question abt ogg theora container

[ferrous66]

Will the upcoming Ogg Theora container allow to use any codec? or will it be limited to VP3? What is its status?

Thanks.

[Sirber]

There is no OGG Theora container, OGG Theora is a video codec that will be stored into OGM (OGG Container) or maybe other containers also.

[ChristianHJW]

Originally posted by Sirber
There is no OGG Theora container, OGG Theora is a video codec that will be stored into OGM (OGG Container) or maybe other containers also.

OGM =! OGG !!!

Ogg Theora is using a Xiph internal way to identify the stream content and the codec that was used, similar to what OGM does to identify a Vorbis audio track in it.

OGM is using a Windows centric Video for Windows structure to identify codecs, mainly BITMAPINFOHEADER and also VIDEOINFOHEADER AFAIK. I doubt that Xiph will decide to use this method to identify non-Xiph video streams, but maybe they will make their constant promises become reality and adapt this way that Tobias has chosen for OGM, and will use it for the official Ogg Theora library also.

Another thing that differentiates OGM from Ogg Theora is the way the GRANULEPOS is used to describe to position in time ( similar to a timestamp ), as Monty has modified this for Theora to be able to identify keyframes from the GRANULEPOS, without the need to ask the codec where to find the next keyframe, hidden in all the Ogg pages. Adapting this method for non-Xiph codecs would make a lot of sense IMHO, but then automatically all old OGM files would never comply with the official Ogg container video storage solution, unless some special 'OGM mode' was put into the specs, allowing normal GRANULEPOS also.

[bilu]

Originally posted by ChristianHJW
OGM is using a Windows centric Video for Windows structure

:rolleyes:

http://bunkus.org/videotools/ogmtools/index.html


Bilu

[Sirber]

Linux can write windows structure :)

[Suiryc]

IIRC Ogg Theora is stored in an Ogg bitstream a similar way than Vorbis. i.e. there are 3 important packets at the beginning (for the stream general information, the comments, and the setup information) and then the data packets.

At least it was this way the last time I looked. So currently there is no 'official' way to store any other video/audio format in Ogg, each codec would need a specific library (libvorbis for vorbis, libflac for FLAC, and I guess libtheora for theora, libtarkin for tarkin, etc).

Originally posted by Sirber
Linux can write windows structure :)

Yup, but on computers where endianness is a matter it become a bit more complex ;)

[Neo Neko]

Originally posted by ferrous66
Will the upcoming Ogg Theora container allow to use any codec? or will it be limited to VP3? What is its status?

Thanks.

Originally posted by Sirber
There is no OGG Theora container, OGG Theora is a video codec that will be stored into OGM (OGG Container) or maybe other containers also.

Actually you are both wrong. I talked to Emmett back when they were just getting ready to start on theora. Theora is not the container nor the codec. It is more a project name than anything else. In the end it is going to be a posssibly Xiph tweaked version of VP3 in Ogg. Theora is what they are calling VP3 in Ogg. Theora == Ogg(VP3). Theora != Ogg(!VP3)

Hehehe. Programmer speak.

[Animaniac]

Knowing them, I doubt they worked as much as they hyped.

[ChristianHJW]

LOL !

http://article.gmane.org/gmane.comp.multimedia.ogg.theora.general/178

and then the answer :

http://article.gmane.org/gmane.comp.multimedia.ogg.theora.general/179

Ehehehehe ... anybody care to tell them about Blacksun's OggPrak :D ??

BTW, the fact they decided to use the same extension for audio and video files, and by any means, was one of the factors that confirmed me in my decision to support a new, alternative a/v container best i could ..... ;) .....

[Neo Neko]

There is nothing wrong with the way they chose to do it. Simply put many of them are coming from a non Windows world. Windows is the only world where extensions are king. Everywhere else content decides before extension in most cases. Linux, BSD, BeOS, OSX, etc all do alot of content based differentiation. With a tiny bit of extension window dressing here and there.

[bond]

and BlackSuns OggPrak really does a great work! (for those who dont know it, OggPrak can be used to automatically pass .ogg video files to a video player and .ogg audio files to an audio player)

get it from here (http://blacksun.corecodec.org/moo/oggprak.rar)

[Neo Neko]

Indeed. I still remember when he and I broached the subject to Emmett well over a year ago. What we really need is a larger general purpose loader to replace the deficient windows one. :D But it is indeed a good start.