[Ffmpeg-devel] [Ss][Nn][Oo][Ww] spelling^wbranding

[Tuukka Toivonen]

>> 	Oh, I understand. The name of the codec is "Vorbis", "MPEG-4",
>> 	etc. Codec "0x42" would never make sense. However, in the
>> 	transport formats (AVI/MOV/Real/MPEG), they are identified by
>> 	numbers.

IIRC, GUID (128-bit number) is used to denote formats in asf
and there is a standard way to map 32-bit fourccs into GUIDs.

I believe Gstreamer uses some kind of string for format description 
althought can't find that just at the moment.
(granted, it's not a container, but it has to map format descriptions from 
containers into internal representation).

A great advantage from strings are that they're very extensible.
You can easily have sub-type and whatever, like "MPEG-4 / level 1" or 
"MPEG-4 (ffmpeg x.y.z)" just like HTTP does for browser identification.
Danger for name collisions is low and there is little need for central 
registry, like for fourccs.

The main problem from strings is that if you're broad/multicasting,
or want to repeat the header information frequently for error resilience,
it might take up a little more space.