Hydrogenaudio Forums > Why do I get different mp3 song duration?

yongwpi

Mar 30 2006, 11:26

I used directshow IMediaseeking::getduration and windows media format sdk to extract mp3 duration, but I got different results. Duration from IMediaSeeking is about 5 times longer than that from sdk. Thanks for any information about this problem.

Firon

Mar 30 2006, 22:13

One of them probably doesn't know how to read the time properly with VBR files.

yongwpi

Mar 31 2006, 09:13

QUOTE(Firon @ Mar 30 2006, 11:13 PM)

One of them probably doesn't know how to read the time properly with VBR files.

Thanks for your information. Yes, it is VBR file. So there is no way to extract duration correctly from VBR files, right?

Firon

Mar 31 2006, 19:56

Well, there's two kinds of VBR headers, the Xing header, and the VBRI header (and LAME if you wanna get technical). Some players don't support VBRI, Xing is typically more supported. LAME writes headers that are extensions of the Xing header, but are still compatible. They both provide ways to figure out the bitrate and length.
http://www.codeproject.com/audio/MPEGAudio....asp#XINGHeader
http://gabriel.mp3-tech.org/mp3infotag.html#versionstring

yongwpi

Apr 1 2006, 15:27

QUOTE(Firon @ Mar 31 2006, 08:56 PM)

Well, there's two kinds of VBR headers, the Xing header, and the VBRI header (and LAME if you wanna get technical). Some players don't support VBRI, Xing is typically more supported. LAME writes headers that are extensions of the Xing header, but are still compatible. They both provide ways to figure out the bitrate and length.
http://www.codeproject.com/audio/MPEGAudio....asp#XINGHeader
http://gabriel.mp3-tech.org/mp3infotag.html#versionstring

Thanks. They are really helpful!