Metadata passthrough - AWS Elemental MediaPackage

Metadata passthrough

AWS Elemental MediaPackage automatically passes through ID3 and key-length-value (KLV) metadata from a channel's input to the channel's output stream. You don't need to adjust your endpoint's configuration to enable metadata passthrough.

For more information about how MediaPackage handles metadata, see the following sections.

ID3 metadata considerations

Timed ID3 metadata is a general-purpose mechanism that adds synchronized metadata to streams. The metadata is used for a variety of purposes, ranging from interactive applications to audience measurement.

Supported MediaPackage endpoint types

MediaPackage supports ID3 metadata passthrough for the following endpoint types:

  • Live and VOD HLS, DASH, and CMAF endpoints

Metadata carriage

Here is how ID3 is carried as metadata in the following specifications:

  • HLS - Metadata is carried in the elementary stream. For more information, see section 2.0 of the Apple Timed Metadata for HTTP Live Streaming reference.

  • CMAF and DASH - Metadata is carried in the Event Message box version 1. For more information, see Carriage of ID3 Timed Metadata in CMAF. Event Message boxes include a scheme_id_uri field set to https://aomedia.org/emsg/ID3 and a value field set to 0.

Metadata signaling

DASH manifests include a <InbandEventStream schemeIdUri="https://aomedia.org/emsg/ID3" value="0"/> element in AdaptationSets that include tracks with ID3 metadata.

HLS manifests don't have specific metadata signaling.

MediaLive configuration

You can produce ID3 metadata in AWS Elemental MediaLive MediaPackage output groups either by passing through ID3 metadata, or inserting ID3 metadata using the schedule.

KLV metadata considerations

KLV is a data encoding standard for including synchronized metadata in streams. The binary nature of KLV makes it efficient when the volume of metadata is significant. KLV can be used for various use cases ranging from aerial surveillance to transmitting sensors data in industry use cases, or for real-time athlete and object tracking in live sports use cases.

Supported MediaPackage endpoint types

MediaPackage supports ID3 metadata passthrough for the following endpoint types:

  • Live DASH endpoints

Metadata carriage

Metadata is carried in the Event Message box version 1, as described in the MISB ST 1910.1 specification. For synchronous KLV tracks, Event Message boxes include a scheme_id_uri field set to urn:misb:KLV:bin:1910.1 and a value field set to KLVx:01FC. For asynchronous KLV tracks, the value field is set to KLVx:01BD . In both cases, x is the index of the track in the stream.

Metadata signaling

DASH manifests include a <InbandEventStream schemeIdUri="urn:misb:KLV:bin:1910.1" value="KLVx:01FC"/> or <InbandEventStream schemeIdUri="urn:misb:KLV:bin:1910.1" value="KLVx:01BD"/> element in AdaptationSets that include tracks with KLV metadata, depending on the synchronicity nature of the carried track.

MediaLive configuration

You can pass through KLV metadata from your MediaLive channel. For more information, see klv in the AWS Elemental MediaLive User Guide.