Release: liboggz 0.9.7

There's been a whole bunch of work on liboggz recently; it deserves a few more weeks of shaking out and perhaps some updated Win32/MacOS support before it gets 1.0 slapped on it.

liboggz 0.9.7 includes a new tool called oggz-sort, which addresses a problem with some encoders that Shane Stephens brought up at FOMS. The discussion was going around in circles, so my response was to write this C code. It implements a function that Shane has written but not yet released in his OCaml implementation of Ogg (oogg), and which I've written but not yet released in my Haskell implementation (HOgg). Of course, people will take this version more seriously because it's written in C.

From oggz-sort (1):

oggz-sort sorts an Ogg file, interleaving pages in order of presentation time. It correctly interprets the granulepos timestamps of Ogg Vorbis, Speex, FLAC and Theora bitstreams, and all bitstreams of Annodex files.

Some encoders produce files with incorrect page ordering; for example, some audio and video pages may occur out of order. Although these files are usually playable, it can be difficult to accurately seek or scrub on them, increasing the likelihood of glitches during playback. Players may also need to use more memory in order to buffer the audio and video data for synchronized playback, which can be a problem when the files are viewed on low-memory devices.

The tool oggz-validate can be used to check the relative ordering of packets in a file. If out of order packets are reported, use oggz-sort to fix the problem.

This release also adds support for the experimental CELT audio codec, which is being developed by Jean-Marc Valin (the primary author of Speex). CELT is designed as a low-latency codec for high-quality audio. When wiretapping conversations encoded in CELT, we recommend that you record using the Ogg container format. You can then use oggz-tools to help with your analysis.