Why pull the audio out of a video?
There are plenty of honest reasons to separate the sound from a clip you already own. Maybe you recorded a lecture, a meeting, or an interview on your phone and only need the words, not the picture. Maybe you filmed a rehearsal or a gig and want the music as a standalone track to listen to later. Voice memos disguised as videos, family recordings, a podcast take you shot on camera, narration you want to reuse in an edit: all of these are cases where a compact audio file is far more useful than a heavy video. Extracting the audio also makes the file dramatically smaller and easier to share, archive, or drop into another project. The Extract Audio from Video tool on mastik handles exactly this, working only on files you upload yourself. It is not a downloader and never touches anyone else's content.
Step by step: extracting the audio
Open the Extract Audio from Video tool and either drag your video in or click to browse for it. Common formats like MP4, MOV, MKV and WebM all work, as do existing audio files if you just want to convert one. Once the file loads, pick your output format, MP3, M4A or WAV, and start the process. The first time you use it, the tool downloads a roughly 30MB processing engine (ffmpeg compiled to WebAssembly); this happens once and is then cached, so later visits are instant. Your file is decoded and the audio track is written out right there in the browser. When it finishes, a download button appears. Save the file and you are done. If your clip has a section you do not need, use Trim Video (Cut Clip) to cut it down first, which makes the extraction faster and the output tidier.
MP3 vs M4A vs WAV: which format to choose
Each format is a trade-off between compatibility, quality and file size. MP3 (encoded with libmp3lame) is the safe universal choice: every phone, car stereo, browser and player understands it, and it compresses the audio to a small size with quality that is more than good enough for speech, podcasts and casual listening. M4A uses AAC, which is a more modern compressed format; at a similar file size it generally sounds a touch cleaner than MP3, and it plays nicely across Apple devices and most modern players. WAV is uncompressed and lossless, meaning it keeps every bit of the original audio with no quality loss at all, but the files are much larger. As a rule: pick MP3 for sharing and everyday use, M4A when you want efficient quality, and WAV when you plan to edit or need a pristine master.
Tips for the best possible quality
Audio extraction can only preserve what is already in your file, it cannot add detail that was never recorded, so quality starts at the source. Always work from the highest-quality original you have rather than a version that has already been shrunk or re-shared. If the end goal is editing, mixing, or running the audio through effects, choose WAV so you keep a lossless copy to work from, then export a compressed MP3 or M4A once you are finished. If the audio is only for listening or sending to someone, a compressed format is the sensible pick and saves a lot of space. Avoid the temptation to convert a compressed file back into WAV expecting an upgrade; that just makes a bigger file without recovering lost detail. Should the resulting file still be too large to share, run it through Video Compressor afterward to bring the size down.
Doing it on your phone or on a desktop
This works on both, since everything runs inside a normal web browser. On a desktop or laptop you get the smoothest experience: more memory, faster processing and easy access to your download folder, which matters for long recordings or large video files. On a modern phone it works too; open the page in your mobile browser, pick the video from your camera roll or files, and the same in-browser engine does the job. Keep in mind that phones have less memory, so very long or high-resolution videos may process more slowly or strain older devices. If you are on mobile and hitting limits, trimming the clip down first with Trim Video (Cut Clip) or starting from a smaller file helps a lot. For a one-off voice memo or a short clip, a phone is perfectly capable of handling it start to finish.
Private by design: nothing leaves your device
Because the whole thing runs on WebAssembly inside your browser, your file never gets uploaded to a server. There is no account, no queue, and no copy of your recording sitting in the cloud waiting to be processed; the decoding and exporting all happen locally on your own machine. That is genuinely important when your video is a private interview, a personal voice note, confidential meeting audio, or unreleased music you are not ready to share. The only download involved is the one-time processing engine, and after that even your network connection is not needed to extract the audio. If instead of keeping the sound you want to strip it out of a video, Mute Video (Remove Audio) removes the audio track entirely, and if you simply need to change one audio file into another format, Video Converter does that in the same private, in-browser way.