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Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 2:12 am
by kenmo
Is anyone familiar with the OGG/Vorbis audio file format? Does anyone know how to find the length inside the file? (I need it in seconds, but obviously I can calculate that from samples * sample rate.)
I'm looking through the Vorbis specification (
here) but it seems a bit more complex than WAV or ID3 which I've parsed before.
I am playing OGG music in my program, but I need to detect when the song ends and/or starts over (if I specify the Loop flag). Until PureBasic has either a SoundLength() or SoundPlaying() function, I have to manually detect this based on elapsed time...
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 2:53 am
by IdeasVacuum
Good description here:
http://en.wikipedia.org/wiki/Ogg#File_format
...but it seems as though length is not a recorded value?
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 8:27 am
by RASHAD
Code: Select all
Procedure AF_Load(Nb,file.s)
i=mciSendString_("OPEN "+Chr(34)+file+Chr(34)+" Type MPEGVIDEO ALIAS "+Str(Nb),0,0,0)
If i=0
ProcedureReturn #True
Else
ProcedureReturn #False
EndIf
EndProcedure
Procedure AF_GetLength(Nb)
a$=Space(#MAX_PATH)
i=mciSendString_("Status "+Str(Nb)+" length",@a$,#MAX_PATH,0)
ProcedureReturn Val(a$)
EndProcedure
Procedure.s AF_TimeString(Time)
Time/1000
sec=Time%60:Time/60
min=Time%60:Time/60
ProcedureReturn RSet(Str(Time),2,"0")+":"+RSet(Str(min),2,"0")+":"+RSet(Str(sec),2,"0")
EndProcedure
File$=OpenFileRequester("","","ALL|*.*;*.mid|Wave|*.wav|mp3|*.mp3|OGG|*.OGG|MID|*.MID",0)
AF_Load(1,File$)
Debug AF_TimeString(AF_GetLength(1))
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 1:45 pm
by kenmo
Rashad, that seems to work fine with MP3 files, but it returns 0:00 for all the OGG files I tested! (Exported as OGG from Audacity, if that matters.)
Also I should have mentioned that I need a Mac-compatible solution, so reading the file directly is probably the best way.
I will look into the format more later...
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 1:58 pm
by RASHAD
I tested it with an OGG file I have
Now can you give me a link to any of your files just for testing
I looked at the OGG format header and it seem that we can get the bitrate so with the file data
may be we can get the total playing time
I will try
See you soon
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 9:13 pm
by kenmo
Here is a 6-second OGG I generated and exported from Audacity: deleted...
It shows up as 0:00 using your code (Win XP if that matters). Thanks for helping.
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 9:27 pm
by RASHAD
PB 4.61 x86 Win 7 x64
Worked as expected Time 00:00:06
It seems that it is a matter of the proper CODEC
Is that file is playable on your system kenmo?
Re: Calculate audio length from OGG file
Posted: Sat Jun 23, 2012 10:24 pm
by kenmo
Yes, it plays in PureBasic, Winamp, VLC, etc...... but it does NOT play in Windows Media Player, that might be a problem.
Either way, mciSendString_() is Windows only, so I shouldn't spend too much time trying to get it to read OGG.
I've downloaded their open source "libvorbis" and I will look through that.
Re: Calculate audio length from OGG file
Posted: Sun Jun 24, 2012 4:21 am
by MachineCode
This VB media player supports OGG, so maybe look at its source:
http://www.planet-source-code.com/vb/sc ... 2&lngWId=1
Re: Calculate audio length from OGG file
Posted: Wed Jun 27, 2012 1:28 am
by kenmo
Well I hacked together an ugly procedure to calculate Ogg Vorbis length. It finds the sample rate (from the beginning of the file) and the number of samples (from the end) so the length in (milli)seconds can be calculated.
In case anybody else ever needs this, I'll post it here. It's NOT guaranteed to work with every Vorbis file!!!
I only used the bare minimum of the Vorbis specification that I needed... basically the 'OggS' and 'vorbis' headers.
2019-08-13 - Updated the code slightly to work with PB 5.70 / Unicode mode
Code: Select all
; Cross-platform procedure for determining length (in milliseconds)
; of an Ogg Vorbis audio file. It can easily be adapted to return
; seconds, or samples, or sample rate, etc.
; Absolutely NOT GUARANTEED to work with every .ogg file,
; but it seems to work with all the ones I'm using...
; 2019-08-13 : Updated to PureBasic 5.70 (Unicode fixed)
Procedure.i GetOggLength(File.s)
Protected BufferSize.i = 8192
Protected FN.i, *Buffer, FilePos.i, *P.LONG
Protected Result.i, Samples.q
Protected SampleRate.d
If (File)
FN = ReadFile(#PB_Any, File)
If (FN)
*Buffer = AllocateMemory(BufferSize)
If (*Buffer)
; Find sample rate (search forward from start)
FilePos = 0
Repeat
FileSeek(FN, FilePos)
If (ReadData(FN, *Buffer, BufferSize))
*P = *Buffer + 1
While (*P < *Buffer + BufferSize - 15)
If (*P\l = $62726F76) ; 'brov'
If ((PeekU(*P + 4) = $7369) And (PeekA(*P - 1) = 1)) ; 'si'
SampleRate = PeekL(*P + 11)
Break 2
EndIf
EndIf
*P + 1
Wend
Else
Break
EndIf
FilePos + BufferSize/2
Until (FilePos >= Lof(FN))
If (SampleRate > 0)
; Find number of samples (search backwards from end)
FilePos = Lof(FN) - BufferSize
If (FilePos < 0)
FilePos = 0
EndIf
Repeat
FileSeek(FN, FilePos)
If (ReadData(FN, *Buffer, BufferSize))
*P = *Buffer + BufferSize - 4
While (*P >= *Buffer)
If (*P\l = $5367674F) ; 'SggO'
Samples = PeekQ(*P + 6)
If (Samples > 0)
; Calculate audio length (milliseconds)
Result = Int(1000.0 * Samples / SampleRate)
Break 2
EndIf
EndIf
*P - 1
Wend
Else
Break
EndIf
If (FilePos > 0)
FilePos - BufferSize/2
Else
FilePos = -1
EndIf
Until (FilePos < 0)
EndIf
FreeMemory(*Buffer)
EndIf
CloseFile(FN)
EndIf
EndIf
ProcedureReturn (Result)
EndProcedure
; Test:
File.s = OpenFileRequester("OGG", "", "Ogg Vorbis|*.ogg", 0, #PB_Requester_MultiSelection)
While (File)
Length.i = GetOggLength(File)/1000
Debug Str(Length/60) + ":" + RSet(Str(Length % 60), 2, "0") + " " + GetFilePart(File)
File = NextSelectedFileName()
Wend