Open the popup
Click the ScopeLab toolbar icon on the video tab. The popup shows how many videos it found. A detected video may still be blocked from pixel capture.
DVP Tools / Quality Control
How to Use ScopeLab
Select video on the current Chrome tab, inspect its browser-decoded preview, and save your scope readings. This guide covers the controls in version 1.0.3. Analysis works only when Chrome lets ScopeLab read the video's pixels.
Quick start
From video to scopes
Pin the extension in Chrome, then open a tab containing an HTML5 video. Start playback or scrub until the video has a visible frame.
Choose your sources
Select Auto Detect for the largest one or two videos, or Scan & Select Videos to click Source A and then Source B on the page.
Check the connection
The scope window opens when at least one source yields pixels. Look for Preview pixels received or Partial preview before trusting a panel. The popup can reopen the scope window.
Source setup
Choose what to inspect
Source A and Source B come from the tab where you start ScopeLab. Changing tabs does not switch the capture source. Closing the scope window or navigating the source tab stops capture.
One video or two
Auto Detect chooses up to two videos on the page. With one video, it feeds A and B from the same source and labels the frame difference Same Source. For a deliberate A/B review, put both videos on the same page and use Scan & Select Videos.
- Play or scrub both sources to comparable points before reading the difference strip.
- If their media times differ by more than 0.1 seconds, ScopeLab shows Not aligned instead of a pixel difference.
Crop two regions
Choose Crop Region Mode when both views sit inside a page layout. Move and resize the Source A box, click Set as Source A, then repeat for B. Each box must overlap a capturable video.
Keep in mind
Different crops, scaling, playback times, and browser decoding can create visible differences unrelated to source quality.
Console controls
Read and adjust the preview
The scopes show browser-decoded 8-bit preview values. They help compare appearance; they do not certify a delivery file.
Switch the lower panels
Vec + Wf shows a vectorscope and luma/RGB waveform for each source. Vec + Hist swaps in histograms; Vec + Parade shows RGB parades. The 16/235 guides are preview references, not a legal-range test.
Inspect exposure
Zebra highlights bright areas; False C replaces the difference strip with a Source A exposure map. They are mutually exclusive. The vectorscope skin-tone line is a visual reference, not a measured target.
Adjust the display
Trace and Gain change how traces appear. The resolution button cycles through Full Res, 1/2 Res, and 1/4 Res. Pause freezes the scope display while the page video keeps playing.
Time and panel size
Click either A or B time display to switch between timecode and media time. Drag the scope dividers to resize panels, or focus a divider and use the arrow keys. The split is remembered on this device.
Compare what is visible
For aligned A and B, the difference strip shows average and peak channel differences and changed pixels. RGB Range counts preview pixels with a channel below 16 or above 235; it is not a gamut or broadcast legality result.
Audio meters
The audio meters show levels when Chrome provides a capturable audio stream. If they stay empty, the video scopes can still work. Clicking the video page may allow Chrome to resume audio metering.
New in 1.0.3
Save your review
The export buttons become available after ScopeLab receives preview pixels. They download files to your device.
PNG snapshot
Click PNG to save the displayed scope panels and difference strip as scopelab-scopes.png. It is a picture of the analysis display, not a video-frame export.
JSON metrics
Click JSON to save scopelab-report.json. It records the app version, export time, source metrics, media times, mode, and resolution step. It does not include video frames or page URLs.
Capture help
When scopes do not appear
Version 1.0.3 distinguishes finding a video from receiving readable pixels. Use the message in the popup or scope window to decide what to try.
Waiting for a decoded frame
Play or scrub the video until a frame appears, then try again. A loading or poster-only video can be detected before its pixels are ready.
Chrome blocked pixel access
The page may play video while preventing the extension from reading pixels. Try a video that Chrome exposes on an accessible page; this restriction may not be fixable on the current page.
Embedded frame inaccessible
ScopeLab cannot inspect the video inside this embedded frame. If you have access to the video on its own page, try opening it there.
Unsupported page or partial preview
Chrome blocks extensions on some pages. Open a regular video page instead. Partial preview means only one selected source is yielding pixels; check the other source's message.
For final delivery
ScopeLab samples browser-decoded frames locally, up to 10 times per second at a maximum analysis width of 640 pixels. It cannot certify legal levels, color gamut, or broadcast compliance. Check delivery files with a calibrated, format-aware tool.