Working memory has a viewing purpose
A player following a long presentation may not need to retain every previously played sample indefinitely. Keeping selected media ahead and some history can balance continued playback with available capacity. The exact policy belongs to the application and implementation, rather than a universal fixed number of minutes.
Imagine playback at minute forty while old local media from the opening minutes is removed. The programme can continue normally. A server may still allow a later request for the opening, or it may no longer retain it. Buffer removal itself does not answer that separate availability question.
Removal has state and range rules
The documented SourceBuffer remove operation uses start and end times in seconds and has state restrictions. A developer must not treat it as deleting an arbitrary range of file bytes. Media-time coordinates and representation offsets are different systems.
For a hypothetical retention decision, an application may want to free a region well behind the current position. It still needs to coordinate that operation with append processing and avoid disrupting samples required for immediate playback. A viewer should not manipulate private player buffers as a casual repair for interruptions.
Interpret missing history carefully
If a seek-back position no longer plays, inspect the current seekable range and whether a new request can obtain the media. The cause might concern a moving live window, a network failure or the application's navigation policy. The absence of locally buffered history alone is not proof that a recording was erased.
For a developer report, record playback position, buffered ranges before and after removal, the requested range and operation result. Label this as browser buffer management. Keep service recording retention and supported offline-download terms in their own records, because their commercial and storage meaning cannot be inferred from an in-memory buffer operation.
Questions about this guide
Is buffer removal the same as deleting a cloud recording?
No. They concern different systems.
Are SourceBuffer removal positions byte offsets?
No. They are media-time range values in seconds.