The Live Audio effect reads audio directly from the sound card input. It replaces any audio on the track so it is normally applied to an empty track. To use Live Audio, highlight a horizontal region of an audio track or define In and Out points. Then drop the Live Audio effect into it. Create extra tracks and attach shared copies of the first Live Audio effect to the other tracks to have extra channels recorded. Live Audio uses the sound driver selected in Settings → Preferences → Playback A → Audio Out for recording, but unlike recording it uses the playback buffer size as the recording buffer size and it uses the project sample rate as the sampling rate. These settings are critical since some sound drivers can not record in the same sized buffer they play back in.
Live audio has been most reliable when ALSA is the recording driver and the playback fragment size is 2048. Drop other effects after Live Audio to process sound card input in realtime. With live audio there is no read-ahead, so effects like compressor will either delay if they have read-ahead enabled or playback will under-run. A potential problem is that sometimes the recording clock on the sound card is slightly slower than the playback clock. The recording eventually falls behind and playback sounds choppy. Live Audio does not work in reverse.
The CINELERRA-GG Community, 2021