A multimedia converter, compressor, and downloader built with Electron, FFmpeg, Sharp, and MuPDF. Convert, compress, and download videos, audio, images, documents, and PDFs -- entirely offline on your machine.
MP4, MKV, AVI, MOV, WEBM, FLV, WMV, TS, M2TS, MTS, 3GP, OGV, VOB, MPG, MPEG, M4V, DIVX, ASF, RM, RMVB, F4V
MP3, WAV, OGG, FLAC, AAC, M4A, OPUS, WMA, AIFF, AC3, ALAC, DTS, AMR, AU, RA, WV, APE
JPG, PNG, GIF, BMP, TIFF, WEBP, SVG, AVIF, HEIC, HEIF, ICO, JXL, JP2, PSD, RAW, CR2, NEF, DNG
TXT, MD, HTML, CSV, JSON, XML, YAML, YML, TSV, LOG, RTF, HTM, Markdown
PDF to Image (PNG, JPG, WEBP, AVIF, TIFF, BMP, GIF) and Image to PDF
- Video -- MP4, MKV, AVI, MOV, WEBM, FLV, WMV, TS, 3GP, OGV, M4V, MPG
- Audio -- MP3, WAV, OGG, FLAC, AAC, M4A, WMA, OPUS, AIFF, AC3, ALAC
- Image -- JPG, PNG, WEBP, AVIF, GIF, BMP, TIFF, HEIF, ICO, JXL, SVG
- Document -- HTML, TXT, MD, CSV, JSON, PDF (between document formats)
- PDF -- PDF to image and image to PDF (multi-page support)
- GIF Creation -- Convert any video to animated GIF
- Video to Audio -- Extract audio from any video (MP3, M4A, WAV, FLAC, OGG, OPUS, etc.)
- Animated GIF to Video -- Convert GIF to MP4 or WEBM
- Compression -- Reduce file sizes for video, audio, image, and GIF with quality control
- Batch Processing -- Convert multiple files at once with per-file progress tracking
- File Previews -- Thumbnails for images/videos and full preview modal with navigation
Convert documents to well-structured, styled HTML with full parser support:
- Markdown to HTML -- Headers, bold, italic, strikethrough, links, images, code blocks, blockquotes, lists (ordered and unordered), tables, and horizontal rules
- CSV / TSV to HTML -- Generates styled HTML tables with headers, proper escaping, and quoted field support
- JSON to HTML -- Syntax-highlighted JSON with color-coded keys, strings, numbers, booleans, and nulls
- XML to HTML -- Formatted and escaped XML code display
- YAML to HTML -- Formatted code display
- Plain Text to HTML -- Paragraph wrapping with line break preservation
- Log to HTML -- Monospace line-by-line display
- RTF to HTML -- Basic RTF control code stripping and text extraction
Additional document conversions:
- HTML to Markdown -- Reverse conversion (headings, bold, italic, links, images, lists)
- HTML to Plain Text -- Tag stripping with entity decoding
- CSV to JSON -- Structured array-of-objects output
- JSON to CSV -- Flat JSON arrays to comma-separated values
- Any Document to PDF -- Text extraction and PDF generation via PDFKit
- YouTube -- Download video and audio via yt-dlp
- TikTok and Other Platforms -- Generic yt-dlp support for 1000+ sites
- Format Selection -- MP4, WEBM video or MP3, M4A, WAV, FLAC, OGG audio
- Quality Options -- Best, 1080p, 720p, 480p
- Proxy Support -- Optional HTTP/SOCKS proxy configuration
- Progress Tracking -- Real-time progress with speed and ETA display
- 100% Local -- All processing happens on your machine. No uploads, no servers.
- Cross-Platform -- Windows (macOS and Linux support coming soon)
| Layer | Technology |
|---|---|
| Frontend | Astro (static output) |
| Desktop | Electron 33 |
| Video/Audio | FFmpeg via fluent-ffmpeg |
| Images | Sharp, Jimp (BMP fallback) |
| MuPDF (PDF to image), PDFKit (image to PDF) | |
| Documents | Built-in parsers (Markdown, CSV, JSON, XML) |
| Downloads | yt-dlp |
Konvrt/
├── electron/
│ ├── main.cjs # Electron main process, IPC handlers, static server
│ ├── preload.cjs # Context bridge (renderer to main)
│ ├── converter.cjs # FFmpeg, Sharp, MuPDF, PDFKit, document parser engine
│ ├── dev.cjs # Dev helper (waits for Astro server)
│ └── downloader/
│ ├── index.cjs # Unified download API (routes YouTube vs generic)
│ ├── settings.cjs # Paths, proxy config, yt-dlp binary location
│ ├── http.cjs # HTTP/HTTPS utilities, file download with progress
│ ├── youtube.cjs # YouTube-specific yt-dlp download
│ └── ytdlp.cjs # yt-dlp binary management, generic downloads
├── src/
│ ├── layouts/
│ │ └── Layout.astro # Global shell, CSS design system, color variables
│ ├── components/
│ │ ├── Header.astro # Navigation tabs (Convert, Compress, Download, Tools)
│ │ ├── DropZone.astro # Drag-and-drop file input with format tags
│ │ ├── FileList.astro # File list with thumbnails, progress, preview modal
│ │ ├── ConvertBar.astro # Bottom bar: format, quality, mode, actions
│ │ ├── ToolsPanel.astro # Converter and compressor tool grids (6 categories)
│ │ └── DownloadView.astro# Download UI: URL input, info, options, progress
│ ├── pages/
│ │ └── index.astro # App entry, script bootstrap
│ └── scripts/
│ ├── main.ts # Init, event wiring, IPC listeners
│ ├── state.ts # Reactive application state
│ ├── render.ts # DOM rendering with smart patching
│ ├── convert.ts # Conversion loop, progress tracking
│ ├── download.ts # Download handlers, toast notifications
│ ├── file-ops.ts # File array management, type detection
│ ├── preview.ts # Image/video preview modal
│ ├── helpers.ts # Utilities (format, duration, preview)
│ ├── constants.ts # Format lists (video, audio, image, document, PDF)
│ ├── tools-data.ts # 120+ tool cards for tools grid
│ └── types.ts # TypeScript interfaces
├── package.json
├── astro.config.mjs
├── tsconfig.json
└── Dockerfile
- Node.js (v18+)
- npm
git clone https://github.com/hazavi/Konvrt.git
cd Konvrt
npm installStart the Astro dev server and Electron together:
npm run devOr run them separately:
npm run dev:astro # Start Astro on localhost:4321
npm run dev:electron # Launch Electron (requires Astro running)Build the Astro frontend and package the Electron app:
npm run buildThis runs astro build then electron-builder for Windows, macOS, and Linux. Output goes to release/.
Build and run the Astro static preview in a container:
docker build -t konvrt .
docker run -p 4321:4321 konvrtNote: The Docker image serves the Astro static frontend only. Electron desktop features (file conversion, downloads) require the native desktop build.
| Command | Action |
|---|---|
npm install |
Install dependencies |
npm run dev |
Start Astro + Electron concurrently |
npm run dev:astro |
Start Astro dev server on port 4321 |
npm run dev:electron |
Launch Electron (connect to running Astro) |
npm run build |
Build frontend and package desktop app |
npm run preview |
Preview the Astro build locally |
| From / To | Video | Audio | Image | GIF | |
|---|---|---|---|---|---|
| Video | Yes | Yes | -- | Yes | -- |
| Audio | -- | Yes | -- | -- | -- |
| Image | Yes | -- | Yes | Yes | Yes |
| GIF | Yes | -- | Yes | -- | -- |
| -- | -- | Yes | -- | -- |
| From / To | HTML | TXT | MD | CSV | JSON | |
|---|---|---|---|---|---|---|
| Markdown | Yes | -- | -- | -- | -- | Yes |
| HTML | -- | Yes | Yes | -- | -- | Yes |
| CSV / TSV | Yes | -- | Yes | -- | Yes | Yes |
| JSON | Yes | -- | -- | Yes | -- | -- |
| XML | Yes | -- | -- | -- | -- | -- |
| YAML | Yes | -- | -- | -- | -- | -- |
| Plain Text | Yes | -- | -- | -- | -- | Yes |
| RTF | Yes | Yes | -- | -- | -- | -- |
| Log | Yes | -- | -- | -- | -- | -- |
Planned features and improvements for future releases:
- Download Manager -- Queue, pause/resume, show in folder and manage multiple downloads at once
- Linux and macOS Builds -- Tested and signed native packages (.AppImage, .deb, .dmg)
- More Tools -- Trim video, extract audio, crop/resize images, merge PDFs, watermark
- Drag and Drop Reorder -- Reorder files in the conversion queue
- Auto-Update -- In-app update notifications and one-click install
MIT