Library for reading audio files

I want to process audio online/live where I constantly read audio samples from an audio file, process these (e.g. apply some effect), and forward the processed samples to an audio output device like a soundcard. The input files have common formats such as wav, mp3, perhaps even ogg. Is there a library available similar to libav/ffmpeg for audio files which simplifies reading various audio formats and provides me a constant stream of raw audio samples? Or is the best solution to use individual libraries for each format? The libraries should be c/c++ and cross-plattform compatible (Mac, Win, Linux, ARM). EDIT Thanks for all answers. I have evaluated all libraries and came to the conclusion that it is best to just stick with libav/ffmpeg because most of the libraries require ffmpeg as a backend.