libspatialaudio is an open-source and cross-platform C++ library for Ambisonic encoding and decoding, filtering and binaural rendering. It is targetted to render High-Order Ambisonic (HOA) and VR/3D audio samples in multiple environments, from headphones to classic loudspeakers. Its binaural rendering can be used for classical 5.1/7.1 spatial channels as well as Ambisonics inputs. The library allows you to encode, decode, rotate, zoom HOA Ambisonics audio streams up to the 3rd order. It can output to standard and custom loudspeakers arrays. To playback with headphones, the binauralizer applies an HRTF (either a SOFA file or the included MIT HRTF) to provide a spatial binaural rendering effect. The binauralization can also be used to render multichannels streams (5.1, 7.1...).