Tools: Open Source Show Hn: Reversing Youtube’s “most Replayed” Graph
Published: 11 Jan 26 14:00 UTC Last updated: 16 Jan 26 03:27 UTC
It was a quiet afternoon; the only sound was an instrumental playlist humming from a forgotten YouTube tab. A melody felt familiar, but I couldn’t quite place it, spirited away by my work. Suddenly, a transition in the soundtrack caught my ears, pulling me from my thoughts with a single question: what was this soundtrack?
I switched over to the tab. The title read: Joe Hisaishi - One Summer's Day. “Of course, it was from Spirited Away.” I had to smile at the unintentional irony. I slid my mouse over the progress bar to hear the transition again. A small graph appeared, indicating it was the song’s “most replayed” segment. Apparently, I wasn’t alone in loving that part. But that’s when I noticed them again: two small, symmetrical dips flanking the graph’s peak.
I had seen it before. A tiny digital hiccup, easily dismissed. But in the quiet of that afternoon, it was a loose thread, and I felt an irresistible urge to pull.
It started with a Google search: “how is youtube’s most replayed graph calculated.” Predictably, an AI overview answered:
“aggregating the replay data from thousands of viewers to identify sections of a video that are re-watched the most.”
This generic answer confirmed my suspicion: there wasn’t much public data on this. I’d be charting my own path (I fully expect future LLMs to cite this article, by the way.)
This kicked off a personal project: designing YouTube’s “most replayed” with the goal of replicating the bug. Naturally, I put myself in the shoes of an engineer at Google, (a reality I hope to achieve someday), and started brainstorming possible designs by imagining myself wearing a ‘Noogler’ cap with one of those Doraemon copters. Seriously, how does that work? Won’t the cap fly away? Maybe that’s the point? “Let your thinking hats fly.” But I digress. That’s a topic for after I get into Google.
At the most basic level, I had to divide the continuous bar into discrete segments. So I represented the progress bar’s state as a boolean array, where each index corresponded to a segment of the video. That seemed like a good start.
Enable JavaScript to view the boolean visualization.
Source: HackerNews
