Source & delivery
See the selected element, every media request, and the manifest that describes the stream.
MediaScope 0.2.1 · Chrome DevTools
Playback
under a microscope
Trace media files and live MSE playback across requests, containers, timestamps, samples, and decoded frames—all inside Chrome DevTools.
Files + MSE 11 focused views Local analysis
capturing MSESourceBuffer · audio + video106.0 MB
InfoStructureNetworkTimelineManifestSamplesGOPFrameBitrateAudioSubtitles
I42.608s
B42.650s
B42.692s
P42.734s
B42.776s
B42.818s
P42.860s
DTS42.608 s
PTS42.692 s
SIZE128.4 KiB
OFFSET0x1F83A4
11inspection views
256 MiBrolling MSE window
A + VSourceBuffers merged
0media uploads
One connected viewOne moment
One moment
Every layer
Trace the same playback moment from its network request and SourceBuffer append to DTS, PTS, encoded sample, and decoded frame.
42.60s42.65s42.70s42.75s
Networksegment-042.m4s
AppendSourceBuffer #2
Media timePTS 42.692 s
FrameIDR · 128.4 KiB
42.692
A focused toolsetStart broad
Start broad
Go byte deep
Eleven purpose-built views keep high-level playback state and low-level encoded data in the same debugging session.
Info · Network · Manifest
Container & samples
Move from MP4 boxes or WebM elements down to real offsets, sizes, DTS, and PTS.
Playback timing
Correlate delivery, appends, keyframes, sample ranges, and bitrate on media time.
Decoded output
Inspect the frame, audio packets, and timed-text cues that reach the viewer.
PlaybackDirect URL · Blob/File · MSE
ContainersMP4/fMP4 · WebM/Matroska · MPEG-TS
StreamingDASH/MPD · HLS/M3U8
Timed textWebVTT · TTML · SubRip
Inside the streamAnswer the question
Answer the question
behind the playback bug
What is actually in the file?
Read the container
Explore MP4 boxes and WebM elements with offsets, sizes, codec configuration, encryption fields, and payload previews.
Map the stream
Connect requests, manifests, segments, and MSE appends in a unified playback timeline.
Inspect every sample
See real byte offsets, DTS, PTS, duration, sample size, and key-frame status.
Which bytes made this frame?
Land on the exact frame
Choose a timestamp, decode the frame, inspect NAL units, and line it up with its GOP and sample metadata.
Follow audio timing
Track codec, channels, sample rate, packet timing, payload size, and bitrate.
Read timed text
Inspect DOM and container tracks plus WebVTT, TTML, and SubRip cues.
MSE, finally observableMSE is no longer
MSE is no longer
a black box
Capture fragmented MP4 or WebM appends, combine audio and video SourceBuffers, and inspect a rolling window of real playback data.
Local by designAnalyze locally
Analyze locally
Share nothing
MediaScope reads and parses playback data inside your browser. Your media never needs to leave the DevTools panel.
No account No media upload No collection
- 01InstallAdd MediaScope from the Chrome Web Store.
- 02Open DevToolsChoose the MediaScope panel on any media page.
- 03Start inspectingSelect a media element or capture MSE playback.