MuLine is low-level library which provides an audio line to J2ME applications compliant with CLDC1.0 and MIDP2 specifications. It's released under LGPL licence.

MuLine library is still in alpha stage. Check project progress and compatibility for using it in your project or a specific device.


  • For devices that support streaming: developers can directly write PCM audio data in the line instead of having to develop a custom DataSource and a WAV writer. See How to use audio line example.
  • For devices that don't support streaming: MuLine allows to create easily WAV samples from PCM audio data which can be played with the MIDP2 media player. See How to create WAV from PCM data example.

MIDP2 limitations

A lot of MIDP2 developers need to generate and play sounds in real time. They need an output audio line similar to the J2SE one. But MIDP2 specifications doesn't require that the player implementation supports streaming. Nevertheless the MMAPI specifications should allow to deal with streaming. But for the moment, it seems that only a few MMAPI implementations are fully compliant with the specs : a lot don't support streaming.