Video to SWF Converter
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Supports: 3G2, 3GP, 3GPP, ASF, AV1, AVCHD +30 more
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Need help?How to Convert Video to SWF Online
- Upload Your Video File: Drag and drop or click "+ Add Files" to add MP4, MOV, AVI, WebM, MKV, FLV, WMV, MPEG, 3GP, TS, or other video files. Batch uploads are supported — every file uses the same output settings.
- Pick Video Codec and Quality Preset: SWF defaults to the FLV video codec with MP3 audio — these are the only combinations actual SWF players (and the Ruffle emulator) reliably decode. Open Advanced Options and use Quality Preset (Very High, High, Medium, Low) for a one-click setting, or switch to Constant Bitrate, Constant Quality, or Specific file size when you need to hit a precise target.
- Resize and Trim (Optional): Use Preset Resolutions (240p, 360p, 480p, 720p, 1080p) or Resolution Percentage to shrink the frame — small dimensions matter for SWF, which was designed for early-2000s broadband. Use Trim with a Time Range to cut to a specific in/out point if you only need a clip.
- Convert and Download: Click Convert. Files process server-side and the download link appears in your browser — no sign-up, no watermark, no Flash Player install required.
Why Convert Video to SWF?
SWF (Small Web Format, originally "Shockwave Flash") was Adobe's container for animation, vector graphics, and video on the web. Adobe ended Flash Player support on December 31, 2020 and blocked SWF playback in Flash Player on January 12, 2021, so SWF is no longer a delivery format for the open web. It is, however, very much alive in three contexts: legacy player ecosystems, the Ruffle emulator, and offline kiosk/archival workflows. Converting modern video into SWF is almost always a compatibility task — you have a tool, a device, or an archive that still expects this container.
- Feed legacy Flash projector executables. Standalone Flash projectors (.exe on Windows, .app on macOS) bundle the Flash runtime and still run SWF locally. Studios, museums, and corporate training systems built around projectors from 2005-2015 keep working as long as the content is delivered as SWF.
- Embed video inside Adobe Animate / legacy ActionScript projects. Adobe Animate (formerly Flash Professional) can still publish to SWF, and ActionScript 2.0 or 3.0 projects routinely embed FLV-encoded SWF clips as cutscenes, tutorials, or background loops.
- Drop video into Ruffle-hosted archives. Ruffle (the open-source Flash emulator written in Rust) is now used by the Internet Archive and BlueMaxima's Flashpoint to preserve Flash games and animations. Ruffle plays SWF with FLV video streams; converting an MP4 to SWF lets you slot modern footage into a Flash-style preservation context.
- Run on offline kiosks, ATMs, and digital signage that never upgraded. Industrial signage and self-service terminals from the Flash era still autoplay SWF loops from local storage. Replacing the original SWF asset is often easier than swapping the entire playback system.
- Convert Flash-era CD-ROM material in reverse. Educational CD-ROMs, e-learning courseware, and children's titles from 2000-2012 (Reader Rabbit, JumpStart, language software) shipped as SWF. Converting modern source video to SWF keeps the format consistent when patching or extending those titles.
- Produce a small, vector-friendly container for short animations. SWF compresses simple cartoons, logos, and short loops efficiently with FLV's H.263-based encoder — fine when the destination explicitly requires SWF.
SWF vs MP4 — Format Comparison
| Property | SWF | MP4 (H.264/AAC) |
|---|---|---|
| Year introduced | 1996 (FutureWave FutureSplash; bought by Macromedia 1996, Adobe 2005) | 2003 (ISO/IEC 14496-14) |
| Native browser playback | None — Chrome, Firefox, Edge, Safari all removed Flash by Dec 2020 | All modern browsers, since IE9 / Safari 3+ |
| Typical video codec | FLV (H.263 / Sorenson Spark), or VP6 | H.264 (also H.265, AV1) |
| Typical audio codec | MP3, or ADPCM | AAC |
| Designed for | Vector animation + scripting; video bolted on later | Streaming video at any resolution |
| Adobe support | Ended December 31, 2020 | Ongoing |
| Practical playback today | Standalone Flash projector, Ruffle, Adobe Animate, FFmpeg-based tools | Every browser, phone, TV, editor |
| File size for same content | Larger than MP4 at equal quality | Smaller and higher quality |
| Common use case in 2026 | Archival, legacy kiosks, Animate projects, Flash game preservation | Universal video delivery |
Quality Preset Quick Guide
| Preset | Use when | Trade-off |
|---|---|---|
| Very High (default) | Archiving a clip you may re-extract later | Largest file; safest for re-encoding |
| High | Standalone projector playback on a desktop | Good detail; moderate file size |
| Medium | Embedding in an Animate timeline as a cutscene | Smaller payload alongside vector art |
| Low | Looping background, kiosk, or signage at <480p | Smallest file; visible compression on detail |
Frequently Asked Questions
Will the SWF file play in my browser?
No. Chrome 88 (Jan 2021), Firefox 85, Edge 88, and Safari 14 all removed the Flash plugin. To play the converted SWF you need either the standalone Flash projector (still downloadable from Adobe's archive), the Ruffle emulator (browser extension or desktop app), or a desktop video player like VLC or MPV that bundles FFmpeg's SWF demuxer.
Why does SWF only support FLV video and MP3 audio here?
The SWF container spec supports a narrow set of codecs — FLV (Sorenson Spark / H.263), VP6, and Screen Video for the video stream, with MP3 or ADPCM for audio. AAC and H.264 are not part of the legacy SWF spec that classic players and Ruffle decode, so picking them would produce a file most SWF players cannot open. We default to FLV + MP3 to maximize compatibility.
Will Ruffle play the converted SWF?
Yes for the audio and the H.263-based video stream. Ruffle's video support has been ramping up — as of 2026 it handles FLV/H.263 video reliably for SWF1-SWF8 content. ActionScript-driven SWFs that load video at runtime are well supported (~99% of AS1/AS2 APIs, ~77% of AS3). A plain SWF that simply contains a video stream from a converter falls in the well-supported set.
What resolution should I pick for SWF?
Lower than you'd pick for MP4. SWF was designed for 320x240 to 640x480 web video in the early 2000s; FLV/H.263 starts to look blocky above 720p and the file sizes balloon. For projector or kiosk use, 480p or 720p is the sweet spot. Only go to 1080p if your target player is known to handle it (Animate's projector does; some embedded systems do not).
Can I keep the audio from my MP4?
Yes — the audio is re-encoded to MP3 inside the SWF container. AAC isn't part of the legacy SWF spec, so we transcode AAC to MP3 by default. The bitrate stays close to the source unless you cap it via Constant Bitrate.
Is there a file size limit?
We support multi-GB video uploads, but SWF is a poor choice for long or high-resolution footage. FLV/H.263 inside SWF produces files several times larger than the equivalent MP4. If you're converting anything longer than a few minutes or above 720p, consider whether the destination actually requires SWF — for most modern uses, MP4 is the better target.
Should I convert SWF back to MP4 instead?
For almost every modern playback target, yes. If your goal is to view, share, or embed video on the web today, convert in the opposite direction with SWF to MP4. The Video-to-SWF direction makes sense only when a downstream tool, projector, or legacy system specifically requires the SWF container.
Why doesn't Adobe Animate just publish my video as SWF directly?
Adobe Animate still publishes SWF, but its export pipeline for video has shrunk — Animate no longer embeds long video clips well and Adobe Media Encoder dropped SWF as a target. Using a converter to produce the SWF and then loadMovie/loadMovieNum (AS2) or Loader.load (AS3) it into your Animate project is the workflow most legacy developers use today.
Can I trim a long video before converting?
Yes — open the Trim section, switch to Time Range, and set the start and duration in seconds. This is the cheapest way to keep SWF output small, because the H.263 encoder inside SWF is much less efficient than modern codecs and every second saved is meaningful. For more options see the dedicated SWF trimmer.