Compressability of DV

[ulfschack]

I tried it with Jonny's tool (few threads down)

At an input resolution of 704x560 @ 2300 kbps Gknot yields:

22,8% Interlaced
26% Deinterlaced with greedy
27,8% Separted frames, Temporalsmoother(2), weave + greeedy

Kinda puts a number on what we DV camera owners have to go through getting a good "rip" of our families :)

cheers

[ShinerSpoon]

It would be interesting to see what those figures were after the source was run through Dynapel's SteadyHand first. I think there is a demo with a logo if you are interested to try it.

[ulfschack]

Tried it with steadyhand now as well. I get

33.3 % (plus greedy) - Quite an improvement

The trial logo is fat mo-fo, tho. I seriously think it's big enough to affect complexity in a significant degree.

Do you use it yourself, Shinerspoon?

[ShinerSpoon]

Yes, that is quite an improvement. I was thinking it might help, especially with the crap video that I shoot :) Everyone of those fast pans or zooms just kills compression.

I have played around just a bit with Steadyhand but not enough to have an opinion. I have read a lot of your posts on DV and you seem much more versed on DV than I, so I just thought I would point it out to you in the hopes you might give your opinion. I have not purchased it yet, but it's functionality seems to warrant it the next time I actually sit down and try to do something real with all this footage I have accumulated. Editing this stuff is really a grind for me and not one I find all that fun.

[theReal]

A DV video I tried recently brought up the following:

At a Bitrate of 2500 with Divx5 and b-frames, resolution 640x464, I got the best result (~59%) when I used VirtualDub's precise bilinear resize and before that smartdeinterlace(2,10,true,true,true) and temporalsmoother(2).

That would about underline your values, I think ( = DV is hard to compress!)

[ulfschack]

Sure is a bitch and a half making good family fun :)

I tried out this dynapel a bit further. This is what I think of it:

It get's rid of shakes and bobbing in a very efficient way, at least to the extent it can without making stuff up. It does that by tracing objects filmed and thusly have to cut off the borders in a very selective way to make the objects maintain their distance to them, so that it will look as if the camera was steady.

The price is not that the interpolation back to full frames gives a blurred picture. In fact it does that very well. The main thing is that it as I mentioned takes away stuff you've filmed.

I measured a zoom factor as high as 20%! Totally unacceptable for me and would be the equivalent of cropping 55 pixels top/bottom and 72 pixels left/right. My (and most) DVs have a narrow angle enuff, making it difficult for indoor shots allready. And the clip I tried it on wasn't a very "shaky" one at that. Imagine what you'd loose when f.i filming from a car.

I could probably still use it for shorter sequences where I need the extra compressability (it is considerable. A second test with tweaked parameters gave a few percent further than the above stated figures.) But I certainly won't use it for whole projects. It comes for about 50 pounds (I seem to remember), so not an awful lot.

cheers

[theReal]

I downloaded the steadyhand trial a few days ago but haven't tried it yet. However, I think I could use it for some single scenes that are messed up with too much shaking, which I don't want to cut out totally.

I'm thinking of vacation videos filmed by my dad... he loves to zoom when he shouldn't and usually the best motives that should really be in the final film are really shaky. I hope steadyhand is good to save some of these messed up scenes, but I think temporalsmoother is better for filtering all of the material.

The "MotionPerfect" seems interesting as well. You can make slo-mo scenes with it, it takes two frames and produces in-between frames so you can make a 5fps slo-mo into a 25fps slo-mo. Don't know why I would need it, but it's interesting :)

[ShinerSpoon]

Hey, my shooting is more like theReal's father :)

It makes my unusable stuff useable so I can live with a lot from it.

BTW, I played with motion perfect also and one of the things I really liked, besides the slomo, was its ability to cut the framerate to 15 without any jitters. I can take my regular edits and just run them through this process before I email them to my relatives to watch on their PCs. They have never even noticed the reduced framerate and it makes the files smaller for sure.