M3U8란?
M3U8 플레이리스트 형식과 HLS 스트리밍 프로토콜을 설명하는 실용 가이드입니다.
소개
M3U8은 HLS(HTTP Live Streaming)에서 사용하는 UTF-8 플레이리스트 형식입니다. 보통 비디오 자체가 아니라 세그먼트, 화질, 키, 메타데이터를 가리킵니다.
HLS는 Apple이 도입했으며 현재 브라우저, 앱, OTT에서 라이브와 VOD에 널리 사용됩니다.
M3U8 작동 방식
1. Server segmentation
The server splits a video into short TS or fMP4 segments and writes an M3U8 index file.
2. M3U8 index
The playlist records segment URLs, playback order, duration, variants, and related metadata.
3. Progressive download
The player downloads segments in order and starts playback before the full video is available.
4. Adaptive bitrate
A master playlist can provide multiple qualities, so the player switches according to network conditions.
M3U8 파일 구조
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXTINF:9.009,
http://media.example.com/first.ts
#EXTINF:9.009,
http://media.example.com/second.ts
#EXTINF:3.003,
http://media.example.com/third.ts
#EXT-X-ENDLIST#EXTM3U - file header for an M3U playlist
#EXT-X-VERSION - HLS protocol version
#EXT-X-TARGETDURATION - maximum segment duration
#EXTINF - segment duration and URL
#EXT-X-ENDLIST - marks VOD playlist end
M3U8 vs MP4
M3U8 장점
- Supports live streaming.
- Adapts quality to bandwidth.
- Starts quickly without downloading the full file.
- Works well with CDN caching.
- Supports encryption.
M3U8 제한
- Not ideal for local file playback without an HTTP server.
- Many files can be harder to manage.
- Latency can be higher than direct file playback.
- Older devices may need a compatible player.
- Saving offline is less simple than MP4.
일반 사용 사례
Live video
Sports, news, events, and game streams.
VOD platforms
Video sites, online education, and OTT libraries.
Mobile apps
Video playback in phone and tablet applications.
M3U8 사용 방법
Online playback
Open a direct M3U8 URL in an HLS-capable player such as M3U8 Player.
Download and save
Use an M3U8 downloader to fetch segments and merge them when you have permission.
Format conversion
Use FFmpeg or a converter to create MP4 from an allowed M3U8 source.