Instagram and Facebook deliver instant playback and boost user engagement with Media3 PreloadManager

Meta (Facebook and Instagram) adopted Jetpack Media3's PreloadManager to achieve instant video playback for billions of users. Previously relying on warmup and disk-based prefetch strategies, Meta migrated to memory-level preloading with tailored strategies per app: a 'current-only' approach for Facebook Newsfeed (mixed content feed) and an 'adjacent preload' strategy for Instagram Reels (pure vertical video). To handle device diversity, they built a Device Stress Detection system that monitors CPU and I/O signals in real-time, pausing preloading under heavy load to preserve UI responsiveness. The result was measurable improvements in playback start times, reduced stall rates, and increased total watch time on both platforms. Key recommendations include aligning preloading strategy with UI patterns, using memory-level rather than disk caching, and implementing device-aware optimizations.