SMI to SCC Subtitle Converter
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100% local processing in your browser. No upload. No waiting.
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Supports .smi, .sami, .html files up to 50 MB
More Subtitle Tools
How It Works
Upload SMI File
Drag & drop or select your .smi file
Convert Instantly
We process it locally in your browser
Download SCC
Get your .scc file immediately
Why Choose AllSubConverter?
Your Privacy Matters
Everything runs in your browser. Your files are never uploaded.
Lightning Fast
Optimized processing engine converts files in seconds.
Free & Local
Each file can be up to 50 MB. Batches can contain up to 200 files or 1 GB total.
Works Everywhere
Works on Windows, Mac, Linux, iOS, Android - any modern browser.
Free Online SMI to SCC Converter
Our SMI to SCC converter reads Synchronized Accessible Media Interchange input and produces Scenarist Closed Captioning output entirely in your browser. Source SMI timing (whole milliseconds (Start=...)) is converted to SCC timing (SMPTE HH:MM:SS:FF at 29.97fps). SMI styling and markup are stripped, and unsupported characters are replaced in the basic ASCII caption stream. The conversion runs client-side, so your subtitle files are never uploaded to a server.
Input Format
SMISMI (SAMI, Synchronized Accessible Media Interchange) is a Microsoft subtitle format built from HTML-like <SYNC> elements whose Start attribute is given in milliseconds. SMI supports multiple language tracks through CSS classes and was widely used for Windows Media Player captions and accessibility content.
Output Format
SCCSCC (Scenarist Closed Captioning) is the industry-standard format for delivering CEA-608 (Line 21) closed captions to North American broadcast television and streaming services. SCC encodes caption text as hexadecimal byte pairs paired with SMPTE timecodes at 29.97 fps and begins with a Scenarist_SCC V1.0 header.
Features
Why Convert?
Format Differences
Common Use Cases
Broadcast Caption Delivery
Produce basic SCC files for broadcast-oriented workflows, then verify them against the recipient's CEA-608 specification.
Streaming Compliance
Generate SCC when a streaming platform explicitly accepts it, and confirm the current delivery specification.
FCC Compliance
Create SCC as part of a compliance workflow; professional delivery requires final specification checks.
Related Formats
SRT (SubRip)
The universal plain-text alternative: convert to SRT for maximum device compatibility.
VTT (WebVTT)
The web alternative: convert to VTT if your target is HTML5 video or YouTube.
STL (Spruce Subtitle)
The DVD/broadcast alternative: convert to STL for Spruce or DVD authoring workflows.
Frequently Asked Questions
It reads a Synchronized Accessible Media Interchange file, parses each cue's timing and text, strips SMI markup, and writes a .scc file. Source SMI timing (whole milliseconds (Start=...)) is converted to SCC timing (SMPTE HH:MM:SS:FF at 29.97fps).
Absolutely. Every conversion runs client-side in your browser. No subtitle data, file contents, or metadata is ever transmitted to a server.
SMI styling and markup are dropped. Unsupported characters are replaced with ?, and timing is quantized to 29.97 fps SCC frames, so review delivery-critical output before use.
Yes, completely free with no sign-up, no watermarks, and files up to 50 MB each. All processing happens in your browser, so your files are never uploaded to a server.
Source SMI timing (whole milliseconds (Start=...)) is converted to SCC timing (SMPTE HH:MM:SS:FF at 29.97fps).
Yes. The converter is fully responsive and works in any modern mobile browser on iOS and Android.