Hi,
Assuming that your encoder doesn’t buffer the delayed output stream, it would be safer to rely on the EXT-X-PROGRAM-DATE-TIME tag instead of the EXT-X-MEDIA-SEQUENCE tag in the HLS playlist to identify matching content between different streams. However, if some buffering occurs in the encoder, the EXT-X-PROGRAM-DATE-TIME tag in the playlist would be later than the actual start time of the segment referred to. Your software would have to compensate for the buffering delay in this case.
Note: The HLS specification mentions that the EXT-X-MEDIA-SEQUENCE tag for a segment should not be used to identify matching content between different streams.
Please advise if you are encoding live or recorded content.
Don