Introduction

Read, edit and write SWF (Shockwave Flash) files — their AVM1 ActionScript, and render them to images or SVG — entirely in code, on .NET 10. Fast, allocation-light, and round-trips losslessly.

Getting started

Install the packages and load your first SWF.

SWF reading & writing

Disassemble a SWF into a mutable tag tree, edit it, assemble it back losslessly.

AVM1

Disassemble DoAction bytecode and evaluate data scripts to a typed value tree.

Serialization

Map AVM1 globals to your own types, System.Text.Json style.

Rendering

Render shapes, sprites and text to images and SVG via Skia.

Highlights

Lossless round-trip — parse a real-world .swf and re-assemble it without losing data; byte-identical for canonically-encoded files, validated on 20k+ production SWFs.
Broad tag coverage — shapes, fonts, text, sounds, bitmaps, sprites, buttons, morph shapes, video, ABC, filters; unknown tags are kept verbatim.
AVM1 data scripts — evaluate localization/config bytecode into a typed value tree, edit it, write it back, or map it to typed records.
Typed & allocation-light — a mutable tag tree over ReadOnlyMemory<byte>, exact fixed-point value types, and typed exceptions.

What it isn't

Scope

No AVM2 (DoABC) execution — ABC bytecode is preserved verbatim, never run.
The AVM1 evaluator is linear only (data scripts): no control flow, function calls, or display objects.
The AS2 listing is best-effort, not a full decompiler.