Is it Lossless?

[rajking86]

I have an AVI file on my PC. When I burn it to DVD does it lose a small percentage of quality? Or become better, or same?
Basically,I need to know if DVD Authoring is a lossless process.

[tim6661234]

Well as a rule it won't make it better unless you put some filters on it when you convert it to DVD MPEG-2. You Will generally lose quality when encoding, just the way it is.

I've got to say I've never noticed much loss but it depends on your settings.

[rajking86]

Really? So why when old movies such as Scarface are suddenly digitally remastered and look amazing on DVD?

Wouldn't a DVD version of the same file look the same or at least not better? Argh

[yoda313]

Hello,
Studios use the original MASTERS. They also have HUGE budgets to remaster classics. Don't forget, we're using small files by comparison. Also, how do you know your avi file is EXACTLY the same as the dvd?

We can make things look good. Studios have the resources to make them look great.
Kevin

[rajking86]

What do you mean, "how do I know if my AVI file is the same as my DVD?"

[yoda313]

Hello,
What I'm getting at is that you can't make a source look better (unless you use filters as noted earlier) just by putting it in dvd format. The studios use special processes to enhance older films.

When you turn one file into another format it doesn't automatically make it better.
Kevin

[junkmalle]

Really? So why when old movies such as Scarface are suddenly digitally remastered and look amazing on DVD?

Because they are remastered from the original film which is much higher resolution than DVD.

In general, every time you go through a decode/encode cycle with any lossy codec like MPEG you will lose quality.

DVD authoring is definitely not a lossless process.

[yoda313]

Hello,

junkmalle-Because they are remastered from the original film which is much higher resolution than DVD

Thanks for agreeing with me. I said something just like that earlier. The master of the film is WAY better than anything we have access to.
Kevin

P.S. If rajking86 wants to play the avi at original quality without converting just buy a dvd player that plays divx files (or ones that play .mpg files). That way you just burn it to a disc {without authoring- drag and drop it} and play it exactly as it is on the computer.

[junkmalle]

Hello,

junkmalle-Because they are remastered from the original film which is much higher resolution than DVD

Thanks for agreeing with me. I said something just like that earlier. The master of the film is WAY better than anything we have access to.
Kevin

Yes, you said "Studios use the original MASTERS." I just wanted to make sure he understood that meant film.

[gshelley61]

Plus, the studios digitally sample each frame of film at very high resolution, "clean" and enhance the high res digital video frame by frame, then use very sophisticated and expensive encoders to create DVD compliant MPEG2. The process can cost hundreds of thousands of dollars.

[rajking86]

Ah...I see. Thanks Yoda, and everyone else.

So in conclusion, you will lose a slight percentage of your original quality because it has to compress the AVI to Mpeg2 (DVD format) ?

[junkmalle]

So in conclusion, you will lose a slight percentage of your original quality because it has to compress the AVI to Mpeg2 (DVD format) ?

MPEG lets you specify how much compression you want to use. The more you compress the more quality you lose. The loss could be anywhere from imperceptable to huge depending on your source (some things don't compress as well as others) and how much you compress it.

[ZippyP.]

DVD authoring is definitely not a lossless process.

For the record...Authoring is completely lossless. You are merely taking the mpeg and creating the dvd structure, no conversion is taking place.

Re-encoding or conversion (eg avi to dvd) is not lossless, but it can be pretty close if it's done right with a good encoder.

[rajking86]

For the record...Authoring is completely lossless. You are merely taking the mpeg and creating the dvd structure, no conversion is taking place.

Re-encoding or conversion (eg avi to dvd) is not lossless, but it can be pretty close if it's done right with a good encoder.

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ok you said, taking the mpeg straight to dvd is lossless, in my case it's an AVI so is it encoding it into an mpeg 2, so it can be played on DVD and in the process losing some small percentage of quality?

[yoda313]

Hello,

rajking86-taking the mpeg straight to dvd is lossless, in my case it's an AVI so is it encoding it into an mpeg 2, so it can be played on DVD and in the process losing some small percentage of quality?

YES! You're finally starting to get the hang of this
Kevin

[indolikaa]

I could be wrong on this one, but the best way to insure the least amount of loss during compression to the MPEG format is to use the highest bitrate possible with an 'I-Frame Only' setting?

I-Frames take their data from the source frame, but P and B frames don't. So if you are only recording I-Frames, you are encoding based on a snapshot of each individual frame from the source, not the xth frame down the line...

[petar]

I could be wrong on this one, but the best way to insure the least amount of loss during compression to the MPEG format is to use the highest bitrate possible with an 'I-Frame Only' setting?

Well, in theory - yes, but you have a limited bitrate. An I-frame only MPEG stream will require hell of a lot of bitrate to achieve a decent quality (above the DVD limits in most cases but depends on the complexity of the video too).

rajking86,
Don't be too worried about the fact that MPEG compression is a lossy one. Analog to digital conversion is always lossy to start with, whether it's video or audio. Facts of physics. But what's lost is normally stuff you don't see/hear because human eyes/ears (and mind) are not perfect. You need a good encoder, learn how to get the best of its settings for a given video, learn maybe how to apply some filters and you'll get good MPEG streams.