April 2024 - This site, and Kamaelia are being updated. There is significant work needed, and PRs are welcome.

Please note:The documentation here is lagging, quite badly at the moment, behind the bulk of Kamaelia, which is where all the interesting effort is going right now. Whilst everything you see here should largely still be valid, be aware that this really needs updating. We hope to rectify this ASAP. Good documenters very welcome!

Kamaelia's modules divide into 2 main sections:

A core subsystem of modules which provide the main concurrency support

Modules for Kamaelia itself.

This document is the starting point for Kamaelia itself.

This file provides an overview of the current Kamaelia files, what they are and where appropriate, how they work. This is designed to be a living document, but not designed as raw API documentation. (There are better ways of building API documentation) Essentially the purpose of this documentis to act as "the next layer up" the documentation layers - stating how and why the different parts are joined together.

Multimedia Modules

These three files are all related to the same purpose - playback of audio, and also decoding ogg vorbis. There are some restrictions on some of these, and there is a recommendation on which ones to use. Each of these requires a set of libraries - these are covered below.

AOPlayer.py is deprecated, the actual component has moved location, and you really ought not to use this at the moment. This may change at some point in time.

oggFilePlayComponent.pyis the oldest piece of code that can be used for decode and playback. It uses the official xiph python bindings to decode ogg vorbis. On the surface this is useful and if all you want to do is decode audio from a file, this does work.

This file contains the following components:

oggPlayer - legacy component - you used to be able to choose between AOPlayer and

PlayerComponent - This is an abstract class that provides the main functionality of a player. Is is overridden by client subclasses. Subclasses are only expect to override the write method. The key method in the payer component is a play generator. Nastily, this generator calls VorbisFile to enable file reading, unpacking of ogg and decode.

Current concrete subclasses:

It's worth noting that the execution here is pretty ugly, and it was the motivation for writing the next file. However, if all you want is to use libvorbisfile, oggFilePlayComponent.py can be useful.

vorbisDecodeComponent.py was written to overcome the limitations metioned above. Specifically this provides 2 components - one that will accept ogg vorbis data on an inbox and provide back raw decoded audio on its outbox, and another that takes audio on its inbox and plays the audio. This provides much cleaner separation. The testing spike included shows how to use a file reading component in conjuction with these two components to provide a file reading/decode chain.

The two components provided are:

These components rely on the following libraries being installed:

The python bindings required are:

RTP Related Modules


bitfieldrec.py -Module containing utility functions to allow structures with arbitrary structures for bitstreams/bitfields. Currently only supports packing. Does not support unpacking (yet).Bit Field Record Support. Usage:
1. subclass bfrec
2. Define a class var "fields"
3. The value for this field should be a list of "field"s, created by calling the static method field.mkList. This takes a list of tuples, one tuple per field. (fieldname, bitwidth, None or list)

class field(str)

class bfrec(AxonObject)

__init__(self, **args):



serialiseable(convert,aField) - Returns an iterable collection of values. (eg list) Either an existing one, or puts scalar/singleton values into a list. Doing this removes a special case.


NullPayloadPreFramer.py - .…

Subcomponents functionality:

FileControl: - Only if RFA internal - isn't

Format Decoding


Command Interpreter (Likely to be component core code)


MIME & Disk Related modules


Testing Modules


Experimentation Modules


Support Files