(In reply to comment #0)
> Currently the MIME type for Flash video is "application/x-flash-video" with the
> following aliases:
> flv-application/octet-stream
> video/flv
> 
> The latter does not seem to be registered at IANA, though
> (http://www.iana.org/assignments/media-types/video/). As it's apparently used
> by youtube, though, perhaps it should stay but the more correct video/x-flv be
> added?

The canonical mime-type within shared-mime-info is "application/x-flash-video" which is an IANA-correct mime-type for unregistered mime-types. video/flv is only provided as an alias. Only canonical mime-types need to be IANA mime-types, aliases are used for types found "in the wild".

My request was not to remove video/flv but to add video/x-flv which is one of those found in the wild.

(In reply to comment #2)
> My request was not to remove video/flv but to add video/x-flv which is one of
> those found in the wild.

Got an example?

from xine-lib/src/demuxers/demux_flv.c:
static const char *get_mimetypes (demux_class_t *this_gen) {
  return "video/x-flv: flv: Flash video;";
}

Which I changed to:
static const char *get_mimetypes (demux_class_t *this_gen) {
  return "video/x-flv: flv: Flash video;"
         "video/flv: flv: Flash video;"
         "application/x-flash-video: flv: Flash video;";
}

for one of the latest releases. Still older versions of xine only report video/x-flv.

(In reply to comment #4)
> from xine-lib/src/demuxers/demux_flv.c:
> static const char *get_mimetypes (demux_class_t *this_gen) {
>   return "video/x-flv: flv: Flash video;";
> }
> 
> Which I changed to:
> static const char *get_mimetypes (demux_class_t *this_gen) {
>   return "video/x-flv: flv: Flash video;"
>          "video/flv: flv: Flash video;"
>          "application/x-flash-video: flv: Flash video;";
> }
> 
> for one of the latest releases. Still older versions of xine only report
> video/x-flv.

This is a consumer mime-type, not a creator mime-type. As in, xine-lib registers itself as handling video/x-flv, but it doesn't create/offer files of that type. Let me know if you find a website offering FLV videos with that mime-type, or another system registering that mime-type themselves.