HTML5 media speed controller + subs

Speed controls and subtitles for HTML5 media.

Use to control speed on HTML5 video and audio streams. Can add SRT files as WEBVTT tracks, style the subtitles and set the delay so that they are in sync (tip: use the console log to help you) (Press the underscore button on the UI to start/complete the process of adding subtitles). This extension is safe to use in incognito mode as the only data it stores is the settings; I recommend enabling it for file URLs. You can add a colour matrix and other video CSS, but there is one enabled by default that makes greens and pinks more realistic. Changelog: 15/10/2023: Picture-in-Picture button added to bar; more efficient code used to search for streams. 05/01/2023: Faster code used when searching for streams. 01/12/2022: Colour matrix added as a blob URL rather than by inserting a tag into the web page. 25/11/2022: No longer shows the native HTML5 video controls when playbackRate is changed. 24/10/2022: Improved element handling (e.g. searching for tags); better hiding of HTML elements other than the video hide controller now causes the extension name to be printed before the hiding status. 16/10/2022: Video controls will show up more often when toggling hide controller. 05/10/2022: Fixed issue with timeout of mutationObserver that delayed or even prevented the activation of the speed controller. 13/08/2022: Removed spam of "Current site is blacklisted from speed controller." in the console and now shows you which blacklist entry is relevant. 26/05/2022 - Converted all "event.path" into "event .composedPath()" 09/04/2022 - Can now attach to media hidden in shadow DOMs, can accept .vtt subs if a .vtt fle is selected, and smoother dragging. 15/06/2021 - Amended remaining time for some live streams (see 09/01/2020), to better reflect how much time ahead of the current time has buffered. 17/03/2021 - Made video CSS '!important'. 08/03/2021 - Updated to manifest v3. 24/02/2021 - Bugfix for last update. 24/02/2021 - Fixed issue where the bar would appear closer to the top-centre than the top-left on some videos. 02/02/2021 - Changed options page to a standalone one from from a popup. 28/01/2021 - Minor amendments to mouse and keyboard events. 27/01/2021 - MAJOR UPDATE! Improved encapsulation, i.e. methods/functions are now much better linked to their own bars (when there are multiple bars) (replaced many global variables), but keybindings will likely affect all bars at once. One can double click on the bar (not on a button thereon) to return it to its default position. Improved dragging of the bar. Fixed bugs relating to subtitles processing. Plus various other amendments. 25/01/2021 - Now when the bar auto-hides, if you place the cursor where it was, it will reappear if it was clickable (unless perma-hidden). 21/01/2021 - Alt+Shift+1-6 now gives speeds 11-16x, and Alt (+ Shift) + 0 gives 10x. 15/01/2021 - Fixed options page bugs, and styling (for compatibility with dark mode). 18/10/2020 - Amended focus/hover handling; now reads tags in SRT text written right to left; and SRT timecodes for 100 hours+ now supported. 15/10/2020 - Fixes disappearing bug when the subs box, link div and controller bar are focussed/hovered over. 07/10/2020 - Fixed incorrect switch button text when the video (currentSrc/)src changes, and also sets the playback rate to 1 when this happens (to avoid issues on some sites when they detect an attempt to speed through ads); amended link button code; made main bar padding and margins proportional. 04/10/2020 - Works on all URI schemes (including ftp etc.); adds a new 'link' button ("🔗") that shows the src of the current media (may be 'blob://*') (Double click on the src text field to select all.) 13/09/2020 - Fixed site blacklisting. 23/08/2020 - Amended default subtitle text-shadow CSS and changed default font-size to 148% 21/08/2020 - Replaced default subtitle text-shadow CSS with proportional values. 19/08/2020 - Replaced deprecated 'mousewheel' event listener. 18/06/2020 - Remaining time indicator now updates when just the duration changes. 17/06/2020 - Remaining time indicator now updates even when the video is paused. 16/05/2020 - Minor fix to cleanup code. 14/05/2020 - Better handling of subtitle tags, improved cleanup, and other minor fixes. 07/05/2020 - Keeps video controls showing when video is isolated. 05/05/2020 - The 'Toggle hide controller' key now attempts to display only the video with its controls enabled as well as toggling keys, this can help where the progress bar is normally inaccesible. The close button now only hides the bar, it can be brought back with the 'Toggle hide controller' key. Plus other minor fixes. 23/01/2020- Prints current 'translate( (left/right)%, (top/bottom)%) )' to the console after having moved the subtitles. 09/01/2020 - Amended remaining time indicator for some live streams (tells you how far behind the last buffered frames you are), and fixed the remaining time and switch button text. 17/04/2019 - Fixed a bug where keys set as shortcuts could not be typed in text boxes. 13/04/2019 - Now removes obsolete instances and fixes bug were arrow keys were disabled in the YouTube search bar. 01/04/2019 - Disables undesired default shortcuts. 25/03/2019 - Amended default colour matrix (makes black truly black). 20/03/2019 - Amended default colour matrix. 03/03/2019 - Fixed subtitle text area updating on file selection. 02/03/2019 - Fixed subtitle toggling. 02/02/2019 - Amendment to subtitle balancing. 01/02/2019 - Fixed subtitle balancing. 26/01/2019 - Only specified shortcuts will override native shortcuts.