In this guide
A variant is more than a resolution labelRendition groups make selection multidimensionalMetadata must match the resourcesAn HLS multivariant playlist describes choices a player can make. Older documentation often calls it a master playlist. Its variants can link to different video renditions, and rendition groups can provide alternate audio, subtitles or closed-caption information.
The menu is metadata, not a measurement of the connection or a promise that every listed combination works on every client. A player still has to understand the declared formats and successfully retrieve the selected resources.
A variant is more than a resolution label
EXT-X-STREAM-INF attributes describe the resources associated with a variant. BANDWIDTH concerns peak segment bit rate for the playable combination under the protocol’s rules; AVERAGE-BANDWIDTH, when supplied, describes an average. RESOLUTION describes pixel dimensions. CODECS identifies the sample formats needed for the advertised combination.
Those fields answer different questions. A 1920×1080 variant and a 1280×720 variant can use the same codec family but different bit rates, profiles or frame rates. A label such as HD cannot substitute for this information when investigating a decoder limitation.
Rendition groups make selection multidimensional
A variant may refer to an AUDIO group containing language alternatives. Choosing a lower video variant does not necessarily mean selecting a different language track. Conversely, a device may support the video codec but fail on one audio rendition’s format. Group associations therefore matter when a picture appears without sound.
| Field or relationship | Useful interpretation |
|---|---|
| RESOLUTION | Advertised frame dimensions |
| CODECS | Declared sample formats |
| BANDWIDTH | Peak-rate metadata for adaptation |
| AUDIO group | Which alternate audio choices belong with the variant |
Metadata must match the resources
An original hypothetical check compares two variants: both declare the same audio group, but only one video playlist loads. That observation concerns one branch of the resource tree; it does not establish that the audio group or the whole account is broken. Record which branch the player selected.
For authors, accurate metadata helps the client make a sensible selection. For viewers, metadata can explain a decision but should not be treated as evidence of received picture quality. The rendered track and successful segment requests provide additional evidence.