MediaScope

Inspect <video> elements on the page — metadata, MP4 box tree, and per-sample list.

MediaScope adds a "MediaScope" panel to Chrome DevTools for inspecting the <video> elements on the page you're debugging. Select any video on the current page and MediaScope shows you: • DOM state — current source, resolution, currentTime, readyState, network state, and the usual <video> flags (loop, muted, autoplay, …). • Container info — format, duration, tracks, codecs, and bitrate. • MP4 box tree — an expandable ISO BMFF box tree with each box's offset, size, and a hex preview of its payload. • Samples / packets — a per-sample list with timestamp, duration, size, and the key-frame flag. • Single-frame decode — decode and preview a frame at a chosen timestamp. • Bitrate chart — visualize per-sample size over time. It works on videos that play from a direct file URL (MP4 / WebM and similar) or from a real blob:/File source. For MP4 files it also parses the raw box structure; other containers fall back to an MPEG-TS packet view. How it works: MediaScope runs entirely in your browser. To parse a video it reads that file's bytes (via HTTP Range requests for networked URLs, or by reading the page's in-memory blob) and analyzes them locally inside the DevTools panel. Nothing is uploaded, and the extension talks to no servers of its own. Limitations: • Videos played through MSE (Media Source Extensions) are not supported — there are no downloadable bytes behind their blob: URL. MediaScope detects this and tells you. • Raw box-tree view is implemented for MP4/ISO BMFF; WebM/Matroska tree view is not yet available. • The sample list is capped at 5000 packets to keep the UI responsive. MediaScope does not collect, store, or transmit any personal data.