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-   -   KDVD: How to force notch filtering ? (http://www.digitalfaq.com/archives/encode/8423-kdvd-how-force.html)

rmax 03-02-2004 01:52 AM

KDVD: How to force notch filtering ?
 
Hello!
I spent couple months trying to make MPEG-video using "notch"-matrices. Now i think that the "notch" like natural phenomena - it is can not be predicted, when and how it will be.
Sometimes i had an exellent results and sometimes the results was not so good.
I read in this forum that the "notch" make "filtering effect".

1) So, the point of question is - that features input video must to has to make "notch" filtering working? The main goal (as i understund) is to suppress blockiness at all. I agree to have less cripness video, but i can not agree with any visible blocks in video picture. And no blocks must be visible then the picture is zoomed.

It seem to me, the "notch" phenomena depend on some criteria in input video.
I found that:
1) ligter-darcker picture is minor factor for "notch" - there no need to balance "luma"
2) scenes with nature allways good for "notch" - so the picture must have much color as possible - it is disareble to encrease "chroma"
3) scenes colored in one tone is allways bad

Simple way i found to determine that "notch" is good - the media player can not show length of video correctly. And seems then the mistake bigger - "notch" filtering more good.

And thas second question: if my video is "notch-resist" how i can "force" "notch" to start? - Must i vary GOP length or suppres cripness of video or reduce size of picture or anything else?

incredible 03-02-2004 01:58 AM

Go and do a search using google, to see whats on quantization matrixes!.
Also in here do a look using "search" on "dct" and my alias then youll find it.

Quote:

the media player can not show length of video correctly
Thats NOT a matrix issue! And if I remember we didn't in here find out on what this belongs to. Some players like 224kbit audio to show the timestamp correctly and others do need other things in the stream.

rmax 03-02-2004 02:44 AM

I understand that all of MPEG is use common algorithm.
Reading this forum i found that some people wrote about pretty good results of encoding using "notch"-matrix.
I make several tests and in two cases have a very good picture with a very tine filesize. I thougth that was the true "notch" phenomena. But it was only 2 file from 20 was encoded. And i decide, that in other 18 cases "notch" was not start...
Tell me please - am i right? Or my "notch" results is simple episodic?

kwag 03-02-2004 11:40 AM

rmax,

When you have some time, have a long read here ;)
http://www.kvcd.net/forum/viewtopic.php?t=2073

-kwag


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