As of the 3.10 release, the public domain (Unlicense) media server MistServer (https://mistserver.org) gained a new feature: the ability to mix raw (UYVY pixel format only, for now) video streams and raw audio streams (PCM) with resizing, overlapping, aspect ratio keeping and support for non-uniform frame rates between sources. Not only that - but it's even possible to control the configuration in real time without any downtime. This talk shows off what is possible, and explains how we did it in technical detail.

Covered topics:

• How to efficiently store a multi-frame raw video buffer in shared memory
• Synchronization handling between multiple sources
• Handling sources being added or removed without interruptions
• How we implemented decoding and encoding between raw and encoded formats
• The user interface that was built to control the mixing in a user-friendly way (though "raw" control through JSON is also possible)