Goal
Seweryn Durczok is a DJ and MC from Silesia with more than a decade on stage and 500+ events behind him. His site had to sell what clients actually buy: a charged room, a full dancefloor, the drop, the lights, and a steady voice on the mic. Photos could support that story, but they could not lead it. We put real performance footage on the first screen, then engineered it to behave on hotel Wi-Fi, train LTE, mid-range Android phones, and older laptops without making the entrance feel like a wait.
The risk
The easy version is a single MP4. It also creates the failure mode. One encode has to serve every screen and every connection. Tune it for desktop and mobile visitors wait; tune it for mobile and the footage loses weight on larger displays. The browser still has to pull too much before playback feels safe, so the strongest asset on the page can become its slowest moment. For a DJ, that is the wrong first beat.
Adaptive delivery
We turned the hero into an adaptive HLS stream. The source clip is transcoded with FFmpeg into a bitrate ladder, from a small low-bitrate rendition to full HD, then split into short segments described by an .m3u8 playlist.
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HLS.js handles playback where the browser needs it; Safari and iOS use native HLS. The player reads real throughput and selects the current rendition segment by segment.
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Playback begins on a low rung for a quick first frame, climbs as bandwidth allows, and drops back the moment the network weakens instead of buffering.
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The browser fetches only the segments actually watched, so a phone on metered LTE never pulls the full 1080p master.
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A lightweight AVIF/WebP poster owns the first paint, the video payload stays lazy until needed, and Save-Data / reduced-data signals are respected.
Full portfolio
Around the hero we built the complete portfolio: an "O mnie" bio, a four-part offer for weddings, studniówkas, corporate events, and special occasions, a gallery served as responsive AVIF/WebP through next/image, testimonials, partner logos, and a contact form with phone and email. The whole site stays mobile-first because most couples start the DJ search on a phone.
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Polish-language content with structure and metadata prepared for SEO and AI discovery.
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Deployed on Vercel, with HLS segments and responsive images served from the CDN for low latency across Poland.
Launch result
At launch, the site has a performance-led hero that starts quickly and stays smooth across devices and networks without shipping one heavy file to everyone. The poster keeps Largest Contentful Paint quick while HLS takes over for playback, and adaptive delivery limits mobile data use by sending only the quality the connection can handle. The result is a fast, mobile-first portfolio where the most demanding element on the page is controlled from the first frame, with the foundation in place for visibility to grow over time.