MTS to SWF Converter

Convert MTS to SWF: Read This First

MTS is the AVCHD stream your Sony or Panasonic camcorder writes to its memory card — H.264 video up to 1920x1080 with AC-3 or LPCM audio. SWF is Adobe's Flash container, and Adobe ended Flash Player support on December 31, 2020, then pushed an update on January 12, 2021 that blocks Flash content from running in the official player; every major browser has since removed Flash entirely. So converting modern HD camcorder footage into SWF produces a file almost nothing can play natively in 2026. Most people who land here actually want a file that plays everywhere — that is MTS to MP4, not this. Only continue with SWF if a specific legacy system genuinely requires a .swf.

How to Convert MTS to SWF

1. Upload Your MTS File: Drag and drop your .MTS clip onto the page, or click "Add Files" to browse. You can queue several clips and they share the same output settings.
2. Set the Video Codec to FLV: Open "Show All Options" and leave Video Codec on FLV (Sorenson Spark, the H.263-class codec Flash players expect) — this is the default and the safe choice. MJPEG is the only other SWF-compatible option; it stores each frame as a JPEG, which balloons file size but suits frame-accurate ingest into old authoring tools. H.264 is not a valid codec inside this SWF output.
3. Pick Quality, Resolution, and Trim (Optional): Choose a Quality Preset (the default is "Very High (Recommended)") or switch to Constant Bitrate or Specific file size for an exact MB target. Drop the resolution with Preset Resolutions or Resolution Percentage — Flash-era playback targeted small frames, so 480p or smaller is usually right. Switch Trim from "Unchanged" to a Time Range to export just one section.
4. Convert and Download: Click Convert and download your .swf. No sign-up, no watermark.

Walk-through: codec, resolution, and audio for a file that will actually play

The honest part of this conversion: H.264 (inside your MTS) is far more efficient than the Flash-era FLV/Sorenson Spark codec SWF uses. Re-encoding into FLV means matching the same quality needs a higher bitrate, or quality drops if you keep the bitrate low — and you are doing this to hit a legacy player, not to gain anything. Set the options around the actual target:

• Keep the codec on FLV unless a tool demands MJPEG. FLV decodes in Ruffle and standalone Flash projectors and is what virtually every Flash-era player expects. MJPEG files are several times larger with no temporal compression; pick it only when a downstream importer specifically wants Motion JPEG frames.
• Match the legacy target's resolution, and expect it to be small. Most Flash kiosks and courseware were authored at 640x480 or 800x600. Use Preset Resolutions or Resolution Percentage to scale the 1080p source down; pushing SWF to 1280x720 rarely helps and defeats the purpose, since anything that can play 720p comfortably can play MP4.
• Audio becomes MP3. SWF predates AAC and never supported AC-3 (Dolby Digital), so the converter transcodes the AVCHD audio track to MP3, the maximum-compatibility audio codec for SWF. There is no way to keep a 5.1 surround track inside a SWF container.
• Export one section instead of the whole clip. A long 1080p AVCHD recording re-encoded to FLV will be large and many legacy players choke on big files — switch Trim to a Time Range and set the start and duration.

Common Errors and How to Fix Them

• "The SWF won't open in my browser" — that is expected, not a conversion fault. Browsers removed Flash after the December 31, 2020 end-of-life. Play the file with Ruffle (an open-source Flash emulator written in Rust) or a standalone Flash Player Projector instead.
• "File is much larger than the MTS" — the FLV/Sorenson Spark codec is roughly half as efficient as H.264, so matching quality takes more bits. If you also picked MJPEG, every frame is a standalone JPEG. Stay on FLV, drop to 480p or smaller, and use a lower bitrate.
• "Output looks soft or blocky" — FLV needs more bitrate than the H.264 source did. Raise the Quality Preset or set a higher Constant Bitrate; a 1080p clip will not look identical at a low Flash-era bitrate.
• "No audio after import into the old player" — confirm the player supports the MP3 audio track SWF uses; some very old Flash 1-4 era tools expect ADPCM, in which case a .swf with MP3 audio may be silent.

When This Doesn't Work

For almost every real-world goal in 2026, SWF is the wrong target — you would be re-encoding modern HD into a format the web abandoned, for no playback benefit. If you just want camcorder footage that plays on a phone, laptop, browser, or smart TV, convert to MTS to MP4 instead; H.264-in-MP4 keeps your quality and plays everywhere. The only honest reason to make a .swf is an un-migrated legacy system that still runs standalone Flash projectors or archived Flash tooling — a corporate CBT/LMS course built in Captivate or Articulate, a museum or trade-show kiosk wrapping a Flash projector, or a Ruffle-driven archive. If you want a flexible Flash-era container without the strict SWF constraints, MTS to FLV keeps Sorenson-class video in a more forgiving wrapper. And a genuinely corrupted or partially-copied camera clip can't be fixed by any converter — re-copy the original .MTS off the camcorder card.

Frequently Asked Questions

Why would I convert HD MTS footage into SWF at all?

Honestly, for almost no modern reason. The one legitimate case is feeding an un-migrated legacy system that still requires .swf — an older corporate training course (Captivate, Articulate, Lectora), a standalone Flash projector kiosk, or a Ruffle-based archive. If none of those apply, MTS to MP4 keeps your quality and plays in every browser, phone, and editor without an emulator.

Will the converted SWF play in Chrome, Edge, Firefox, or Safari?

No, not natively. Adobe ended Flash Player support on December 31, 2020 and blocked Flash content from running in the official player starting January 12, 2021, and every major browser removed Flash after that. To play the .swf you need Ruffle (an open-source Flash emulator that runs as a browser extension or embedded script) or a standalone Flash Player Projector executable.

Which video codec does the SWF use, and can I get H.264?

The default and recommended codec is FLV (Sorenson Spark), the H.263-class codec Flash players expect. MJPEG is the only other SWF-compatible option here, and it produces much larger files because each frame is a standalone JPEG. H.264 is not available as a codec inside this SWF output — if you need H.264, you are really looking for MTS to MP4.

What happens to the AC-3 or LPCM audio from my MTS?

It is transcoded to MP3, the maximum-compatibility audio codec for SWF. SWF predates AAC and never supported AC-3 (Dolby Digital) or multichannel surround, so a 5.1 track from the camcorder is downmixed to stereo MP3 during conversion. There is no way to keep the original surround mix inside a .swf.

What resolution should I pick for SWF output?

Small. Flash-era kiosks and courseware were typically authored at 640x480 or 800x600, and the FLV codec was tuned for those sizes. Use Preset Resolutions or Resolution Percentage to scale the 1080p source down to roughly 480p; going higher rarely improves perceived quality, bloats the file, and defeats the purpose since anything that plays 720p smoothly can play MP4.

Why is the SWF so much larger than the original MTS?

Two reasons. First, the FLV/Sorenson Spark codec is from the 1990s and is roughly half as efficient as the H.264 in your MTS, so matching quality needs a higher bitrate. Second, if you chose MJPEG, you are storing every frame as a separate JPEG with no inter-frame compression, which can multiply size several times over. Stay on FLV, lower the resolution to 480p or below, and reduce the bitrate to keep the file reasonable.

What happens to my file after I convert it?

Your MTS is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion. Files are never shared or made public, and there is no sign-up or watermark.