[MPlayer-users] [OT] AC3 vs. DTS

Giacomo Comes comes at naic.edu
Mon Aug 1 17:43:00 CEST 2005

On Fri, Jul 29, 2005 at 05:17:11PM -0400, Rich Felker wrote:
> On Fri, Jul 29, 2005 at 05:37:40PM +0200, Alexander Roalter wrote:
> > Rich Felker wrote:
> > >You already answered the question about what the problem is: 4 stereo
> > >tracks, 1 5.1 ac3 track, and 1 DTS track. Change that to 1 5.1 ac3
> > >track and nothing else and you'll have no problem with space.
> > 
> > That's the deal if you're into the plain vanilla disc thingo, but for me 
> > this simply doesn't do the thing - at least I won't be willing to pay 
> > this amount of money for it.
> How do you call this plain vanilla? No offense, but dubs are pure crap
> and even more of a waste of space than including both DTS and AC3.
> Maybe you mean director's commentary, but that's just a single stereo
> track and can be done at very low bitrate, if you insist.
> > >>2-Disc is no problem with mplayer. Dump the tracks beforehand, cat'em 
> > >>together and you don't have any flicker/click or something else in the 
> > >>transition, especially with part 2 & 3, where the break is not that well 
> > >>placed as in the first part with a fade to black. On the 2nd, you even 
> > >>hear it on the soundtrack, the 2nd disc starts with a sound fading out!
> > >>
> > >>All you need is ~20 GB of free space, and you can watch the movie in one 
> > >>rush.
> > >
> > >
> > >ROTFL! I'm supposed to dump 20 gigs to hdd every time I want to watch
> > >a movie? This is the most ridiculous suggestion I've seen on this list
> > >in a long time..
> > 
> > Everyone caring for some showmanship who presents a movie to an audience 
> > would easily use such measures. In theatres movies nowadays are also put 
> We're not talking about a theater here, but sitting down to watch a
> movie with your friends in your home. Do you really want to spend an
> hour copying the movie to hdd after everyone picks which title they
> want to watch? By that time everyone will be bored and gone home, or
> too drunk to care about a movie... ;)
> > >There's already a proper solution. It's called ripping the whole thing
> > >to a 1.4gig mpeg4 file, at same or better quality than the original
> > >dvd. However the point is that DVDs are stupidly mastered, and that
> > >still stands.
> > 
> > Now how would you get a better quality in a mpeg4-file with data from 
> > original dvds?
> By fixing the errors in the encode, like blocking, noise, hard
> telecine, ... The mpeg2 encoding on DVDs is atrociously bad, and it
> requires heavy processing that's not really feasible in realtime to
> fix it.
> > For the future I'm still waiting for the next big thing, since I'm not 
> > that happy with the heavily protected new HD formats. I still want to be 
> Heavily protected? Any cryptography where the attacker has the key is
> not heavily protected, it's just basic obscuring/obfuscation and will
> be cracked in no time, just like CSS.

That's completly false. You are talking only about weak encription 
algorithms like CSS. CSS was a "secret" algorithm. Once people understood
how it was working (knowing some keys) they found how weak it was 
and how to guess the keys analizing the encrypted data (what libdvdcss does).

Good strong encryption algorithm are the ones that although the algorithm 
is already known, the only way to decrypt the data is having the key.
For these kind of algorithms there is no known attack, and brute
force attack would requires many months or years to find the key.

Some examples of such algorithms? All the ones used by ssh
(AES, Blowfish, 3DES, CAST128, Arcfour) and many others.

Of course no algorithm is 100% safe. Tomorrow an attack can be
discovered that can be used to defeat an algorithm considered safe
today, but the strong encryption algorithm are the ones for which
such attacks are unlikely to be found soon.


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