Extract audio from video — Settings and quality

Worked example

Three choices matter: the format (MP3, M4A or WAV), the audio quality in kbps (96, 128, 192, 256 or 320) and, optionally, sample rate and channels.

The defaults, MP3 at 192 kbps with source sample rate and channels kept, suit most jobs.

MP3 plays everywhere, M4A (AAC) gives slightly better quality than MP3 at the same bitrate and usually matches the sound already inside a video, and WAV is uncompressed, so it avoids another lossy step but weighs about 635 MB per hour at 44.1 kHz stereo.

Choose the bitrate by content. For a single speaker, 96 to 128 kbps is enough and a one-hour lecture lands near 43 to 58 MB; for music, 192 to 256 kbps is the sweet spot at about 86 to 115 MB per hour; 320 kbps rarely sounds different from 256 and adds about a quarter more data.

Channels work differently for compressed and uncompressed formats. At a fixed bitrate, picking Mono does not make an MP3 or M4A smaller, it gives the single channel more bits, which can help speech; with WAV, Mono halves the size to roughly 317 MB per hour.

Keep the sample rate on Keep source unless you have a reason, because video audio is usually 44.1 or 48 kHz and converting adds nothing for a listener. Lower values such as 22.05 kHz cut the top end and suit only voice-only files.

Local video containing an audio track

MP3 audio track

File size is mostly bitrate times duration, so pick the bitrate first and the rest of the choices matter far less.