View Full Version : Compression techniques.


Kevin Kimmell
December 15th, 2004, 02:45 PM
I've been shooting a lot of live music footage and in the past our releases were 2 or 3 DVDs each. I've been watching a lot of other band's video archive stuff and I've seen 3 hour shows on a single DVD with excellent sound and video qulity on a single layer DVD.

Is there some trick to this? Is it possible that they're using specialized hardware or software that makes more than the 2-pass technique that I usually see as an option?

Thanks,
Kevin

Gary Kleiner
December 15th, 2004, 03:53 PM
>I've seen 3 hour shows on a single DVD with excellent sound and video qulity on a single layer DVD.<

Let me know when you find out how to do this.

Gary

Kevin Kimmell
December 15th, 2004, 04:06 PM
Is that sarcasm or general interest?

:)

The stuff that I've seen is from the Grateful Dead so I'm sure they've got resources if there is specialized equipment that can do multiple passes to get things compressed well.

What really gets me is that the shows are sometimes mostly dark with a light show and movment so with a lot of compression I'd expect to see all sorts of artifacts but that's not the case.

Rob Lohman
December 16th, 2004, 03:28 AM
With a good encoder (TMPGEnc/CCE/Canopus) with VBR and 9
passes such a thing is certainly possible depending on the type
of footage.

However, it also highly depends on the equipment you are using
to watch it on and how you look at things. What you might find
perfect someone else might find bad (no offense) quality wise.

How do you know there is 3 hours on there? Have you timed this?
How do you know the disc isn't two layers?

Do you know if the footage is 24p? Anamorphic 16:9? Letterboxed?

For example. 24p gives you 20% extra space on a disc which can
give you 24 extra minutes if you can succesfully put 2 hours of
30p material on a disc (just to give you an idea).

Kevin Kimmell
December 16th, 2004, 10:28 AM
Well I know that it's almost three hours because I've watched it. It's a full Dead Show - 2 sets. The running time is 168 minutes.

I ASSUME it's single layer becasue the first one I saw was an illegally copied version of it. My first inclination was to ask if it was compressed when the guy copied it but he didn't know. He says that he used DVD shrink. This made me watch it even more closely for choppiness and artifacting.

It was standard 4:3 but I'm not sure about frames. Since then I've bought a couple of them so I'll see what I can find out when I get home tonight.

Lars Siden
December 16th, 2004, 12:14 PM
Hi,

DVDShrink - recompresses whatever input to fit onto a 4.7gb disc. We'rnt supposed to speak about illegal things here, but please have a look at:

http://www.dvdshrink.info

// Lazze

Kevin Kimmell
December 16th, 2004, 12:32 PM
I know that it "does" this to make stuff fit and I know it's illegal. I'm certainly not condoning it's use and reprimanded the person in question. Having said that, I should say that knowing that it was illegal didn't stop me from learning from what I saw.

And what I saw was a single layer DVD of 2 3/4 hours length with varying light and motion settings that looked very impressive.

Now that I have legitimate DVDs that are similar by the same production company, I'm not exactly sure how to find out if the original is dual-layer.

Will the disc check type utilities with Nero tell me that sort of info?

Rob Lohman
December 21st, 2004, 05:09 AM
If you have a DVD player in your computer it is very easy. Insert
the disc and cancel anything that it starts. Open "my computer"
and right-click on the disc and choose properties. You should
see some numbers and a pie diagram. Look at the number after
"used space". If it is over 4.70 GB it is a dual-layer disc, otherwise
it is not.

Another way is to righ-click on the drive and choose "open" (so
no software starts) and then navigate to the VIDEO_TS folder.
You can see what the total is by looking at the information bar
underneath the window.

Edward Troxel
December 21st, 2004, 09:00 AM
NOTE: A 4.7 Gig DVD can only hold 4.3 Gig of data! If it's over 4.3 Gig (actually 4.37) then it would require dual layer.

Rob Lohman
December 21st, 2004, 09:13 AM
Edward: are you sure? I'm pretty sure I've at least gotten 4.4 GB
on a disc once and perhaps even 4.5.

However, I was talking about commercially pressed discs which
should be able to hold 4.7 GB (I have a single layer (pressed) disc
here where explorer says 4.60 GB).

So it would at least be interesting to see if this would be a pressed
disc or a burned one... Kevin?

Kevin Kimmell
December 21st, 2004, 09:16 AM
I'll have to check it when I get home. Actually I'm stopping in at lunch so I'll see what the size of the disc in question is.

Edward Troxel
December 21st, 2004, 10:12 AM
Rob, I'm sure commercial discs are different. As for DVD-R (+R), the boxes say 4.7Gig but that's "base 10" gig. Translate that to computers and you only have 4.37 Gig of space.

Kevin Kimmell
December 22nd, 2004, 07:48 PM
I'm looking at the properties of the disc now and it's reporting 6.87 Gigs of space. So since it is dual layer I guess I have to assume that they probably didn't use some super duper multi-pass method to compress it down.

I'm still puzzled then by how well DVDShrink did on it. As you can imagine, a live show has lots of things that are generally bad for compression but I watched that video that was made illegally and it looked very good.

So back to Rob Lohman's original response:

"With a good encoder (TMPGEnc/CCE/Canopus) with VBR and 9 passes such a thing is certainly possible depending on the type of footage."

Is this part of the normal (Vegas) packages or is this an encoder that I must purchase separately?

Where would I find the best MPEG encoder for the dollar as far as this type of compression goes? Is TMPGEnc the only option?

Thanks,
Kevin

Rob Lohman
December 23rd, 2004, 05:01 AM
The best encoder is one we cannot afford, but the list for kind
affordable encoders goes like this at the moment:

1. Canopus ProCoder (www.canopus.com) (medium price)

2. Cinema Craft Encoder (CCE) (www.cinemacraft.com) (high price)

3. TMPGEnc (www.tmpgenc.net) (low price / free)

MPEG encoding is an artform that requires a good encoders, patience
and some skill/experience. However, with these encoders you
should be able to get very good results (and yes, 9 pass VBR
encoding might sound over the top, but it really works, at least
in TMPGEnc).

Since it is dual-layer I would guess they still used a multi-pass
VBR encoding, that's what most people who profesionally encode
discs do.

For guides on TMPGEnc see the following threads:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=35635
http://www.dvinfo.net/conf/showthread.php?s=&threadid=35781

There are guides on CCE and probably ProCoder as well, two
sites (which these links came from as well) to look at are:

www.doom9.org (see the guides menu on the left)
www.vcdhelp.com

Kevin Kimmell
December 23rd, 2004, 08:01 AM
Thanks for all of the info Rob. Have you used more than one of the listed examples? Can you tell the difference?

Rob Lohman
December 29th, 2004, 04:36 AM
I have tried all of them out at one point and I could see the difference
depending on the type of footage, however I didn't play enough
with ProCoder. I know (from other people) that ProCoder has
the best (cheap) encoder currently available. That comes from
peope I trust. Anyway, all three encoders are top notch and
certainly better than the encoders bundled with at least Sony
Vegas & Adobe Premiere.

Nate Cannon
January 11th, 2005, 02:45 PM
<<<-- Originally posted by Rob Lohman : I have tried all of them out at one point and I could see the difference
depending on the type of footage, however I didn't play enough
with ProCoder. I know (from other people) that ProCoder has
the best (cheap) encoder currently available. That comes from
peope I trust. Anyway, all three encoders are top notch and
certainly better than the encoders bundled with at least Sony
Vegas & Adobe Premiere. -->>>

I currently have Vegas 5 and am considering purchasing ProCoder.

I'm assuming that I render my DV project to AVI (DV Setting) and then import the result file into ProCoder. Is this correct?

Thanks inadvance.

Kevin Kimmell
January 12th, 2005, 01:09 PM
Good question.... Rob?

Dan Euritt
January 12th, 2005, 10:53 PM
you can frame serve off of the vegas timeline to procoder, using a freebie tool written by a guy named satish.

i believe that vegas uses the mainconcept mpeg encoder, which does a pretty good job... don't run out to spend big $$$ on procoder without demo'ing the differences between the two first.

procoder is more efficient, but it typically gives a softer picture than the mainconcept encoder... that said, i've run 'em both extensively, and procoder works better for the type of footage i work with... ymmv.

Rob Lohman
January 18th, 2005, 05:51 AM
I would try it in the following order:

1. frameserve (see post above and my comments below)

2. uncompressed AVI

3. DV AVI

Satish has a frameserver that was mentioned in a sticky post
on top of this Vegas forum:

http://www.dvinfo.net/conf/showthread.php?s=&threadid=30426

The link to Satish's site is: http://www.debugmode.com/

Get the frameserver there. Frameserving is the technique that
allows you to transfer footage from one application to another
without storing it on the harddisk (and thus saving [lots of] space).