Le mardi 29 septembre 2009 à 07:48 -0600, Craig Matsuura a écrit : > So BACKVIDEO would be the quickest as it is writing to video memory > and doing a pan or flip. Where as the BACKSYSTEM is implemented to do > a copy from system memory (or video ram) to the visible frambuffer. > Sinced the BACKSYSTEM is a memcpy is would be slower than the > BACKVIDEO. (Unless the memcpy is implemented in away to use DMA or > some other processor like a DSP that shares tha same memory).
Usually, the copy is done by the blitter (DMA). So it's equivalent to pan/flip in term of CPU usage, unless you want to use your blitter at its maximum performance for OSD composition. In that case, you have to keep in mind you can only pan/flip on vSync. If you flip faster, you will have flick on screen. > > The reason for the clairification is I am looking at implementing > support for the IBitBlit from TI that is a plugin for the Codec Engine > 2 from TI. If I can speed up the BACKSYSTEM using there IBitBlit I > suspect my app will use less of the ARM and execute a bit faster as > there will be no memcpy from the BACKSYSTEM buffer by the ARM. > Definitely. -- Lionel Landwerlin <lionel.landwer...@openwide.fr> _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
