标签在HLS规范的draft-09中引入，没有任何示例。
3.4.13. EXT-X-MAP
The EXT-X-MAP tag specifies how to obtain the Transport Stream PAT/
PMT for the applicable media segment. It applies to every media
segment that appears after it in the Playlist until the next EXT-X-
DISCONTINUITY tag, or until the end of the playlist.
The EXT-X-MAP tag MUST NOT appear unless the Playlist also contains
the EXT-X-I-FRAMES-ONLY tag. It is RECOMMENDED that the EXT-X-MAP
tag only be used for segments whose resource does not start with a
PAT/PMT.
Its format is:
#EXT-X-MAP:<attribute-list>
The following attributes are defined:
URI
The value is a quoted-string containing a URI that identifies a
resource that contains the Transport Stream PAT/PMT. This attribute
is mandatory.
BYTERANGE
The value is a quoted-string specifying a byte range into the
resource identified by the URI attribute. This range SHOULD contain
only the Transport Stream PAT/PMT. The format of the byte range is
described in Section 3.4.1. This attribute is optional; if it is not
present, the byte range is the entire resource indicated by the URI.
The EXT-X-MAP tag appeared in version 5 of the protocol.