How to Convert MP4 to WAV

An MP4 file is a container that usually holds video plus a compressed audio track, often AAC. Turning it into WAV means extracting that audio and decoding it to uncompressed PCM, the format most audio editors, transcription tools and broadcast workflows accept. This guide uses FFmpeg for the conversion because its commands are the same on Windows, macOS and Linux, and covers how to check the result.

Before you start

• Confirm the MP4 actually contains audio. Screen recordings and some camera clips are saved without a sound track.
• Check whether the file is copy-protected. Purchased or streamed videos with DRM cannot be converted by standard tools.
• Make sure you have free disk space. Uncompressed 16-bit, 44.1 kHz stereo WAV takes roughly 10 MB per minute, far more than the original audio track.
• Decide where the conversion runs. FFmpeg and desktop audio editors process the file on your own computer. Browser-based converters usually upload the file to a server, so check the service's own statement on storage and deletion before using it for private recordings.
• Keep the original MP4. The conversion creates a new file and does not change the source, so you can repeat it with different settings.

Step-by-step instructions

Install FFmpeg from its official distribution or your system's package manager, then open a terminal (Command Prompt or PowerShell on Windows) in the folder that contains the video. Run ffmpeg -version first. If the command is not recognized, FFmpeg is not on your system path yet.

Look at the streams inside the file with ffprobe input.mp4. Find the lines marked Audio. They show the codec, sample rate and channel layout, and reveal whether there is more than one audio track.

Run the basic conversion: ffmpeg -i input.mp4 -vn -c:a pcm_s16le output.wav. The -vn option drops the video, and pcm_s16le writes standard 16-bit PCM, which almost every player and editor opens. Without further options, FFmpeg keeps the source sample rate and channel count.

Set a specific format only if the target tool requires it. Add -ar 48000 or -ar 44100 to change the sample rate, and -ac 1 for mono or -ac 2 for stereo. For example, ffmpeg -i input.mp4 -vn -c:a pcm_s16le -ar 16000 -ac 1 output.wav produces a small mono file of the kind many speech-recognition tools ask for. Use -c:a pcm_s24le instead if your editing workflow expects 24-bit files.

If the video has several audio tracks, choose one with -map. The command ffmpeg -i input.mp4 -map 0:a:1 -c:a pcm_s16le output.wav takes the second audio track, because counting starts at 0.

To extract only part of the clip, add a start time and duration: ffmpeg -ss 00:01:30 -i input.mp4 -t 00:00:45 -vn -c:a pcm_s16le clip.wav saves 45 seconds starting at 1 minute 30 seconds.

To turn a whole folder of MP4 files into WAV on macOS or Linux, run: for f in *.mp4; do ffmpeg -i "$f" -vn -c:a pcm_s16le "${f%.mp4}.wav"; done. In PowerShell, use: Get-ChildItem *.mp4 | ForEach-Object { ffmpeg -i $.FullName -vn -c:a pcm_s16le ($.BaseName + ".wav") }.

If you prefer a graphical tool, audio editors such as Audacity can open MP4 files when FFmpeg support is available and then export the audio as WAV. Menu names and import options differ between versions, so follow the documentation for the version you have installed.

Check the output

• Run ffprobe output.wav and confirm the codec is listed as pcm_s16le (or the PCM format you chose) with the expected sample rate and channel count.
• Compare the duration with the original MP4. A much shorter WAV means the conversion stopped early or a trim option was applied.
• Play the beginning, middle and end of the file to check for silence, the wrong language track or out-of-sync edits.
• Open the file in the program you plan to use it in, since some tools accept only certain sample rates or bit depths.

WAV is lossless only from this point forward. If the MP4 audio was compressed, the WAV is an exact decoded copy of that compressed sound and does not recover detail that was lost. Raising the sample rate or bit depth makes the file larger without improving the original recording.

Common problems and next steps

FFmpeg reports that the output contains no streams: the MP4 has no audio track, or the -map index points to a track that does not exist. Check the ffprobe listing and adjust the track number.

The WAV is silent or contains the wrong audio: the file probably has several audio tracks, such as commentary and game sound or separate microphone channels. Select the correct one with -map, or extract each track to its own WAV file and compare them.

Very long recordings stop opening correctly: standard WAV files are limited to about 4 GB. For multi-hour material, lower the sample rate or channel count, split the recording with -ss and -t, or add -rf64 auto so FFmpeg writes the extended RF64 format when needed, keeping in mind that not every program reads RF64.

Paths with spaces fail: wrap file names in quotes, as in the batch examples above. If FFmpeg asks whether to overwrite an existing WAV, answer n and choose a new name unless you are sure the old file is no longer needed.

If you only need a smaller audio file rather than an editable one, WAV may be the wrong target. Extracting to a compressed format such as AAC or FLAC keeps files compact, while WAV remains the safer choice for editing, mixing and tools that require uncompressed input.