Don't Melt the Phone: Autoplaying Video Grids in Jetpack Compose

Every cell autoplays a video, no spinners, no "tap to play" - then you run it on a mid-range phone and watch it catch fire.

This is the field guide I wish I'd had, built in three layers.

The client: a poster, an ExoPlayer, a staggered grid - all pure Compose.
The backend: small MP4s, a CDN, and an answer to "why didn't you just use WebP?".
The measurement: a five-minute tour of Perfetto and the one metric your profiler hides, with a live look at the grid under load.

We close somewhere honest: what "good enough" means, and when you shouldn't play 8 video players at the same time.