Hi,

I'm a c++ programmer and I have a large set of audio files saved in wave format. I need a way of estimating the loudness of these files.

For example, from a C++ program I'd like to find those samples that have roughly the same loudness as that of a particular sample.

I'm open to all suggestions, either existing API's, programs, or papers which outline the requied algorithm. free or otherwise.

Thanks for your help,

Barry.

replaygain.hydrogenaudio.org - includes matlab code, and there are open source C implementations of the algorithm out there (particularly in the FLAC sources).

ITU-R BS.1770 is an alternative (similar) algorithm, with fewer implementations.