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Post-production file converter

Convert SRT to MCC

Turn SRT subtitles into MacCaption MCC files with complete CDP packets at 29.97 drop-frame, for HD broadcast.

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browseSRT filesConverted in your browser. Files never leave your device.About an hour of footage is free. Bigger files: $3 a file, or Pro.

up to 2 files · 100 KB each

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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. It holds CEA-708 caption distribution packets that carry 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 wrap to the 32-column caption grid and use the 608 character set.

  2. Convert SRT to MCC

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

  3. Download your result

    Download the converted file, or one ZIP when you convert a batch.

SRT file and MCC broadcast captions, explained

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

Turn SRT subtitles into MacCaption MCC files with complete CDP packets at 29.97 drop-frame, for HD broadcast. 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. Each packet carries your captions as channel-1 pop-on CEA-608 data, the compatibility track every broadcast decoder reads. The converter does not generate native 708 service blocks such as windows and pen styles.

Is the output really spec-compliant?

Each line carries a complete SMPTE 291 ancillary packet. That means correct DID/SDID, a CDP header with frame-rate code and sequence counters, cc_count padding, the CDP checksum and the trailing ANC checksum. The structure matches MacCaption output, and we validated it against real broadcast files.

MCC or SCC: which does my delivery need?

Check the spec sheet. SD and legacy workflows usually ask for SCC. HD and file-based workflows more often ask for MCC. The caption content is the same either way, and CutConvert makes 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 required 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. That is a fraction of the cost of desktop captioning software.

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Questions, answered

Where are my files processed?

In your browser. The file never leaves your computer, and CutConvert only records that a conversion happened. We never see, store, sell or share your media.

Is it free? Do I need an account?

Files up to about an hour of footage convert free on every converter. CapCut projects are free up to 500 KB. Guests get five conversions a month; a free account has no monthly cap within the free size caps. Bigger files are $3 each, or $5 for a project conversion from one program to another. Pro is $9 a month ($90 a year) for files up to 50 MB. Studio is $19 a month ($190 a year) for files up to 500 MB.

What do I get when I convert multiple files?

One ZIP with every converted file. A single file comes back on its own. Press + to add more output formats: they go in the same ZIP, and each file still counts as one conversion.

Which formats are supported?

Projects in: Premiere .prproj, DaVinci Resolve .drp, Avid AAF and bins, Final Cut FCPXML, CapCut drafts and Audition sessions. Projects out: FCP7 XML, FCPXML, Resolve .drp, AAF, CapCut and REAPER, plus CMX 3600 EDL and shot-list CSV. Transitions, markers, titles, keyframes, levels, speed changes and nested sequences carry over wherever the target app can hold them. Captions: SRT, WebVTT, SBV, ASS, TTML, DFXP, iTT, SCC, MCC, EBU-STL, Avid caption TXT, timed CSV, Word and plain text. Transcripts: Whisper, WhisperX, AssemblyAI, Deepgram, Rev.ai and CapCut JSON, Premiere transcript JSON and .prtranscript, and Rev, Otter and Word-style text. Styling, placement and speakers come along where the output supports them.

Can I pick a frame rate?

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