[Ffmpeg-devel] [RFC] libavcodec/mpeg12.c refactor

Michael Niedermayer michaelni
Wed Feb 7 02:09:13 CET 2007


On Wed, Feb 07, 2007 at 11:19:08AM +1100, Nigel Pearson wrote:
> Aeons ago, Michael wrote:
> >Subject: Re: [Ffmpeg-devel] MPEG-2 Acceleration Under Mac OS X -  
> >Can We Move This Forward?
> >
> >Hi
> >
> >On Tue, Aug 29, 2006 at 11:15:49AM +0200, Michael Niedermayer wrote:
> >[...]
> >>PS: also if anyone does that, please merge the decode_block_foobar 
> >>() and
> >>decode_block_foobar_fast() functions they are nearly identical and  
> >>i should
> >>have implemented them like descibed above furthermore merging them  
> >>will half
> >>the number of functions which need to be changed for apple hw  
> >>decoding support
> >
> >additional tip, to merge the functions, dump them to a file each  
> >and run diff
> >over them
> Well, I finally got around to trying this. I know the attached
> diff isn't commit ready (I have purposely used bad formatting,

it looks pretty good, formatting changes must be in a seperate patch
anyway and removing the old code can be done in a seperate change too

> and left dead code there, to minimise the size of the diff),
> but I would appreciate comments. e.g. Is this what was meant?


> Changes seem to pass regression tests, but I
> suspect that these don't use CODEC_FLAG2_FAST?

then test it (the mpeg1 and 2 files in tests/data/ can simply be
used with rawvideo output and md5sum)

> I have not benchmarked these (still haven't worked out how).


> They may be marginally slower due to the extra conditional -
> if (fast) - inside some of the loops. If anyone has a clever
> way to optimise this, please share!

gcc will remove this if the code gets inlined which it should ... well

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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