Calculate Beats-Per-Minute for Songs

This project is for an application that can calculate the beats-per-minute (BPM) of a given music file (mp3 etc.). An emphasis is placed on speed - we need the application to calculate an estimated BPM in 1-10 seconds per song. This can be done by examining only a portion of the song. The application should be able to work on unprotected (no DRM) mp3, wma, aac and ogg files. The code will need to be able to be integrated into an existing Visuall C++ 6.0 project (which will be provided for you). It doesn't matter how the integration works (via shared .dll or some other way) but the final deliverable for the project will be the original project with the BPM functionality added.