KLV Metadata and OTT QoS

Executive Summary

• AWS described expanded support for Key-Length-Value (KLV) metadata processing across AWS Media Services and AWS Elemental Appliances & Software, including ingest, pass-through, preservation during transcode, and re-packaging workflows.
• AWS also documented a monitoring approach for virtual linear OTT channels with dynamic ad insertion (DAI), using an ad decision server (ADS), AWS Elemental MediaTailor, Amazon CloudFront, and Amazon CloudWatch dashboards with QoS and ad-delivery metrics.

Key Industry Developments

• Expanded KLV metadata processing across live and file workflows
• AWS announced “expanded feature support for Key-Length-Value (KLV) metadata processing” across multiple services and appliances.
• AWS Elemental Live added input support for KLV carried in SMPTE-2038 ancillary data in software version 2.25.1 GA, and supports KLV in HLS outputs when MPEG-TS is used as the container format.
• AWS Elemental Link devices added KLV metadata pass-through from SDI input to outputs as SMPTE-2038 ancillary data when encoding.
• AWS Elemental MediaLive added input support for KLV carried in SMPTE-2038 ancillary data streams and added KLV support to HLS output groups, including preserving KLV in HLS output groups when using MPEG-TS and publishing to an origin such as Amazon Simple Storage Service (S3).
• KLV preservation through transcode and packaging formats
• AWS Elemental MediaConvert added preservation of KLV metadata during file transcodes using MPEG-TS container formats, and preservation when transcoding from MPEG-TS to ISOBMFF used by CMAF and MPEG-DASH.
• AWS Elemental MediaPackage supports re-packaging live streaming content containing KLV metadata from HLS (HLS-TS) to MPEG-DASH (ISOBMFF) in conjunction with AWS Elemental MediaLive, enabling a workflow where KLV is carried through live ingest/output and then re-packaged across streaming formats.
• QoS monitoring for virtual linear OTT with server-side ad insertion
• A documented setup uses an ad decision server (ADS) with AWS Elemental MediaTailor for dynamic ad insertion, where a MediaTailor configuration can take a Channel Assembly output as the content source and replace ad opportunity markers with dynamic server-side ads.
• Amazon CloudFront can be configured as the CDN with separate origins and cache behaviors for content segments and ad segments, supporting scalable distribution patterns for both program and ad media.
• QoS and ad reporting can be visualized using an Amazon CloudWatch dashboard with SSAI and origin metrics, including indicators such as AdDecisionServerTimeouts and AdDecisionServerLatency.

Real-World Use Cases

• Embedded metadata pass-through from SDI into cloud workflows
• A workflow can pass embedded KLV metadata in an SDI input through AWS Elemental Link outputs as SMPTE-2038 ancillary data when encoding, maintaining the metadata alongside the encoded video transport.
• AWS Elemental MediaLive can then acquire metadata from AWS Elemental Link connected devices using its input support for SMPTE-2038 ancillary data streams, enabling downstream processing while keeping KLV aligned with the live feed.
• Publishing and preserving KLV in HLS and beyond
• AWS Elemental Live and AWS Elemental MediaLive support KLV in HLS outputs when MPEG-TS is used as the container format, enabling HLS-TS delivery that retains KLV.
• MediaLive can preserve KLV in HLS output groups and publish to an origin such as Amazon S3, supporting origin-based distribution patterns where the HLS-TS segments and playlists are stored and served from object storage.
• File transcode and format transitions with KLV retention
• AWS Elemental MediaConvert can preserve KLV metadata during file transcodes that use MPEG-TS container formats, allowing codec changes without dropping the KLV payload.
• MediaConvert can also preserve KLV when transcoding from MPEG-TS to ISOBMFF used by CMAF and MPEG-DASH, supporting workflows that move from transport-stream-based mezzanine or contribution files into fragmented MP4-based delivery formats.
• Virtual linear OTT channels with DAI and operational monitoring
• A virtual linear OTT channel can be configured for dynamic ad insertion using an ADS and AWS Elemental MediaTailor, with MediaTailor using a Channel Assembly output as the content source and performing server-side ad replacement at ad opportunity markers.
• QoS and ad delivery can be monitored using an Amazon CloudWatch dashboard that visualizes SSAI and origin metrics, including request counts, latencies, avail duration, fill rate, and errors/timeouts, as well as ADS-specific indicators such as AdDecisionServerTimeouts and AdDecisionServerLatency.

Why It Matters

• Metadata integrity across protocols and containers
• KLV support described across SMPTE-2038 ancillary data, SDI pass-through, HLS with MPEG-TS, and re-packaging to MPEG-DASH with ISOBMFF indicates an emphasis on keeping metadata intact as content moves between live ingest, streaming outputs, and packaging formats.
• Operational observability for ad-supported streaming
• The documented CloudWatch dashboard approach ties SSAI and origin metrics to ad decisioning behavior (for example, ADS timeouts and latency), providing a concrete method to observe how ad insertion performance correlates with playback QoS and ad delivery outcomes.
• Workflow composability across AWS media components
• The described building blocks—Elemental Link for SDI ingest and metadata pass-through, MediaLive for live processing and HLS output groups, MediaPackage for re-packaging, MediaConvert for file transcodes, MediaTailor for SSAI, CloudFront for CDN, and CloudWatch for monitoring—illustrate how specific protocol and format capabilities can be combined into end-to-end pipelines.

Sources

• https://aws.amazon.com/blogs/media/expanding-support-for-klv-metadata-processing-across-aws-media-services-and-aws-elemental-appliances-software/
• https://aws.amazon.com/blogs/media/monitoring-qos-of-virtual-linear-ott-channels-with-dynamic-ad-insertion/