[FFmpeg-devel] Unused symbols in vc1data

Kostya kostya.shishkov
Wed Apr 30 19:46:25 CEST 2008


On Wed, Apr 30, 2008 at 06:32:18PM +0200, Diego Biurrun wrote:
> On Wed, Apr 30, 2008 at 06:33:08PM +0300, Kostya wrote:
> > On Wed, Apr 30, 2008 at 04:26:11PM +0200, Diego 'Flameeyes' Petten? wrote:
> > > 
> > > (Beside the fact I still have a queue of patches I should be
> > > polishing..)
> > > 
> > > I wrote a new script today to deal with ELF object files, it finds
> > > functions that are not used in a project beside for the unit they are
> > > defined. While this triggers false positive for exported symbols (unless
> > > the project uses hidden visibility for non-exported symbols), it also
> > > shows unused symbols. It needs a bit of fiddling to become safe, but the
> > > results are interesting.
> > > 
> > > For FFmpeg I've seen there are a few symbols defind in vc1data that are
> > > never used, not in FFmpeg's source tree at least. They are prefixed with
> > > ff_ so I suppose they would be exported.
> > > 
> > > Do you want a patch to get rid of them? It would probably reduce the
> > > size of libavcodec..
> > > 
> > > ff_vc1_adv_interlaced_4x4_zz (./libavcodec/vc1data.o)
> > > ff_vc1_adv_interlaced_4x8_zz (./libavcodec/vc1data.o)
> > > ff_vc1_adv_interlaced_8x4_zz (./libavcodec/vc1data.o)
> > > ff_vc1_adv_interlaced_8x8_zz (./libavcodec/vc1data.o)
> > > ff_vc1_norm6_spec (./libavcodec/vc1data.o)
> > > 
> > > I'm looking at a few more now, will see to get a full report once I'm
> > > done.
> > 
> > Err, I was intending to add more of such unused data and then use it
> > in interlaced decoding.
> 
> In the near future?  Most likely not, so why not comment this stuff out
> and resurrect it once you continue working on interlacing?

Ehh, I work on it time from time. One of my development snapshots has
some support for field-based interlace mode.
It's more fun than H.264 interlaced mode but not significantly better :(.
 
> > ff_vc1_norm6_spec can be commented out though.
> 
> Done.
> 
> Diego




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