How do you calculate audio length of mp3 without header

From https://java.net/jira/browse/JAUDIOTAGGER-453

Incorrectly calculating length of mp3 (MPEG-1 Layer 3) encoded at 32kbits, working out length of audio to be over 6 times its actual length, dont think file is corrrupt because iTunes calculates it correctly.

Seems to be VBR file without VRBI header so need to find other header or go through all frame headers to get accurate value

User Comment: there are (still) quite a few VBR files around without a XING or VBRI frame. As far as I understand the matter, the length (and bitrate) are then calculated using the first audio frame. The result is often wide off the mark. It would be cool to have a method to get the exact length for these files. Even if it needs a long time to examine all audio frames. In some use cases accuracy is more important than speed

Comments (2)