[XviD-devel] Re: qpel smearing/noise problem

[Christoph Lampert]

On Wed, 8 Jan 2003, Christoph Lampert wrote:
> 3) Let F be the set of 4096 blocks Bi[y][x] (i=0..4095) defined as follows:
> 
>   a) Bi[0][0] = i - 2048
>   b) Bi[7][7] = 1 if Bi[0][0] is even, Bi[7][7] = 0 if Bi[0][0] is odd
>   c) All other coefficients Bi[y][x] other than Bi[0][0] and Bi[7][7] are
>      equal to 0
> 
> For each block Bi[y][x] that belongs to set F defined above, an IDCT that
> claims to be compliant shall output a block f[y][x] that as a peak error
> of 1 or less compared to the reference saturated mathematical 
> integer-number IDCT f(x,y). 
> 
> In other words, | f[y][x] - f(x,y)| shall be <= 1 for all x and y.


It seems we pass this, too, at least if one compares results of  
idct_int32, idct_mmx and idct_xmm with the reference idct (as in
xvid_bench.c). 

gruel