[theora] ogg, ogm or mkv

[Gregory Maxwell]

On Mon, May 18, 2009 at 6:45 AM, Hannes
<theora.list at soulrebel.in-berlin.de> wrote:
> Am Montag, 18. Mai 2009 04:04:18 schrieb Conrad Parker:
>> 2009/5/18 Remco <remco47 at gmail.com>:
>> > What are the strengths and weaknesses of ogv, ogm and mkv? Matroska
>> > seems to be most feature-rich. Why is that format not a
>> > recommendation?
>>
>> It sounds like you are making a suggestion in favour of Matroska.
>> Please explain which Matroska features you are using.
>>
>> Conrad.
>
> Matroska has support for chapters, in-file subtitles of different formats,
> multiple (multi-channel) [vorbis] audio tracks (with language identifiers) and
> has lower file-format overhead than ogg.

Ogg also has support for in-file subtitles (in multiple languages) and
multiple audio tracks though both are probably not as widely supported
in Ogg playing applications as the equivalents are in MKV.

(Is supporting multiple subtitle *formats* a feature?  Ogg also has
multiple subtitle formats, but I consider that to be something of a
bug…)

About overhead. Is that actually true?  I had long believed it to be
true but while researching for my prior email I found a number of
measurements (i.e.
http://www.matroska.org/technical/overhead/index.html) which appear
are indicating overhead in the same general ballpark as Ogg. (which is
unfortunate: Ogg with its constant headers and error protection
*should* be higher overhead)

> I heard that some of these features are also available with Ogg Skeleton, but
> I have not yet found a useable tool, that makes use of them. And I am above
> average user, I think.

You don't need skeleton for those things.

For example, ffmpeg2theora will create files with subtitles.

> I heard ogg is better for streaming, but I have seen neither streamed, so I
> can't tell.

Ogg is widely streamed: Every Vorbis running internet radio station is
using streamed ogg. The usage of ogg in the HTML5 video tag result in
streaming.

Formats that depend on indexes are basically un-streamable. You might
be able to fake streaming if you have transport that supports seeking,
but that doesn't work for live realtime use.

Not that everyone should care about streaming… but it is an important
use case. (As is general non-linear modification, which Ogg's
streaming nature is unsustainable for)

> Note, that I am not complaining here, free media is important, thats why I am
> on this list ;-)
> But if Matroska turns out to be better for movie-archiving (and I am not
> saying it is or has to be) one should think about recommending it.

Absolutely.