The EXT-X-BYTERANGE tag indicates that a Media Segment is a sub-range
of the resource identified by its URI. It applies only to the next
URI line that follows it in the Playlist. Its format is:

#EXT-X-BYTERANGE:<n>[@<o>]

where n is a decimal-integer indicating the length of the sub-range
in bytes. If present, o is a decimal-integer indicating the start of
the sub-range, as a byte offset from the beginning of the resource.
If o is not present, the sub-range begins at the next byte following
the sub-range of the previous Media Segment.

If o is not present, a previous Media Segment MUST appear in the
Playlist file and MUST be a sub-range of the same media resource, or
the Media Segment is undefined and the client MUST fail to parse the
Playlist.