Hextage

HextageComing soon

Hex editor that knows the time (macOS)

"Which byte is this?" and "which second is this?" are always the same question.

Hextage is a hex viewer and editor that reads any file as bytes. Open a photo, audio or video file and it reads as time too, so every row of the dump shows the playback time of its bytes. In a multiplexed MP4 the video and audio rows alternate, and you can see the interleaving as it is.
Beyond basic editing — typing over bytes, inserting, deleting, truncating — it also handles media-specific edits in one move, such as cutting the last few seconds or removing the media data while keeping the index. Put the original and a modified copy side by side in two windows and see every differing byte in red.
Mac App StoreComing soon to the Mac App Store
macOS 15 or later. English and Japanese.
Time column, waveform, structure tree and inspector

Screens

1. Search by hex or text
2. Select by time, leave a bookmark
3. Reparse from any position
4. Compare before and after

Features

View & inspect

  • Time column: every row of the dump shows the playback time of its bytes
  • Timeline band: a waveform for anything with audio (WAV read directly, MP3 and video audio decoded), data rate for everything else. Click to jump, hover for the frame and time
  • Structure tree: ISOBMFF (MP4/MOV/HEIF/AVIF), RIFF (WAV/AVI), PNG/APNG, JPEG, GIF, TIFF, MP3 (ID3v1/v2), FLAC, AAC (ADTS), EBML (MKV/WebM), MPEG-TS, PDF
  • Metadata: Exif with GPS, ID3, QuickTime tags, RIFF INFO, PNG text — each one linked to the bytes it lives in
  • Reparse from here: read any position as a box, chunk, marker, frame or packet and see how the rest of the file would be read from there
  • Search: hex with wildcards (DE AD ?? EF), UTF-8 and UTF-16LE text. Runs over multi-gigabyte files without loading them into memory
  • Jump and select by address or by time, copy as hex, C, Swift, Python or ASCII, and a player linked both ways to the dump

Edit

  • Type over bytes in hex or ASCII, insert, delete, truncate, paste, write typed values (UInt32, Float …) in the current endianness
  • Cut the last N seconds, or remove only the media data and keep the index
  • Save in place, or export a modified copy while keeping the original
  • Edit history in its own window: position, before → after, timestamp; jump to any row or restore the file to that state
  • Bookmarks with notes that survive closing and follow insertions and deletions
  • Link two windows to scroll together, align them across insertions, and see every differing byte highlighted
  • Add a reparsed unit to the structure tree

How people use it

1. Testing

Make a broken file

Jump to a time, overwrite a byte, export under a new name. Useful for testing with intentionally broken data or checking a validation pipeline.
2. Troubleshooting

See where playback stops

Type the time where the player stalled and you are at that byte. The structure tree tells you which box it is in; reparse-from-here shows how the rest would be read.
3. Learning a format

Follow an MP4 with your eyes

ftyp, moov and mdat in order, video and audio interleaved, sample tables mapped to time — the diagrams from the spec, on your own file.

Pricing

Hextage is free to download. Buy the one-time in-app purchase "Hextage Pro" to unlock every feature without limits. No subscription — buy once and use it on the Macs signed in with the same Apple Account.

Requirements

  • Mac with macOS 15 or later

Languages

  • English, Japanese

Distribution

  • Mac App Store (coming soon)
For questions about the app, please use our contact form. See also the privacy policy for our apps.
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