VoIP Media Manager (Windows CE 5.0)
The VAIL, which handles call control (the setting up and tearing down of calls) and media transport (the converting of audio waveforms to and from IP packets), defers all media transport to the VoIP media manager object, which implements the IVoIPMediaMgr interface.
This enables the VAIL to expose an API that is independent of the media transport implementation, enabling the media transport implementation to change without requiring code that uses VAIL to change.
Windows CE 5.0 includes a reference media manager implementation that uses the Real-time Transport Protocol (RTP) stack included in the Real-time Communications (RTC) Client API Catalog item.
In many cases, customers might decide to implement their own media manager object to provide additional functionality or make the best of use of available hardware.
A custom media manager implementation can support additional functionality, like tailored jitter buffering or acoustic echo cancellation.
Custom media managers can also make the best of use hardware. For example, one of the main tasks accomplished by the media manager is to create packets and encode/decode audio, which might be best implemented using a DSP.
If you build a phone that includes a main processor and a DSP, you can implement a media manager that uses the DSP.
This offloads the processor-intensive media work to more appropriate hardware. It can also mean that the processor running the OS can be slower and cheaper than it would have to be if it also handled encoding and decoding.
For detailed information about responsibilities of the media manager, see Media Manager Responsibilities.
For instructions that explain how to connect a custom implementation so the VAIL creates it instead of the reference implementation, see How the VAIL Creates the Media Manager.
See Also
Send Feedback on this topic to the authors