obuparse

Simple and portable single file AV1 OBU parser

Simple and portable single file AV1 OBU parser written in mostly C89 with a tiny bit of C99. * No allocations; only works on user-provided buffers and the stack. * OBU header parsing. * Sequence Header OBU parsing. * Metadata OBU parsing. * Tile List OBU parsing. * Tile Group OBU parsing. * Frame Header OBU parsing. * Frame OBU parsing.