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.
- Dump the unencrypted backup components to disk:
signalbackup-tools [backupfile] [password] --output [directory]
- Process message attachments:
signal-backup-shrink.py [directory]
- Re-encrypt backup with processed attachments:
signalbackup-tools [directory] --replaceattachments -o OUTPUT.backup -op [password]
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