The FindUtils Audio Metadata Extractor reports file details, decoded duration, channel count, sample rate, and an estimated average bitrate. Select an audio file that the browser can decode to read these values.
This tool does not parse title, artist, album, artwork, or codec headers. Its sample rate comes from decoded audio, which can differ from the rate stored in the source. Use a dedicated metadata reader when you need the original tags or encoding parameters.
What does audio metadata describe?
Audio metadata includes both technical fields and descriptive tags. A technical field can describe channels or encoding. A descriptive tag can identify an artist or album. Different tools read different parts of a file.
The FindUtils extractor focuses on file information and decoded audio properties. This makes it useful for a quick duration or channel check. It does not replace a container parser that reads the file's original encoding headers.
Before you start, decide which question you need to answer:
- How long is the decoded recording?
- Does the decoded audio contain one channel or several channels?
- What sample rate does the browser use for the decoded samples?
- What average bitrate follows from the file size and duration?
- Do I need original tags or codec parameters from another reader?
Inspect an audio file
Step 1: Select the recording
Open the FindUtils Audio Metadata Extractor. Select the file. The inspection code reads the file in the browser.
Keep the original filename during the check. Renaming an extension can hide useful context without changing the underlying format. If decoding fails, open the original in an application that supports its codec.
Step 2: Read the file fields
The report includes the filename and file size. These describe the selected file. They do not establish which codec produced the audio.
A browser-supplied MIME type can also depend on the file extension. Treat it as a label to investigate, not independent verification of the encoded stream.
Step 3: Read the decoded audio fields
Review duration, channel count, sample rate, and estimated bitrate. Compare them with the requirements for your next task.
A one-channel voice note and a two-channel recording require different output settings. A duration that differs from the expected recording length also needs investigation before conversion or trimming.
Step 4: Record the result and its limits
Copy the report if you need a record for a conversion task. Include the filename and the question you checked. Label the bitrate as an estimate and the sample rate as a decoded value.
For example, a handoff note can say: “The browser decodes two channels. The duration is 60 seconds. The report estimates average bitrate from file size.” This avoids presenting an estimate as a direct header measurement.
Read the fields correctly
| Field | What the tool uses | Main limit |
|---|---|---|
| Filename | Selected file name | A suffix does not prove the codec |
| File size | Number of bytes in the file | Includes metadata and container overhead |
| Duration | Decoded audio buffer | The file must decode successfully |
| Channels | Decoded audio buffer | Does not describe every original channel label |
| Sample rate | Decoded audio buffer | Can differ from the source header |
| Estimated bitrate | File size divided by duration | Not a parsed codec setting |
| Title, artist, album, artwork | Not parsed here | Use a tag reader |
Why can the sample rate differ from the source?
Web Audio decoding converts the source into an audio buffer at the audio context's sample rate. The decodeAudioData documentation describes this resampling behavior.
The extractor reads the buffer's sample rate. It therefore reports the rate of decoded samples, not necessarily the rate written in the source file. A delivery specification that requires a particular original rate needs a direct header inspection.
Do not use this field alone to prove that a file was recorded at 44.1 kHz or 48 kHz. A resampled copy can contain a different rate from the recording process.
How does the bitrate estimate work?
The estimate divides the file's bit count by decoded duration:
estimated bits per second = file size in bytes × 8 ÷ duration in seconds
For example, a 1,200,000-byte file with a duration of 60 seconds gives 160,000 bits per second. This is an arithmetic example. It does not prove that the encoder used a fixed 160 kbps setting.
Tags, embedded artwork, and container overhead contribute to the file size. Variable-bitrate audio also changes its rate over time. The estimate averages the whole file and does not show those changes.
Common interpretation mistakes
Treating the estimate as a codec header
A calculated average can resemble a familiar bitrate setting. That does not make it a header measurement. Use a codec-aware reader when a client requires a specific encoding profile.
Expecting music-library tags
This extractor does not read title, artist, album, or artwork fields. A blank or absent tag field in this report does not prove that the source lacks the tag. Use an application that explicitly reads those tags.
Using bitrate as a sound-quality score
Bitrate alone does not describe recording noise, clipping, microphone placement, or earlier compression. Listen to the file as well as reading its properties.
Confusing decoding with file repair
A decoding failure is a limit or error, not proof that the file is empty. The browser may lack the required decoder. Check the file in a compatible application before you replace it.
Choose the next audio task
Use the Audio Resampler when the receiving application needs an explicit sample rate. Use the Audio Trimmer when only part of the recording belongs in the output.
The Audio Format Converter currently writes PCM WAV. Read its output limits before you select a format. The Media Info Viewer provides a separate inspection workflow; confirm that it reports the exact field you need.
FAQ
Q1: Does the extractor show the original sample rate? A: It shows the decoded buffer's rate. The browser can resample during decoding, so this can differ from the source header.
Q2: Does the extractor read MP3 title and artist tags? A: No. The current tool does not parse descriptive tags or album artwork.
Q3: Is the bitrate a precise encoder setting? A: No. The tool estimates the average from file size and duration. The calculation includes container and metadata bytes.
Q4: Does a high bitrate prove that the recording sounds good? A: No. Bitrate does not reveal noise, clipping, or information already lost during earlier conversion.
Q5: Does the extractor upload the selected file? A: The inspection code processes the selected file in the browser. The statement applies to this inspection operation.
Q6: What should I do when the file does not decode? A: Check the original in an application that supports its codec. The browser may not support the file's encoding.
