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- #------------------------------------------------------------------------------
- # 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.
- #
- # --- Ogg Framing ---
- 0 string OggS Ogg data
- >4 byte !0 UNKNOWN REVISION %u
- ##>4 byte 0 revision 0
- >4 byte 0
- ##>>14 lelong x (Serial %lX)
- # --- First vorbis packet - general header ---
- >>28 string \x01vorbis \b, Vorbis audio,
- >>>35 lelong !0 UNKNOWN VERSION %lu,
- ##>>>35 lelong 0 version 0,
- >>>35 lelong 0
- >>>>39 ubyte 1 mono,
- >>>>39 ubyte 2 stereo,
- >>>>39 ubyte >2 %u channels,
- >>>>40 lelong x %lu 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:
- >>>>>44 lelong !-1
- # Vorbis RC2 has a bug which puts -1000 in the min/max bitrate fields
- # instead of -1.
- >>>>>>44 lelong !-1000
- >>>>>>>44 lelong x >%lu
- >>>>>48 lelong !-1
- >>>>>>48 lelong x ~%lu
- >>>>>52 lelong !-1
- >>>>>>52 lelong !-1000
- >>>>>>>52 lelong x <%lu
- >>>>>48 string <\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff kbps
- # -- 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 %.8s
- # Map to beta version numbers:
- >>>>>>(84.b+120) string <20000508 (<beta1 - prepublic)
- # The string has not changed from beta1 to 2 - they are indistinguishable.
- >>>>>>(84.b+120) string 20000508 (beta1/2)
- >>>>>>(84.b+120) string >20000508
- >>>>>>>(84.b+120) string <20001031 (beta2-3)
- >>>>>>(84.b+120) string 20001031 (beta3)
- >>>>>>(84.b+120) string >20001031
- >>>>>>>(84.b+120) string <20010225 (beta3-4)
- >>>>>>(84.b+120) string 20010225 (beta4)
- >>>>>>(84.b+120) string >20010225
- >>>>>>>(84.b+120) string <20010615 (beta4-RC1)
- >>>>>>(84.b+120) string 20010615 (RC1)
- >>>>>>(84.b+120) string 20010813 (RC2)
- >>>>>>(84.b+120) string 20010816 (RC2 - Garf tuned v1)
- >>>>>>(84.b+120) string 20011014 (RC2 - Garf tuned v2)
- >>>>>>(84.b+120) string 20011217 (pre-RC3 CVS)
- >>>>>>(84.b+120) string 20011231 (RC3)
- # Then come the comments, again length-counted (and number-counted).
- # Some looping constructs and registers would allow reading them but now
- # it's impossible. However we can print the number of comments present
- # (skipping by the vendor string length):
- ##>>>>(109.l.113) lelong 0 \b, no comments
- ##>>>>(109.l+113) lelong >0 \b, %lu comments
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