Why use Ogg Vorbis ?

[CzechRipper]

Why should I use Ogg Vorbis rather than MP3 or AC3 ? How is it better ?

[theReal]

Ogg is a container format for video and audio, just like avi.

Obviously it's better than avi for some reasons (less overhead, more possibilities for adding multiple soundtracks), but it is still not a well known standard like avi.

Vorbis audio sounds better than mp3 or AC3 at low bitrates (~ 64-96kbit).

However, the original AC3 sounds best, so I use it whenever I can (I have to admit I never use ogg)

[CzechRipper]

What's overhead, I never undestood that overhead stuff even with AVI ?

What you mean when you say :more possibilities for adding multiple soundtracks ?

And when you say :Vorbis audio sounds better than mp3 or AC3 at low bitrates , do you mean that Vorbis audio gives beter quality than MP3 at 96 kbps ?

[theReal]

I'm not at all an expert for ogg and vorbis, but avi files can only have two soundtracks (and even that is, I think, a little out of specifications). So you can add i.e. a Czech and English soundtrack to an avi file, but then you can't add the director's comments as well (whoever wants to do that...).

Many people say that vorbis at 96kbit has the same quality than mp3 at 128kbit. Just like with Realaudio, a vorbis stereo file, 44.1kHz at 64kbit still sounds ok, while you can forget that bitrate for stereo mp3.

I really don't know more about it because I never use ogg and vorbis (I like to stick to the more common formats, at least in the near future)

[ookzDVD]

@CzechRipper,

Sure, I use the vorbis for all my DVD->1CD rip, the 64 kbps is
small and good quality, for 2 hours movie the filesize is just
about 60 + 4(overhead)=64mb, so my video size is 700-64=636mb.

Thank you.

[CzechRipper]

Originally posted by ookzDVD
@CzechRipper,

Sure, I use the vorbis for all my DVD->1CD rip, the 64 kbps is
small and good quality, for 2 hours movie the filesize is just
about 60 + 4(overhead)=64mb, so my video size is 700-64=636mb.

Thank you.

TY

Sounds great, but can some1 explain me that overhead thing ? What is it ???

[theReal]

If you add vbr-mp3 to an avi file of 120 minutes, you lose about 11MB just for combining audio and video. With AC3 and avi, it's about 8MB for 120 minutes. This is the overhead.

And like ookzDVD said with ogg vorbis it's only about 4MB for 120 minutes.

[ookzDVD]

@CzechRipper,

..about overhead...
when you mux the video (avi soundless) + vorbis the total bytes
is not just like the exact video size + audio size, but there is
should be a certain bytes overhead to be added.
let's say if your video is 100mb and your audio is 10mb,
the final movie us not 100+10=110mb but should be like 110+x
the x value for 1CD rip as far as my experience is about 4-5mb.

sorry..it's not from theorytical point of view ;)

I hope it might help you.

[MvB]

Originally posted by theReal
I'm not at all an expert for ogg and vorbis, but avi files can only have two soundtracks (and even that is, I think, a little out of specifications). So you can add i.e. a Czech and English soundtrack to an avi file, but then you can't add the director's comments as well (whoever wants to do that...).


Sorry, i've produced avis with more than two audio stream (3 and 4). It's no problem. As i've heard, it's no problem to have even more than one videostream, too.

MvB

[iago]

@ookzDVD

the x [overhead] value for 1CD rip as far as my experience is about 4-5mb. So far, my experience has been even lower than that (for ~ 120-140 min movies/using OggMux): I always set the overhead value for ogg as 2.5 mb maximum, and I haven't got any (oversize) problems with that value yet ;).

regards,
iago

[[Toff]]

The overhead is how much data are dedicated to the container to store you movie.
In AVI you need to know that 1st stream is video, 2nd stream is audio, the codec used for them. You have an index of all key frame so you can seek quicker in your file...
All data that are not "essential".

The ogg format is more space efficient and mcf format is even better.
You can get more details on the mcf page :
http://mcf.sourceforge.net/

[Rash]

Just a question here. Then when you do DivX+Ogg (OGM) you aim 696Mbs on GKnot and "No Audio" in the AVI&Overhead options?

Because I've made an OGM file and it turned out too big to fit a 700Mbs CD (by very little - like 2-3Mbs).

Thanks

[JohnMK]

Correct. Aim for 695MB, since it's just in the drop down list (so easy) and gives you more safety room.

[Crawler]

I found that using 1xac3 audio overhead setting gives results that are very close to muxing one or two vorbis streams into an ogm container, so if you select this you should be able to hit your overall target size.

[Rash]

Thank you guys! ;)

Testing it tonight.