samestream

Watch video together on any site, in sync.

samestream keeps a video in sync for people watching it together, each on their own computer. Play, pause, seeking and the episode stay the same for everyone in the room. How to use it 1. Open the page with the video you want to watch. 2. Click the samestream icon, enter the name the others will see, click "Agree" (asked once, before your first room), and click "Watch together". A link to the room is copied. 3. Send the link to the person you are watching with. When they open it in Chrome with samestream installed, it asks their name and, the first time, their agreement; then the same page opens in their tab and joins the room. Later links show "Joining as {their name}" with "Change" for two seconds, then join. The popup shows "Your name" above "Watch together", to change it before a room. If they do not have samestream yet, the link explains how to get it. 4. Watch. When anyone plays, pauses or seeks, everyone else's video follows. A small caption line on the video shows the room's state ("Syncing…", "In sync", "Waiting for Bob: video loading"), and the popup shows it too, with who is in the room. samestream is not made for particular websites. It works with the HTML5 video on the page you have open, including players embedded from another domain. No account or sign-up. What samestream does on the page - Finds the video that is playing, and reads and sets its time and play state. While you watch together it keeps the playback speed at 1×. - Shows a small caption line with the room's state over the video, also in full screen, kept off the player's own controls. When it cannot tell whether your video is the room's episode, or cannot find that episode on your page, the line asks you ("Is this S1 · E5?", "Pick S1 · E5 in the player") instead of guessing. "Don't wait for me" on your line lets the room play on without you. - In the room's tab, opens the room's page: for the person who opens a room link, and when someone in the room picks another video. - Presses the page's own controls when the room needs it: play, and the season, episode or voice the room is watching. It finds them by what it learned on that site, by the buttons and list items that the person who chose the video clicked, by the page's own names for them, or, when those leave it open, by asking an AI model which of the page's buttons and list items to click. - Compares frame fingerprints to check that everyone's copy shows the same video and to line up copies that do not start at the same point, and briefly speeds up or moves a copy that fell behind. To check a paused copy, it may move it to a few moments and back, showing the picture where it stopped meanwhile. When a video's frames cannot be read directly, it may capture the visible tab for a moment, reduce the video's area to the same numbers on your device and discard the picture. - When your copy does not load or start, it tries the gentle steps first (playing it muted for a moment, a tap on a player that waits for one), then reloads the player or the page, and it asks you when only a press of yours can help ("Tap the video to start"). If it had to start your video without sound, the line says "Sound is off · click the video". - Skip video ads (experimental, on unless you turn it off in the popup): in a room's tab, when an ad holds the room's video, samestream mutes and hides a short ad video (under a minute) that plays beside it in the player or in the video's own element and skips it to its end, or, for a longer ad in the video's own element, presses the ad's own Skip button once it shows, so the room does not wait for it. It never clicks the ad itself or anything that leads to the advertiser, leaves the ad alone while you are using the player, and does nothing outside a room. Your data Before your first room, samestream asks once: "Session traces are kept for 30 days. The developer may read them to fix and improve samestream." It starts or joins no room until you click Agree. Apart from a deletion request you make yourself ("Delete my traces"), nothing leaves your browser until you start or join a room. In a room, samestream sends to the samestream relay, a server on Cloudflare: your name and a random participant id; playback (play, pause, seek, position and speed) and what you choose in samestream; about every 2 seconds while the room plays or your copy is not ready, whether your video is the room's and where it stands and, when it is not ready, why, since when and what samestream is doing about it, whether samestream is asking you something, whether you chose not to be waited for, whether your tab is in view, and the round-trip time of your connection; the page you are watching: its address, the address of its player's frame, a digest of its video file's address, and the season, episode, voice, length and frame rate of its video; the names of the buttons and list items you clicked to choose the video (up to six), so that your partner's samestream can choose the same; and frame fingerprints (64-bit numbers computed on your device from a 32 × 18 brightness grid of the video's frames, never images or sound), also of a few moments samestream looks at to check whether two copies show the same episode. The other people in the room see your name, what you do with playback, which page you are on, which of its buttons and list items you clicked to choose the video, and why the room is waiting for you. To find the season, episode or voice in a player, samestream may send the roles and visible names of the buttons, links, tabs, lists, menus, selects and headings of the video page and its player frames, and of the other elements those pages make clickable (which of them are selected or expanded or look set apart, and their order; up to 96,000 characters), with the season, episode and voice the room is watching (or, when the room's video names none, the episode after the one it watched before), through the relay to Cloudflare Workers AI. It never sends what you type into fields, sections it recognises as comments, reviews or account areas, forms with a password field, the room's page or link, or the names of the people in the room. The answer, which items to click, goes back only to you. A small script on each page notes the addresses of the video streams the page's own player loads and, when the player gives the browser the video in pieces, the size of each piece and a 32-bit checksum of its last 256 bytes (the first 16 pieces of the picture and of the sound, then one each time the player's buffer reaches another minute). In a room they are kept in the session trace, and to tell whether you and your partner play the same file samestream sends your partner the sizes and checksums of the first pieces (numbers only). The script changes no request and reads no other part of the video. While a tab is in a room, samestream uploads a session trace to the relay, kept for 30 days under a random id of this browser, not under your name. It holds the version of samestream, whether it was installed from the Chrome Web Store and whether "Skip video ads" is on, and, when a room needs a newer version, each time samestream asked Chrome for its update and Chrome's answer; playback events and what samestream did and why (where it placed your copy against the room's, in seconds and rates; the moments it looked at and the times of subtitle lines near them, numbers only, never their words); the clicks it made on the player and what they changed, and the video ads it skipped; the titles and addresses of the room's pages and their frames, a digest of each video file's address, and the addresses the room's tab began to open (in every address the values of query parameters and random-looking parts become short digests, IP addresses a placeholder, and the part after "#" and login details are dropped); the names in the room; for each comparison of frames only its outcome, never the fingerprints; the sizes and checksums of video pieces; the text sent to the AI with its answer, and of samestream's own choices in a player only which kind of button or list item it clicked and what that changed; what the page says it plays (its name, series, season and episode for search engines, the title, artist and album for the browser's media controls, the item its player marks as current); the reports each video gives about once a second (position, state, size, whether something lies over it); your choices in samestream and your answers to its questions; the names of the buttons and list items you clicked to choose the video; when you clicked, touched or pressed a key on the page, where the press landed against the video and whether a key is one players use to seek or to play and pause, but never which key or what you typed; which media keys the page or samestream handled; and each navigation of the room's tab, with whom samestream took it for. The developer reads the traces of people who agreed, to fix problems and improve samestream. "Delete my traces" in the popup has the relay delete, within a few minutes, every trace this browser uploaded. samestream shows no ads and sells no data. The privacy policy linked on this page has the details. Works in Chrome and other Chromium browsers, version 130 or later. Everyone in the room needs samestream 4.0 or later.