Is LFE channel completely lost when downmixing 5.1 to stereo using ffmpeg?

Question

so, I've been reading a lot about downmixing 5.1 to stereo, but as documentation provides, it creates L and R channels, so is the LFE channel being included down the mix? Is it completely lost? I've tried using -ac 2.1, but there's no option for that. It actually returns Expected int64 for ac but found 2.1. Sorry if this sounds like a newb question, but I can't seem to find a dead end answer to this.

Answer 1

Yes. See the FFmpeg Wiki. By default the LFE channel is omitted when using -ac 2.

You can of course create your own mixes if you want to keep the LFE channel.