"VBR" showing instead of MP3 Duration

I’ve been using Audacity for years and have never needed to post a question before. I’ve just installed the latest version of Audacity (v2.1.2) running on Windows 10.
(I’ve also read the “Windows 10 MP3 Length” post which doesn’t help).

Using default settings in Audacity, I’ve created and exported a number of MP3 files (as I have done lots of times before) and then in either iTunes/Windows Media player saved it/exported a playlist as normal creating an .m3u file which contains the file name and the duration e.g. 120 would be 2 minutes.

However when I play the MP3 in my car (which I’ve done successfully lots of times using previous Audacity version 1.3) instead of showing 2 minutes as the MP3 duration, all that is shown is “VBR”. To compare I created the same file in Audacity v1.3 on Win7 and that showed as it should (i.e. 2:00 minutes).

Tried it with 6 different files and they all do the same in Win 10 latest Audacity version, whereas they are fine in the Win7 older Audacity version.
What is different with the MP3 files because no matter what i change the .m3u playlist value duration to, all that is ever shown is “VBR” for these new files?
I’m using the default settings, so could you suggest what I could try to ensure the duration shows instead of “VBR”?
Normally this would show 2:00 and count back to 0.
The other display setting (showing time played which starts at 0 and counts up) is working normally.

In 2.1.2 the default MP3 Bit Rate Mode was changed from Constant Bit Rate (CBR) to the “Standard” preset which is Variable Bit Rate (VBR). VBR does tend to produce better quality for the same file size, but it was pointed out at the time that the new default would be unsatisfactory for those streaming MP3’s and for players which have problems reading the length of VBR files.

All you probably need to do is change the MP3 “Format Options” to “Constant” (click the radio button) when you export MP3. See image below.


Thanks very much that worked.
Also I found out from a car audio forum that this widely used audio system can’t handle duration settings of VBR files.

The “right way” to get the playing time is to calculate it. With variable bitrate files, the software has to pre-scan the file to find the bitrate for each frame.

There is an optional ID3 tag field for playing time but I don’t know if any software uses it.

Most player software gets it right, but some car stereos have some strange quirks and limitations.

Sometimes when the file is not correctly tagged as VBR, the player reads the bitrate for the 1st frame and the time can get fouled-up. But, I don’t think that’s the problem because I’m pretty sure the current LAME MP3 encoder gets it right, and you car stereo does seem to know it’s a VBR file.