hachoir-strip is an experimental program based on hachoir-parser and hachoir-editor: it removes "useless" informations from a file. Don't use it to create smaller file, you have better to recompress your data :-) hachoir-strip can be used if you would like to remove spy information which can be used to know the origin of a file.

Download

Examples

Our victim: 

$ hachoir-metadata KDE_Click.wav.new
Common:
- Creation date: 2001-02-21   <== here they are
- Producer: Sound Forge 4.5   <== spy informations :-)
- MIME type: audio/x-wav
- Endian: Little endian
Audio:
- Duration: 39 ms
...

Clean up the file: 

$ hachoir-strip KDE_Click.wav
[+] Process file KDE_Click.wav
Remove field /info
Remove 56 bytes (3.1%)
Save new file into KDE_Click.wav.new

$ hachoir-metadata KDE_Click.wav.new
Common:
- MIME type: audio/x-wav
- Endian: Little endian
Audio:
- Duration: 39 ms
...

So hachoir-strip removed creation date (2001-02-21) and producer (software used to record/edit the sound: Sound Forge 4.5). The file is also 56 bytes smaller.

Supported format and what is removed

  • AU audio: "info" (comment)
  • JPEG picture: "psd" (Photoshop metadata) and "exif" (EXIF metadata)
  • MPEG audio: "id3v1" and "id3v2" (ID3 metadata)
  • PNG picture: "text[*]" (commands) and "time" fields (timestamp)
  • RIFF container (AVI video, WAV audio): "junk" (padding), "nb_sample" (audio length), "info" (metadata), "index" (video index)
  • TAR archive: informations about user (name, identifier), user group (name, identifier) and timestamp

Option --strip

You can select field types to remove using --strip:

  • (default): remove all useless fields
  • --strip=useless: remove really useless fields (eg. padding)
  • --strip=metadata: remove metadata like ID3 tags and EXIF and IPTC metadatas
  • --strip=index: remove video index

You can combine options with comma: --strip="useless,metadata".

See also

  • jpegoptim: Program to recompress JPEG picture, gain is 5 to 50% in lossless mode (so can more in non-lossless mode)