
#------------------------------------------------------------------------------
# $File: vorbis,v 1.26 2020/08/22 18:30:55 christos Exp $
# vorbis:  file(1) magic for Ogg/Vorbis files
#
# From Felix von Leitner <leitner@fefe.de>
# Extended by Beni Cherniavsky <cben@crosswinds.net>
# Further extended by Greg Wooledge <greg@wooledge.org>
#
# Most (everything but the number of channels and bitrate) is commented
# out with `##' as it's not interesting to the average user.  The most
# probable things advanced users would want to uncomment are probably
# the number of comments and the encoder version.
#
# FIXME: The first match has been made a search, so that it can skip
# over prepended ID3 tags. This will work for MIME type detection, but
# won't work for detecting other properties of the file (they all need
# to be made relative to the search). In any case, if the file has ID3
# tags, the ID3 information will be printed, not the Ogg information,
# so until that's fixed, this doesn't matter.
# FIXME[2]: Disable the above for now, since search assumes text mode.
#
# --- Ogg Framing ---
#0		search/1000	OggS		Ogg data
0		string	OggS		Ogg data
>4		byte		!0		UNKNOWN REVISION %u
##>4		byte		0		revision 0
>4		byte		0
##>>14		lelong		x		(Serial %lX)
# non-Vorbis content: FLAC (Free Lossless Audio Codec, http://flac.sourceforge.net)
>>28		string		\x7fFLAC	\b, FLAC audio
# non-Vorbis content: Theora
!:mime		audio/ogg
>>28		string		\x80theora	\b, Theora video
!:mime		video/ogg
# non-Vorbis content: Kate
>>28		string		\x80kate\0\0\0\0	\b, Kate (Karaoke and Text)
!:mime		application/ogg
>>>37		ubyte		x		v%u
>>>38		ubyte		x		\b.%u,
>>>40		byte		0		utf8 encoding,
>>>40		byte		!0		unknown character encoding,
>>>60		string		>\0		language %s,
>>>60		string		\0		no language set,
>>>76		string		>\0		category %s
>>>76		string		\0		no category set
# non-Vorbis content: Skeleton
>>28		string		fishead\0	\b, Skeleton
!:mime		video/ogg
>>>36		leshort		x		v%u
>>>40		leshort		x		\b.%u
# non-Vorbis content: Speex
>>28		string		Speex\ \ \ 	\b, Speex audio
!:mime		audio/ogg
# non-Vorbis content: OGM
>>28		string		\x01video\0\0\0	\b, OGM video
!:mime		video/ogg
>>>37		string/c	div3		(DivX 3)
>>>37		string/c	divx		(DivX 4)
>>>37		string/c	dx50		(DivX 5)
>>>37		string/c	xvid		(XviD)
# --- First vorbis packet - general header ---
>>28		string		\x01vorbis	\b, Vorbis audio,
!:mime		audio/ogg
>>>35		lelong		!0		UNKNOWN VERSION %u,
##>>>35		lelong		0		version 0,
>>>35		lelong		0
>>>>39		ubyte		1		mono,
>>>>39		ubyte		2		stereo,
>>>>39		ubyte		>2		%u channels,
>>>>40		lelong		x		%u Hz
# Minimal, nominal and maximal bitrates specified when encoding
>>>>48		string		<\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff	\b,
# The above tests if at least one of these is specified:
>>>>>52		lelong		!-1
# Vorbis RC2 has a bug which puts -1000 in the min/max bitrate fields
# instead of -1.
# Vorbis 1.0 uses 0 instead of -1.
>>>>>>52	lelong		!0
>>>>>>>52	lelong		!-1000
>>>>>>>>52	lelong		x		<%u
>>>>>48		lelong		!-1
>>>>>>48	lelong		x		~%u
>>>>>44		lelong		!-1
>>>>>>44	lelong		!-1000
>>>>>>>44	lelong		!0
>>>>>>>>44	lelong		x		>%u
>>>>>48		string		<\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff	bps
# -- Second vorbis header packet - the comments
# A kludge to read the vendor string.  It's a counted string, not a
# zero-terminated one, so file(1) can't read it in a generic way.
# libVorbis is the only one existing currently, so I detect specifically
# it.  The interesting value is the cvs date (8 digits decimal).
# Post-RC1 Ogg files have the second header packet (and thus the version)
# in a different place, so we must use an indirect offset.
>>>(84.b+85)		string		\x03vorbis
>>>>(84.b+96)		string/c	Xiphophorus\ libVorbis\ I	\b, created by: Xiphophorus libVorbis I
>>>>>(84.b+120)		string		>00000000
# Map to beta version numbers:
>>>>>>(84.b+120)	string		<20000508	(<beta1, prepublic)
>>>>>>(84.b+120)	string		20000508	(1.0 beta 1 or beta 2)
>>>>>>(84.b+120)	string		>20000508
>>>>>>>(84.b+120)	string		<20001031	(beta2-3)
>>>>>>(84.b+120)	string		20001031	(1.0 beta 3)
>>>>>>(84.b+120)	string		>20001031
>>>>>>>(84.b+120)	string		<20010225	(beta3-4)
>>>>>>(84.b+120)	string		20010225	(1.0 beta 4)
>>>>>>(84.b+120)	string		>20010225
>>>>>>>(84.b+120)	string		<20010615	(beta4-RC1)
>>>>>>(84.b+120)	string		20010615	(1.0 RC1)
>>>>>>(84.b+120)	string		20010813	(1.0 RC2)
>>>>>>(84.b+120)	string		20010816	(RC2 - Garf tuned v1)
>>>>>>(84.b+120)	string		20011014	(RC2 - Garf tuned v2)
>>>>>>(84.b+120)	string		20011217	(1.0 RC3)
>>>>>>(84.b+120)	string		20011231	(1.0 RC3)
# Some pre-1.0 CVS snapshots still had "Xiphphorus"...
>>>>>>(84.b+120)	string		>20011231	(pre-1.0 CVS)
# For the 1.0 release, Xiphophorus is replaced by Xiph.Org
>>>>(84.b+96)		string/c	Xiph.Org\ libVorbis\ I	\b, created by: Xiph.Org libVorbis I
>>>>>(84.b+117)		string		>00000000
>>>>>>(84.b+117)	string		<20020717	(pre-1.0 CVS)
>>>>>>(84.b+117)	string		20020717	(1.0)
>>>>>>(84.b+117)	string		20030909	(1.0.1)
>>>>>>(84.b+117)	string		20040629	(1.1.0 RC1)
>>>>>>(84.b+117)	string		20050304	(1.1.2)
>>>>>>(84.b+117)	string		20070622	(1.2.0)
>>>>>>(84.b+117)	string		20090624	(1.2.2)
>>>>>>(84.b+117)	string		20090709	(1.2.3)
>>>>>>(84.b+117)	string		20100325	(1.3.1)
>>>>>>(84.b+117)	string		20101101	(1.3.2)
>>>>>>(84.b+117)	string		20120203	(1.3.3)
>>>>>>(84.b+117)	string		20140122	(1.3.4)
>>>>>>(84.b+117)	string		20150105	(1.3.5)

# non-Vorbis content: Opus https://tools.ietf.org/html/rfc7845#section-5
>>28		string		OpusHead	\b, Opus audio,
!:mime		audio/ogg
>>>36		ubyte		>0x0F		UNKNOWN VERSION %u,
>>>36		ubyte&0x0F	!0		version 0.%u,
>>>>46		ubyte		>1
>>>>>46		ubyte		!255		unknown channel mapping family %u,
>>>>>37		ubyte		x		%u channels
>>>>46		ubyte		0
>>>>>37		ubyte		1		mono
>>>>>37		ubyte		2		stereo
>>>>46		ubyte		1
>>>>>37		ubyte		1		mono
>>>>>37		ubyte		2		stereo
>>>>>37		ubyte		3		linear surround
>>>>>37		ubyte		4		quadraphonic
>>>>>37		ubyte		5		5.0 surround
>>>>>37		ubyte		6		5.1 surround
>>>>>37		ubyte		7		6.1 surround
>>>>>37		ubyte		8		7.1 surround
>>>>40		lelong		!0		\b, %u Hz (Input Sample Rate)