[FFmpeg-devel] [PATCH] adpcm: Clarify a comment

Michael Niedermayer michaelni
Sun Nov 14 04:25:26 CET 2010


On Sun, Nov 14, 2010 at 02:17:17AM +0200, Martin Storsj? wrote:
> On Thu, 4 Nov 2010, Martin Storsj? wrote:
> 
> > On Wed, 3 Nov 2010, Michael Niedermayer wrote:
> > 
> > > On Wed, Nov 03, 2010 at 09:07:26PM +0200, Martin Storsjo wrote:
> > > > ---
> > > >  libavcodec/adpcm.c |    2 +-
> > > >  1 files changed, 1 insertions(+), 1 deletions(-)
> > > > 
> > > > diff --git a/libavcodec/adpcm.c b/libavcodec/adpcm.c
> > > > index 455b477..f298ef5 100644
> > > > --- a/libavcodec/adpcm.c
> > > > +++ b/libavcodec/adpcm.c
> > > > @@ -354,7 +354,7 @@ static void adpcm_compress_trellis(AVCodecContext *avctx, const short *samples,
> > > >          int sample = samples[i*stride];
> > > >          memset(nodes_next, 0, frontier*sizeof(TrellisNode*));
> > > >          for(j=0; j<frontier && nodes[j]; j++) {
> > > > -            // higher j have higher ssd already, so they're unlikely to use a suboptimal next sample too
> > > > +            // higher j have higher ssd already, so they're likely to yield a suboptimal next sample too
> > > 
> > > how much is gained without that assumtion?
> > 
> > Current code:
> > stddev:   31.99 PSNR: 66.23 MAXDIFF: 2643 bytes:  2646016/  2649218
> > Runtime 16.6 s
> > 
> > range = 1 for all nodes:
> > stddev:   31.97 PSNR: 66.23 MAXDIFF: 2112 bytes:  2646016/  2649218
> > Runtime 19.3 s
> > 
> > So I think the general idea of the assumption is quite good as such, since 
> > it gives quite a big gain in performance compared to the. With this patch 
> > in place, the comment says what the code actually does.
> 
> Ping

fixing typos is ok if you are sure its wrong before and correct afterwards, no
need to ask (note i didnt check it now)

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

If you think the mosad wants you dead since a long time then you are either
wrong or dead since a long time.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20101114/82c17c05/attachment.pgp>



More information about the ffmpeg-devel mailing list