DVD image looks bloated

[feisty2]

I have the original master tape and the corresponding DVD release of a few videos,,, and the DVD image looks bloated/dumb/coarse comparing to the master tape, the overall image texture of the master tape looks more fragile/delicate, I don't really know the exact technical term for this...

Master tape
http://i.imgur.com/dLbneWe.png
http://i.imgur.com/EAMB3Wg.png
DVD
http://i.imgur.com/PHU2r9n.png
http://i.imgur.com/U4CXj3K.png

I don't think this kind of degradation is caused by MPEG-2 compression, it also doesn't quite look like blurring cuz blurring would destroy the edges and the DVD release preserved the edges in the master tape..
I do think they deliberately processed the master tape before MPEG-2 encoding for some unknown reasons and that wicked processing is the cause of quality degradation

anyone knows the exact technical term for this degradation and its cause?

[StainlessS]

Dont know but this is what you get with subtract and amplify on first image.


AM=Imagesource("AMast_dLbneWe.png",end=0)
AD=Imagesource("ADVD_PHU2r9n.png",end=0)
BM=Imagesource("BMast_EAMB3Wg.png",end=0)
BD=Imagesource("BDVD_U4CXj3K.png",end=0)
#AM++AD++BM++BD

AM=AM.Crop(0,0,0,-1)
AD=AD.Crop(0,1,0,0)
#AM++AD
ClipDelta(AD,AM,Amp=true)

https://s20.postimg.cc/75lu95abh/Feisty_zps5t4f0csy.jpg (https://postimg.cc/image/4biovp855/)

EDIT: White bits are lighter in DVD, black bits darker.
EDIT: Missing Image fixed.

[LoRd_MuldeR]

Looks low-pass filtered to me, i.e. the highest frequency coefficients "zero'ed out". More or less the expected result of quantization, as done in lossy image/video compression.

For example, your "Master tape" image processed with this DCT quantization matrix...
https://i.imgur.com/W8XOR9e.png

...gives the following result/difference (contrast enhanced to make it more visible):
https://i.imgur.com/69eGJK2.png
https://i.imgur.com/vSfAy8o.png

[GMJCZP]

I think LoRd_MuldeR if it has not hit the nail, is close. Perhaps they used in the coding a matrix that does not take all the details of the image. If you have the DVD file you can use ReStream_v090 to observe the matrix used. You can also know the value of dc, which for high quality should be 10, etc.

[StainlessS]

And the Dark Lords image subtracted (in same direction as my original post, white is lighter in mod, ie mod-orig instead of orig-mod) and amplified.

https://s20.postimg.org/n54hsp6d9/Lord_M_zps7mf1zud7.jpg (https://postimg.org/image/rr0m11rw9/)

EDIT: script

# Return Clip Difference of input clips (amp==true = Amplified, show==true = show background)
Function ClipDelta(clip clip1,clip clip2,bool "amp",bool "show") {
amp=Default(amp,false)
show=Default(show,false)
c2=clip1.levels(128-32,1.0,128+32,128-32,128+32).greyscale()
c1=clip1.subtract(clip2)
c1=(amp)?c1.levels(127,1.0,129,0,255):c1
return (show)?c1.Merge(c2):c1
}

AM=Imagesource("AMast_dLbneWe.png",end=0)
AD=Imagesource("ADVD_PHU2r9n.png",end=0)
BM=Imagesource("BMast_EAMB3Wg.png",end=0)
BD=Imagesource("BDVD_U4CXj3K.png",end=0)

ALM=Imagesource("ALM_69eGJK2.png",end=0)

#AM=AM.Crop(0,0,0,-1) AD=AD.Crop(0,1,0,0)
#AM++ALM
ClipDelta(ALM,AM,Amp=true)

[Katie Boundary]

They look 100% the same to me. Who's the girl?

[feisty2]

http://i.imgur.com/WHxernU.png
@GMJCZP
I'm not sure what this means..

@LoRd_MuldeR
yeah, I can see some slight compression artifacts in your quantized image, but the overall image texture didn't change, it still looks "delicate" as the uncompressed image which is expected from lossy compression...
the DVD image I posted earlier looks different, the whole "delicate" and "fine" texture is lost and there's also no obvious compression artifacts in the image, I think they might deliberately make the image like this before encoding so there would be less compression artifacts after encoding, but I'm not sure
the difference image you posted looks more "random" (just random dots all over the place)
and the one StainlessS posted looks more "structured", you can see some obvious structured pattern like
http://i.imgur.com/vArwwhZ.png

[StainlessS]

What Is described as amplified (for ClipDelta) is not really correct, anything above 128 is saturated to full white, and below to full black.
I did not check if the Dark Lords 'contrast enhanced' was similarly saturated but in opposite subtract direction.

On second thoughts, dont think L.M.'s amp'ed image could just be opposite, about center of image there are a few square blocks of
white, in same position in mine (of same image), they are grey (128), dont know how that could have come about for the same image.

EDIT:
Here, original (my post of) Dark Lord's image on top, and opposite subtract direction on bottom, both
using clipDelta(amp=true)

Z1=ClipDelta(ALM,AM,Amp=true) # orig my post of LM
Z2=ClipDelta(AM,ALM,Amp=true)
StackVertical(Z1,Z2)

https://s20.postimg.cc/cwc0mvibh/LM3_zpsde31ityz.jpg (https://postimg.cc/image/nj5tsaqgp/)

Square block I mentioned, still grey in 2nd image above.

EDIT: I must be blind, all of the grey in my images is white in LM's. :stupid:
Maybe something like 255 - absolute difference.
EDIT: Missing image fixed.

[GMJCZP]

The problem with DVDs, unlike, for example, x264, is that it is difficult to know all the encoding parameters. Apparently they used TMPGEnc MPEG Editor which is an all in one (it is not the worst program but it is inferior to HCEncoder, that by the way, if I do not miss the memory the encoder is the same as Sony Vegas for DVD encoding). By the values of Inter Matrix the matrix seems to be MPEG, so that's not the problem. The value of dc is 8, it should have been 10 for high bitrate, but still not something that stands out.
The only thing I can conclude is that the encoder of TMPGEnc possibly to avoid the macroblocks "washes" or alters the image too much for your liking.

[thank you]

looks like blurred horizontally

[thank you]

idk if u noticed this, but these music videos even the master tapes, they all look like they've been sharpened horizontally and blurred vertically, and this kinda sharpen increase some kinda halo looks like ringing but not from compresssion

[SeeMoreDigital]

This is a four year old topic :scared: