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hanfrunz
20th October 2004, 20:16
Hello everyone,

i hope this is the right place to ask a view questions about motion vectors.

I want to experiment with motionvectors to make "video-art". For example i want to use the motionvectors of one video (lets say a soccer game) and change some I-frames (lets say to colorfull patterns), so the result is the patterns with motion of soccer players.

Is this possible somehow, with a modded xvid encoder/decoder? Or are there tools, that can change i-frames? Or is it possible to extract the motion vectors to a textfile, so i can use this data in other applications?

thanks,
hanfrunz

Leak
20th October 2004, 21:38
Originally posted by hanfrunz
I want to experiment with motionvectors to make "video-art". For example i want to use the motionvectors of one video (lets say a soccer game) and change some I-frames (lets say to colorfull patterns), so the result is the patterns with motion of soccer players.

How about using Manono's MVTools and AviSynth for this? It easily allows you to analyze one source and apply the found motion vectors to a different one, and it might produce better motion vectors for your use as video compression can easily compensate for or even benefit from weird/unrealistic motion vectors (by compensating for the difference this causes), while this won't really help in your case...

np: Quinoline Yellow - Factungconceal (Cyriack Parasol)

hanfrunz
20th October 2004, 22:30
sounds great, i will check that.

hanfrunz

Mug Funky
21st October 2004, 10:04
i've tried this as well. the main problem is that i can't figure a way of feeding MVcompensate with the previous compensated frame. there's no looping happening.

sysKin
21st October 2004, 10:12
This sounds like fun to code. Quite easy too, as a modified (and broken) version of xvid.
Unfortunately I have no time to do that, at all.

Manao
21st October 2004, 12:29
Mug Funky, hanzfrunz : I'll make an looping MVCompensate in the next release.

Mug Funky
21st October 2004, 15:08
manao :)

you're the best :)

lordadmira
22nd October 2004, 00:36
sysKin! you have a new Totoro icon. ^_^

Mug Funky
23rd October 2004, 16:22
oh, manao: would it be possible to allow filtering such as blindpp deblocking inside this looping MVcompensate? i'm currently trying to achieve the denoising and compressibility boost that dust offers. i'm close, but looping looks like it'd be useful too. it'd also make Hanfrunz's "drifting stills" melt more gracefully.

of course, it's not all that important in the grand scheme of things :)

Manao
23rd October 2004, 19:42
Mug Funky : wait for the next release of the MVTools. Now, when I make the motion search, the compensation is also computed and stored inside the motion vectors stream. You can "release" it using one of the mode of MVCompensate ( the other two being the classic one, and the looping one ), and you can put back into a vectors stream a compensation using MVChangeCompensate. So basically, you can deblock the compensation.

That's very useful since I made another MVDenoise, which can take n vectors stream containing compensation in input, and provided that all these compensations are the same frame, it makes an intelligent temporal blur along the compensation( intelligent meaning it takes into account the quality of the compensation ).

However, adding a deblocking inside the looping MVCompensate is imho useless ( since I know what the result looks like, it ain't pretty, and a deblocking won't improve things ).

Anyway, adding it won't be too hard, so I may do it, but later ( i want first to see if I can come up with an ugly in-loop trick in order to do something more general than adding a parameter saying "do a deblocking" ).

The next release could come soon ( without the temporal interpolators, which are still a mess ), or later, if I try to make them less messy.

Mug Funky
24th October 2004, 17:29
no rush: i bow my head to you already. any further i might have neck problems.