenz/libvpx,charup/https---github.com-webmproject-libvpx-,abwiz0086/webm.libvpx,cinema6/libvpx,jacklicn/webm.libvpx,mwgoldsmith/vpx,kalli123/webm.libvpx,mbebenita/aom,stewnorriss/libvpx,turbulenz/libvpx,matanbs/webm.libvpx,mbebenita/aom,mwgoldsmith/libvpx,Topopiccione/libvpx,charup/https---github.com-webmproject-libvpx-,liqianggao/libvpx,mbebenita/aom,thdav/aom,shareefalis/libvpx,stewnorriss/libvpx,WebRTC-Labs/libvpx,Maria1099/webm.libvpx,mwgoldsmith/libvpx,altogother/webm.libvpx,kim42083/webm.libvpx,liqianggao/libvpx,goodleixiao/vpx,webmproject/libvpx,gshORTON/webm.libvpx,shacklettbp/aom,mbebenita/aom,webmproject/libvpx,felipebetancur/libvpx,mbebenita/aom,openpeer/libvpx_new,vasilvv/esvp8,vasilvv/esvp8,turbulenz/libvpx,ittiamvpx/libvpx-1,turbulenz/libvpx,reimaginemedia/webm.libvpx,reimaginemedia/webm.libvpx,turbulenz/libvpx,running770/libvpx,jmvalin/aom,ittiamvpx/libvpx,hsueceumd/test_hui,charup/https---github.com-webmproject-libvpx-,Topopiccione/libvpx,sanyaade-teachings/libvpx,matanbs/vp982,GrokImageCompression/aom,mwgoldsmith/vpx,Topopiccione/libvpx,Topopiccione/libvpx,thdav/aom,gshORTON/webm.libvpx,Suvarna1488/webm.libvpx,zofuthan/libvpx,Topopiccione/libvpx,Laknot/libvpx,matanbs/vp982,hsueceumd/test_hui,Distrotech/libvpx,lyx2014/libvpx_c,matanbs/webm.libvpx,sanyaade-teachings/libvpx,smarter/aom,ShiftMediaProject/libvpx,hsueceumd/test_hui,iniwf/webm.libvpx,goodleixiao/vpx,jdm/libvpx,kalli123/webm.libvpx,Distrotech/libvpx,stewnorriss/libvpx,goodleixiao/vpx,cinema6/libvpx,turbulenz/libvpx,cinema6/libvpx,kleopatra999/webm.libvpx,running770/libvpx,kleopatra999/webm.libvpx,shareefalis/libvpx,webmproject/libvpx,thdav/aom,sanyaade-teachings/libvpx,shareefalis/libvpx,vasilvv/esvp8,jdm/libvpx,VTCSecureLLC/libvpx,ittiamvpx/libvpx-1,jacklicn/webm.libvpx,ittiamvpx/libvpx-1,gshORTON/webm.libvpx,vasilvv/esvp8,iniwf/webm.libvpx,shacklettbp/aom,matanbs/webm.libvpx,lyx2014/libvpx_c,shyamalschandra/libvpx,openpeer/libvpx_new,turbulenz/libvpx,mbebenita/aom,Maria1099/webm.libvpx,charup/https---github.com-webmproject-libvpx-,sanyaade-teachings/libvpx,WebRTC-Labs/libvpx,altogother/webm.libvpx,reimaginemedia/webm.libvpx,kim42083/webm.libvpx,n4t/libvpx,matanbs/vp982,shacklettbp/aom,reimaginemedia/webm.libvpx,Suvarna1488/webm.libvpx,jdm/libvpx,reimaginemedia/webm.libvpx,Suvarna1488/webm.libvpx,luctrudeau/aom,shyamalschandra/libvpx,VTCSecureLLC/libvpx,kim42083/webm.libvpx,liqianggao/libvpx,openpeer/libvpx_new,ittiamvpx/libvpx,GrokImageCompression/aom,WebRTC-Labs/libvpx,lyx2014/libvpx_c,felipebetancur/libvpx,webmproject/libvpx,Acidburn0zzz/webm.libvpx,Suvarna1488/webm.libvpx,Laknot/libvpx,cinema6/libvpx,n4t/libvpx,Acidburn0zzz/webm.libvpx,abwiz0086/webm.libvpx,ShiftMediaProject/libvpx,charup/https---github.com-webmproject-libvpx-,altogother/webm.libvpx,mwgoldsmith/libvpx,kleopatra999/webm.libvpx,n4t/libvpx,pcwalton/libvpx,luctrudeau/aom