BSAC AAC Decoder

by Young Han Lee for FFmpeg / Libav

In MPEG-4 audio, formally ISO/IEC 14496-3, 3 kind of GA coding algorithm, AAC, BSAC, and TwinVQ, were standardized in sub-part 4. The differences are how to quantize and encode the scaled spectral bins. FFmpeg/Libav, one of the most popular open-source project of audio/video codec including a lot of functionality, has independent version of AAC decoder with good performance. However, BSAC and TwinVQ are not implemented in FFmpeg/Libav yet. This project aims at making the BSAC decoder.