Revision17
1st March 2005, 05:22
I know that vorbis is usually put in an ogg container. Vorbis+Theora go in an ogg container. Is the type of ogg container used for vorbis alone the same as the one used for theora?
Also, awhile back I was reading a pdf by the avimux-gui author (I'll host it if anyone wants to see it). Here are some relevant quotes (I'm not trolling ogm or ogg here):
Now you might wonder why the overhead of OGM files is that high. To
explain this, it is necessary to look closer at the (very simple) main structure
of OGG and OGM file formats.
Each OGG file consists of pages. Each page header contains 28 bytes, plus
a list of segment sizes. One segment can have a size of up to 255 bytes, one
page can contain 255 segments. In other words, for each 255 bytes of video
or audio data, you get at least one byte of overhead, as well as 28 bytes for
each 4 kByte.
---
While there is a sufficient amount of documentation available on AVI and Matroska,
there is virtually none for OGM, except for the source code. Writing
an OGM parser or an OGM muxer from scratch, as I did for AVI, Matroska
and OGG/Vorbis, is a problem, as a verification of OGM files is not possible.
Something like a ’valid OGM file’ is just not defined.
----
Finally, here the excerpt of a ’discussion’ between one of the most famous
OGM Zealot and other people:
Zealot: "Who would put ac3 or dts into ogm btw.? OGM is meant to be
a container for ogg vorbis sondtracks and video as well as subtitles."
Someone else: "So you acknowledge the fact that OGM is just a technology
demonstration to advertise Vorbis ? Not a general purpose container ?"
Zealot: "You know very well that OGM is a general purpose container..."
As you can see, not even OGM Zealots trying to defend OGM at all costs
(again, OGM, I don’t speak about OGG here!) can write reasonable sentences
not contradicting each other.
The author of the pdf seems to be using ogg and ogm kinda interchangably until:
(again, OGM, I don’t speak about OGG here!)
So it would appear they are different. So is OGM a container format based upon ogg, then forked into a separate project? What are the differences between ogg and ogm? From the author's point of view why would he/she differentiate ogg and ogm in that one part?
Also, awhile back I was reading a pdf by the avimux-gui author (I'll host it if anyone wants to see it). Here are some relevant quotes (I'm not trolling ogm or ogg here):
Now you might wonder why the overhead of OGM files is that high. To
explain this, it is necessary to look closer at the (very simple) main structure
of OGG and OGM file formats.
Each OGG file consists of pages. Each page header contains 28 bytes, plus
a list of segment sizes. One segment can have a size of up to 255 bytes, one
page can contain 255 segments. In other words, for each 255 bytes of video
or audio data, you get at least one byte of overhead, as well as 28 bytes for
each 4 kByte.
---
While there is a sufficient amount of documentation available on AVI and Matroska,
there is virtually none for OGM, except for the source code. Writing
an OGM parser or an OGM muxer from scratch, as I did for AVI, Matroska
and OGG/Vorbis, is a problem, as a verification of OGM files is not possible.
Something like a ’valid OGM file’ is just not defined.
----
Finally, here the excerpt of a ’discussion’ between one of the most famous
OGM Zealot and other people:
Zealot: "Who would put ac3 or dts into ogm btw.? OGM is meant to be
a container for ogg vorbis sondtracks and video as well as subtitles."
Someone else: "So you acknowledge the fact that OGM is just a technology
demonstration to advertise Vorbis ? Not a general purpose container ?"
Zealot: "You know very well that OGM is a general purpose container..."
As you can see, not even OGM Zealots trying to defend OGM at all costs
(again, OGM, I don’t speak about OGG here!) can write reasonable sentences
not contradicting each other.
The author of the pdf seems to be using ogg and ogm kinda interchangably until:
(again, OGM, I don’t speak about OGG here!)
So it would appear they are different. So is OGM a container format based upon ogg, then forked into a separate project? What are the differences between ogg and ogm? From the author's point of view why would he/she differentiate ogg and ogm in that one part?