The first real test of ShareBox with an actual file was an 8 GB MKV — HEVC encode, DTS audio, PGS subtitles burned from a Japanese Blu-ray. The <video src="..."> I had put in place opened, spun for two seconds, and stopped in complete silence. No error event, no console message. Just a spinner going nowhere.
ShareBox started from a simple premise — share large files without a third-party cloud. Video streaming was supposed to be one feature among others. Except real-world files are not clean H.264/AAC MP4s: there are MKVs, HEVC encodes, Dolby audio tracks, bitmap subtitles. The native browser player gives up without a word. So I built a full player: on the server side, download.php orchestrates three ffmpeg streaming modes. On the client side, a JS state machine handles mode selection, stall recovery, image subtitle burn-in, and UX. This post documents what I built — and where it cost more time than expected.
Three server-side streaming modes
The entry point is download.php?stream=MODE. Three modes are available, selected dynamically by the JS based on the detected codec.
native — X-Accel-Redirect
