Convert MP4 to MP3 - extract audio
Pull the audio out of any MP4 as an MP3 file. Wave decodes only the audio track and re-encodes it with LAME at 192 kbps - a rate that's audibly transparent for most source material.
What actually changes
MP4's audio track is almost always AAC. MP3 is a different codec entirely, so this is always a re-encode - there's no "just repackage" path from AAC to MP3. Wave uses libmp3lame, which remains the reference-quality open-source MP3 encoder.
The output is 192 kbps constant bitrate, joint-stereo where the source is stereo. That's roughly the "sounds identical to source on consumer gear" threshold. Voice content would sound clean at much lower bitrates; if you want higher, pick AAC instead - the AAC path is a lossless remux when the source is already AAC.
Three steps.
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01
Step 1
Drop the MP4 onto the card.
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02
Step 2
On the inspect screen, pick MP3 as the output format.
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Step 3
Convert. Save the MP3.
Answers, specifically.
Will the MP3 sound as good as the source?
At 192 kbps, effectively yes for music on any consumer setup. Voice content is transparent at much lower bitrates.
Can I choose a different bitrate?
Not yet. Wave ships a single sensible default to keep the UI clean. Bitrate options are on the roadmap.
Why MP3 and not AAC or WAV?
Wave outputs one audio format on purpose - MP3, because it plays on literally every device that plays sound. The main product is video → MP4; audio extraction is the one adjacent shortcut, kept deliberately narrow so the UI stays a single choice.
What if the MP4 has no audio track?
Wave detects that during inspect and stops with a friendly message before any conversion runs.
Does the ID3 metadata carry over?
Basic tags (title, artist if present) are copied. Album art doesn't transfer through the current pipeline.