hm base constant 2.718 281 828...) Cos( x) is the trigonometric cosine function operating on an argument X in units of radians, and TT is Archimedes' constant 3.141 592 653 Rec. ITU-T H.264 (01/2012) The band-pass filtering of blocks gaussRv may be performed in the discrete cosine transform (DCT) domain as follows: for( (y=0;y<16;y++) for(x=0;x<16;x++) f((x<comp_model_value[c][s][3]&&y<comp_model_value[c][s][4]) (D-23) gaussRv[x,y]= filteredRv=IDCT16x16(gaussRv) = where IDCT16x16(z) refers to a unitary inverse discrete cosine transformation (IDCT) operating on a 16x16 matrix argument Z as specified by IDCT16x16(z)=r*z*r (D-24) where the superscript T indicates a matrix transposition and r is the 16x16 matrix with elements rij specified by (D-25) where Cos(x) is the trigonometric cosine function operating on an argument X in units of radians and T is Archimedes' constant 3.141 592 653. Q[ C ] is formed by the frequency-filtered blocks filteredRv. NOTE 7 - Coded model values are based on blocks of 16x16, but a decoder implementation may use other block sizes. For example, decoders implementing the IDCT on 8x8 blocks, should down-convert by a factor of two the set of coded model values comp_model_value[ c ][ S [[]] for i equal to 1..4. NOTE 8 - To reduce the degree of visible blocks that can result from mosaicing the frequency-filtered blocks filteredRv, decoders may apply a low-pass filter to the boundaries between frequency-filtered blocks. Otherwise (model_id is equal to 1), an auto-regression model enables simulating the original film grain for C = 0..2, X = 0..PicWidthInSamples, and y=0..PicHeightInSamples as specified by G[ X, y, c ]=(comp_model_value[c][s][0]*n[x,y,c] = log2_scale_factor)) log2_scale_factor)+G[x+1,y-1,c])- comp_model_value[c][s]5]*(G[x-2,y,c] + (2*log2_scale_factor))) comp_model_value[c][s]| 1*G[x,y,c-1])>>log2_scale_factor (D-26) where n X, y, C ] is a random value with normalized Gaussian distribution (independent and identically distributed Gaussian random variable samples with zero mean a