MediaScope

Inspect media metadata, MP4/WebM structures, packets, audio, subtitles, and MSE streams.

MediaScope adds a dedicated panel to Chrome DevTools for debugging file-based and Media Source Extensions (MSE) video and audio playback, including HLS and DASH streaming. FEATURES • Info — View live playback metrics, history charts, buffer ranges, source details, container metadata, tracks, codecs, and MSE SourceBuffers. • Structure — Browse MP4 boxes or WebM/Matroska elements with track-type filters, offsets, sizes, semantic fields, codec configuration, encryption metadata, and payload previews. • Network — Inspect media requests, byte ranges, response sizes, timing, cache status, headers, and byte-signature matches with captured MSE appends. • Timeline — View playback events, network requests, SourceBuffer appends, sample ranges, DTS, PTS, and keyframes on a unified timeline. • Manifest — Parse DASH MPD and HLS M3U8 manifests, including variants, representations, renditions, segments, timelines, and content-protection fields. • Samples — Inspect audio, video, and subtitle samples with track types, codecs, byte offsets, DTS, PTS, duration, size, and key-frame status. • GOP — View GOP boundaries, key-frame intervals, decode and presentation ranges, sample counts, byte sizes, and average bitrate. • Frame — Decode a frame at a selected timestamp and inspect its encoded NAL units with an optional codec-specific grid overlay. • Bitrate — Visualize encoded sample sizes and keyframes over the loaded media time range. • Audio — Inspect audio codec details, sample rate, channels, language, packet timing, payload size, and bitrate. • Subtitles — Inspect DOM and container subtitle tracks and parse cues from WebVTT, TTML, and SubRip network responses. SUPPORTED PLAYBACK MediaScope supports MSE streams used by DASH and HLS players, direct MP4 and WebM files, real blob/File sources, and MPEG-TS packets. Enable MSE capture and reload the inspected page to capture fragmented MP4 or WebM data appended to SourceBuffers. Structure and packet-analysis views refresh through their own Reload buttons. The “Auto refresh metadata” control updates MSE container and track metadata separately. PRIVACY All inspection and parsing run locally inside your browser. MediaScope does not upload media, communicate with its own servers, or collect, store, or transmit personal data. WHAT’S NEW IN VERSION 0.3.0 • Live playback observation — Added observed frame rates, dropped frames, displayed video size, buffer ranges, waiting intervals, and 60-second history charts. • Playback event history — Added playback, pause, seek, waiting, resolution-change, and error events to Timeline. • Export playback observations — Added Copy Stats, JSON export for metrics and events, and CSV export for sampled metrics. • Clearer track identification — Added SourceBuffer grouping and track-type filters in Structure, plus track types and codecs in Samples. • Safer Structure inspection — Fixed captured-byte addressing and added detection of evicted data. • Performance and usability — Added Timeline pagination, preserved history across sampling interruptions, and clarified manual reload controls.