Publisher to SWF Converter

PUB to SWF: What Ends Up Inside the Flash File

Converting a Microsoft Publisher document to a Shockwave Flash file is not a translation between two similar things — it is a rasterise-and-hold operation. Your .pub is rendered page by page into pictures, and those pictures are held on screen inside a .swf movie as a silent, motionless clip. Nothing about the layout becomes a Flash symbol, a timeline object or editable ActionScript, because there is no path from a print layout to a Flash authoring document.

That makes this a narrow tool with one honest use: feeding a .swf file to something from the Flash era that still refuses anything else — an old learning-management system, a kiosk player, a digital-signage box that was never migrated. Adobe ended Flash Player support on 31 December 2020 and began blocking Flash content on 12 January 2021, so no browser will open the result. If you actually want to read, print, email or archive the publication, stop here and use PUB to PDF; if you want something that plays today, PUB to MP4.

How to Convert PUB to SWF

1. Upload Your Publisher File: Drag the .pub onto the page or click "+ Add Files" to browse. Several publications can be queued and they share one set of settings.
2. Set Merge strategy and Image Duration: Merge strategy chooses "Merge images" (everything joins into one clip) or "Video per image" (a separate .swf per uploaded file). Image Duration runs from a single frame at 60 fps up to 10 seconds per frame, with 5 seconds preselected — this is how long each rendered page stays on screen.
3. Choose Video Codec, Background Color and Video resolution: Video Codec offers FLV (Sorenson Spark, preselected) and MJPEG. Background Color fills any letterbox area and opens on White, with Black and 23 other colours in the list. Video resolution opens on Keep original; Fixed Resolutions gives exact width-by-height pairs and is what you want here, for the reason in the next section.
4. Convert and Download: Click Convert and save the .swf. Files are uploaded over an encrypted connection, rendered and encoded on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public.

The Numbers That Come Out of the File

A .swf header declares its own stage size, frame rate and frame count, so the result is easy to inspect rather than guess at. We rendered a US Letter Publisher page, converted it at the default 5-second duration, and read the header back:

Three things worth taking from that. The encode genuinely runs at 1 frame per second, so the duration you pick is the frame count, one identical picture per second. MJPEG stores every frame as an independent JPEG with no prediction between them, which is why its file grows almost linearly with duration while the FLV barely moves — an eight-second MJPEG clip of a static page is over three times the size for no extra information. And the MJPEG path writes a declared frame count of 0 into the header while the FLV path writes the real number, so if anything downstream reads the header to size a timeline, FLV is the safer choice.

The stage size is the other thing to fix before you convert. A Letter page renders at 2550 x 3300 pixels at 300 DPI, and a Flash stage that size is far outside anything the format was designed around. Set Video resolution to Fixed Resolutions and take a real raster from the list — 1024 x 768 or 800 x 600 are closer to what Flash-era players expect than the native render.

Which Target Does a Publisher File Really Want?

Because .pub is a document, the sensible output depends entirely on what happens to it next.

Publisher itself is on a clock: Microsoft ends support on 1 October 2026 for Microsoft 365 and 13 October 2026 for perpetual licences. Whatever you convert to today, keeping a PDF alongside it is the safe move.

Frequently Asked Questions

Why is my SWF completely silent?

Because a Publisher document has no audio in it, and the converter does not invent any. For image and document sources the Audio Codec controls are not offered at all, so the .swf is written with a video track only. Lay music or narration over the file in an editor afterwards if you need sound — nothing on this page can add it.

Does the SWF animate, or is it a still?

It is a still, held. Each page is rendered once and repeated at one frame per second for the Image Duration you chose, so a five-second setting produces five identical frames. There is no pan, no zoom and no transition between pages — a multi-page publication plays as a hard cut from one held page to the next, in upload order.

What happens to a multi-page publication?

Every page is rendered separately and then concatenated into one clip, each held for the Image Duration. A three-page .pub at the default 5 seconds becomes a fifteen-second movie. If you would rather have one file per page, that is what image targets do — PUB to PNG writes a separate image for each page instead of a single timeline.

Should I pick FLV or MJPEG?

FLV for almost every case. It is the preselected codec, it is what Flash-era players and encoders expect to find in a .swf, and it compresses a static page far more efficiently — in the header comparison above, the eight-second MJPEG clip was over a megabyte where the FLV was 289 KB. MJPEG is worth choosing only when a specific downstream tool wants every frame to be an independent JPEG, and you should expect a much larger file and a header that declares zero frames.

Will the file play in a browser?

No. Adobe ended Flash Player support on 31 December 2020 and started blocking Flash content on 12 January 2021, and no mainstream browser has shipped a Flash runtime since. The container itself is still readable — VLC and anything built on FFmpeg decode the video stream directly without needing Flash — but if you want something that opens for an ordinary viewer, convert to PUB to MP4 instead.

Why is my Flash stage 2550 pixels wide?

Because "Keep original" means the render's own size, and the render happens at a fixed 300 DPI: a Letter page is 8.5 x 11 inches, which is 2550 x 3300 pixels, and A4 comes out near 2481 x 3507. That is a sensible size for a printed page and a strange one for a Flash movie. Switch Video resolution to Fixed Resolutions and choose an explicit pair before converting.

Does the Quality Preset actually do anything on this page?

Not on a document source. For codecs that support CRF the preset maps to a quality number, but neither FLV nor MJPEG works that way — for them the pipeline falls back to scaling the source video's bitrate, and a rendered page has no source bitrate to scale. The control that does move the output is Constant Quality, whose slider is an MPEG quantiser running 1 to 31 where 1 is best (2 to 31 on MJPEG), opening at 5. Treat it the opposite way round from a CRF number on an MP4 page.

Why are there coloured bars around my page?

Because a portrait page does not fill a landscape frame, and rather than cropping or stretching the artwork the converter pads the difference with the Background Color — which starts on White. On a page that is already white that is invisible; against a dark player background it looks like a bright border. Change the colour before converting, or pick a Fixed Resolution whose aspect ratio matches your page.

Can I get the Publisher layout back out of the SWF?

No, and nothing can. The conversion is one-way and destructive to structure: text frames, styles, linked images and the page model are all discarded the moment the layout becomes pixels. Keep the original .pub, and make a PUB to PDF copy as the archival version — that is the format Microsoft points to before Publisher support ends, and it keeps the text as text.

How is my file handled during conversion?

It is uploaded over an encrypted connection, converted on our servers, and both the upload and the .swf it produced are deleted automatically after a few hours. Files are never shared or made public, and there is no sign-up, no watermark and no email required.