AV1 Video in MPEG-TS Legacy Broadcast Infrastructure

This article examines whether the AOMedia Video 1 (AV1) codec can be encapsulated and transmitted over legacy MPEG-2 Transport Stream (MPEG-TS) broadcast architectures. While the MPEG-TS container is fundamentally codec-agnostic and official specifications from standards bodies like the Digital Video Broadcasting (DVB) consortium define how to packetize AV1, significant practical constraints exist. Deploying AV1 across existing broadcast distribution chains requires specialized signaling support at the multiplexer level and depends entirely on the decoding capabilities of consumer reception equipment.

The Standardization of AV1 in MPEG-TS

AV1 can be carried over MPEG-TS. The standardization work required for this encapsulation has already been formalized, most notably by the DVB Project in its core specification, ETSI TS 101 154.

This specification establishes clear rules for:

• Packetization: Encapsulating AV1 Open Bitstream Units (OBUs) into Packetized Elementary Stream (PES) packets.
• Timing: Mapping AV1 presentation timestamps and decode timestamps (PTS/DTS) to the PES header to ensure synchronization with audio and metadata.
• Signaling: Allocating specific stream_type values and descriptor formats in the Program Map Table (PMT) so downstream equipment can identify the AV1 video track.

Headend and Transport Network Compatibility

At the network distribution layer, an MPEG-TS containing an AV1 payload can pass through most legacy broadcast pipelines without structural modification, provided the equipment operates strictly at the transport packet level (PID routing).

However, operational challenges emerge when intermediate devices interact directly with the elementary stream:

• Statistical Multiplexers: Traditional hardware statistical multiplexers rely on parsing the video elementary stream to dynamically allocate bitrate. Legacy statmux systems cannot parse AV1 bitstreams and require software or hardware upgrades.
• Monitoring and Splicing Tools: Legacy equipment used for ad-insertion (SCTE 35 splicing), stream health verification, and PES analysis will fail to decode or inspect the AV1 stream unless explicitly updated.

Receiver and Decoder Limitations

The primary bottleneck for carrying AV1 over legacy broadcast infrastructure is the end-user device. Broadcast television distribution (via DVB-T2, DVB-S2, or ATSC) relies on fixed-function hardware decoders integrated into set-top boxes and smart television sets.

• Lack of Hardware Decoding: Legacy television sets and set-top boxes deployed with MPEG-2, H.264 (AVC), or H.265 (HEVC) hardware decoders cannot decode an AV1 bitstream. Software decoding is rarely an option due to the limited processing power of legacy consumer premises equipment (CPE).
• Signaling Rejection: Older receivers encountering an unrecognized stream_type in the MPEG-TS PMT will typically ignore the video stream entirely, resulting in black screens or "unsupported format" errors for the consumer.

Summary

Carrying AV1 over MPEG-TS is technically standardized and functionally possible within modern or software-defined broadcast systems. However, in purely legacy broadcast infrastructures, its utility is constrained by the inability of existing headend processing tools to parse the format and the universal absence of AV1 hardware decoders in legacy receiving devices.