MP3 audio export — Verify the result

Worked example

To verify an MP3 export, compare its duration and size with what your settings predict, then play it in the app that will receive it.

The arithmetic is simple: size in bytes is roughly bitrate in kbps times seconds divided by 8, times 1000. A 3:30 track at 192 kbps should land near 5.0 MB, and at 128 kbps near 3.4 MB. If a 3-minute file at 192 kbps comes out at 1 MB or at 20 MB, something other than your setting changed it.

Duration should match the source to within a fraction of a second; encoder padding can shift it by a few tens of milliseconds, a difference of whole seconds cannot be explained that way. Then open the downloaded file, not the on-page preview, in a normal player and jump straight to the last ten seconds.

A typical case is a wedding videographer sending a 3-minute ceremony song to an editor. The mistake is listening to the first chorus only and discovering at delivery that the last drum hit sounds hissy. Listen to the opening 15 seconds, one loud passage with cymbals or consonants, and the final tail where the music fades.

Finally, check left and right on headphones: a stereo file that came out one-sided usually means the source had a silent channel. Pan between L and R once, and compare against the original with the same volume setting.

Accessible WAV/M4A/OGG/FLAC audio

MP3 audio

A tiny size difference from the estimate is normal because MP3 frames carry a small header, but a mismatch in duration is not.