yuv_vs_quant.txt

基于C语言的小波处理

	RGB -> YUV

	introduces error just like a quantizer

	(actually you could make it lossless with YUV_EXTRA == 4 ,
	but thats add four nearly-random bits !)

	so, compare on the beam1.128x3 texture image, with dct :

		YUV , quant by 1.0 , 3.363 bpp

		quantized by 2.3 , 3.414 bpp

	same PSNR = 51.15

	equality of psnr at qu=2.3 seems quite common

==============================================================

Q:\wt>et128 beam1 -td -i -qu2.3

Q:\wt>wt c:\ccc\images\textures\beam1.128x3.raw 128 128 -p3 -td -i -qu2.3
WaveCoder v1.5, (c) 1998 by cBloom
got option: planes = 3
got option: use DCT
got option: interleaved planes
got option: quantizer = 2.300000
using default coder : BitPlane
forward transform...
encoding...
decoding...
reverse transform...
LL band           :     768 ->     859 =  8.947 bpb =  0.894 to 1
H bands           :   48384 ->   20121 =  3.326 bpb =  2.404 to 1
beam1.128x3.raw   :   49152 ->   20980 =  3.414 bpb =  2.342 to 1
error: av= 0.40,max= 8,mse= 0.503,rmse= 0.71,psnr= 51.15
forward:0.0672,encode:0.1262,decode:0.1028,inverse:0.0649

Q:\wt>
Q:\wt>

Q:\wt>et128 beam1 -td -i -y

Q:\wt>wt c:\ccc\images\textures\beam1.128x3.raw 128 128 -p3 -td -i -y
WaveCoder v1.5, (c) 1998 by cBloom
got option: planes = 3
got option: use DCT
got option: interleaved planes
got option: do 3-planes with YUV
using default coder : BitPlane
forward transform...
encoding...
decoding...
reverse transform...
LL band           :     768 ->     726 =  7.562 bpb =  1.057 to 1
H bands           :   48384 ->   19937 =  3.296 bpb =  2.426 to 1
beam1.128x3.raw   :   49152 ->   20663 =  3.363 bpb =  2.378 to 1
error: av= 0.36,max= 7,mse= 0.503,rmse= 0.71,psnr= 51.15
forward:14.143928,encode:0.0956,decode:0.1043,inverse:0.0911