A video preload hint does not prove a complete download
The HTML media preload property expresses a loading hint. Verify actual requests and readiness instead of treating auto as a completed offline copy.
The journal
The viewing journal — page 63
Practical reading about streaming, devices and the decisions behind a better prepared setup.
A screen wake lock can be released after a tab becomes hidden
A wake lock request can succeed and later be released by the system. A page must track that lifecycle instead of assuming the original handle remains active.
A browser encrypted event is different from waiting for a decryption key
Encountering encryption initialisation data does not itself mean playback failed. waitingforkey describes a more specific inability to continue decoding without a key.
Browser media error 3 is not an HTTP status code
MediaError has its own small set of media failure categories. Keep that namespace separate from HTTP responses and application-specific error numbers.
A browser progress bar needs to handle unknown and unbounded duration
HTML media duration can be NaN before data is available or Infinity for media without a known end. Treat those states explicitly instead of calculating a misleading percentage.
An Android file picker result is not always an ordinary file path
The Storage Access Framework returns a document URI through a provider. Use that access model rather than assuming the displayed name is a local filesystem path.