[gst-devel] mimetypes/caps

Benjamin Otte in7y118 at public.uni-hamburg.de
Sat Jun 21 11:20:02 CEST 2003

On 21 Jun 2003, Ronald Bultje wrote:

> Some remarkable things people will want to know:
> * audio/raw and video/raw don't exist anymore. They're far too broad.
> int audio, float audio, ADPCM audio etc. etc. are all raw, but they're
> not actually similar in any way. Same goes for RGB/YUV video.
> * video/avi doesn't exist either. Codecs actually all have a name now.
> If not, it needs adding. Usage of video/avi + fourcc (in HEAD) as a way
> of identifying a codec will be punished in the most horrible way that we
> can collectively think of.
> * We're trying to separate muxing/parsing format from the actual codec
> as much as possible. This goes for Ogg/Vorbis (application/ogg vs.
> audio/x-vorbis) and a lot more. I propose to keep it this way. This
> might not work for all formats (mp3, flac, ...), but that shouldn't stop
> us from doing it that way as much as possible.
> * RGB 24/32 bpp is *always* in big-endian format. The masks actually
> tell us where the bytes are located.
> * for each video codec, width/height can be given. For each audio codec,
> rate/channels can be given.

All of it.

> Some things that I'm not 100% happy about, but where I can't think of a
> better way:
> * divx, xvid, mpeg-4 all have different mimetypes. This is wrong, since
> a xvid decoder can (sort of...) decode divx, too. Currently, that
> doesn't work, obviously, because the mimetypes don't match.
If we take the my definition that David liked so much yesterday, they
should all have the same mimetype with a property. This will have some
problems with autoplugging and ranks, but I prefer to do it right and
break the autoplugger for now.

For all people not in the know, the definition was this: "Two mimetypes
should be the same, if the properties are properties where plugins usually
care about the values."


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