Are commercial DVD's VBR or CBR

[trinidav]

Are commercial DVDs usually encoded with a constant or variable bit rate?

[jel]

hi trinidav and welcome to the forum.

i split yoiur question from the sticky you originally posted to as i feel it did not belong there.

in answer to your question, i have seen both ;)

most (if not all) main movie and extra features are encoded using VBR, however some menus/stills etc are encoded using CBR.

hth
j

[manono]

Hi-

most (if not all) main movie and extra features are encoded using VBR...

Hehe, you just haven't seen enough lousy DVDs. I see CBR encoded main movies all the time. I assume he's talking only about the video, and not the audio, which is always CBR, isn't it?

Here are some examples (check the Bit Rate Viewer graphs):

http://www.dvdbeaver.com/film/DVDCompare10/impact_.htm
http://www.dvdbeaver.com/film/DVDReviews15/tokyo_twilight.htm
http://www.dvdbeaver.com/film/DVDCompare5/pyaasa.htm

[MrTroy]

Hehe, you just haven't seen enough lousy DVDs.Just wanted to note that a DVD doesn't have to be lousy if it uses CBR. If it contains a short movie (an hour or less), CBR might work just as good - if not better - than VBR.

[Audionut]

Star trek 2 the wrath of khan PAL version.

8.5 mbps CBR.

Looks great.

[manono]

Hi-

Just wanted to note that a DVD doesn't have to be lousy if it uses CBR.

Yes, if, as Audionut implies, the bitrate is high enough, not the case with any of the 3 examples I gave. Except maybe the Ozu film, but only because nothing ever happens in an Ozu film. That is, he doesn't usually have much for complex scenes except for a few outdoors scenes with tree leaves waving around. But I could give examples of other Ozu films done by the same company where the bitrate is much lower, as often DVD5s are used.

http://www.dvdbeaver.com/film/DVDReviews11/Equinox%20Flower%20.htm

However, when you see CBR encoding, there are often other things wrong with the DVD, such as interlaced encoding of Film (NTSC), or the Standard Matrix being used, because, I think, of cheap, obsolete encoders being used, or incompetent encoding practices being employed.

[Audionut]

the Standard Matrix being used..... cheap, obsolete encoders being used, or incompetent encoding practices being employed.


:( It's a right royal pain in the a**, spending $30 Aus on a dvd that has had the above applied to it.

It astounds me how many dual layer dvd's there are out there with only 5-6gb on them.
They should either compress more and save money by using dvd5 discs, or better, increase bitrate and fill the dvd9 discs.

[Awatef]

My encoding tests showed that encoding in CBR mode always leads to macroblocking in flashing scenes, even at very high bitrates beyond 8 Mbps.
So I would qualify CBR DVDs to be lousy too, like manono :D

No serious company would encode a DVD in CBR mode.
But I saw (too) many DVDs encoded in 1-pass VBR mode, which is quite crappy too.