# Extracts mp3 files.
# Depends on perl and mpg123 from http://www.mpg123.de/ 
#
# If you use this together with the mp3-id3v2 recipe, specify this recipe
# AFTER the other. Otherwise files will be extracted twice.
#
# Currently this recipe is very slow because the header to match against is
# way too small. Therefore the command is executed very often, and it could
# take a whole day to complete.
# The good thing is that it will match every single frame, so even if an mp3
# file is split in 10 fragments it will find every one of them (possibly losing
# one frame where each split happens). Putting the pieces together won't be an
# easy puzzle, though.

0 char \xff
0 int32 FFfa0000 FFfe0000
extension mp3

# The command below is a bit hairy, here's how it works:
# We copy out a 100KB sample. If mpg123 can decode the sample without spitting
# out errors we try to let it play those 100KB into "$1.pcm". Then we call the
# extractor, which first sees if "$1.pcm" is big enough, and then tries to
# extract the file.
command dd bs=102400 count=1 of="$1" 2>/dev/null; if mpg123 -t "$1" 2>&1|egrep 'Illegal|too large|not allowed|Giving up' >/dev/null; then rm -f "$1"; else mpg123 -s "$1" > "$1.pcm" 2>/dev/null; mp3extract.pl "$1"; rm -f "$1.pcm"; fi

min_output_file 102401