What Is HLS?
HLS stands for HTTP Live Streaming, a media streaming protocol originally developed by Apple. Instead of sending a listener one large video file to download before they can watch (like a traditional MP4), HLS breaks a video into many small segments — usually just a few seconds each — and streams them to the listener’s device one after another as they watch. In simple terms, HLS helps video start faster and play more smoothly by adjusting the video quality to the listener’s Wi-Fi or cellular connection. This means less buffering and more continuous playback, although a very weak or interrupted connection can still cause delays. Alongside those segments, the server also generates a playlist file (technically called an .m3u8 manifest) that tells the app which segments exist, in what order, and at what quality levels. The player reads this playlist and requests segments on the fly, rather than pulling down the entire episode at once.
Why Apple Built This for Podcasts
Apple Podcasts has always distributed video episodes through a standard RSS enclosure — essentially a link to a single MP4 file. That approach works, but it has real limitations:
- Slow startup. The player has to buffer a meaningful chunk of a single, fixed-quality file before playback can begin.
- One-size-fits-all quality. A listener on a fast Wi-Fi connection and a listener on spotty cellular data both get the same file, whether or not their connection can handle it well.
- Two feeds to manage. Podcasters who wanted both an audio-only and a video version of a show often had to maintain two entirely separate RSS feeds.
Apple’s new HLS workflow solves these by rebuilding video delivery around adaptive streaming and a single, unified feed.
Adaptive Bitrate Streaming, Explained
When an episode is prepared for HLS, multiple versions are created at different video quality levels. The player automatically chooses the version that works best for the listener’s current internet connection and can adjust the quality as that connection changes.
- The player monitors the listener’s connection and automatically adjusts the video quality as needed, helping the episode continue playing without noticeable interruptions.
- Faster playback start, because the player can begin with a small, low-bitrate segment rather than waiting on a large file.
- Fewer stalls and buffering interruptions, because the player adjusts quality instead of stalling out.
- Better quality when conditions allow, because the player will step up to higher resolutions automatically once bandwidth supports it.
One Feed, Two Formats
Rather than requiring a separate video feed, Apple’s HLS workflow is built around a single RSS feed that carries both:
- An HLS video stream — used by Apple Podcasts and any other app that supports HLS playback.
- A standard audio enclosure (MP3) — used automatically by podcast apps that don’t support HLS video.
The podcast host handles generating and hosting both versions from a single uploaded source file. Podcast apps simply use whichever version they’re built to support: HLS-capable apps play the video stream, and everything else falls back to the familiar audio enclosure. Listeners never notice a difference in availability — they just get audio or video depending on what their app can do.
What This Means for Listeners
In the Apple Podcasts app specifically, this workflow enables listeners to switch seamlessly between watching and listening to the same episode. Because both formats come from the same feed and the same underlying episode, moving from video to audio (or vice versa) is instant, without switching shows or feeds.
What This Means for Podcasters
For creators, the practical upside is simplification:
- One upload — a single video file per episode.
- One RSS feed — no more maintaining parallel audio and video feeds.
- Automatic compatibility — apps that support HLS get video; apps that don’t get the audio fallback automatically.