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

[Rich Felker]

On Fri, May 13, 2005 at 12:02:39PM +0300, Tuukka Toivonen wrote:
> >>	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.

This is a disadvantage because idiots are more likely to use random
variants on the basic string, and then all player apps need to be
updated to know about every single stupid variant someone uses.
Fourccs have the advantage of being a fairly limited space without
room for alternate spellings, misspellings, typos, etc.

Rich