Video to MP3

Which audio format should you pick?

All three carry the same sound. What changes is how much space it takes and which apps open it without complaint. MP3 plays on practically anything, M4A holds AAC audio, which Apple devices play natively and video editors import, and WAV is uncompressed: it adds no loss of its own, but at 48 kHz stereo it is eight times the size of a 192 kbps MP3.

The sizes are arithmetic, not guesses. For MP3 and M4A: bitrate × 600 seconds ÷ 8 bits per byte, so 192 kbps gives 192,000 × 600 ÷ 8 = 14,400,000 bytes, or 14.4 MB. For WAV: 48,000 samples a second × 2 bytes per sample × 2 channels × 600 seconds = 115,200,000 bytes. A WAV follows the sample rate and channel count of your source, so a 44.1 kHz stereo soundtrack comes to 105.8 MB. Containers add a little on top: on our 10-second test clips every MP3 came within 0.3% of the formula for its measured length, the M4A within 2% and every WAV within 100 bytes.

How it works

1. 1

   Pick the video. Drop it on the box above or choose it from your disk. The tool reads its length, codecs and audio track at once, so you see what you are working with. Audio files such as MP3, WAV or M4A are accepted too.

2. 2

   Set format, bitrate and range. MP3 at 192 kbps is preselected. Switch to WAV or M4A, change the bitrate, or turn on “Only part of it” and drag the handles (or type the times) to keep one section. The estimated size updates as you change things.

3. 3

   Convert, listen, download. Press Convert and follow the progress bar; Cancel stops it at any moment. When it is done, play the result right on the page before you save it, then go back to try another format with the same file.

What you get

Only the sound is decoded

The picture track is set aside, never decoded, so the resolution of your video hardly matters: in our tests a vertical 1080p clip converted no slower than a 640-pixel web video of the same length.

One section, not the whole file

Keep a single answer from an interview or the chorus of a live recording. The range handles and the time fields work to a tenth of a second, and only that stretch is encoded.

The original audio, when possible

If the soundtrack is already AAC and you want M4A, or the file is already an MP3, “Keep original” copies the whole soundtrack as it is: no second round of compression, and it finishes almost instantly. Cutting out a section re-encodes it.

The size before you start

The workbench estimates the output size from the format, bitrate and length you chose, so you know whether a 90-minute lecture will fit in an email or a chat before you press Convert.

Questions people ask