How does compressing a DVD movie effect audio?

[jlove]

Hi everyone. I'm about to back up a DVD video concert and I am wondering what to make of the Roxio estimate that compressing from a double layer disk to a single will have "excellent" results. I don't care if my backup copy has a slightly compromised video, but since it is a concert, I'd want the audio to be as good as the original (with multichannel sound, etc). I can use a double layer disk and get a closer to perfect backup, but as these disks are still much more expensive than single layer, I would prefer to use the cheaper alternative.

 

And behind this question is one of quite genuine intellectual interest--I am clueless about the compression algorithms that software like Roxio uses, so it would be nice to know some approximation of what it does.

 

As always, thanks in advance for any advice proffered.

 

-- jlove

[jlove]

I would think that compressing a DL DVD to a standard DVD will result in loss of both video and audio quality. Why don't you simple simply split the DL DVD video and create 2 standard DVDs?

 

As to the compression algorithms that Roxio uses, I don't think anybody here can really give much of an answer. You would have to ask Roxio directly

 

Well, I will continue to show my novice stripes here--can you give me some guidance on how to split the DVD into two standard DVDs? This would be pretty nice to know for many other projects...

 

Regarding the compression, the reason I asked is that I imagine that the audio portion (even with 5.1, etc) takes up much less space than video, so I thought it was at least possible that the compression algorithm would concentrate on the video aspect and leave the audio intact.

 

Thanks for taking the time...

 

-- Jack

 

You can get get Verbatim DL's for about $1.80 each (better if you buy more and look around each week for sales). To me, the extra quality of a concert is worth the $1 or so more to put it on a DL disc.

My opinion is that EMC9 Disc Copier does a pretty good job of compressing at the best quality possible and I've never viewed a bad disc that was listed as 'Excellent' but when going from 8.5 gb to 4.3, I'm surprised it's still listed as Excellent.

 

Well, I haven't paid more than about a buck for my DL disks in quite a while <grin>. You're quite right that this is a small price to pay for the quality, but it's nice that Roxio offers the compression option as well, and as you say, for many things it seems to work very well.

 

The compression algorithm interests me because sometimes it reports that a title will be "very highly compressed" when it has just 5G data, other times the full 8G says "excellent", so it just makes me wonder what makes the difference.

 

-- Jack

[sknis]

Well, I will continue to show my novice stripes here--can you give me some guidance on how to split the DVD into two standard DVDs? This would be pretty nice to know for many other projects...

 

Regarding the compression, the reason I asked is that I imagine that the audio portion (even with 5.1, etc) takes up much less space than video, so I thought it was at least possible that the compression algorithm would concentrate on the video aspect and leave the audio intact.

 

Thanks for taking the time...

 

-- Jack

 

Well, I haven't paid more than about a buck for my DL disks in quite a while <grin>. You're quite right that this is a small price to pay for the quality, but it's nice that Roxio offers the compression option as well, and as you say, for many things it seems to work very well.

 

The compression algorithm interests me because sometimes it reports that a title will be "very highly compressed" when it has just 5G data, other times the full 8G says "excellent", so it just makes me wonder what makes the difference.

 

-- Jack

 

Time (length of the production), not file size is the controlling factor. One hour of best quality video on a single sided disc; almost two hours with compression.

[bimicher]

Hi everyone. I'm about to back up a DVD video concert and I am wondering what to make of the Roxio estimate that compressing from a double layer disk to a single will have "excellent" results. I don't care if my backup copy has a slightly compromised video, but since it is a concert, I'd want the audio to be as good as the original (with multichannel sound, etc). I can use a double layer disk and get a closer to perfect backup, but as these disks are still much more expensive than single layer, I would prefer to use the cheaper alternative.

 

And behind this question is one of quite genuine intellectual interest--I am clueless about the compression algorithms that software like Roxio uses, so it would be nice to know some approximation of what it does.

 

As always, thanks in advance for any advice proffered.

 

-- jlove

 

I would think that compressing a DL DVD to a standard DVD will result in loss of both video and audio quality. Why don't you simple simply split the DL DVD video and create 2 standard DVDs?

 

As to the compression algorithms that Roxio uses, I don't think anybody here can really give much of an answer. You would have to ask Roxio directly

[Beerman]

You can get get Verbatim DL's for about $1.80 each (better if you buy more and look around each week for sales). To me, the extra quality of a concert is worth the $1 or so more to put it on a DL disc.

My opinion is that EMC9 Disc Copier does a pretty good job of compressing at the best quality possible and I've never viewed a bad disc that was listed as 'Excellent' but when going from 8.5 gb to 4.3, I'm surprised it's still listed as Excellent.