[FFmpeg-devel] [RFC] use ff_avc_find_startcode in ff_find_start_code

Michael Niedermayer michaelni
Tue Feb 19 16:41:35 CET 2008


On Tue, Feb 19, 2008 at 04:18:49PM +0100, Reimar D?ffinger wrote:
> Hello,
> On Tue, Feb 19, 2008 at 03:45:40PM +0100, Michael Niedermayer wrote:
> > Heres a benchmark from just the call in the decoder (duron & matrixbench_mpeg2)
> > ffmpeg -v 9 -i matrixbench_mpeg2.mpg -an -y -f rawvideo /dev/null
> > current
> > 2504 dezicycles in A2, 131069 runs, 3 skips
> > 
> > proposed
> > 2832 dezicycles in A2, 131068 runs, 4 skips
> 
> Same command:
> current:
> 751 dezicycles in A2, 15913 runs, 471 skips
> 759 dezicycles in A2, 31825 runs, 943 skips
> 774 dezicycles in A2, 63647 runs, 1889 skips
> real    0m7.437s
> user    0m7.136s
> sys     0m0.280s
> 
> 
> mine:
> 852 dezicycles in A2, 15912 runs, 472 skips
> 843 dezicycles in A2, 31824 runs, 944 skips
> 844 dezicycles in A2, 63644 runs, 1892 skips
                                    ^^^^
please do something about the skips!
like:
Index: libavutil/common.h
===================================================================
--- libavutil/common.h	(revision 11927)
+++ libavutil/common.h	(working copy)
@@ -348,7 +348,7 @@
   static uint64_t tsum=0;\
   static int tcount=0;\
   static int tskip_count=0;\
-  if(tcount<2 || tend - tstart < FFMAX(8*tsum/tcount, 2000)){\
+  if(tcount<2 || tend - tstart < FFMAX(32*tsum/tcount, 320000)){\
       tsum+= tend - tstart;\
       tcount++;\
   }else\


[...]
> And yes, I remembered to disable speedstep this time.

Thanks you
Also please dont run anything else (like mp3 players) while testing
and provide benchmark scores for 3 runs so we know how much randomnes
is in there.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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