.M3U8 File Format – Media playlist

HTTP Live Streaming playlist

A media playlist lists the segments of one rendition, in order. Each segment is a URI line; the tags before it describe it. A live playlist is fetched again and again, and grows at the end while old segments drop off the start. The low-latency tags are on Low-latency HLS.

Playlist tags

Each appears at most once, before the first segment unless noted.

TagValueDefaultMeaning
#EXT-X-TARGETDURATION:swhole seconds, at least 1requiredThe longest segment duration: every EXTINF, rounded to the nearest whole second, must be no more.
#EXT-X-MEDIA-SEQUENCE:nwhole number0The sequence number of the first segment listed; each later one is one more.
#EXT-X-DISCONTINUITY-SEQUENCE:nwhole number0How many discontinuities have scrolled off the start, so that renditions stay in step. Before any EXT-X-DISCONTINUITY.
#EXT-X-ENDLISTnoneNo more segments will be added. May appear anywhere.
#EXT-X-PLAYLIST-TYPE:tEVENT or VODneitherEVENT: segments are only ever added at the end. VOD: the playlist never changes.
#EXT-X-I-FRAMES-ONLYnoneVersion 4. Each segment is one I-frame, lasting until the next; used for fast forward and thumbnails.

Segment tags

TagApplies toMeaning
#EXTINF:duration,[title]the next segment; required for eachDuration in seconds; whole seconds before version 3. The title after the comma is optional, informative text; the comma itself is required.
#EXT-X-BYTERANGE:n[@o]the next segmentVersion 4. The segment is n bytes at offset o of the resource; without @o it follows the previous range of the same resource.
#EXT-X-DISCONTINUITYthe next segmentSomething changes: the file format, the tracks or the timestamps (required); encoding settings (recommended).
#EXT-X-KEY:…following segments, until the next key with the same KEYFORMATHow segments are encrypted. See Segments and encryption.
#EXT-X-MAP:…following segments, until the next mapWhere the initialisation section is (version 5 or 6).
#EXT-X-PROGRAM-DATE-TIME:datethe next segmentThe real date and time of the segment’s first sample, ISO 8601 with milliseconds and a time zone, such as 2026-11-12T19:30:00.000Z; UTC if no zone.
#EXT-X-GAPthe next segmentThe segment is missing and should not be fetched.
#EXT-X-BITRATE:kbpsfollowing segments without a byte range, until the nextThe approximate bit rate in kilobits per second, within 10% of each segment’s real rate.
EXT-X-MAP attributeTypeMeaning
URIquoted string, requiredThe resource holding the initialisation section (an ftyp and moov for fragmented MP4; a PAT and PMT for transport streams).
BYTERANGEquoted string "n@o"Its byte range; the whole resource if absent.

Date ranges

#EXT-X-DATERANGE marks a span of real time, such as an advert break or a programme, so that players and apps can act on it. A playlist with date ranges must have at least one EXT-X-PROGRAM-DATE-TIME.

AttributeTypeMeaning
IDquoted string, requiredUnique in the playlist. Tags with the same ID add to one range, with identical values for shared attributes.
CLASSquoted stringA kind of range defined by the application. Ranges of one class may not overlap.
START-DATEquoted ISO 8601 date, requiredWhen it starts.
CUElist of PRE, POST, ONCERun the action before playback, after it, and/or only once; not both PRE and POST.
END-DATEquoted ISO 8601 dateWhen it ends; must equal start plus DURATION if both are given.
DURATIONfloat, not negativeIts length in seconds.
PLANNED-DURATIONfloat, not negativeIts expected length, when the real one is not yet known.
END-ON-NEXTYESEnds where the next range of the same class starts. Needs CLASS; no DURATION or END-DATE.
SCTE35-CMDhexadecimalA whole SCTE-35 splice_info_section, big-endian, for commands such as splice_null.
SCTE35-OUThexadecimalThe SCTE-35 section that starts a break (out_of_network_indicator 1).
SCTE35-INhexadecimalThe section that ends it (out_of_network_indicator 0).
X-namequoted string, hexadecimal or signed floatAny application-defined attribute, such as X-COM-EXAMPLE-AD-ID.

With no DURATION, END-DATE or END-ON-NEXT, the length is unknown, even if PLANNED-DURATION is given.

Worked example

#EXTM3U
#EXT-X-VERSION:7
#EXT-X-TARGETDURATION:6
#EXT-X-MEDIA-SEQUENCE:2680
#EXT-X-DISCONTINUITY-SEQUENCE:3
#EXT-X-MAP:URI="init.mp4"
#EXT-X-PROGRAM-DATE-TIME:2026-11-12T19:30:00.000Z
#EXTINF:6.006,
seg2680.m4s
#EXT-X-DATERANGE:ID="ad1",START-DATE="2026-11-12T19:30:06.006Z",PLANNED-DURATION=30.0,SCTE35-OUT=0xFC30…
#EXT-X-DISCONTINUITY
#EXT-X-MAP:URI="ad-init.mp4"
#EXTINF:6.0,
ad-0.m4s
#EXT-X-GAP
#EXTINF:6.0,
ad-1.m4s
A live playlist (no EXT-X-ENDLIST). The first segment listed is number 2680; an advert break starts after it, with a discontinuity and a new initialisation section. ad-1.m4s is missing and must be skipped.