MP3 and FLAC tags and cover editor

About this mp3 and flac tags and cover editor

Edit MP3 ID3 or native FLAC title, artist, album, date and cover locally; preserve compressed audio bytes without re-encoding Processes streaming audio and video buffers directly in the browser using HTML5 Media and Web Audio APIs with zero server uploads.

Audio and video decoding pipeline

Reads supported ID3v2.3/v2.4 text and PNG/JPEG APIC frames, with ID3v1 text fallback. Writes ID3v2.3 TIT2, TPE1, TALB and TYER text as UTF-16 with BOM, plus the selected APIC cover, while copying MPEG Layer III audio bytes without re-encoding. Download the original cover bytes or convert the image to PNG locally. Alternatively, choose ID3v2.4 to write UTF-8 TIT2, TPE1 and TALB, plus the four-digit year in TDRC, and the selected PNG/JPEG APIC. ID3v2.4 uses synchsafe tag/frame sizes and zero tag/frame flags. Reads one leading ID3v2.3 or ID3v2.4 tag with an extended header. ID3v2.3 accepts the ordinary extension or a CRC extension and validates declared zero padding; its CRC covers frames only. ID3v2.4 accepts any combination of update, CRC and restriction flags with their prescribed payload lengths; its CRC covers frames and padding. A checksum mismatch is rejected. Writing replaces the extension with an ordinary tag in the selected version and preserves MPEG audio bytes. Reads ID3v2.3/v2.4 tag-level unsynchronisation and experimental-indicator flags; verifies an ID3v2.4 footer and excludes it from the MPEG audio offset. Writing emits an ordinary tag without tag unsynchronisation or a footer and preserves MPEG audio bytes. Writes UTF-8 TITLE, ARTIST, ALBUM and DATE Vorbis comments and a PNG/JPEG front-cover PICTURE block. Keeps the vendor, other comments, STREAMINFO, padding, application and seek-table blocks, and all compressed audio bytes. No decoding or re-encoding of audio. To extract the current FLAC front cover, choose Prepare cover PNG, then Download cover PNG. Reads ID3v2.3/v2.4 frame status flags and grouping IDs, plus ID3v2.4 per-frame unsynchronisation and data-length indicators. Interprets supported flags and writes changed frames with zero flags while preserving MPEG audio bytes. Ordinary unflagged PRIV frames are retained as opaque data when editable content remains; clearing all text and the cover removes the entire ID3v2 tag. Read-only frames and unknown frames marked for preservation block writing. Reads ID3v2.3/v2.4 zlib-compressed frames up to 10,000,000 decompressed bytes per frame and 20,000,000 per tag. Compressed v2.4 frames require a matching data length indicator. Zlib frames using preset dictionaries and encrypted frames remain unsupported.

Worked media transformation example

Buffer duration & codec support limits

Operational constraints and validation boundaries: MP3 input must be smaller than 100 MB (100,000,000 bytes); each PNG/JPEG cover must be smaller than 10 MB (10,000,000 bytes). This MP3 section accepts MP3 only; use the separate FLAC section for native FLAC. Reads ordinary uncompressed, unencrypted ID3v2.3/v2.4 frames with the supported status/grouping and v2.4 unsynchronisation/DLI flags; reserved flags and unsupported features are rejected. Writing replaces editable fields and omits additional pictures. Ordinary unflagged PRIV frames are retained opaquely when editable content is rewritten; clearing all text and the cover removes the entire ID3v2 tag. Empty text omits that field, and removing the cover omits APIC. PNG conversion uses browser image decoding and canvas; it does not preserve the original image file bytes. An update-marked ID3v2.4 tag is read on its own; earlier tags or stream updates are not merged. Restriction bytes are encoding declarations: they do not change decoding, and this tool does not certify that every restriction was met. Rewriting removes those declarations. Malformed extension sizes, flag payloads, checksums and nonzero padding are rejected. ID3v2.3/v2.4 tag unsynchronisation and experimental-indicator flags are accepted; ID3v2.4 footer copies are checked and excluded from MPEG audio. Writing emits an ordinary tag without unsynchronisation or a footer. Missing v2 text fields fall back to ID3v1 Latin-1 text. Only the first PNG/JPEG APIC is selected. Images must decode in the browser and fit within 8192 pixels per edge and 16,777,216 pixels total. The year must be empty or four digits; v2.4 TDRC is reduced to its first four characters and the remaining date/time is not retained. Each text field is limited to 10,000 UTF-16 code units; control characters and malformed Unicode are rejected. Writing also removes any old ID3v1 tail so cleared values cannot return through fallback. The same limited input subset applies to either output version. If all text and the cover are removed, no ID3v2 tag is written, regardless of the selected version. Native fLaC only, input and output <100,000,000 bytes; cover <10,000,000 bytes, ≤8192 pixels per edge and ≤16,777,216 pixels. Up to 64 metadata blocks and 16 MiB of metadata, 10,000 comments, 100,000 bytes per comment and 10,000 UTF-16 units per edited field. Rejects CUESHEET/reserved blocks, multiple pictures, non-front-cover pictures, repeated editable fields, malformed metadata and unsupported images. Ogg FLAC, audio-frame CRC/MD5 verification, audio repair and desktop-player compatibility are not provided. Date is free text; no calendar validation. Cover PNG conversion uses browser image decoding and canvas; its pixels follow browser decoding and its file bytes differ from the original image.

Audio and video rendering in MP3 and FLAC tags and cover editor depends on browser hardware and supported media codecs. Verify playback compatibility on your target platforms.

In-memory audio-video processing boundary

File buffers and document assets in MP3 and FLAC tags and cover editor are processed in-memory via local browser APIs with zero file uploads to CZOA servers.

HTML5 Media & Web Audio standards

W3C Web Audio API specifications and HTML5 media container standards:

• ID3v2.3/v2.4 tag structure (supported subset)
• ID3v1 text fallback
• MPEG Layer III frame boundaries
• PNG/JPEG artwork; browser Canvas PNG export

MP3 and FLAC tags and cover editor verification · Audit standards

How to use it

1. Choose an MP3 and read its tags. Review title, artist, album and year; keep, replace or remove the cover. Clear text fields only when you want to remove their values. Write and download the updated MP3. Select the output version before writing; ID3v2.3 is the default.
2. Review parameter fields, units, or options configured for MP3 and FLAC tags and cover editor.
3. Write and download it.