[Theora] OGG/OGM media container

Nilesh Bansal bansal
Tue Jul 6 18:42:08 PDT 2004

Hi all,

First of all, Thanks everybody for replying(on theora mailing list) to my
earlier questions.

Here is what I understood, and I have some doubts, so please read on and
correct if anything is wrong.

Ogg is a container format, which is designed to wrap any kind of
video/audio. But, presently because of lack of developers, oggmerge
supports only MNG video(not even theora) with vorbis audio. But, specs of
Ogg are final and usable but it requires some developer to code that in C?

xiph supports ogg, but since there is no good tool to create oggs, many
people are using ogm.

Matroska, has a different philosophy (and will coexist with ogg). But I
wasn't able to understand what they mean by "High error recovery".

Suppose while downloading a file, after half the download connection
closes. I was easily able to play ogm, but with mkv i had to provide -idx
switch to mplayer to make it seekable (so ogm is better than mkv in that
sense). Simmiliarly what if while downloading file gets corrupt? I expect
mplayer to skip corrupt frames and continue playing.

Also, someone said mencoder can produce mkv files but I wasn't able to
find a option (I installed mkvtoolsnix and recompiled mplayer, but
mencoder -of help lists mpeg, avi and rawvideo only). No support for
encoding to Ogg(audio only) either (I don't know if oggenc provides a
library or not that mencoder can link to).

PS: xiph CVS is not working, it says connection refused everythime i try
to connect.

Nilesh Bansal

On Tue, 6 Jul 2004, Nilesh Bansal wrote:

> Hi all,
> Xiph aims at developing open-standards media formats. Though xiph.org tells
> about vorbis/theora/flac/speex, nothing is mentioned about container to use
> (that is ogg/ogm). I have a few questions
> Is there a difference between ogg and ogm? I guess its only the extension
> that is different and everything else is same.
> Some tools (like ogmtools) are available to create ogm files. What is state
> of that code? It it stable? Is it advisable to start convering my AVIs to
> OGMs? ogm specs are final or they will probably change and are not yet final?
> If answer to previous question is yes, why mencoder don't produce ogm? Why
> people are still sticking to AVI? Is it just lack of time/energy of
> developers or something more technical?
> What are main advantages/disadvantages of matroska(http://matroska.org/) over
> ogg/ogm? Why 2 different projects? Why not ditch one and concentrate on one?
> Why www.xiph.org don't provide any info about ogm? I was not able to find
> specs. Also, xiph.org doesn't link to any of ogmtools site.
> PS: I have recently joined xiph team as webmaster of xiph.org, and if I get
> answers to above questions I can create a page of ogg/ogm at xiph.org with
> details about same.
> Nilesh Bansal
> http://www.cse.iitb.ac.in/nilesh/
> _______________________________________________
> Theora mailing list
> Theora at xiph.org
> http://lists.xiph.org/mailman/listinfo/theora

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