obuparse

A simple and portable single file AV1 OBU parser written in mostly C89 with a tiny bit of C99, with a permissive license.

Why?

I got tired of rewriting ad-hoc OBU parsers for various tasks suchs as ISOBMFF muxing, MSE codec string generation, level verification, etc. So I decided to write once, as correctly as possible, and to use it everywhere in place of probably subtly-broken ad-hoc parsers.

I could have ripped out an OBU parser from other projects, but they're all either very intertwined with their respective encoder/decoder, written in very unportable manners, or in non-FFI friendly languages. At the time of writing this, I am not aware of any permissively licensed (or otherwise) OBU parsers that actually work portably.

How?

Simply copy obuparse.c and obuparser.h into your project, or use this repository as a git submodule.

By default, the parser uses a checked bitreader, but you can define OBP_UNCHECKED_BITREADER to use the unchecked version if that really matters to you.

All API documentation lives in obuparse.h.

There is also a Makefile provided for building a simple shared library on Linux. It should be straightforward to build for other OSes; all public symbols are namespaced with obp_. All public enums and types are namespaced with OBP.

Features

This section will expand as more of the library becomes complete, and it moves out of being a work in progress.

• 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.

Tools

The tools directory contains a simple tool to parse and serialize OBUs from an IVF file into JSON, called dumpobu.