is halo == ringing?

[Yama4050242]

searching and surfing in the forum, i found someone use halo while the other use ringing. are they exactly the same thing? if it is, i know what are they since some screenshot. if not, what are the difference?

since my native language is not English, so i want to make it clear.

[Mug Funky]

they are very similar. "ringing" usually refers to Gibb's phenomenon occuring within DCT blocks (or other transforms, like in wavelet or h.264 codecs which aren't only 8x8 DCT), where "haloes" are most often caused by some kind of frequency filtering, either in analog or digital (oversharpening).

in the case of frequency based denoise filters (fft3dfilter), you could probably use both terms interchangably.

[Backflip]

The ringing effect, a phenomenon still seen in this day and age's next generation MPEG-4 compression. I wonder if there will be a day when ringing is non-existent or will media etc have caught up to a point where compression is not required?

[Yama4050242]

@Mug Funky

except "ringing" and "haloes" have different "parents", are they visiblely the same? or not?

if not, can u kindly provide some screenshots

[Soulhunter]

Ok, I made some samples for you...

Source
http://img295.imageshack.us/img295/7302/source1dh.png

Halos
http://img295.imageshack.us/img295/9899/halo9zl.png

Ringing (and blocks)
http://img295.imageshack.us/img295/4086/ring4xm.png


Bye

[Yama4050242]

Soulhunter thank u very much

[Soulhunter]

The ringing effect, a phenomenon still seen in this day and age's next generation MPEG-4 compression. I wonder if there will be a day when ringing is non-existent or will media etc have caught up to a point where compression is not required?
Well, after HDTV there will be UHDTV (7680x4320 @ 60fps afaik). This means a datarate of ~5700MB per second (uncompressed RGB). So, even a 40.000GB HDD would be too small for some hollywood flicks! The other prob is the datarate itself, even if they're able to produce 40TB HDDs one day, you'd still need hw that is able to read/write/transmit the data at such immense rates... :\


Bye

[fccHandler]

@Soulhunter:

I thought the term "ringing" was descriptive of the lines drawn around a telephone in cartoons (when the telephone is ringing). In that sense it seems to mean the same as halos and Gibbs. WRT the effect shown in your third picture, I thought that was called "mosquitoes."

[Soulhunter]

@Soulhunter:

I thought the term "ringing" was descriptive of the lines drawn around a telephone in cartoons (when the telephone is ringing). In that sense it seems to mean the same as halos and Gibbs. WRT the effect shown in your third picture, I thought that was called "mosquitoes."
Hmm, afaik mosquito noise (or edge noise) is just another name for ringing!?

Ringing = Frequency distorsion caused by quantization...

But feel free to correct me... ^^


Bye

[fccHandler]

I always thought the term came from those lines they draw around a ringing telephone in comics. That might just be an urban legend though.

I've heard it said that some resampling kernels exhibit ringing. (Lanczos, for instance.) Supposedly it's an inherent property of the taps, or splines, or something like that. But this usage of the term seems to have nothing to do with MPEG, and might even predate MPEG for all I know...

[Soulhunter]

I've heard it said that some resampling kernels exhibit ringing. (Lanczos, for instance.) Supposedly it's an inherent property of the taps, or splines, or something like that. But this usage of the term seems to have nothing to do with MPEG, and might even predate MPEG for all I know...
Yeah, you are right... :)

Seems for resampling methods the term "ringing" is used to describe haloing!?

http://img191.imageshack.us/img191/8290/snap0818kp.png


Bye

[fccHandler]

Just to add to the confusion, I've also heard the term "ringing" used to describe badly compressed audio. But maybe here they're comparing it to the high-pitched annoying squeal of the telephone's ringer. ;)

[Soulhunter]

Just to add to the confusion, I've also heard the term "ringing" used to describe badly compressed audio. But maybe here they're comparing it to the high-pitched annoying squeal of the telephone's ringer. ;)
:D :D :D


Bye

[Yama4050242]

so can i conclude that the 2 words are the same to describe the thing in the picture



http://img191.imageshack.us/img191/8290/snap0818kp.png

[fccHandler]

I would conclude that ringing = halos = Gibbs, in the strictest sense. But the term "ringing" seems vague, as it may refer to different kinds of artifacts depending on who you talk to. (We can't even be sure where the term comes from.) At this point I'd say it's better to avoid it if you want to be precise in your description.

[manono]

They are both often used as synonyms for Edge Enhancement. Maybe ringing also has other meanings, I don't know, but it's definitely not another word for mosquito noise:

http://www.videophile.info/Guide_EE/Page_01.htm

[Soulhunter]

They are both often used as synonyms for Edge Enhancement. Maybe ringing also has other meanings, I don't know, but it's definitely not another word for mosquito noise...
But deringing (decoder post-processing) removes mosquito noise, doesnt it?


Bye

[Soulhunter]

Maybe we can put it like this... ^^

Halo: A bright ring (halo, the thing angels have above their head)
Halos in digital video: A bright ring around edges (caused by EE)
Ringing: Noise or unwanted alteration around edges in general
Ringing in analog video: Edge-echo/ghost (but not caused by EE)
Ringing in image/audio compression: High-frequency distortion caused by quantization


Bye

[manono]

Good question, Soulhunter. I don't use any post-processing, so I never cared to learn much about it. However, if it's intended to soften the areas around hard edges, then I guess it'll smooth the mosquito noise, as well as the EE. So, in that sense I guess you're right, and I stand corrected. According to the post by Manao here (http://forum.doom9.org/showthread.php?p=242431#post242431), that's exactly what it does. If so, I think Deringing is misnamed.

Edit: I was answering your post 2 posts up.

[Soulhunter]

According to the post by Manao here (http://forum.doom9.org/showthread.php?p=242431#post242431), that's exactly what it does. If so, I think Deringing is misnamed.
Maybe coz Demosquitonization is too hard to write/read/speak... :D


Bye

[manono]

DeMN. DeDot. Yeah, that's it, DeDot. Kind of catchy, doncha think? :)

[Soulhunter]

DeMN. DeDot. Yeah, that's it, DeDot. Kind of catchy, doncha think? :)
Well, there's alraedy a AviSynth filter with this name... ;)

-> DeDot: The dot-crawl remover (http://forum.doom9.org/showthread.php?t=98219)


Bye

[manono]

Yeah, but I don't think he copyrighted the name. XviD's post-processing can "borrow" it.

[Soulhunter]

And FFDShow... and MPlayer... and... :rolleyes: :D :D

Ok, lets write a chain-letter to inform the devs !!!


Bye