Converting an MP4 to MP3 keeps only the sound of the video: a lecture to listen to on the way, a song from a recorded performance, the audio of an interview. MP3 plays on every phone, computer, car stereo and music player.
How to convert MP4 to MP3
- Upload the MP4 (up to 2 GB and 4 hours).
- Keep Save as: MP3 and choose the quality: 192 kbps is a good default for music, 128 kbps saves space, 64–96 kbps is enough for speech.
- Download the MP3.
What happens to the sound
MP4 videos almost always carry AAC sound, which MP3 players don't read, so the sound is decoded and encoded as MP3 at the bitrate you choose (constant bitrate, which every player handles). Mono stays mono; stereo stays stereo; surround sound (5.1) is mixed down to stereo, because MP3 holds two channels at most. Sample rates above 48 kHz are brought down to 48 kHz.
The title, artist and album tags of the MP4, if it has any, are copied into the MP3. The video's location and recording date are not.
MP3 or M4A?
If you only need the sound and your player reads M4A, choose M4A instead: the AAC sound of the MP4 is then copied without re-encoding, so there is no quality loss at all and it takes seconds. MP3 is the choice when the file has to play on anything.
Tips
- To keep only part of the sound, trim the video first.
- A video with several sound tracks (for example two languages) gives the main track; the result tells you when there are more.
- Videos without a sound track can't be converted; the result says so.
More about what this tool reads and writes: Extract Audio from Video.