What is the difference between ID3v1 and ID3v2?

ID3v1 is a fixed 128-byte block at the very end of the file with short, length-limited fields. ID3v2 sits at the start of the file, uses named frames like TIT2 (title) and TPE1 (artist), supports Unicode and has no practical length limit. This tool reads both and writes ID3v2.3.

Does editing change the audio quality?

No. Tag editing only rewrites the metadata block at the front of the file; the MPEG audio frames are copied byte-for-byte. There is no re-encoding, so the sound is identical to the original.

Why does my year or genre show oddly?

Year is read from the TYER (v2.3) or TDRC (v2.4) frame and genre from TCON, which may contain a numeric code in parentheses like (17) for Rock. The editor shows the raw decoded text so you can correct it directly.

Can it read embedded album artwork?

It detects the presence of an APIC (attached picture) frame and reports its size and MIME type. Full artwork rendering and replacement are intentionally out of scope to keep the tool dependency-free and fast.

Is my file uploaded anywhere?

No. All parsing and tag writing happen entirely in your browser using FileReader and Blob. Nothing is sent to a server, so the tool works offline once loaded.

ID3 Tag Viewer & Editor

Inspect and edit the ID3 metadata embedded in an MP3 — the title, artist, album, year, genre and track number that music players read. Everything runs locally in your browser: the file is parsed with the FileReader API, never uploaded, and a retagged copy is written back out as a download.

How it works

MP3 files carry two kinds of metadata. ID3v2 lives at the start of the file and is the modern standard. Its 10-byte header is ID3 followed by a version byte, a flags byte and a 4-byte synchsafe size (each byte uses only its low 7 bits, so the size is decoded as (b0 << 21) | (b1 << 14) | (b2 << 7) | b3). After the header come frames, each with a 4-character ID, a 4-byte size and the frame body. Text frames begin with an encoding byte: 0 is Latin-1 and 1 is UTF-16 with a byte-order mark.

The common text frames this tool decodes are:

TIT2 → Title        TPE1 → Artist
TALB → Album        TYER → Year (v2.3)
TDRC → Year (v2.4)  TCON → Genre
TRCK → Track        APIC → Attached picture

ID3v1 is a 128-byte trailer at the end of the file beginning with the ASCII TAG, holding fixed-width title, artist, album, year and comment fields. When no ID3v2 tag is present the viewer falls back to reading ID3v1.

Writing tags back

When you edit a field and download, the tool builds a fresh ID3v2.3 tag: for each non-empty field it emits a text frame with a Latin-1 encoding byte, computes the frame size, then wraps all frames in a header whose total size is re-encoded as a synchsafe integer. The original ID3v2 block (if any) is stripped and the audio frames are concatenated unchanged after the new tag, so the audio is bit-identical.

Tips

If a field looks garbled, it was likely stored as UTF-16; the tool decodes the BOM, but very old encoders sometimes mislabel encodings.
To strip all tags, clear every field and download — only frames with content are written.
Genre codes like (17) are a legacy ID3v1 numeric reference (Rock). Replace them with the plain genre name for best compatibility.