[MPlayer-dev-eng] TODO

[Michael Niedermayer]

Hi

On Tuesday 12 February 2002 11:07, Arpi wrote:
[...]
> URGENT:
[...]
> - mencoder: image cut/crop/extend filter, colorspace conversion
>   *** Maybe SwScale can do all of these for us?
hmm, maybe :)

[...]
> runtime:
> - add --enable-runtime or something (should change VERSION header and
> enable runtime cpu detect and print banner telling users to recompile for
> speed) - runtime cpu detection in:
>      vo_dga.c (asm stuff may be removed and replaced by fastmemcpy?)
the current fastmemcpy is perhaps not optimal for mem -> agp/pci copies 
because it assumes that read/writes go over the same bus, so it simply reads 
a few kb (they are in the L1 cache after that) and then reads them again and 
stores them (the trick is from amd's manual not from me ...)
if both source &  destination are in main mem then the bus will be 100% busy 
cuz the data is read from L1 cache on the read/write pass and the accesses 
will be sequential instead of alternating between 2 locations so its faster
but if the destination is on an agp card than the agp bus will be idle 50% of 
the time and the mem bus will be idle the other 50% ... pretty bad
allthough i didnt benchmark the mem->agp variant so its just theory ...

[...]

Michael