addon for xvid

[ammer]

could a simple and quick denoiser be added to xvid to add to its number of features. sort of to round things out a little like other codecs/encoders i.e. cce and vp6. plus apps without filters could use it a lot to improve compression and quality. after all isn't that what compression codecs/encoders are about.

[Nic]

"after all isn't that what compression codecs/encoders are about."
No, encoders and codecs are about compressing and try to be as minimalist on other things as possible. The XviD team won't want prefilters such as noise filters built in to the XviD library....

(And I don't think they belong in the vfw either...)

-Nic

[d'Oursse]

so why have they added a cartoon mode ?

[Manao]

'cartoon mode' isn't about prefiltering. Please read the post of sysKin here (http://forum.doom9.org/showthread.php?s=&postid=405600&highlight=cartoon+mode#post405600) to understand how it works.

[d'Oursse]

- detect_static_motion is a motion estimation flag. The threshold below which a macroblock is concidered static is tripled, or something like that. It really helps saving many bits with would otherwise be used to code noise on a static picture.


for me, this acts like a denoiser...

edit : as they added a process which might help when ripping some kind of video, it could be considered as some prefiltering. I'm not an expert, so if someone could explain me in details...

[Manao]

No because a filter ( denoiser ) modifies the pixels before they are sent to the encoder ( or after they are output by the decoder ), while, in that case, you modify a setting of the codec itself, which makes the codec act as if there was a lot less noise when he has to decide whether a macroblock is static or not, but the noise is still there in the picture for the other calculations the codec may do.

[dragongodz]

i hate to disagree but this still makes it a prefilter really, just not a denoiser. :)

[Manao]

In that case, please define what you mean by prefiltering :)

For me, it is something that is done prior to encoding, not while encoding. And in this particular case, cartoon mode act clearly during the encoding, and can't be made work outside the whole encoding process, because it has an effect on motion vectors ( which are intermediates of calculations made by the codec ), not on pixels.

btw, by my definition, the classical postprocessing ( deblocking, reringing ) made by XviD, FFDshow or DivX 5 is not a postprocessing, because it can't be made outside the codec ( it uses the quantizer level of a frame to adapt the strength of the filtering ).

[sysKin]

"Filter" is a techinical term. It describes, more or less, something which processes and changes the signal. In our video coding, the signal is picture - its pixels.
Just remember that and it will be clear that XviD has one filter - chroma optimizer. Nothing else is a filter.

Radek

[dragongodz]

hate to disagree again but it is still filtering. you are filtering the amount of noise that is seen for encoding decision making. so as i said its not denoising etc. so no its not what people generally think of as traditional filtering(of the picture itself) but filtering of information for(as i said) decision making.

"my definition, the classical postprocessing ( deblocking, reringing ) made by XviD, FFDshow or DivX 5 is not a postprocessing, because it can't be made outside the codec"
huh ? of course its postprocessing. the picture is being changed(processed) from its stored form. it does not matter that the codec is doing it at all.

[Manao]

I think we should stop argueing over semantic, especially since english isn't my first language. Let's say we're both right ( even if I'm more right than you :D ), OK ?

[dragongodz]

hahaha were we arguing ?

anyway enough as you say with 1 last little comment or 2.

i agree that traditional filtering should not be added to the codec and i also think that the cartoon mode is a good idea for the specific purpose it is aimed at. i never said i didnt or complained it was there.

more right ? uh ye right. ;)