Format guide · Stenograph
Open SGMCA files without Case CATalyst
Your CATalyst audio backup is an .sgmca file nothing else can play. Here's what's actually inside it — and the 30-second, no-license way to turn it into WAV or MP3.
What is an SGMCA file?
Stenograph's Case CATalyst records deposition audio into .sgmca files. Inside, the
audio is completely standard Ogg Vorbis — but CATalyst prepends a 96-byte proprietary header,
and that's enough to make every media player, editor, and transcription tool give up before reaching the audio.
That means the recording is fine; only the wrapper is the problem. Strip the header and any tool on earth can play what's left. That's exactly what DepoAudio does — it scans the first few kilobytes, finds where the real Ogg stream begins, and hands the clean audio to FFmpeg. No quality loss, no re-recording, no CATalyst license.
(proprietary)
Convert SGMCA to WAV or MP3
- Download DepoAudio — free, open source, Windows and macOS.
- Drag your .sgmca files in — one or a whole folder. The format is detected on drop.
- Pick your output — WAV for editing, MP3 for emailing a scopist, FLAC for archive. SGMCA records four channels, so you can also split one file per participant (Reporter, Witness, Attorney 1, Attorney 2).
- Click Convert. Files land in the library, organized by case name.
Everything runs on your machine — DepoAudio makes zero network calls during conversion, so client audio never leaves your computer.
Not sure your file is really SGMCA?
Drop it below. The identifier reads the first 8 KB right in your browser, shows you the evidence — then unwraps the Ogg stream and plays it on the spot. No upload, no install.
What's this file?
Drop any court recording — identified and played right here in your browser. Nothing is uploaded, ever.
✓ Identified & played locally in your browser — 0 bytes uploaded.
Common questions
What is an SGMCA file?
An SGMCA file is a proprietary audio format used by Stenograph's Case CATalyst software. It is an Ogg Vorbis audio container with a 96-byte proprietary header prepended at the start. DepoAudio scans the first 8 KB of the file, finds and strips that header, then passes the clean Ogg stream to FFmpeg for conversion — no quality loss.
How do I open an SGMCA file without Case CATalyst?
You can't play an SGMCA file directly — media players don't recognize the 96-byte proprietary header. DepoAudio strips that header and converts the audio to WAV, MP3, FLAC, or Opus so you can open it in any player or editor. No Case CATalyst license required.
How do I convert SGMCA to WAV or MP3?
Download DepoAudio (free, Windows and macOS). Drag your SGMCA file into the window, choose WAV or MP3 from the format selector, and click Convert. Done in a few seconds per hour of audio. No command line, no FFmpeg install — it's bundled.
Is there a free alternative to Stenograph for converting audio?
DepoAudio is free, open-source, and purpose-built for converting Stenograph SGMCA files (plus FTR, BWF, and other court recording formats). Unlike Stenograph's proprietary tools, DepoAudio requires no license, no subscription, and no account. MIT licensed — free forever.
Free · Open source · Local
Convert it in the app — 30 seconds, no upload.
Windows 10/11 & macOS 12+ · install steps