The Datastead Multipurpose Encoder is a Directshow multiplexer and sink filter, able to transcode audio/video streams through the command line of a LGPL build of FFmpeg included.
It can encode in H264 through the OpenH264 codec, and supports hardware encoding through the Intel QuickSync or NVidia NVENC technologies.
This filter is natively supported by ourTVideoGrabber SDK, allowing to record or re-stream real time sources like webcams, HD PCIe cards or IP cameras.
To configure the filter, just invoke SetCommandLine from the filter interface and specify the desired command line.
Some examples are provided in the documentation.
Technically, when the Directshow graph runs, the transcoding process starts in the background, and stops when the graph is stopped. Pause/Resume is supported.
Several instances of the filter can be used concurrently in the same application.