Read an audio file's codec, bitrate, sample rate and tags

How to view audio metadata

1. Drop an audio file on the box or press Choose a file. MP3, M4A, AAC, WAV, OGG, Opus, FLAC and WebM files, and video files with sound, can be read.
2. Press Read details.
3. Read the summary (Duration, and Title and Artist if tagged) and the Details table.
4. Download the table as CSV if you need to keep it.

What it does and when to use it

Use it to check a file before you hand it over: does a podcast host’s 128 kbps limit match, is that “lossless” download really FLAC, did a recorder save at 48 kHz 24-bit as set, are the title and artist tags filled in, is cover art embedded? It is also a quick way to see why a program refuses a file, for example an unusual codec or a WAV stored as 32-bit float.

To see the sound itself, use the waveform viewer. To change what you found, the audio converter changes codec and bitrate, and the sample rate converter changes the rate. To measure tempo from the sound rather than a tag, use the BPM detector.

How it works

Nothing is decoded or uploaded; the tool only reads the file’s structure on your device.

• WAV files are parsed directly: the RIFF header gives the encoding (PCM integer or IEEE float, with its format tag), bit depth, sample rate, channels, byte rate, total frames, the list of chunks, and any LIST/INFO text tags.
• Other formats are opened with the Mediabunny library, which reads the container (MP3, MP4/M4A, Ogg, WebM/Matroska, FLAC and others) and the first audio track: codec and its parameter string, sample rate, channels, language, and duration. Overall bitrate is file size × 8 ÷ duration. Tags come from ID3, MP4 or Vorbis comments: Title, Artist, Album, Album artist, Genre, Track, Disc, Year/date, BPM, Comment, and the count and type of cover images.

Worked example

A 12.5-second stereo recorder file, take-03.wav, saved at 24-bit 48 kHz, gave this summary: Duration 0:12.50, Format 24-bit 48 kHz, Channels 2. The Details table listed:

The byte rate checks out: 48,000 samples × 2 channels × 24 bits = 2,304,000 bits per second.

Limits and tips

• Formats the library does not recognise return “This format is not recognised.” Convert with audio to WAV, which has an ffmpeg fallback, to learn more.
• For an MP3 or M4A, the audio bitrate is an average, so a variable-bitrate file reads as one number.
• Only the first audio track of a multi-track video is described.