Add your SSA file
Drop one or more .ssa files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
SSA to DFXP
Converting a .ssa file to .dfxp extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop SSA files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting SubStation Alpha subtitles to DFXP timed text
Converting a .ssa file to .dfxp extracts the document's content from its office package into a portable form. An .ssa file is a SubStation Alpha subtitle script — the v4.00 predecessor of Advanced SubStation Alpha. It uses the same [Script Info] / styles / [Events] layout and the same Dialogue timing, with a smaller style table and no v4+ extensions.
A .dfxp file is a TTML document written to the Distribution Format Exchange Profile — the profile the W3C defined for handing finished captions to a distributor. The extension signals the profile; the contents are ordinary TTML, which is why the same parser reads both. For this route the practical draw is accepted by name across a wide set of streaming ingest specifications and fully TTML, so any TTML tool can read and validate it — balanced against the distinct extension implies a distinct format and regularly confuses tooling, which is worth knowing before you commit a large batch.
Why convert SSA to DFXP?
The practical trigger for this conversion is usually a mismatch: with .ssa, superseded by .ass, which every current authoring tool writes instead. Switching to .dfxp buys you accepted by name across a wide set of streaming ingest specifications, which is why it is the better fit for delivering captions to a platform whose spec names DFXP by extension. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
SSA vs DFXP at a glance
| Aspect | SubStation Alpha subtitles (.ssa) | DFXP timed text (.dfxp) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | the [V4 Styles] section uses TertiaryColour and AlphaLevel fields that the later [V4+ Styles] table replaced | the document is TTML: a <tt> root, a <body>/<div> structure, and <p> cues with begin and end attributes |
| Strongest at | reading subtitle scripts from late-1990s and early-2000s releases | delivering captions to a platform whose spec names DFXP by extension |
| Weak spot | superseded by .ass, which every current authoring tool writes instead | the distinct extension implies a distinct format and regularly confuses tooling |
| Metadata | the v4 style table and script headers describe presentation only; timing and text survive conversion, styling does not | profile and parameter attributes are read for timing purposes only; styling and layout are not carried into caption targets that cannot express them |
Pick DFXP as the output
Select .dfxp in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if DFXP is selectable, the route is real and validated.
Convert on your device
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid DFXP file. Outputs keep the original filename with the .dfxp extension.
SSA to DFXP questions, answered
Will converting SSA to DFXP lose quality?
There is no visual quality to lose — ssa is text-oriented and dfxp is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert SSA files here?
Yes — the .ssa file is processed inside your browser tab and never uploaded. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded. Close the tab and the file is gone from memory.
Where will the DFXP file work?
Streaming ingest pipelines, caption editors such as Subtitle Edit and CaptionMaker, and any TTML-aware library open .dfxp. Browsers and consumer players do not. Novus Convert reads it through the same hardened TTML parser used for .ttml — no document types, no external entities, no network access — and writes any of the twelve timed-text targets.
Will the DFXP file be bigger or smaller than my SSA?
It depends on the content: the document is TTML: a <tt> root, a <body>/<div> structure, and <p> cues with begin and end attributes. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my SSA file?
In .ssa, the v4 style table and script headers describe presentation only; timing and text survive conversion, styling does not. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert DFXP back to SSA?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .ssa → .dfxp → .ssa is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.