oggsyncbuffer

Ogg sync buffer, referred to in the libogg library as the ogg_sync_buffer function, is a part of Ogg's page synchronization mechanism. It provides a pointer to an internal writable buffer where raw input data can be placed before the library analyzes it to extract Ogg pages. The function is used in conjunction with the surrounding sync API to assemble a complete Ogg bitstream from a stream of bytes, such as from a file or network source.

The typical usage pattern involves initializing an ogg_sync_state with ogg_sync_init, repeatedly obtaining space to write data by calling ogg_sync_buffer, filling that space with new bytes, and then notifying the library of how many bytes were written using ogg_sync_wrote. After data is written, the code can check for available pages with ogg_sync_pageseek or related functions, continuing the loop as more data arrives. When parsing is finished, the state is released with ogg_sync_clear.

Key details include:

- The function returns a pointer to a writable area of the internal buffer, with room for up to the requested size.

- It does not allocate memory; the caller uses the memory managed by the sync state.

- Proper usage relies on subsequent calls to ogg_sync_wrote to advance the synchronization process and enable page extraction.

- This buffer is central to assembling Ogg pages from streams, and is commonly used when demultiplexing streams such as Vorbis or Theora inside the Ogg container.

Ogg sync buffer is part of the lower-level data handling in libogg, distinct from higher-level bitstream parsing but essential for robust streaming and demultiplexing.