/usr/lib/ruby/1.8/mp3info.rb is in libmp3info-ruby1.8 0.5-2build1.
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# License:: Ruby
# Author:: Guillaume Pierronnet (mailto:moumar_AT__rubyforge_DOT_org)
# Website:: http://ruby-mp3info.rubyforge.org/
require "delegate"
require "fileutils"
require "mp3info/extension_modules"
require "mp3info/id3v2"
# ruby -d to display debugging infos
# Raised on any kind of error related to ruby-mp3info
class Mp3InfoError < StandardError ; end
class Mp3InfoInternalError < StandardError #:nodoc:
end
class Mp3Info
VERSION = "0.5"
LAYER = [ nil, 3, 2, 1]
BITRATE = [
[
[32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448],
[32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384],
[32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320] ],
[
[32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256],
[8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160],
[8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160]
]
]
SAMPLERATE = [
[ 44100, 48000, 32000 ],
[ 22050, 24000, 16000 ]
]
CHANNEL_MODE = [ "Stereo", "JStereo", "Dual Channel", "Single Channel"]
GENRES = [
"Blues", "Classic Rock", "Country", "Dance", "Disco", "Funk",
"Grunge", "Hip-Hop", "Jazz", "Metal", "New Age", "Oldies",
"Other", "Pop", "R&B", "Rap", "Reggae", "Rock",
"Techno", "Industrial", "Alternative", "Ska", "Death Metal", "Pranks",
"Soundtrack", "Euro-Techno", "Ambient", "Trip-Hop", "Vocal", "Jazz+Funk",
"Fusion", "Trance", "Classical", "Instrumental", "Acid", "House",
"Game", "Sound Clip", "Gospel", "Noise", "AlternRock", "Bass",
"Soul", "Punk", "Space", "Meditative", "Instrumental Pop", "Instrumental Rock",
"Ethnic", "Gothic", "Darkwave", "Techno-Industrial", "Electronic", "Pop-Folk",
"Eurodance", "Dream", "Southern Rock", "Comedy", "Cult", "Gangsta",
"Top 40", "Christian Rap", "Pop/Funk", "Jungle", "Native American", "Cabaret",
"New Wave", "Psychadelic", "Rave", "Showtunes", "Trailer", "Lo-Fi",
"Tribal", "Acid Punk", "Acid Jazz", "Polka", "Retro", "Musical",
"Rock & Roll", "Hard Rock", "Folk", "Folk/Rock", "National Folk", "Swing",
"Fast-Fusion", "Bebob", "Latin", "Revival", "Celtic", "Bluegrass", "Avantgarde",
"Gothic Rock", "Progressive Rock", "Psychedelic Rock", "Symphonic Rock", "Slow Rock", "Big Band",
"Chorus", "Easy Listening", "Acoustic", "Humour", "Speech", "Chanson",
"Opera", "Chamber Music", "Sonata", "Symphony", "Booty Bass", "Primus",
"Porn Groove", "Satire", "Slow Jam", "Club", "Tango", "Samba",
"Folklore", "Ballad", "Power Ballad", "Rhythmic Soul", "Freestyle", "Duet",
"Punk Rock", "Drum Solo", "A capella", "Euro-House", "Dance Hall",
"Goa", "Drum & Bass", "Club House", "Hardcore", "Terror",
"Indie", "BritPop", "NegerPunk", "Polsk Punk", "Beat",
"Christian Gangsta", "Heavy Metal", "Black Metal", "Crossover", "Contemporary C",
"Christian Rock", "Merengue", "Salsa", "Thrash Metal", "Anime", "JPop",
"SynthPop" ]
TAGSIZE = 128
#MAX_FRAME_COUNT = 6 #number of frame to read for encoder detection
V1_V2_TAG_MAPPING = {
"title" => "TIT2",
"artist" => "TPE1",
"album" => "TALB",
"year" => "TYER",
"tracknum" => "TRCK",
"comments" => "COMM",
"genre_s" => "TCON"
}
# mpeg version = 1 or 2
attr_reader(:mpeg_version)
# layer = 1, 2, or 3
attr_reader(:layer)
# bitrate in kbps
attr_reader(:bitrate)
# samplerate in Hz
attr_reader(:samplerate)
# channel mode => "Stereo", "JStereo", "Dual Channel" or "Single Channel"
attr_reader(:channel_mode)
# variable bitrate => true or false
attr_reader(:vbr)
# length in seconds as a Float
attr_reader(:length)
# error protection => true or false
attr_reader(:error_protection)
#a sort of "universal" tag, regardless of the tag version, 1 or 2, with the same keys as @tag1
#this tag has priority over @tag1 and @tag2 when writing the tag with #close
attr_reader(:tag)
# id3v1 tag as a Hash. You can modify it, it will be written when calling
# "close" method.
attr_accessor(:tag1)
# id3v2 tag attribute as an ID3v2 object. You can modify it, it will be written when calling
# "close" method.
attr_accessor(:tag2)
# the original filename
attr_reader(:filename)
# Moved hastag1? and hastag2? to be booleans
attr_reader(:hastag1, :hastag2)
# Test the presence of an id3v1 tag in file +filename+
def self.hastag1?(filename)
File.open(filename) { |f|
f.seek(-TAGSIZE, File::SEEK_END)
f.read(3) == "TAG"
}
end
# Test the presence of an id3v2 tag in file +filename+
def self.hastag2?(filename)
File.open(filename) { |f|
f.read(3) == "ID3"
}
end
# Remove id3v1 tag from +filename+
def self.removetag1(filename)
if self.hastag1?(filename)
newsize = File.size(filename) - TAGSIZE
File.open(filename, "rb+") { |f| f.truncate(newsize) }
end
end
# Remove id3v2 tag from +filename+
def self.removetag2(filename)
self.open(filename) do |mp3|
mp3.tag2.clear
end
end
# Instantiate a new Mp3Info object with name +filename+
def initialize(filename)
$stderr.puts("#{self.class}::new() does not take block; use #{self.class}::open() instead") if block_given?
raise(Mp3InfoError, "empty file") unless File.stat(filename).size? #FIXME
@filename = filename
@hastag1 = false
@tag1 = {}
@tag1.extend(HashKeys)
@tag2 = ID3v2.new
@file = File.new(filename, "rb")
@file.extend(Mp3FileMethods)
begin
parse_tags
@tag1_orig = @tag1.dup
@tag = {}
if hastag1?
@tag = @tag1.dup
end
if hastag2?
@tag = {}
#creation of a sort of "universal" tag, regardless of the tag version
V1_V2_TAG_MAPPING.each do |key1, key2|
t2 = @tag2[key2]
next unless t2
@tag[key1] = t2.is_a?(Array) ? t2.first : t2
if key1 == "tracknum"
val = @tag2[key2].is_a?(Array) ? @tag2[key2].first : @tag2[key2]
@tag[key1] = val.to_i
end
end
end
@tag.extend(HashKeys)
@tag_orig = @tag.dup
### extracts MPEG info from MPEG header and stores it in the hash @mpeg
### head (fixnum) = valid 4 byte MPEG header
found = false
5.times do
head = find_next_frame()
head.extend(NumericBits)
@mpeg_version = [2, 1][head[19]]
@layer = LAYER[head.bits(18,17)]
next if @layer.nil?
@bitrate = BITRATE[@mpeg_version-1][@layer-1][head.bits(15,12)-1]
@error_protection = head[16] == 0 ? true : false
@samplerate = SAMPLERATE[@mpeg_version-1][head.bits(11,10)]
@padding = (head[9] == 1 ? true : false)
@channel_mode = CHANNEL_MODE[@channel_num = head.bits(7,6)]
@copyright = (head[3] == 1 ? true : false)
@original = (head[2] == 1 ? true : false)
@vbr = false
found = true
break
end
raise(Mp3InfoError, "Cannot find good frame") unless found
seek = @mpeg_version == 1 ?
(@channel_num == 3 ? 17 : 32) :
(@channel_num == 3 ? 9 : 17)
@file.seek(seek, IO::SEEK_CUR)
vbr_head = @file.read(4)
if vbr_head == "Xing"
puts "Xing header (VBR) detected" if $DEBUG
flags = @file.get32bits
@streamsize = @frames = 0
flags[1] == 1 and @frames = @file.get32bits
flags[2] == 1 and @streamsize = @file.get32bits
puts "#{@frames} frames" if $DEBUG
raise(Mp3InfoError, "bad VBR header") if @frames.zero?
# currently this just skips the TOC entries if they're found
@file.seek(100, IO::SEEK_CUR) if flags[0] == 1
@vbr_quality = @file.get32bits if flags[3] == 1
@length = (26/1000.0)*@frames
@bitrate = (((@streamsize/@frames)*@samplerate)/144) >> 10
@vbr = true
else
# for cbr, calculate duration with the given bitrate
@streamsize = @file.stat.size - (@hastag1 ? TAGSIZE : 0) - (@tag2.valid? ? @tag2.io_position : 0)
@length = ((@streamsize << 3)/1000.0)/@bitrate
if @tag2["TLEN"]
# but if another duration is given and it isn't close (within 5%)
# assume the mp3 is vbr and go with the given duration
tlen = (@tag2["TLEN"].is_a?(Array) ? @tag2["TLEN"].last : @tag2["TLEN"]).to_i/1000
percent_diff = ((@length.to_i-tlen)/tlen.to_f)
if percent_diff.abs > 0.05
# without the xing header, this is the best guess without reading
# every single frame
@vbr = true
@length = @tag2["TLEN"].to_i/1000
@bitrate = (@streamsize / @bitrate) >> 10
end
end
end
ensure
@file.close
end
end
# "block version" of Mp3Info::new()
def self.open(filename)
m = self.new(filename)
ret = nil
if block_given?
begin
ret = yield(m)
ensure
m.close
end
else
ret = m
end
ret
end
# Remove id3v1 from mp3
def removetag1
if hastag1?
newsize = @file.stat.size(filename) - TAGSIZE
@file.truncate(newsize)
@tag1.clear
end
self
end
def removetag2
@tag2.clear
end
# Does the file has an id3v1 or v2 tag?
def hastag?
@hastag1 or @tag2.valid?
end
# Does the file has an id3v1 tag?
def hastag1?
@hastag1
end
# Does the file has an id3v2 tag?
def hastag2?
@tag2.valid?
end
# write to another filename at close()
def rename(new_filename)
@filename = new_filename
end
# Flush pending modifications to tags and close the file
def close
puts "close" if $DEBUG
if @tag != @tag_orig
puts "@tag has changed" if $DEBUG
@tag.each do |k, v|
@tag1[k] = v
end
V1_V2_TAG_MAPPING.each do |key1, key2|
@tag2[key2] = @tag[key1] if @tag[key1]
end
end
if @tag1 != @tag1_orig
puts "@tag1 has changed" if $DEBUG
raise(Mp3InfoError, "file is not writable") unless File.writable?(@filename)
@tag1_orig.update(@tag1)
#puts "@tag1_orig: #{@tag1_orig.inspect}"
File.open(@filename, 'rb+') do |file|
file.seek(-TAGSIZE, File::SEEK_END)
t = file.read(3)
if t != 'TAG'
#append new tag
file.seek(0, File::SEEK_END)
file.write('TAG')
end
str = [
@tag1_orig["title"]||"",
@tag1_orig["artist"]||"",
@tag1_orig["album"]||"",
((@tag1_orig["year"] != 0) ? ("%04d" % @tag1_orig["year"].to_i) : "\0\0\0\0"),
@tag1_orig["comments"]||"",
0,
@tag1_orig["tracknum"]||0,
@tag1_orig["genre"]||255
].pack("Z30Z30Z30Z4Z28CCC")
file.write(str)
end
end
if @tag2.changed?
puts "@tag2 has changed" if $DEBUG
raise(Mp3InfoError, "file is not writable") unless File.writable?(@filename)
tempfile_name = nil
File.open(@filename, 'rb+') do |file|
#if tag2 already exists, seek to end of it
if @tag2.valid?
file.seek(@tag2.io_position)
end
# if @file.read(3) == "ID3"
# version_maj, version_min, flags = @file.read(3).unpack("CCB4")
# unsync, ext_header, experimental, footer = (0..3).collect { |i| flags[i].chr == '1' }
# tag2_len = @file.get_syncsafe
# @file.seek(@file.get_syncsafe - 4, IO::SEEK_CUR) if ext_header
# @file.seek(tag2_len, IO::SEEK_CUR)
# end
tempfile_name = @filename + ".tmp"
File.open(tempfile_name, "wb") do |tempfile|
unless @tag2.empty?
tempfile.write("ID3")
tempfile.write(@tag2.to_bin)
end
bufsiz = file.stat.blksize || 4096
while buf = file.read(bufsiz)
tempfile.write(buf)
end
end
end
File.rename(tempfile_name, @filename)
end
@file = nil
end
# inspect inside Mp3Info
def to_s
s = "MPEG #{@mpeg_version} Layer #{@layer} #{@vbr ? "VBR" : "CBR"} #{@bitrate} Kbps #{@channel_mode} #{@samplerate} Hz length #{@length} sec. error protection #{@error_protection} "
s << "tag1: "+@tag1.inspect+"\n" if @hastag1
s << "tag2: "+@tag2.inspect+"\n" if @tag2.valid?
s
end
private
### parses the id3 tags of the currently open @file
def parse_tags
return if @file.stat.size < TAGSIZE # file is too small
@file.seek(0)
f3 = @file.read(3)
gettag1 if f3 == "TAG" # v1 tag at beginning
@tag2.from_io(@file) if f3 == "ID3" # v2 tag at beginning
unless @hastag1 # v1 tag at end
# this preserves the file pos if tag2 found, since gettag2 leaves
# the file at the best guess as to the first MPEG frame
pos = (@tag2.valid? ? @file.pos : 0)
# seek to where id3v1 tag should be
@file.seek(-TAGSIZE, IO::SEEK_END)
gettag1 if @file.read(3) == "TAG"
@file.seek(pos)
end
end
### reads in id3 field strings, stripping out non-printable chars
### len (fixnum) = number of chars in field
### returns string
def read_id3_string(len)
#FIXME handle unicode strings
#return @file.read(len)
s = ""
len.times do
c = @file.getc
# only append printable characters
s << c if c >= 32 and c < 254
end
return s.strip
#return (s[0..2] == "eng" ? s[3..-1] : s)
end
### gets id3v1 tag information from @file
### assumes @file is pointing to char after "TAG" id
def gettag1
@hastag1 = true
@tag1["title"] = read_id3_string(30)
@tag1["artist"] = read_id3_string(30)
@tag1["album"] = read_id3_string(30)
year_t = read_id3_string(4).to_i
@tag1["year"] = year_t unless year_t == 0
comments = @file.read(30)
if comments[-2] == 0
@tag1["tracknum"] = comments[-1].to_i
comments.chop! #remove the last char
end
#@tag1["comments"] = comments.sub!(/\0.*$/, '')
@tag1["comments"] = comments.strip
@tag1["genre"] = @file.getc
@tag1["genre_s"] = GENRES[@tag1["genre"]] || ""
end
### reads through @file from current pos until it finds a valid MPEG header
### returns the MPEG header as FixNum
def find_next_frame
# @file will now be sitting at the best guess for where the MPEG frame is.
# It should be at byte 0 when there's no id3v2 tag.
# It should be at the end of the id3v2 tag or the zero padding if there
# is a id3v2 tag.
#dummyproof = @file.stat.size - @file.pos => WAS TOO MUCH
dummyproof = [ @file.stat.size - @file.pos, 2000000 ].min
dummyproof.times do |i|
if @file.getc == 0xff
data = @file.read(3)
raise Mp3InfoError if @file.eof?
head = 0xff000000 + (data[0] << 16) + (data[1] << 8) + data[2]
if check_head(head)
return head
else
@file.seek(-3, IO::SEEK_CUR)
end
end
end
raise Mp3InfoError, "cannot find a valid frame after reading #{dummyproof} bytes"
end
### checks the given header to see if it is valid
### head (fixnum) = 4 byte value to test for MPEG header validity
### returns true if valid, false if not
def check_head(head)
return false if head & 0xffe00000 != 0xffe00000 # 11 bit MPEG frame sync
return false if head & 0x00060000 == 0x00060000 # 2 bit layer type
return false if head & 0x0000f000 == 0x0000f000 # 4 bit bitrate
return false if head & 0x0000f000 == 0x00000000 # free format bitstream
return false if head & 0x00000c00 == 0x00000c00 # 2 bit frequency
return false if head & 0xffff0000 == 0xfffe0000
true
end
end
if $0 == __FILE__
while filename = ARGV.shift
begin
info = Mp3Info.new(filename)
puts filename
#puts "MPEG #{info.mpeg_version} Layer #{info.layer} #{info.vbr ? "VBR" : "CBR"} #{info.bitrate} Kbps \
#{info.channel_mode} #{info.samplerate} Hz length #{info.length} sec."
puts info
rescue Mp3InfoError => e
puts "#{filename}\nERROR: #{e}"
end
puts
end
end
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