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CutConvert
Post-production file converter

Convert SRT to MCC

Turn SRT subtitles into MacCaption MCC ancillary-data files: spec-complete CDP packets at 29.97 drop-frame, ready for HD broadcast workflows.

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browseSRT filesConverted in your browser. Files never leave your device.About an hour of footage is free. Larger files: $3 each, or Pro $9/month for everything up to 50 MB.

up to 2 files · 100 KB each

free to start · project to project: $5 · every other conversion: $3 · Pro $9/month · pricing

Converting as a guest. A free account has no monthly cap on files within the free size limit.

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How to convert SRT to MCC

Convert SRT to MCC online. CutConvert encodes your SRT subtitles as a MacCaption MCC ancillary-data file: CEA-708 caption distribution packets carrying the CEA-608 caption track, the format HD broadcast delivery specs ask for.

  1. Add your SRT file

    Drag the .srt onto the drop zone. Cues are wrapped to the 32-column caption grid and encoded with the 608 character set.

  2. Convert SRT to MCC

    Press Convert. Every video frame gets a checksummed caption distribution packet with frame-rate code, sequence counters, and CDP and SMPTE 291 checksums, at 29.97 drop-frame.

  3. Download your result

    Download the converted file instantly, or a single ZIP archive when you convert a batch of files.

SRT file and MCC broadcast captions, explained

MCC is the HD sibling of SCC: instead of raw 608 hex, it wraps caption data in the CEA-708 ancillary-data packets that broadcast servers ingest directly. This converter builds those packets the way MacCaption does: one CDP per frame, byte-run alias compression, both checksums. The caption content rides the CEA-608 compatibility track that standard broadcast workflows read. The encoding pipeline is verified against Comcast caption-inspector reference decodes of real broadcast MCC files.

Turn SRT subtitles into MacCaption MCC ancillary-data files: spec-complete CDP packets at 29.97 drop-frame, ready for HD broadcast workflows. It is free to start, encrypted in transit, and converts a whole batch into one ZIP — sign in when you need large, high-volume jobs.

SRT to MCC FAQ

What exactly does the MCC contain?

One CEA-708 caption distribution packet per frame at 29.97 fps drop-frame, carrying your captions as channel-1 pop-on CEA-608 data, the compatibility track every broadcast decoder reads. Native 708 service blocks (windows, pen styles) are not generated.

Is the output really spec-compliant?

Each line carries a complete SMPTE 291 ancillary packet: correct DID/SDID, CDP header with frame-rate code and sequence counters, cc_count padding, CDP checksum, and the trailing ANC checksum. It is the same structure as MacCaption output, validated against real broadcast files.

MCC or SCC: which does my delivery need?

Read the spec sheet: SD and legacy workflows usually ask for SCC; HD/file-based workflows increasingly ask for MCC. The caption content is the same either way, and CutConvert produces both from the same SRT.

Why is the MCC file so much bigger than my SRT?

MCC is a per-frame transport: every video frame gets a packet whether or not captions change, plus the mandatory format-description header. A 30-minute program is a few megabytes, which is normal for the format.

Is it free?

Free to try on short files (about 10 minutes of program). Full-length caption files need a one-time $3 conversion or a paid plan, a fraction of the cost of desktop captioning software.

Guides for this workflow

Why editors trust it

Free to start

Convert everyday batches for free. Create an account when you need large, high-volume jobs.

Batch in, one ZIP out

Convert a batch within your allowance and download a single ZIP, or one file if that is all you need.

Made for editors

Whole timelines from Premiere, Final Cut and Avid with transitions, markers, titles, keyframes, levels, nests and bins; captions that keep their italics, colour, placement and speakers across SRT, VTT, ASS, TTML, iTT, SCC and STL, any of them in, any of them out; transcripts into Premiere with the words the engine timed. Frame rates and timecode handled the way post expects.

Private by design

Files are converted in your browser. Queued files can be saved locally to restore your job after checkout. Conversion metadata helps us diagnose errors; file contents are not uploaded.

Questions, answered

Where are my files processed?

In your browser. The converter runs on your own machine and the file never leaves it; the site only records that a conversion happened. CutConvert never sees, stores, sells or shares your media.

Is it free? Do I need an account?

About an hour of footage per file is free, on every converter: 100 KB of subtitles or captions, 500 KB of Word transcript, 2 MB of transcript JSON, 1 MB of Resolve project, 5 MB of Final Cut XML, with Premiere projects and Avid AAF a little under the hour. Guests get five conversions a month, a free account has no monthly cap within those sizes, and above that project-to-project transfers are $5 per file. Every other conversion is $3, including project files to captions, reports or cut lists, and captions or transcripts into an editor. Pro is $9 a month ($90 a year) for every file type up to 50 MB; Studio is $19 a month ($190 a year) for files up to 500 MB. Paid-file access lasts 24 hours.

What do I get when I convert multiple files?

Drop several files and you get back one ZIP archive containing every converted file. Convert a single file and you get that one file back, no ZIP. Tick extra formats under the output chips and the same ZIP carries every one of them, and a file counts as one conversion whatever it is written to.

Which formats are supported?

Timelines: Premiere .prproj, DaVinci Resolve .drp (as exported, or gzip- or Zstandard-wrapped), Avid AAF and Final Cut FCPXML in; FCP7 XML, FCPXML, Resolve .drp, CMX 3600 EDL and shot-list CSV out. A Premiere or Final Cut edit travels with its transitions, markers, titles, opacity and scale keyframes, clip volume, speed changes, nested sequences, bins, audio channel routing and each file's own frame rate, wherever the output has a place for them; an Avid AAF brings its transitions, markers, clip levels with their keyframes, muted tracks, nested stacks and each clip's own rate. Captions and transcripts, read and written: SRT, WebVTT, SBV, ASS, TTML, DFXP, iTT, SCC, MCC (a second 608 channel comes out as its own file), EBU-STL, Avid caption TXT, CapCut drafts of any size, timed CSV, Word, plain text, Whisper, WhisperX, AssemblyAI, Deepgram, Rev.ai and CapCut JSON, TwitchDownloader chat logs as a chat replay, Premiere transcript JSON and .prtranscript, Rev, Otter and Word-style transcripts, with italics, colour, placement and speakers kept where the output can hold them and measured word timing into Premiere. EDLs become event CSV reports. The capability table lists what every pair keeps.

Can I pick a frame rate?

Yes. For EDL and Avid caption output you can choose 23.976, 24, 25, 29.97, or 30 fps, or let CutConvert auto-detect it from your source.