Encoder configuration

A media encoder for encoding a media buffer stream (e.g. data stream, such as video frames) has an encoder pipeline comprising a sequence of processing modules (e.g. pre-processor 103, encoder 104, packetiser 105) for processing a stream of media data (buffers), and pipeline configurator 106 to switch the encoder pipeline from one or more first encode parameters (e.g. frame size, frame rate, bit-rate) to second encode parameters. The first (pre) processing module of the pipeline associates a trigger value with at least first media data processed at the first processing module according to second encode parameters, the trigger value (e.g. via a toggled trigger flag, Figure 2) passing to subsequent modules so as to cause those modules to adopt the second encode parameters. Also claimed is a method of preparing video frames for encoding, comprising: receiving a video frame having first pixel dimensions; re-scaling the frame so one or both first dimensions are no greater than respective predetermined pixel dimension(s) and the aspect ratio is maintained; embedding the rescaled video frame within an output video frame having the predetermined dimensions, and marking pixels outside the rescaled video frame bounds as inactive (e.g. black level).