[MPlayer-users] Re: Quicktime: "No 'moov' atom could be found"

[Moritz Bunkus]

Hi.

> Ogg does have potential as a general container, especially for 
> streaming. I've been using Ogmtools to make ogms (oggs with VFWish 
> MPEG-4 video and Vorbis audio) for quite a while and playing them with 
> MPlayer, Xine, and a couple of Win32 players. It seems to be a de facto 
> standard of sorts, since there are several interoperable implementations.

Ogg does not have the potential to become a general container. It simply
lacks a lot of important things. Most important: there are no specs!

The thing is that Ogg/Ogm development is only done by one person atm
(Nic on doom9). He's a Windows guy using a Windows approach (like using
WAVEFORMATEX and BITMAPINFOHEADER like structures). Not that HAS to be
bad, but neither is xiph.org involved in all this. And being a one man
development team he is not paying a lot of attention to cross platform
issues.

Let's take text subtitles. Ogg does not have a standard way of storing
which charset was used for them. Neither do they have to be stored as
UTF-8.

Next point: No index whatsoever. Pretty big overhead (oh yes!). No way
to know if an Ogg page is part of an Ogg packet spanning several pages
(so I have to throw away the first Ogg page after seeking). Theora is
stored differently in Ogg than all the other stuff is. No "real"
timestamps (just the "granulepos" which is based on the "sample rate"
for the stream - e.g. 1, 2, 3, 4... So no vfps video at the moment
without braking compatibility). No aspect ratio. No standarized way of
storing ANY additional information - be it pictures, text, comments,
playlists...

> Xiph is working on Ogg Theora and they'll eventually be working on Ogg 
> Tarkin. Hopefully, they'll define a generic way of putting video in Ogg.

My guess is: not in the near future. Several people have tried often
enough to contact them. Even Nic doesn't get all that much feedback from
xiph, and he's the one pushing Ogm at the moment!

> The main advantage Quicktime would have over Ogg and Matroska is that it 
> is more standardized and widely implemented in the proprietary world.

Yes. But Matroska has specs, Ogg doesn't (only very basic ones). I don't
see Ogg winning the race for the Next General Purpose Container
Format. Maybe Matroska doesn't win either.

One problem I personally have with MP4 is purely a software issue. The
two OpenSource libraries available (libmp4, libmp4v2) which are based on
libquicktime are put under the Mozilla Public License. Unfortunately
this lincense pretty much prohibits the source to be used together with
GPL'ed source... (Read
http://www.gnu.org/philosophy/license-list.html#GPLIncompatibleLicenses
or http://www.tomhull.com/ocston/docs/mozgpl.html if you're interested
in the legal issues involved.)

-- 
 ==> Ciao, Mosu (Moritz Bunkus)
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