Bastien Sulyan

Independent software developer in Strasbourg, France

I design and build static web software, client-side file utilities, and offline mobile applications. My work focuses on running binary document, media, and image pipelines directly inside the browser using Web Workers, WebAssembly, and native Web APIs so user files do not have to pass through remote servers.

I run Ulysan, an independent web and software studio in Strasbourg, and build Sunasty, a collection of browser-side tools for PDF, image, audio, video, and developer workflows.

Technical Notes

Implementation notes and reference code drawn from building client-side document, image, color, and audio utilities.

• Processing PDF Files in the Browser Without a Backend

  Working with PDF cross-reference tables, ArrayBuffer transfers to Web Workers, page merging, stream recompression, and inspecting /Info dictionaries and XMP packets locally.

• Inspecting and Stripping EXIF, GPS, and C2PA Metadata in the Browser

  Parsing JPEG markers (APP1, APP11), reading TIFF IFD tags and JUMBF c2pa provenance boxes, and stripping metadata without full pixel recompression.

• Decoding Small and Low-Contrast QR Codes on HTML5 Canvas

  Why single-pass jsQR scans fail on full-page screenshots, overlapping 3×3 spatial tiling, local thresholding, and RFC 6238 TOTP generation with SubtleCrypto.

• sRGB, OKLCH, and WCAG 2.1 Contrast Calculations in Pure JavaScript

  Gamma linearization, Björn Ottosson's Oklab matrices, relative luminance ratios, and binary search over perceptual lightness L to meet WCAG AA/AAA targets while preserving hue.

• Client-Side Audio Extraction and Podcast Cleanup in the Browser

  Demuxing MP4 containers to MP3 or WAV in WebAssembly, reading ID3v2 frames, stem separation constraints in memory, and local loudness normalization for spoken-word recordings.

Projects & Open-Source Tools