samsung-notes-format

Reverse-engineered reader for the handwriting in Samsung Notes .sdocx files. Decodes the on-disk pen-stroke format and renders the strokes back out.

This is a research repo, focused on the stroke geometry. For a more complete library that also decodes pressure, tilt, and color and renders full ink, see twangodev/sdocx.

• Write-up (how and why): https://musaab.io/posts/2026/reverse-engineering-samsung-notes/
• Format reference: RESEARCH.md

Usage

python3 render.py note.sdocx [out.svg]

Parses the note, decodes every stroke, and writes an SVG with each stroke drawn inside its stored bounding box. The whole pipeline is one self-contained file, ~190 lines.

Other files

Older research files, kept for reference rather than as the canonical implementation. render.py is the clean, correct one; treat the rest as the trail it was built from.

• sdocx_extractor.py: fuller extractor that dumps all metadata to JSON. Its delta decode is a slight simplification (5 integer bits instead of the full 10); the output is identical on real handwriting, but render.py has the exact decode.
• plot_strokes.py: earlier SVG renderer.
• artifacts/debugging/: scratch scripts from working the format out; they try several wrong encodings before the right one.
• sdocxFiles/, extracted_sdocx/: sample notes.
• blog-artifacts/: figures and the comparison harness for the write-up.
• *.png, Screenshot_*.jpg: leftover render and comparison artifacts from the research, kept as a rough record of progress rather than cleaned out (example.png is the one used above).

Notes

Independent implementation for interoperability and research. The repo contains no Samsung binaries or decompiled code, only original code and the documented format. Samsung Notes is a trademark of Samsung Electronics. The code here is MIT-licensed (see LICENSE).