How do I record just the internal audio with ffmpeg?

Question

ffmpeg -f x11grab -s 1920x1080 -i :0.0 -f alsa -i default -c:a aac -c:v libx264 -crf 18 -preset slower ~/Videos/recording-(date +%F-%I-%M).mp4

I'm using this command to record the screen and my intention is to record only the internal audio. But seems like the source is set to microphone. What will be correct command here?

Answer 1

Okay, after fiddling for an hour I found the solution. At first I got pulseaudio output source by running pactl list short sources. Which showed me this list -

0   alsa_input.usb-046d_0825_3AC10B90-02.mono-fallback  module-alsa-card.c  s16le 1ch 48000Hz   RUNNING
1   alsa_output.pci-0000_06_00.1.hdmi-stereo.monitor    module-alsa-card.c  s16le 2ch 44100Hz   RUNNING
2   alsa_output.pci-0000_06_00.6.analog-stereo.monitor  module-alsa-card.c  s16le 2ch 44100Hz   RUNNING
3   ladspa_output.mbeq_1197.mbeq.monitor    module-ladspa-sink.c    float32le 2ch 44100Hz   RUNNING

In my case the source is ladspa_output.mbeq_1197.mbeq.monitor.

Finally I ran this command selecting the output source -

ffmpeg -f x11grab -s 1920x1080 -i :0.0 -f pulse -i ladspa_output.mbeq_1197.mbeq.monitor -c:a ac3 -c:v libx265 -crf 22 -preset slower ~/Videos/Recording-$(date +%F-%I-%M-%N).mp4

Hope this helps.