Sequence numbers identify order
Suppose a playlist begins at media sequence 240 and contains four segment entries. Their sequence numbers are 240, 241, 242 and 243. On the next update the first entry might disappear and a new one arrive, leaving 241 through 244. The list has moved forward even though it still contains four entries.
The segment filenames do not have to contain these numbers. A file called chunk-A.ts could be sequence 240. Inferring order from a filename is therefore weaker than reading the playlist, and alphabetical sorting can be wrong even when names look numeric.
A sequence is not a date
A sequence value of 240 does not mean 240 seconds after midnight or 240 seconds into the event. Numbering is scoped to the media playlist. Two different renditions can use different sequence numbers for media that belongs to the same presentation time.
To compare two quality levels, use media timestamps and relevant discontinuity information rather than assuming segment 240 in both contains identical moments. Absolute wall-clock mapping, when provided, serves another purpose again. Keeping these identifiers separate prevents apparently neat but false synchronisation calculations.
The limits of a saved playlist
A text copy taken at 8 pm is evidence of what that response listed at that moment. Ten minutes later some referenced segments may have left the server's available window. Saving the playlist does not preserve the video files or guarantee that a later replay can fetch them.
For a technical report, keep the observation time, first sequence and segment count, with private URLs removed. Two observations made a reasonable interval apart can show progress. Repeated identical lists may be a useful clue, but caching, an ended stream and publication failure require different checks before assigning a cause.
Questions about this guide
Can media sequence numbers be compared across channels?
No. They are not a shared broadcast clock or a reliable cross-channel identifier.
Does a moving sequence prove smooth playback?
No. It shows playlist progression. Segment delivery and decoding can still fail.