How to extract audio from a video file, step by step

1. Load the MP4

Open the Audio Extractor and drop the video on it.

• Drop an MP4, MOV or WebM file; MKV works when your browser exposes a decoder for the audio inside it, and MXF does not.
• Read the detected sample rate, channel count, codec and bitrate in the spec strip before exporting anything.
• Camera files are usually 48 kHz AAC or PCM; screen recordings are often 44.1 kHz or 32 kHz.
• Free and pay-per-use runs are capped at 500 MB per file; Pro removes that cap, leaving your machine's memory as the practical limit.

2. Choose the output format

One extraction, three possible outputs: WAV, MP3 or AIFF.

• WAV is the free export and the default for anything going into an edit or a mix.
• AIFF and MP3 exports are Pro; MP3 is written at a fixed 320 kbps and there is no bitrate selector.
• Sample rate and bit depth follow the source unless you change them in the export settings; AIFF tops out at 24 bit.
• The channel layout of the source track is preserved, and the mixer faders you set are baked into the export.

Tip Name the output after the video file so the audio stays visually matched to its picture.

3. Extract and download

One video gives one audio file.

• Check the waveform and play it back to confirm you have the right take.
• Press extract; the audio file is written in the page and lands in your downloads folder.
• Keep the extracted audio in the same folder as the video, with the same base name.
• Do not rename after export or your NLE will lose the visual association.

4. Extracting audio from video on iPhone and Android

The same browser workflow runs on a phone, no app to install.

• Save the video to your Files app (iPhone) or internal storage (Android) first; the extractor reads a local file, not a cloud link.
• Open the Audio Extractor in Safari or Chrome, pick the file and check the detected track.
• Export: WAV for anything going to an edit, MP3 for sharing or transcription.
• The exported file lands in your downloads or Files app, ready to move into an edit or a message.

Tip Large phone recordings in 4K make heavy files; on the free tier keep each file under 500 MB.

5. WAV vs MP3 vs AIFF: which one to choose

The extraction is the same; only the container and the compression change.

• WAV: uncompressed PCM, for editing, post-production, sound design and anything that will be processed further.
• MP3: lossy compression at 320 kbps, for small review copies, reference files, transcription and sharing. Not for a mix.
• AIFF: uncompressed PCM as well, for Logic and Mac-centric workflows where AIFF is preferred or required.
• Extracting dialogue, production sound, ambience or effects for an edit? Take WAV. Sending a take to a client for approval? MP3 is enough.

6. What uncompressed does and does not do

Exporting to WAV or AIFF does not improve the audio already inside the MP4.

• An MP4 usually carries AAC audio, which is lossy: information was discarded when the video was encoded.
• Decoding that AAC and writing it as WAV gives an uncompressed copy of what is left, not a better recording.
• What it does give you is no further generation loss, which is why WAV beats re-encoding AAC to MP3 for editing.
• If a sound recordist was on set, treat the camera track as a sync guide and cut against their files.

7. Quality control

Sync problems come from rate mismatches, so check them first.

• Compare the audio duration with the video duration; they should match to the frame.
• Check the sample rate in the Audio Inspector against the rate detected on import.
• Line the extracted audio against the picture in your NLE and check a clap or a hard consonant at the end of the clip.
• Listen to the last ten seconds: drift, if any, is always worst at the end.