audio quality checker
Check if an mp3 is really 320 kbps or a FLAC is really lossless, free, analyzed in your browser.
the bitrate on the label is only a label
Every lossy encoder throws away the top of the spectrum, and how much it throws away depends on the bitrate: a 128 kbps mp3 stops near 16 kHz, 192 near 18, 256 near 19, and 320 reaches past 20. Re-encoding a low bitrate file at a higher one never brings the top back, so a "320" whose spectrum ends at 16 kHz was a 128 in a past life, and a FLAC that stops at 16 kHz was made from an mp3.
Drop in any number of files. Each one is decoded and its whole-file average spectrum is measured, the cliff is found, and the verdict compares what the container claims with what the audio shows. The plot shows the cliff so you can see it yourself. Nothing is uploaded.
common questions
how can I tell if an mp3 is really 320 kbps?
Look at where its spectrum stops. A real 320 keeps energy up to 20 kHz or beyond; a file that dies in a flat line at 16 kHz was encoded at about 128 kbps no matter what the tag says. This tool measures that cutoff for you and names the likely source bitrate.
can a FLAC be fake?
Yes. FLAC is a lossless container, but if someone converts an mp3 to FLAC, the file is bigger and sounds identical to the mp3. The checker calls this out as a lossless container with a lossy source.
what if a real master has a low cutoff?
Some old or lo-fi masters were low-passed on purpose, and a few genres roll off early. The verdict is about bandwidth, so read it together with what you know about the recording; the plot shows whether it is a hard cliff or a gentle slope.