dvd2onex selective mode

[reemas]

Can anyone explain this mode to me/us? I'm not sure what it is and also, what are those options, low, medium, and high.

I read the website and the help files, but really it doesn't make sense.

thanks.

(hey galactica, have you made any new "advanced guides" maybe with the new selective mode features?)

[WiseWeasel]

Not sure what they do exactly. You might go look on their forums and see if there's some info there. I think there's a bit, but I'm too lazy to look right now...

[alph]

It's a little unclear to me too, but this is how I understand it.

(I'm writing more than i need to here cause I'm working through it in my mind as I write)

Movie basics

The more action there is a scene; the more bits are needed to encode the video. That means that in a movie the slow scenes use less bits and the action scenes use more bits which leads to a given average bit rate for the movie.

If a movie is encoded with a variable bit rate the encoder more or less lets the bit rate vary according to the action while maintaining an average bit rate.

If a movie is encoded at a constant bit rate then the encoder increases the compression on the action scene to maintain that constant bit rate. This leads to blocky and blurry action scene.

DVD2one

With variable ratio Dvd2one varies the level of extra compression it does based on scene action. This can degrade the video the most in certain areas.

With the constant ratio dvd2one compresses all the scene in the same way as to reduce file size while diminishing the amount of compression applied to the action scenes.

With Selective ratio, what I understand DVD2one does is something along the lines of what it does in constant ratio. but it goes further and actually looks at each frame to find the areas of action and the static areas. Think of a scene where you have 2 guys fighting on the right side, but on the left you only see a brick wall. In constant there is a good chance the brick wall would get blocky, but in selective dvd2one will apply the compression to the fighting side of the frame and leave the brick wall part alone. This way the fight action might get blocky, but those blocks are harder to see than looking at a blocky brick wall that does not move. Put another way, for example, constant would apply 50% compression to the entire frame, but selective will doe 75% compression on the fight half, and only 25% on the brick wall half to achieve a similar 50% compression over all.

What I understand low, medium, and high to be is the difference between what it does to the low action part of a frame versus the high action part. Lets say, example, dvd2one still needs overall to compress the frame 50%:

Low will do: 40% compression on low action, and 60% on high action
Medium will do: 30% compression on low action, and 70% on high action
High will do: 20% compression on low action, and 80% on high action

I hope I'm not too far off. Someone let me know if I am.

Cheers

[g4cube]

That seems to be a good explanation of what it does mate nice work. So that being said there is no real best setting that works for everyone but the safe bet would be medium as with all things in life.

[Coopervid]

alph,

your explanation makes sense. I hope it is correct

But it sounds very logical. To be honest - the DVD2One explanation sounded to me like an oracle. To make a long story short: Nobody understands it and it's just too vague. Therefore I even never used the new feature.

Would you mind to send it to dvd2One.com for confirmation? You should also ask for a "marketing fee" if they confirm and use your explanation in the future. The current explanation is just pathetic.

Vid

[deadsierra]

Just to clarify, selecting constant in DVD2OneX means that it compresses all parts of the video uniformly, not that it changes it to a constant bitrate. You'll get exactly the same pattern if you look at the bitrate before and after compression, just the after graph will be lower.

[thoughton]

Is anyone noticing much of a difference with selective mode? I, probably like most people, just switched over from variable to selective medium without too much thought. I've been backing up a lot of 8gig TV series discs and to be honest I can't really notice any difference between the old method and the new. The picture isn't any worse, but I have a hard time telling if it's any better.

[rb5505]

seems the answer is here:

http://www.dvd2one.com/forum/viewtopic.php?t=615&sid=af657d8728533d35b85557fb2750a55c