About the compression?

Mikey790

1)How good is the movie quality compared to other compressions

2) Can you uncompress the dvd back to the original size and quality with DVD2ONE?

Xtreme2003

1)the quality is perfect on most movies(Road to Predition,Red Dragon,007 Die Another Day Full Disc) cant really tell the differents.

2)You always have the original files(either ISO,VIDEO_TS) so if the quality isn't good,delete compressed files and start over again whit the original files!
the files created by dvd2one cant be reversed

Mikey790

I suppose there will be improvements in the area of DVD compression in the future..

I thought the process might be similar to a ZIP or RAR, I guess not.

I was just wondering how a DVD can be compressed.

THANKS

jmp1963

@Mikey790

ZIP and RAR are examples of LOSSLESS compression meaning that the original data is still there waiting to be brought back by uncompressing. It's rather like a sponge - you can squeeze it until it takes up almost no space but when you let go it reverts back to its original size.

The compression used by DVD2one however, is what's termed LOSSY compression. Simply put this means that to decrease the size certain bits are just thrown away. To use my original analogy this would be like cutting pieces off of the sponge and throwing them in the bin in order to reduce the overall size. Once this is done you have no way of ever having the whole sponge again. It is still a sponge though and can be used as such in just the same way as removing enough small portions from a DVD don't stop it from being a DVD - just one that uses less space

Hope this explanation helps!

JMP

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Mikey790

Yas that is as I figured.

The lossless compresion does sound better for movie quality though... someday

A7mag3ddon

Actually its not compression , its transcoding or re sampling , its downsizing the video bitrate.

Eg, Video stream = 4000kbits/ps and you transcode or downsample to say 2000kbits/ps the movie will be aproximatly half the size.

Hope that helps :-)

A7

jmp1963

Direct from the website of DVD2one:-

"World's fastest video compression engine. . . .etc"

Anyway, whatever you want to call it you're still throwing 'bits' away

JMP

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ReneB

Luckily we know our own engine and it's not transcoding, it is truly based on compression!
(and it's going to increase in quality a lot we hope, in the next 1.2 version of that engine!)

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jmp1963

Thanks Rene.

I don't have ANY problems with DVD2one as it is but I am glad to hear we might be getting some quality improvements. At least it might quieten some of the more 'picky' users

Mind you, they say that beauty is in the eye of the beholder and seeing as most of my backups are for my 3 & 5 year old daughters I doubt that they are going to notice the improvements!

Cheers,

JMP

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jzaman

I have been using your product since version 1.01 and it has worked as advertised since day one. However, as the main movie approaches 6.3gb+ it is a challenge for any method to maintain consistent video quality. Any quality improvements that you can offer with 6.3gb+ Movie Only backups with your proprietary method would be icing on the cake.

What is the difference between your compression method and standard transcoding? Is it a "lossy" or "packing" technique? Is bit rate reduction employed? I'm not looking for your trade secrets... I just want to learn more about your product.

ReneB

Transcoding, re-encodes the material and most of the time recalculates the motion.
And compression well uhrmm only compresses the material without recalculating the motion etc.

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Peter McCall

I think we're into semantics here, Rene

Most people understand 'transcoding' as being something different to 're-encoding'.

If I re-encode, I expect to pass the source video stream through an MPEG encoder, presumably with the settings adjusted in order to reduce the size of the target/output video stream (or why else do it?). This gives me a completely new video stream with none of the original encoder's 'ideas' left behind.

If I transcode, I read through the source video stream and reduce the number of bits (and thus the size). However, the original encoder's motion vectors and other parameters are left alone.

Isn't that how you see it?

-Pete

ReneB

Well uuhm yes, that sums it up..

Transcoding is re-encoding with a lower bitrate or a different format

Compression is re-using the original data and remove some visualy redunt parts.
(also called psycho-visual encoding by some but i do believe that's not correct, because that would mean like with psycho-aucoustic that you remove the parts invisseble to the human eye)

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Peter McCall

Thanks, Rene

I didn't know about the psycho-visual thing. I know that rendering the audio channel(s) usually involves the psycho-acoustic model - sounds that are indiscernible to the average human, but I hadn't come across that philosophy applied to the video channel(s).

In any case, it wouldn't work with your average customer, who typically seems to have 40/40 vision and the acuity of a golden eagle!

-Pete

ReneB

I believed that the visual-psycho part was bull to, but the human eye can't see every bit of detail, especialy in the darken area's so it's pretty safe to leave some of these parts out.

I tought the winamp guys based their streaming media coded on that principle. (not 100% sure about this!)

But that's not the sort of compression that DVD2one uses, it's somewhat different and in our eyes not perfect enough.
(what can i say, we are perfectionists, sorry )

But with the new compression engine Erwin is working on, things are getting closer to our own desired level of perfection!

But indeed what you say is true, most people won't really spot the difference with the bare eye. Sometimes i think people aren't really watching the movie but playing a game called "Spot the artifact", it's their good right.

I have to admit we also play that game from time to time, it's amazing the level of detail (or beter the lack of it) you can see on a plasma display device.

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mrbass

ah crapola..you found me out...hehe. I can't recall a movie I watched where I could sit back and watch it for pure entertainment

Phil Thomas

You are so right ReneB.

I can remember a time, when I used to sit and enjoy the movie
Now .... I dont just "spot the artifact", I criticise the camera work too

Can Dvd20ne do anything about bad cameramen ?

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loggy

<hee>
Guilty as charged--with a 42"/480P plasma to prove it!
D2O is great--and has always been. However, improvements to transcoding (by whatever name) are most welcome--so let me add my thanks.
Will 1.2 be different 'across the board', or will it improve by changing/variable ratios to suit 'action' scenes (or when anticipatory flags dictate)? Just curious...

AndrewL733

This thread is very interesting.

Can you say anything about how the dvd2one approach to reducing the size of a DVD file differs from what some of the other programs do -- for instance, DVD Squeeze, or DVDXCopy, or DVD95Copy? Or are they all the same (those that don't copy to CDs)?

One of the programs, I think it was DVD Squeeze, claimed that it basically compressed the "black space" from letterboxed videos. Sounded suspicious to me.

I'm sure you won't give away any trade secrets, but a little more education would be appreciated.

So far, I'm very impressed with the program.

One suggestion for future versions would be allow batch processing. Although it looks as if I can run multiple instances of dvd2one.

Thanks for making a great program.

Peter McCall

I think I'm going to have to get one of those plasma screens.

Don't see why I shouldn't be unhappy too!

-P

loggy

Trust me...you won't be 'unhappy' (except maybe with the price).
480P on a plasma is the only way to watch a dvd (or a nice D2O-copy!).

Richk50

I spent a fortune on a plasma tv and it has only brought me unhappiness. I bought it because I wanted the best image possible, instead I see imperfections in everything. I can't even look at a vcr image. I know it's sick. Like Rene said we play this game looking for imperfections. How do we stop?

loggy

We can exchange addresses, then I'll trade you an older 27" tv for your troublesome plasma?

ReneB

Donating your plasma to me, and i'll give you my normal tube widescreen sony in return is a good start :P

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dun4cheap

We will call it the Quality Anonymous 5 step program

Step 1:

Limit yourself to only 1 hour a day behind or in front of any type electronics.

Step 2:

Spend 1 hour daily in a room without any electronics or power

Step 3:

Joined with step 1, the hour you spend in front of an electronics item should be spent behind a 13" BW non-digital tuner TV watching snow. (Poltergeist effect)

Step 4:

For every additional hour you spend behind an electronic device you should walk a mile.

Step 5:

Take a cold shower and do it all over in the morning.



Please feel free to add to these steps.