I've noticed FFmpeg does not work well when writing to more than one output pipe. So I figured muxing my rawvideo and rawaudio input streams, output the result to a single pipe, and demux it myself when it comes out the other end. Having no desire to write a full-fledged demuxer, I'm looking for the simplest container format FFmpeg supports. I found nut and avi, is there anything simpler? Note I know exactly what format data goes in the pipe, so I only need to be able to distinguish audio from video frames.