MP3 ID3v1 and ID3v2 Tag Reader Functions by TheOneRing2nd Sep 2003 11:54
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Summary An include file with functions to read MP3 ID3v1 and ID3v2 tags. This is useful for things like media players, etc... Description Code ` This code was downloaded from The Game Creators
` It is reproduced here with full permission
` http://www.thegamecreators.com
`--------------------------------------------------------------------
` FILE NAME: ID3TAGS.DBA
` CREATED BY: ADAM PRESLEY adam@it-storm.com
` CREATED DATE: 08.28.2003
`
` DESCRIPTION: Functions for reading ID3v1, ID3v1.1, and ID3v2
` tags in MP3 music files.
`
` All code is copyright (c) 2003 Mighty Atom Software.
` You may use this code in any project, free or commercial. If its
` commercial the only thing I would like is a copy of the program. :)
`--------------------------------------------------------------------
`--------------------------------------------------------------------
` SECTION: ID3v1 Functions
`--------------------------------------------------------------------
`----------------------------------------------------------------
` This function will read the ID3v1 tag into a memblock. It
` returns 0 (false) or 1 (true) for failure and success,
` respectivly.NOTE: The memblock must not exist, and the
` filenumber used for file manipulation is 32.
`----------------------------------------------------------------
function Read_ID3v1_Into_Memblock(Filename$, MemblockNumber)
Success = 0
Signature$ = ""
`-----------------------------------------
` Get the file size and starting position.
`-----------------------------------------
FileSize = file size(Filename$)
StartPos = FileSize - 128
`-------------------------------------------
` Read the last 128 bytes into our memblock.
`-------------------------------------------
make memblock MemblockNumber, 129
open to read 32, Filename$
skip bytes 32, StartPos
for index = 1 to 128
read byte 32, value
write memblock byte MemblockNumber, index, value
next index
close file 32
`----------------------
` Is this an ID3v1 tag?
`----------------------
for index = 1 to 3
value = memblock byte(MemblockNumber, index)
Signature$ = Signature$ + chr$(value)
next index
if Signature$ = "TAG"
Success = 1
else
Success = 0
delete memblock MemblockNumber
endif
endfunction Success
function Get_ID3v1_Title(MemblockNumber)
Value$ = ""
StartPos = 3
for index = 1 to 30
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
endfunction Value$
function Get_ID3v1_Artist(MemblockNumber)
Value$ = ""
StartPos = 33
for index = 1 to 30
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
endfunction Value$
function Get_ID3v1_Album(MemblockNumber)
Value$ = ""
StartPos = 63
for index = 1 to 30
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
endfunction Value$
function Get_ID3v1_Year(MemblockNumber)
Value$ = ""
StartPos = 93
for index = 1 to 4
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
endfunction Value$
function Get_ID3v1_Comment(MemblockNumber)
Value$ = ""
StartPos = 97
for index = 1 to 28
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
value = memblock byte(MemblockNumber, 29 + StartPos)
if value <> 0
Value$ = Value$ + chr$(value)
value = memblock byte(MemblockNumber, 30 + StartPos)
Value$ = Value$ + chr$(value)
endif
endfunction Value$
function Get_ID3v1_Genre(MemblockNumber)
Value$ = ""
StartPos = 127
for index = 1 to 1
value = memblock byte(MemblockNumber, index + StartPos)
Value$ = Value$ + chr$(value)
next index
endfunction Value$
function Get_ID3v1_Track(MemblockNumber)
Value$ = ""
StartPos = 126
value = memblock byte(MemblockNumber, StartPos)
if value = 0
value = memblock byte(MemblockNumber, StartPos + 1)
Value$ = Value$ + str$(value)
endif
endfunction Value$
`--------------------------------------------------------------------
` SECTION: ID3v2 Functions
`--------------------------------------------------------------------
`----------------------------------------------------------------
` This function will read the ID3v2 frames into a memblock. It
` returns the subversion of the ID3v2 tag. Valid values are 2, 3,
` and 4. If 0 is returned, there was an error. NOTE: The
` memblock must not exist, and the filenumber used for file
` manipulation is 32.
`----------------------------------------------------------------
function Read_ID3v2_Into_Memblock(Filename$, MemblockNumber)
SubVersion$ = "0"
Signature$ = ""
TagSize = 0
`----------------
` Load this file.
`----------------
if file exist(Filename$) = 0 then exitfunction $SubVersion$
open to read 32, Filename$
`------------------------------------------------------------
` Determine if there is an ID3v2 tag here. NOTE: ID3v2 tags
` are usually at the beginning of the MP3. They can, however,
` be technically anywhere in the file. This routine only
` supports ID3v2 tags at the beginning of the MP3.
`-------------------------------------------------------------
for index = 1 to 3
read byte 32, value
Signature$ = Signature$ + chr$(value)
next index
if Signature$ <> "ID3" then exitfunction $SubVersion$
`----------------------------------------------------------------
` Get the ID3v2 tag subversion number. Only tested with version 3
`----------------------------------------------------------------
read byte 32, value
if value >= 3
SubVersion$ = str$(value)
`--------------------------------
` Read past the 2 reserved bytes.
`--------------------------------
skip bytes 32, 2
`-------------------------------------------------------------------------------------------
` Now get the size of the ID3v2 tag. This is tricky becuase its stored in big-endian format.
` Got to re-order the bytes.
`-------------------------------------------------------------------------------------------
read long 32, value
TagSize = LittleEndianToBigEndian(value)
`-----------------------
` Allocate the memblock.
`-----------------------
make memblock MemblockNumber, TagSize + 1
`------------------------------------
` Now read the tag into the memblock.
`------------------------------------
for index = 1 to TagSize
read byte 32, value
write memblock byte MemblockNumber, index, value
next index
endif
close file 32
endfunction SubVersion$
function Get_ID3v2_Title(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TIT2")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Track_Number(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TRCK")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Play_Counter(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "PCNT")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Encoded_By(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TENC")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Copyright(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TCOP")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Original_Artist(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TOPE")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Composer(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TCOM")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Genre(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TCON")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Comment(MemblockNumber)
`-------------------------------------------------------------
` Comments are wierd. Most MP3s I've tested on have the values
` e, n, g, null before the actual comment. Lets remove it if
` its there.
`-------------------------------------------------------------
Value$ = ""
StartPos = FindFrame(MemblockNumber, "COMM")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
if lower$(left$(Value$, 3)) = "eng" then Value$ = right$(Value$, len(Value$) - 3)
endif
endfunction Value$
function Get_ID3v2_Year(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TYER")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Artist(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TPE1")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Album(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "TALB")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
function Get_ID3v2_Lyrics(MemblockNumber)
`-------------------------------------------------------------
` Lyrics are wierd. Most MP3s I've tested on have the values
` e, n, g, null before the actual comment. Lets remove it if
` its there.
`-------------------------------------------------------------
Value$ = ""
StartPos = FindFrame(MemblockNumber, "USLT")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
if lower$(left$(Value$, 3)) = "eng" then Value$ = right$(Value$, len(Value$) - 3)
endif
endfunction Value$
function Get_ID3v2_Artist_URL(MemblockNumber)
Value$ = ""
StartPos = FindFrame(MemblockNumber, "WOAR")
if StartPos <> 0
FrameSize = GetFrameSize(MemblockNumber, StartPos)
Value$ = GetFrameData(MemblockNumber, StartPos, FrameSize)
endif
endfunction Value$
`------------------------------------------------------------
` This function takes a little-endian (Intel) style value and
` turns it into a big-endian (Motorola) style value. This
` is needed because the byte-order for the size values in an
` MP3 are big-endian.
`------------------------------------------------------------
function LittleEndianToBigEndian(Value)
`---------------------------------------------------------------------------
` For all you C programmers out there here are those decimal numbers in hex:
`
` 2130706432 = 0x7F000000
` 16777216 = 0x1000000
` 2147483648 = 0x80000000
` 128 = 0x80
` 16711680 = 0xFF0000
` 65536 = 0x10000
` 256 = 0x100
` 65280 = 0xFF00
`---------------------------------------------------------------------------
NewValue = 0
NewValue = ((Value && 2130706432) / 16777216)
if (Value && 2147483648) = 2147483648 then NewValue = (NewValue || 128)
NewValue = (NewValue || ((Value && 16711680) / 65536) * 256)
NewValue = (NewValue || ((Value && 65280) / 256) * 65536)
NewValue = (NewValue || (Value && 127) * 16777216)
if (Value && 128) = 128 then NewValue = (NewValue || 2147483648)
endfunction NewValue
`-------------------------------------------------------------
` This function will find and return the starting position in
` the memblock where a particular frame begins (if it exists.)
`-------------------------------------------------------------
function FindFrame(MemblockNumber, FrameName$)
StartPos = 0
TagSize = get memblock size(MemblockNumber)
Temp$ = ""
for index = 1 to TagSize - 5
Temp$ = ""
for inner = 0 to 3
value = memblock byte(MemblockNumber, index + inner)
Temp$ = Temp$ + chr$(value)
next inner
if Temp$ = FrameName$ then StartPos = index
next index
endfunction StartPos
`-------------------------------------------------------
` This function will get the size of a particular frame.
`-------------------------------------------------------
function GetFrameSize(MemblockNumber, FramePos)
Size = memblock dword(MemblockNumber, FramePos + 4)
Size = LittleEndianToBigEndian(Size)
endfunction Size
`-----------------------------------------------------
` This function will grab the data of a frame. Need to
` know the starting position and size of the frame.
`-----------------------------------------------------
function GetFrameData(MemblockNumber, FramePos, FrameSize)
Result$ = ""
flagBeginCopy = 0
`---------------------------------------------------------------
` A frame consists of a 4-digit name, size of the frame (dword),
` 3 or more padding 0 bytes, then the data.
`---------------------------------------------------------------
StartPos = FramePos + 11
`----------------------------
` Check for any more zeros...
`----------------------------
for index = StartPos to (FrameSize + StartPos) - 2
if flagBeginCopy = 0
value = memblock byte(MemblockNumber, index)
if value <> 0
Result$ = Result$ + chr$(value)
flagBeginCopy = 1
endif
else
value = memblock byte(MemblockNumber, index)
Result$ = Result$ + chr$(value)
endif
next index
endfunction Result$
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