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/
----- Original Message ----- From: "Nilesh Bansal" <bansal@cs.ubc.ca> To: <advocacy@xiph.org>; <theora@xiph.org> Sent: Tuesday, July 06, 2004 5:43 PM Subject: [Theora] OGG/OGM media container> 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. >My understanding is, that the file format is exactly the same, the main difference is the first header in each stream... ogm uses several standardised header formats, audio, video and text, in order to make identifying unknown codecs easier in directshow (and subsequently other frameworks). ie with those three headers you can use any audio or video format you choose without have to write custom header parsing routines for each codec in the demuxer. In other words, so long as the decoder is present on the system, you can play the file and the demuxer be completely oblivious to how the that codecs header is actually structured... this essentially means that the encoders/muxers know how to parse the codec headeer to create an ogm header, but the demuxer doesn't need to know how to do this. It's a matter of preference... i actually think it's a good idea, but others disagree, and will say that limits the flexibility of ogg etc... but my opinion has always been use the standard headers when it makes sense to use the standard ones and use the generic xiph-like unstructured headers when a standard heaerr would be restrictive. This is actually how my directshow demuxer works... if it sees an ogm video header, it sets up a pin and connects to ffdshow without caring if its divx or whatever inside. When it doesn't see an ogm header it tries to identify it as a known xiph header, if it is, then it parses the header.> 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? >OGM headers aren't "officially supported" by xiph. The best way to think of ogm is as a codec wrapper, to shield the demuxer from the imlpementation details of the codec headers. Kind of what an api does... it distills the possible 10's of header fields down to the 3 or 4 that the demuxer actualy cares about.> 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? >Matroska is a different project group... i think they represent two different philosophies... matroska is more a kitchen sink format, whereas ogg is an absolute bare bones format. Which you think is better really depends on what your opinion of how generic is too generic and how specific is too specific.> 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. >Because they don't support it. Zen.
<00ff01c46343$827aa190$0100000a@tiger> Message-ID: <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca>>> Is there a difference between ogg and ogm? I guess its only the extension >> that is different and everything else is same. >> > > My understanding is, that the file format is exactly the same, the main > difference is the first header in each stream... ogm uses several > standardised header formats, audio, video and text, in order to make > identifying unknown codecs easier in directshow (and subsequently other > frameworks). ie with those three headers you can use any audio or video > format you choose without have to write custom header parsing routines for > each codec in the demuxer.So this means ogg/ogm are actually same but ogm uses some standard headers while ogg does not put any such restrictions. That is ogm is a ogg, but not vice-versa. And saying ogg - extension for for audio only files ogm - extension for audio + video files is _wrong_, as the 2 extensions are not just conventions but also differ technically (though they are more-or-less similar).> OGM headers aren't "officially supported" by xiph. The best way to think of > ogm is as a codec wrapper, to shield the demuxer from the imlpementation > details of the codec headers. Kind of what an api does... it distills theSo xiph "officialy support" ogg and not ogm. But i am not able to find any tool to create ogg files. www.xiph.org provide no information about OGG either. Also, what is status of OGM? Is that stable and usable? If yes why mencoder etc, dont provide a option to produce a OGM instead of AVI.> > Matroska is a different project group... i think they represent two > different philosophies... matroska is more a kitchen sink format, whereas > ogg is an absolute bare bones format. Which you think is better reallyCan you please explain. Nilesh Bansal.
<00ff01c46343$827aa190$0100000a@tiger> <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca> Message-ID: <20040706120202.GC1234@ghostscript.com> On Tue, Jul 06, 2004 at 03:51:17AM -0700, Nilesh Bansal wrote:> So this means ogg/ogm are actually same but ogm uses some standard headers > while ogg does not put any such restrictions. That is ogm is a ogg, but > not vice-versa.Correct. I would also say that the ogmtools provides the standard du jeur for encapsulating various common-in-avi codecs in an Ogg bitstream, like 'divx', 'mp3' and so on. As far as I know, the ogmtools source is the best documentation available for those encapsulations> And saying > ogg - extension for for audio only files > ogm - extension for audio + video files > is _wrong_, as the 2 extensions are not just conventions but also differ > technically (though they are more-or-less similar).Yes, this is very wrong. I suppose the ogm extension just implies the presence of the AVI stream headers in the logical bitstreams.> So xiph "officialy support" ogg and not ogm. But i am not able to find any > tool to create ogg files. www.xiph.org provide no information about > OGG > either.Ogg is documented at http://xiph.org/ogg/doc/ (which looks like it needs some webmaster help) The main documents are in http://svn.xiph.org/trunk/ogg/doc and the Ogg format (aside from some of the multiplexing details) are also documented in RFC 3533.> Also, what is status of OGM? Is that stable and usable? If yes why > mencoder etc, dont provide a option to produce a OGM instead of AVI.I understand it's in wide use by the anime fansub community. We officially and actively don't recommend it, both because it doesn't match our technical philosophy for Ogg, and because our whole raison d'etre is to provide free alternatives to mp3 and divx. So please don't encourage people to add support. :)> >Matroska is a different project group... i think they represent two > >different philosophies... matroska is more a kitchen sink format, whereas > >ogg is an absolute bare bones format. Which you think is better reallyI think that's a nice way of saying that the the matroska folks didn't like (or didn't understand) what we were trying to do with the ogg design. I believe their idea was to make a hierarchically searchable file format with the idea that that would work better than ogg for editing. Ogg is designed as a streaming format only, although one could easily build an editing system on top of it. -r
<00ff01c46343$827aa190$0100000a@tiger> <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca> <20040706120202.GC1234@ghostscript.com> Message-ID: <1235311184.20040706144046@guest.arnes.si> On Tuesday, July 6, 2004, 14:02:02, Ralph Giles wrote:> I understand it's in wide use by the anime fansub community.Make that "was in use by anime DVD rip groups" (I only know of 1 fansub that used Ogm). However, most groups that used Ogm switched to Matroska (and I've seen a few fansubs that used it, though most fansub groups still stick to AVI), as it's current implementations offer more features with less problems for the user. -- < Jernej Simoncic ><><><><>< http://deepthought.ena.si/ > < for personal mail, replace guest.arnes.si with isg.si > The more you run over a dead cat, the flatter it gets. -- The "Enough Already" Law
<00ff01c46343$827aa190$0100000a@tiger> <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca> <20040706120202.GC1234@ghostscript.com> <1235311184.20040706144046@guest.arnes.si> Message-ID: <20040706125448.GA5365@ghostscript.com> On Tue, Jul 06, 2004 at 02:40:46PM +0200, Jernej Simon?i? wrote:> Make that "was in use by anime DVD rip groups" (I only know of 1 fansub that > used Ogm). However, most groups that used Ogm switched to Matroska (and I've > seen a few fansubs that used it, though most fansub groups still stick to > AVI), as it's current implementations offer more features with less problems > for the user.Good to know. My impression was that ogm was only popular because it's what the best free subtitling app happened to produce. Is that what happened with the switch? -r
=?iso-8859-1?q?(message_from_Jernej_Simon=E8i=E8_on_Tue, _6_Jul_2004_14:?= =?iso-8859-1?q?40:46_+0200)?References: <Pine.LNX.4.60.0407060224570.14419@albani.cs.ubc.ca> <00ff01c46343$827aa190$0100000a@tiger> <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca> <20040706120202.GC1234@ghostscript.com> <1235311184.20040706144046@guest.arnes.si> Message-ID: <87y8lxur69.fsf@snail.Pool>>>>>> "Jernej" == Jernej Simon?i? <jernej.simoncic@guest.arnes.si> writes:> Make that "was in use by anime DVD rip groups" (I only know of 1 > fansub that used Ogm). However, most groups that used Ogm switched to > Matroska (and I've seen a few fansubs that used it, though most fansub > groups still stick to AVI), as it's current implementations offer more > features with less problems for the user.Just yesterday I incidentally ran into a copy of "Zatoichi" encoded into a .ogm. Japanese Vorbis audio, DivX video and an english ascii subtitle stream. Nothing like this is possible with .avi. Matroska's advantage will be better seeking, as .ogm's don't have an index and require binary search for getting seeking done right. Apparently that's too difficult for many movie-players (or coders...). Mplayers ogg-demuxer still doesn't seek well in .ogm streams :(. What I'd like to mention here: not having a simple ascii subtitle format specified for ogg-theora is really a pitty. David -- GnuPG public key: http://user.cs.tu-berlin.de/~dvdkhlng/dk.gpg Fingerprint: B17A DC95 D293 657B 4205 D016 7DEF 5323 C174 7D40
On Tue, 6 Jul 2004 02:43:41 -0700 (PDT) Nilesh Bansal <bansal@cs.ubc.ca> wrote:> 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?Same reason there is Linux, FreeBSD, NetBSD, OpenBSD, and more. Why don't they all just concentrate on one? [From a seperate e-mail]> So xiph "officialy support" ogg and not ogm. But i am not able to find > any tool to create ogg files. www.xiph.org provide no information > about OGG either.Vorbis files are all created in an ogg container. "vorbis-tools" includes libogg, which would be the library to create Ogg files. Theora also uses libogg to put video in an Ogg container. If you are looking for a single stand-alone program, you'll find it in CVS. The ogmtools were based on "oggmerge", which has it's own directory in Xiph.org CVS. It doesn't support putting MPEG-4 video into an Ogg file, or anything like that. It basically supports putting MNG video into an Ogg with Vorbis audio.> Also, what is status of OGM? Is that stable and usable? If yes why > mencoder etc, dont provide a option to produce a OGM instead of AVI.Yes, it's stable and usable. You will just have to ask the MPlayer developers why they haven't added support for output to Ogm. I would say it's most likely because they didn't want to do all the work, and they couldn't just link to an ogm library, singe ogmtools comes as a standalone program. They implimented Matroska because there was a library they could just link to (as they do with libavcodec, liba52, etc). There are other formats they rightfully could support (such as the modified MOV container, for standards-compliant MPEG-4 video) but they don't. It's probably just lack of interest by those with the skills to do it.
<00ff01c46343$827aa190$0100000a@tiger> <Pine.LNX.4.60.0407060338450.18715@albani.cs.ubc.ca> <20040706120202.GC1234@ghostscript.com> <1235311184.20040706144046@guest.arnes.si> <87y8lxur69.fsf@snail.Pool> Message-ID: <482093772.20040706185809@guest.arnes.si> On Tuesday, July 6, 2004, 16:49:18, David Kuehling wrote:> What I'd like to mention here: not having a simple ascii subtitle format > specified for ogg-theora is really a pitty.Simple ascii subtitle format is too simple for fansubbers - search for ASS (Advanced SubStation Alpha) format specifications on the internet (there's a RTF floating around), to see what the fansubbers actually use. Unfortunately there only way to display these subtitles is to use vsfilter, which is limited to Windows (and eats lots of CPU with more complex effects; last time I checked mplayer, it stripped all formatting from ssa/ass files). Which is probably why most fansubbers still prefer to hardcoded subtitles (also, the only way to put ssa/ass to ogm is to use oggds v0.9.9.6, which is pretty unstable). -- < Jernej Simoncic ><><><><>< http://deepthought.ena.si/ > < for personal mail, replace guest.arnes.si with isg.si > All things considered, life is 9-to-5 against. -- Nick the Greek's Law
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 http://www.cse.iitb.ac.in/nilesh/ 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@xiph.org > http://lists.xiph.org/mailman/listinfo/theora >
<Pine.LNX.4.60.0407061837530.9433@okanagan.cs.ubc.ca> <80cc888e040706184710931d2c@mail.gmail.com> Message-ID: <Pine.LNX.4.60.0407061908170.14738@okanagan.cs.ubc.ca> On Wed, 7 Jul 2004, Kyungjoon Lee wrote:> On Tue, 6 Jul 2004 18:42:08 -0700 (PDT), Nilesh Bansal <bansal@cs.ubc.ca> wrote: >> encoding to Ogg(audio only) either (I don't know if oggenc provides a >> library or not that mencoder can link to). > > Running 'ldd ~/bin/mencoder' on my box shows that it's linked to libvorbis.I mean, mencoder using Ogg library (not vorbis), to produce .ogg files (audio wraped in Ogg container).> >> PS: xiph CVS is not working, it says connection refused everythime i try > > http://www.xiph.org/svn.htmlIts http://snv.xiph.org PS: http://forums.gentoo.org/viewtopic.php?t=63722 is a old thread on gentoo forums, which is mostly a flamewar between matroska and ogg developers. I believe, two have different phiolosphies and none is going to go away.
<Pine.LNX.4.60.0407061837530.9433@okanagan.cs.ubc.ca> <80cc888e040706184710931d2c@mail.gmail.com> <Pine.LNX.4.60.0407061908170.14738@okanagan.cs.ubc.ca> Message-ID: <80cc888e04070619342ea1df56@mail.gmail.com> On Tue, 6 Jul 2004 19:12:20 -0700 (PDT), Nilesh Bansal <bansal@cs.ubc.ca> wrote:> > Running 'ldd ~/bin/mencoder' on my box shows that it's linked to libvorbis. > I mean, mencoder using Ogg library (not vorbis), to produce .ogg files > (audio wraped in Ogg container).Probably not. I thought it might be possible because It was also linked to libogg, but on reading the documents it looks like it doesn't support Vorbis encoding.> >> PS: xiph CVS is not working, it says connection refused everythime i try > > > > http://www.xiph.org/svn.html > Its http://snv.xiph.orgXiph CVS is not working anymore, so you have to use SVN instead. I was just trying to say that you can use the instructions at svn.html to check out the files at svn.xiph.org. :)
<Pine.LNX.4.60.0407061837530.9433@okanagan.cs.ubc.ca> Message-ID: <009a01c463e9$e5e77ea0$0100000a@tiger> ----- Original Message ----- From: "Nilesh Bansal" <bansal@cs.ubc.ca> To: <advocacy@xiph.org>; <theora@xiph.org> Sent: Wednesday, July 07, 2004 9:42 AM Subject: Re: [Theora] OGG/OGM media container> 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? >Also the current head version of my directshow project, can create theora+vorbis files or transcode from YUY2(mpeg) or YV12 video sources and any audio format known to windows, well really any combination of codecs, however i use a different mux/demux that i wrote in C++, which i haven't got around to building for any other platform... but most non-windows developers prefer C to C++ anyway, so that's not much help ! In my proejct it's the library called libOOOgg, which is a seperate independant implementation of ogg. It doesn't however do the packet bit-level functions because all the codecs are pretty much hardwired to libogg to do that.> 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. >Again thats a matter of opinion... ogg has no seek index... on the plus side it means it is better for streaming, and it doesn't care if you get the whole file... on the downside, the binary search you have to use for ogg can be less acurate and less efficient particularly with large files and high latency to the source, ie over a slow network or running a large file from a CD drive.> 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). >In windows at least you can do it in directshow... heres a page of graphedit graphs for transcoding some known audio types... www.illiminable.com/ogg/graphedit.html The how to encode theora how to i'm writing for the next binary release (hopefully today) is still in svn at http://svn.xiph.org/trunk/oggdsf/website/enc_theora_graphedit.html but will go online at www.illiminable.com/ogg/enc_theora_graphedit.html hopefully sometime today when i get the last few changes done for a release, and fix up all the typos and missing/wrong images in it. Zen.
> From: Nilesh Bansal <bansal@cs.ubc.ca> > Date: 2004/07/06 Tue PM 09:42:08 EDT > PS: xiph CVS is not working, it says connection refused everythime i try > to connect.Xiph has switched to subversion instead of cvs. svn.xiph.org> Nilesh Bansal > http://www.cse.iitb.ac.in/nilesh/ > > 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@xiph.org > > http://lists.xiph.org/mailman/listinfo/theora > > > _______________________________________________ > Theora mailing list > Theora@xiph.org > http://lists.xiph.org/mailman/listinfo/theora >