Rémi Denis-Courmont <r...@videolan.org> writes: > On Tue, 15 Sep 2009 22:18:22 +0100, Måns Rullgård <m...@mansr.com> wrote: >>> Attached is an intial patch against libmpeg2 trunk to use NEON for >>> motion compensation. This is preliminary. There are a bunch of known >>> CPU stalls. Those could probably be fixed using plain assembly and >>> interleaving subsequent loads. Also, iDCT is not optimized. >> >> Why don't you steal the functions from FFmpeg instead? They are much >> better optimised than this patch. > > FFmpeg-based MPEG2 decoding was so slow on the target, that I did not even > consider the possibility that it might have been optimized. For whatever > reason, it is (eye-)noticeably slower than current libmpeg2 with the > non-SIMD ARM optimizations. Why is this so? I do not know. There could be
Even if the FFmpeg mpeg2 decoder is slow, the NEON MC and IDCT functions should be fast. > something wrong with VLC, but then again the FFmpeg h.264 decoding is > accelerated fine. Or it could be a build problem, or it could be that I did > not test properly, or it could be a FFmpeg problem in other part. Can you reproduce the difference with ffmpeg and mpeg2dec called directly, not from vlc? Could you do a quick oprofile run? -- Måns Rullgård m...@mansr.com ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Libmpeg2-devel mailing list Libmpeg2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmpeg2-devel
