Convert SB2 to SWF

An old kiosk, archive, or Flash-based application may require an SWF file even when the source project is an SB2 file. Because SB2 contains Scratch project data rather than Flash movie data, producing an SWF requires rebuilding the project, not changing the filename or archive type.

What the SB2 format is

SB2 is the project format used by Scratch 2.0 and the Scratch 2 Offline Editor. It is a ZIP-based archive containing Scratch scripts, sprites, costumes, backdrops, sounds, thumbnails, and metadata; an extracted project normally includes project.json and asset files with MD5-based names.

Scratch 2 creates SB2 files when users save or download projects. The format remains common in older educational projects, backups, and repositories created before Scratch 3 introduced the SB3 format.

What the SWF format is

SWF is a compiled Adobe Flash movie format that can contain vector graphics, bitmap images, audio, video, animation timelines, and ActionScript. It was designed for Adobe Flash Player and Flash-enabled desktop applications, not for Scratch project storage.

Adobe ended Flash Player support on December 31, 2020, and modern browsers block Flash content. SWF is therefore relevant mainly to isolated legacy software, archival systems, and specific kiosks or authoring workflows; it is not a suitable modern web-delivery format.

How to convert an SB2 file

No reputable converter performs a direct, functional SB2-to-SWF conversion. An SB2 project uses Scratch-specific event handling, block semantics, coordinate behavior, cloning, collision logic, and timing. An SWF requires compiled Flash objects and, for interactive behavior, ActionScript. Generic online converters cannot translate those systems reliably.

1. Make a backup of the original .sb2 file and open it in the Scratch 2 Offline Editor using File → Open. If it fails, inspect a copy with 7-Zip or another ZIP utility and verify that project.json and the referenced assets are present.
2. Extract the assets from the archive. Match the costume, backdrop, and sound references in project.json to the files in the extracted folders. PNG and SVG graphics can usually be imported into Flash authoring software; audio may need conversion to an importable WAV or MP3 format.
3. Use Adobe Animate, if an installation with Flash publishing support is available, to create an ActionScript 3.0 document. Scratch 2 projects normally use a stage size of 480 × 360 pixels; match that size unless the project deliberately uses different dimensions.
4. Import the extracted graphics and audio with File → Import → Import to Library. Recreate sprites, costumes, layers, motion, broadcasts, variables, sounds, cloning, and input handling with Animate timelines and ActionScript. There is no automatic equivalent of Scratch blocks in Animate.
5. Choose the Flash or SWF target in File → Publish Settings, then use File → Publish. Test the result only in the runtime required by the recipient. Ruffle can run some SWF and ActionScript content, but compatibility varies, especially for ActionScript 3 features; an unpatched legacy Flash Player should not be exposed to the internet.

The Scratch 2 Offline Editor can open and run the source project but has no native Export to SWF command. TurboWarp Packager and similar Scratch tools can produce HTML or JavaScript-based web packages, not SWF; use them when the actual requirement is browser playback rather than a Flash file.

Online converters and desktop alternatives

Online services that advertise arbitrary SB2-to-SWF conversion generally extract files or convert individual images and do not reproduce Scratch behavior. Do not upload private or student projects to such services. A reputable image or audio converter, such as CloudConvert, may help convert extracted PNG, SVG, WAV, or MP3 assets when its current format support matches the target authoring software, but it cannot convert the complete project.

For a genuine SWF deliverable, Adobe Animate is the practical authoring option when Flash publishing remains available. For preservation or ordinary playback, keep the SB2 and use the Scratch 2 Offline Editor, or record the running project to MP4 and export still images; these options avoid dependence on Flash runtimes.

Quality and compatibility limits

This process is a manual reimplementation, not a lossless format conversion. Text rendering, sprite rotation, pen effects, transparency, cloning, extensions, collision detection, broadcasts, variable scope, and sound synchronization may require custom ActionScript and can behave differently from Scratch.

Retain the original .sb2 file, extracted assets, and any ActionScript source alongside the SWF. The published SWF is compiled output and is not a practical editable replacement for the Scratch project.