Rust native desktop subtitle workstation. It accepts audio or video input, submits audio to MOSS-Transcribe-Diarize, writes SRT/VTT subtitles, and can burn subtitles back into video files.

cargo run

• Rust 1.93+
• MOSS API Key
• FFmpeg for development, either available on PATH or configured with FFMPEG_PATH
• HarmonyOS Sans SC Regular at assets/fonts/HarmonyOS_Sans_SC_Regular.ttf
• FFmpeg source submodule at vendor/ffmpeg-src

FFmpeg lookup order at runtime:

1. FFMPEG_PATH
2. ffmpeg or ffmpeg.exe beside the app
3. macOS .app/Contents/Resources/ffmpeg
4. embedded Windows FFmpeg extracted to the user cache
5. system PATH

Use the platform scripts for release builds:

scripts/build-macos.sh
scripts/build-linux.sh

Windows PowerShell:

scripts\build-windows.ps1

Build outputs:

• dist/macos/MOSS-Subtitle-Workbench.app
• dist/linux/MOSS-Subtitle-Workbench
• dist/windows/MOSS-Subtitle-Workbench.exe

Windows distribution is a single executable. The app embeds FFmpeg, the required MinGW runtime DLLs, and the UI font, then extracts runtime files into the user's cache directory when needed. Do not publish extra DLL, font, or legal folders next to the Windows exe.

FFmpeg source is managed as a git submodule:

git submodule update --init --depth 1 vendor/ffmpeg-src

Distribution scripts build FFmpeg for the current platform before packaging:

vendor/ffmpeg/macos/ffmpeg
vendor/ffmpeg/linux/ffmpeg
vendor/ffmpeg/windows/ffmpeg.exe

macOS and Linux keep FFmpeg beside the app bundle/executable. Windows embeds ffmpeg.exe and its MinGW DLL dependencies into MOSS-Subtitle-Workbench.exe.

Default FFmpeg flags stay LGPL-compatible:

--pkg-config-flags=--static --disable-gpl --disable-nonfree --enable-libass

libass is required for the FFmpeg subtitles filter used by burn-in output.

Build dependencies:

• macOS: brew install libass pkg-config
• Linux: pkg-config and libass-dev or libass-devel
• Windows: MSYS2 MinGW with mingw-w64-x86_64-libass, pkgconf, GCC, nasm, and yasm

The UI uses HarmonyOS Sans SC Regular. The Windows build embeds the font into the single exe. macOS and Linux package scripts copy it into their app resources.

Source files:

assets/fonts/HarmonyOS_Sans_SC_Regular.ttf
assets/fonts/HarmonyOS_Sans_SC_LICENSE.txt

HARMONYOS_FONT_PATH can override the bundled font during development.

GitHub Actions release builds produce one uploaded asset per platform. The Windows job verifies that dist/windows contains only MOSS-Subtitle-Workbench.exe before upload.

New projects are created in ~/MOSS-Subtitle-Workbench/ by default, inside a MOSS-Subtitle-Workbench-<timestamp>/ project directory. The project root can be changed in the app and is not changed when an existing project is opened.

Generated files include:

• audio.m4a: extracted audio for video input
• transcript.json: raw model result
• transcript.txt: full transcript text
• subtitles.srt: SRT subtitles
• subtitles.vtt: WebVTT subtitles
• project.json: editable app project snapshot
• subtitled.mp4: video with burned-in subtitles, when requested

Supported video inputs include MP4, MOV, MKV, WebM, M4V, and AVI. Supported audio inputs include WAV, MP3, AAC, FLAC, OGG, MPEG, M4A, MP4 audio streams, WebM audio streams, and PCM.

1. Video input is preprocessed with FFmpeg to extract audio; direct audio input is uploaded as-is.
2. POST https://studio.mosi.cn/api/v1/files/upload uploads the audio.
3. POST https://studio.mosi.cn/api/v1/asr/tasks creates an async ASR task.
4. The app polls GET https://studio.mosi.cn/api/v1/asr/tasks/{task_id} until completion.
5. The returned JSON is normalized into editable subtitle segments and written to disk.

Keep the license files in assets/fonts, vendor/ffmpeg-src, NOTICE.md, and THIRD_PARTY_NOTICES.md up to date. The Windows single exe embeds redistributable runtime files, so public/commercial release should still review the actual FFmpeg, font, and Rust dependency license obligations.