Base de Conhecimento

HTTP Live Streaming (HLS) delivers video by breaking it into small segments served over standard HTTP, playable natively in most browsers and devices — the most broadly compatible way to deliver both live and on-demand video.

Why HLS Over Raw RTMP for Viewers

RTMP requires specific player support (largely fallen out of favor in browsers); HLS plays natively in Safari and via standard JavaScript players in other browsers, using ordinary HTTP/HTTPS — making it the practical choice for actually delivering video to viewers.

How HLS Works

The video stream is split into short segments (a few seconds each), with a playlist file (.m3u8) listing the available segments — players download the playlist, then fetch and play segments sequentially, requesting updated playlists for ongoing live content.

Prerequisites

• Nginx with the RTMP module (see How to Set Up Nginx RTMP for Live Video Streaming) as the source, or FFmpeg for converting existing video files

Step 1 — Configure HLS Output in the RTMP Block

rtmp {
    server {
        listen 1935;
        application live {
            live on;
            hls on;
            hls_path /var/www/hls;
            hls_fragment 4;
            hls_playlist_length 30;
        }
    }
}

hls_fragment sets segment length in seconds; shorter segments reduce latency but increase overhead, longer segments do the opposite.

Step 2 — Serve the HLS Files

server {
    listen 80;
    server_name stream.yourdomain.com;

    location /hls {
        types {
            application/vnd.apple.mpegurl m3u8;
            video/mp2t ts;
        }
        root /var/www;
        add_header Cache-Control no-cache;
        add_header Access-Control-Allow-Origin *;
    }
}

Step 3 — Play the Stream in a Browser

<video controls>
  <source src="https://stream.yourdomain.com/hls/live.m3u8" type="application/vnd.apple.mpegurl">
</video>

Native support exists in Safari; for broader browser compatibility, use a JavaScript HLS player library (such as hls.js) as a wrapper.

Converting an Existing Video File to HLS (On-Demand, Not Live)

ffmpeg -i input.mp4 -codec: copy -start_number 0 -hls_time 10 -hls_list_size 0 -f hls output.m3u8

Generating Multiple Quality Levels (Adaptive Bitrate)

application live {
    live on;
    hls on;
    hls_path /var/www/hls;
    hls_variant _low BANDWIDTH=500000;
    hls_variant _mid BANDWIDTH=1500000;
    hls_variant _high BANDWIDTH=3000000;
}

Allows players to automatically switch quality based on the viewer's actual available bandwidth — requires configuring FFmpeg to produce these multiple bitrate variants; see How to Set Up a Video Transcoding Pipeline with FFmpeg.

Adding a CDN in Front of HLS Delivery

See How to Optimize Video Delivery with a CDN for Streaming Content — especially valuable for HLS given how many small segment requests a typical viewing session generates.

Common Errors

Playlist loads but video won't play — verify the MIME types for .m3u8 and .ts files are correctly configured, as shown in Step 2; incorrect MIME types cause many players to reject the content.

Playback has excessive delay for live content — reduce hls_fragment size and hls_playlist_length for lower latency, accepting the trade-off of more frequent segment requests.

Continue Reading

• How to Set Up Nginx RTMP for Live Video Streaming
• How to Set Up a Video Transcoding Pipeline with FFmpeg
• How to Optimize Video Delivery with a CDN for Streaming Content

Browse more articles in Media & Streaming Servers.