Record video and sound
Choose a microphone
pactl list sources short
microphone="alsa_input.usb-MU900_MU900_20190805V001-00.analog-stereo"
Start recording
/dev/video0 is usually the default webcam
ffmpeg -f pulse -ac 2 -i "$microphone" -f v4l2 -i "/dev/video0" -vcodec libx265 /path/to/video.mkv
At higher resolutions encoding requires more resources. The output might be very laggy if the computer is not beefy enough.
Workaround: Record raw, then manually reencode. (The raw file will be big, and reencoding will take some time.)
ffmpeg -f pulse -ac 2 -i "$microphone" -f v4l2 -i "/dev/video$virt_cam_num" -c copy video-raw.mkv
ffmpeg -i video-raw.mkv -vcodec libx265 encoded.mkv
Reduce video file size
libx265 crf: https://trac.ffmpeg.org/wiki/Encode/H.265#ConstantRateFactorCRF
crf 28 is the default constant rate factor for libx265.
Max value is 51.
A higher value means lower quality and smaller file size.
ffmpeg -i input.mp4 -vcodec libx265 -crf 30 output.mp4
Download m3u8 stream and convert it to mkv
Find the m3u8 stream on a website:
- open dev tools
- go to Network tab
- filter to m3u8
- click on the result
- copy Request URL from Headers
ffmpeg -i "$URL" -c copy output.mkv