Proposed additions to the portable_audio_player namespace

[Gabriel Burt]

Hi!  Danny Kukawka has been helping us get some new devices added to the
USB music players FDI file.  In addition to getting those new devices
in, I asked Danny about adding some useful keys to the
portable_audio_player namespace.  Certain mass storage Digital Audio
Players place their music/files in particular directories, and some
accept playlist files.  I am proposing embedding that information into
the HAL FDI files.  I think it is comparable to the information
contained in the in/output_formats keys.  It would allow music players
to be smarter about where they put files and whether and where they
read/write playlists onto devices, without each application having to
uniquely identify each player (that's what HAL is for!).

These are the new keys I am proposing for inclusion in the
portable_audio_player namespace:

Key (type)      portable_audio_player.filename_format (string)
Values          examples:
			MUSIC/%Track
			%Artist/%Album/%Track
			mp3s/%Artist/%Album - %Track
Mandatory       no
Description     If portable_audio_player.access_method = "storage",
this may contain a string that will be used to format the file's name
and path before writing it to the device.  If audio files must be placed
in a particular subdirectory, or the device only allows one
sub-directory deep hierarchies, that information should be embedded
here. The variables available for this string are %Artist, %Album, and %
Track.  Applications using this key are responsible for substituting the
appropriate values for these variables when formatting the file's
name/path.

Key (type)      portable_audio_player.audio_folders (stlist)
Values          example: files/music/ voice/ linein/
Mandatory       no
Description     If portable_audio_player.access_method = "storage",
this may contain a white-space separated list of folders in which music
can be found.  Paths relative to the mount point of the device.

Key (type)      portable_audio_player.playlist_format (string)
Values          example: audio/x-mpegurl
Mandatory       no
Description     Set to the MIME-type of the playlist format accepted by
this device.  Leave blank if none.

Key (type)      portable_audio_player.playlist_folder (string)
Values          example: playlists/
Mandatory       no
Description     Set to the folder in which playlists belong.  Leave
blank if playlist files are not supported.

Thanks,

Gabriel Burt