File Metadata Reader & Editor

Overview

File metadata is information stored with or around a file. It may describe the file, its creator, the software or device that produced it, when it was created, and—sometimes—where it was created. Metadata is not one universal block shared by every file type.

Each format has its own containers and conventions. JPEG commonly uses EXIF, IPTC, and XMP; PNG uses chunks such as iTXt, tEXt, tIME, and XMP; MP3 uses ID3 frames; MP4 and M4A use atoms; PDF has document properties and XMP. A metadata reader needs a parser for each structure it wants to recognize.

MevoLab processes selected files locally in your browser. PNG and JPEG metadata can currently be edited or removed and exported as a new copy. Other formats may show only the metadata structures currently supported by this tool.

Where it is used

• Recording camera model, lens, exposure, orientation, and GPS coordinates in photographs
• Saving application settings, export details, workflow information, or custom notes
• Storing a title, author, description, copyright notice, or creating software
• Organizing music with title, artist, album, artwork, comments, and custom ID3 fields
• Tracking document authorship, revision details, keywords, and application information
• Checking files for identifying information before publishing or sharing them

Key facts

• Metadata is format-specific; there is no single browser API that returns every field from every file type.
• Custom metadata is valid. PNG iTXt fields and MP3 TXXX frames can store application-specific key/value data.
• A file can contain readable metadata that a particular tool does not recognize.
• The operating system modification date and an embedded metadata date are separate values.
• Removing metadata does not blur faces, erase visible text, or remove information contained in the media itself.
• The original file is never overwritten by this web tool; changes are exported as a new downloadable copy.

Examples

Common mistakes

• Assuming “metadata” is one standard object that every file contains in the same way.
• Assuming that no displayed fields means the file has no metadata. The reader may simply lack a parser for that format or custom structure.
• Expecting an image metadata parser to understand MP3 ID3 frames, PDF properties, or MP4 atoms.
• Treating the filesystem Date modified value as the same field as EXIF DateTime, PNG tIME, or an XMP date.
• Expecting a browser download to preserve or choose the operating system creation and modification timestamps.
• Believing that metadata fields must come from a fixed list. Many formats support custom or application-specific fields.
• Assuming metadata removal makes a file anonymous when identifying details may still be visible or audible in the content.
• Confusing metadata extraction with content analysis, such as speech transcription, OCR, object recognition, or image understanding.

Limitations

• This version edits PNG textual and time metadata and a supported set of JPEG EXIF fields.
• MP3 ID3, MP4/M4A atoms, PDF properties, WAV chunks, and other format-specific structures require additional parsers and are not yet fully inspected.
• Compressed, encrypted, proprietary, damaged, or undocumented metadata may not be readable.
• Some applications discard unknown metadata when they resave a file.
• PNG metadata keys are limited to 1–79 Latin-1 characters, while iTXt values can contain UTF-8 text.
• A PNG tIME chunk stores a timestamp but does not specify a timezone. MevoLab presents and writes it as an embedded file value, separate from filesystem time.
• Very large files require more memory because browsers must read and rebuild the downloadable copy locally.

Technical details

Frequently asked questions