Hello folks! I found the original patch: avutil: Duplicate ff_log2_tab instead of sharing it across libs<http://ffmpeg.org/pipermail/ffmpeg-cvslog/2012-October/055604.html> .
The objectives for this patch was: "*The table is so small that the space gain is not worth the performance overhead of cross-library access*" (:uhu:). I have never heard of such a thing as "*cross-library access*" that "auto-magic" gives you a performance gain when you allocate the exact same object file to different link libraries in the same distribution package. Looking forward to have this "unpatched" ... -- 2013/2/13 Michael Niedermayer <[email protected]> > Hi > > On Wed, Feb 13, 2013 at 04:36:38PM +0100, Lars Hammarstrand wrote: > > Hello, can someone please explain the reason (and how to cope with) that > * > > ff_log2_tab* is defined multiple times with *#include > "libavutil/log2_tab.c*" > > in the ffmpeg v1.1 libraries like libavcodec 54.91.102 and companions ?? > > duplicating the tables causes a small performance increase in some > linking configurations. > > > > > > This results in "duplicate symbols" while linking as listed below. To get > > ride of the problem we need to delete the duplicated entries by hand with > > "ar -d libxxx.a log2_tab.o" for all libraries but one, not a very smooth > > solution. Will this behavior change in the future or do weed need to > > automate a duplicate removal process while building the ffmpeg libraries > > for XBMC? > > Ive posted a patch to ffmpeg-dev, which may fix this: > 0213 19:51 To FFmpeg devel (3.0K) [FFmpeg-devel] [PATCH] buildsys: only > include log2_tab per library for shared builds > > please test and comments welcome > > note, some linkers can also be configured to ignore duplicate symbols > > Thanks for the bug report > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > Concerning the gods, I have no means of knowing whether they exist or not > or of what sort they may be, because of the obscurity of the subject, and > the brevity of human life -- Protagoras >
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