Everything the file will admit to: length, sample rate, channels, bitrate, how loud it really is, and whether it clips.
Press Analyse audio for the full report — including peak and average level, clipped samples, silent stretches and the real bitrate.
Loudness figures are measured from the decoded audio, so they describe the sound itself rather than whatever the file claims in its header.
Audio File Info opens a file up and tells you what is actually inside it — not what the filename or the header claims, but what the sound measures.
The technical facts come first: length, file size, sample rate, channel count and the real overall bitrate worked out from the file size and duration. Then the measurements that matter for how it sounds — the loudest point, the average level, the gap between them (the dynamic range), how many samples are clipped at the maximum, and how much of the file is silence.
Under the numbers you get a plain-English verdict: whether the file is too quiet, whether it distorts, whether it has been squashed flat, and whether it is padded with dead air. The full report downloads as a text file if you need to keep it or send it on.
Digital audio has a hard ceiling. When a recording is pushed past it the tops of the waves are chopped flat, which is heard as harshness or crackle. Once it is in the file it cannot be undone — only re-recording or re-mastering fixes it.
Somewhere between −3 and −0.5 dB for a finished file. Much lower and it is needlessly quiet; at 0 dB exactly there is a real risk some players will distort it.
The gap between the loudest moment and the average. A wide gap (over 15 dB) means natural, unprocessed audio. A narrow one (under 8 dB) means it has been heavily compressed, or that a constant noise floor is holding the average up.
It is calculated from the file size divided by the duration, so it is the true average across the whole file. A variable-bitrate MP3 will not match the number its encoder was set to.
No. This measures the sound itself rather than the metadata around it. Any music player will show you the tags.