[Ffmpeg-devel] Re: Using Intel's fDCT

[g.]

M?ns Rullg?rd <mru <at> inprovide.com> writes:
> IIRC, the output from the MMX/SSE DCT functions is permuted because of
> some design quirk of the CPU.  There's a flag somewhere indicating
> this.  Make sure it is set correctly.
> 

Thanks for the suggestion but having looked at the code, the permuation is 
only relevant to iDCT, not fDCT which is where my problem lies. I tried all 
the different permutation settings anyway, just in case, but it made no 
difference.

Perhaps I have to add a new permutation step to the fDCT function before 
quantisation when using Intel's fDCT?

Can anyone explain what is going on?

g.