A quick post to document how audio and video can be captured on Windows using FFmpeg into different container formats like MKV, MP4 and WebM.
List DirectShow devices
The following command lists the names of audio and video devices currently installed
ffmpeg -list_devices true -f dshow -i dummy
Capture from webcam and microphone
With container format mkv the default video codec is H.264 and audio codec is Vorbis. With the mp4 container format (change output.mkv to output.mp4) the video codec is H.264 and audio code is MPEG AAC. With the webm container format the video codec is the Google/On2 VP8 and audio codec is Vorbis.
ffmpeg -f dshow -i video="video device name":audio="audio device name" -r 25 -s 320x240 output.mkv
I added the -s (video size) and -r (video frame rate) options because with mkv and mp4 I was getting lots of dropped frames.