Awesome

Overview

This is a companion script to signalbackup-tools that reduces the size of a Signal backup by processing message attachments of the following file types:

• .jpg, .png (resized and compressed)
• .gif, .mp4, .mkv, .3gp (replaced with a collage of keyframes)

Using this method, I was able to reduce my Signal backup size by about 80% (from 4GB to 800MB) without having to delete anything and thus lose context in the message history.

Dependencies

• signalbackup-tools
• vcsi
• filetype
• pillow

Usage

1. Dump the unencrypted backup components to disk:

signalbackup-tools [backupfile] [password] --output [directory]

2. Process message attachments:

signal-backup-shrink.py [directory]

3. Re-encrypt backup with processed attachments:

signalbackup-tools [directory] --replaceattachments -o OUTPUT.backup -op [password]

Limitations

Currently, signalbackup-tools only supports replacing attachments with images. Hence, it is not possible to

• process audio files (such as voice recordings)
• replace gifs or videos with smaller versions
• optimize PDFs or other documents