width cap

README.md

@@ -39,7 +39,25 @@ Useful query parameters:
 - `chroma`: background color when transparent output is disabled, default `#00ff00`.
 - `fit`: `contain` or `cover`, default `contain`.
 - `scale`: graphic scale multiplier, default `1`.
-- `maxwidth`: sent to the oEmbed provider, default is based on stage width.
+- `wait`: `1` to keep the graphic hidden until embed media loads, default `1`.
+- `readyDelay`: extra milliseconds to wait after media load before reveal, default `1000`.
+- `maxWait`: safety timeout before reveal, default `10000`.
+- `autoplay`: `1` to request autoplay for iframe and video embeds, default `1`.
+- `muted`: `1` to mute embeds, default `1`. Most browsers require this for autoplay.
+- `maxwidth`: sent to the oEmbed provider and capped at `500`, default `500`.
+- `maxheight`: sent to the oEmbed provider, default `480`.
+
+Autoplay is best-effort for social embeds. The graphic page keeps the original
+social post HTML, adds provider autoplay parameters where possible, and runs a
+small assist script that calls `play()` on any video element it can access.
+Browsers still block scripts from controlling video inside cross-origin iframes,
+which includes Twitter/X widget frames. For broadcast runtimes based on Chromium
+or CEF, also allow autoplay at the browser layer when possible, for example with
+`--autoplay-policy=no-user-gesture-required`.
+
+The renderer caps every social card at `500px` wide so different providers line
+up more consistently on a broadcast canvas. It still uses the oEmbed response's
+height when present.
 
 The service also supports the oembed.link-style form: