Type: Embed bug player Environment Firefox 155.0 MacOS Chrome and Safari: rendering correctly on the same embed Uploaded sources: 8-bit SDR only (no client-side HDR) Behavior On the Gumlet embed ( play.gumlet.io ), the image is correct as long as the cursor is on the player (chrome visible). When the cursor leaves the player and the controls disappear after autohide (~1 s), the image becomes lighter: black raised, like a semi-transparent veil. The problem affects all of our embed videos, not just one. Example page https://www.loisplagnard.com/film-ecole-comestible .html Embed example https://play.gumlet.io/embed/69ee6cb34779ed7c8b81154d?background=false&autoplay=true&loop=true&muted=true&playsinline=true&disable_player_controls=false&start_high_res=true&captions=true&cookie=false Isolation test (support suggestion) With disable_player_controls=true, the bug does not disappear: it becomes constant (image always washed). Firefox Render Config Active controls Correct on hover; lag after mouseleave disable_player_controls=true Continuously lagging Hypothesis The media-chrome player hides inactive chrome with opacity: 0 (userinactive) rather than removing it from the rendering. On Firefox, this seems to switch to <video>a different compositing path (hardware overlay), with black lift. Not correctable from the parent page (cross-origin iframe). Correction track Hide inactive chrome with visibility: hidden/display: none instead of opacity: 0 Or expose noautohide/option to avoid this path on Firefox Attachments [Capture 1: cursor on the player — correct rendering] [Capture 2: Cursor off the player - black raised] [Capture 3: disable_player_controls=true — washed constantly]
