[Ffmpeg-devel] [PATCH] Chinese AVS video decoder

Rich Felker dalias
Thu Jun 29 21:35:52 CEST 2006


On Thu, Jun 29, 2006 at 07:30:46PM +0100, M?ns Rullg?rd wrote:
> Rich Felker <dalias at aerifal.cx> writes:
> 
> > On Thu, Jun 29, 2006 at 02:56:22AM +0200, Michael Niedermayer wrote:
> >> [...]
> >> > +static const int cbp_tab[64][2] = {
> >> > +  {63, 0},{15,15},{31,63},{47,31},{ 0,16},{14,32},{13,47},{11,13},
> >> > +  { 7,14},{ 5,11},{10,12},{ 8, 5},{12,10},{61, 7},{ 4,48},{55, 3},
> >> > +  { 1, 2},{ 2, 8},{59, 4},{ 3, 1},{62,61},{ 9,55},{ 6,59},{29,62},
> >> > +  {45,29},{51,27},{23,23},{39,19},{27,30},{46,28},{53, 9},{30, 6},
> >> > +  {43,60},{37,21},{60,44},{16,26},{21,51},{28,35},{19,18},{35,20},
> >> > +  {42,24},{26,53},{44,17},{32,37},{58,39},{24,45},{20,58},{17,43},
> >> > +  {18,42},{48,46},{22,36},{33,33},{25,34},{49,40},{40,52},{36,49},
> >> > +  {34,50},{50,56},{52,25},{54,22},{41,54},{56,57},{38,41},{57,38}
> >> > +};
> >> 
> >> this fits in an uint8_t which means we could save 75% memory, same issue
> >> with many other tables
> >
> > and for those who don't understand already, memory == performance due
> > to cache pollution.
> 
> Possible exception is machines with large caches and no byte access to
> memory.  Such things exist.

And such things will have hopelessly poor multimedia performance
already. As well as poor string performance, etc...

Rich





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