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AMWA BCP-006-01: NMOS With JPEG XS

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JPEG XS is a technology standardized in ISO/IEC 21122 for video contribution at low latency with very high video quality. A companion RTP payload format specification was developed through the IETF Payloads working group, IETF RFC 9134.

The Video Services Forum developed Technical Recommendation TR-08, which covers the end-to-end application use of JPEG XS compression for video, alongside uncompressed audio and VANC, using the SMPTE ST 2110 suite of protocols. TR-08 mandates the use of the AMWA IS-04 and IS-05 NMOS Specifications in TR-08 compliant systems.

AMWA IS-04 and IS-05 already have support for RTP transport and can signal the media type video/jxsv as defined in RFC 9134.

Use of Normative Language

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.

Definitions

The NMOS terms ‘Node’, ‘Source’, ‘Flow’, ‘Sender’, ‘Receiver’ are used as defined in the NMOS Glossary.

JPEG XS IS-04 Receivers

Nodes capable of receiving JPEG XS video streams MUST have a Receiver resource in the IS-04 Node API, which lists video/jxsv in the media_types array within the caps object. This has been permitted since IS-04 v1.1.

Nodes implementing BCP-004-01 Receiver Capabilities use the existing constraint_sets parameter within the caps object, describing combinations of frame rates, width and height, and other parameters which the receiver can support, using the parameter constraints defined in the Capabilities register of the NMOS Parameter Registers.

If the Receiver supports streams meeting the traffic shaping and delivery timing requirements for ST 2110-22, it SHOULD use the urn:x-nmos:cap:transport:st2110_21_sender_type parameter constraint.

An example Receiver resource is provided in the Examples.

JPEG XS IS-04 Senders, Flows and Sources

Nodes capable of transmitting JPEG XS video streams MUST have Sender, Flow and Source resources in the IS-04 Node API.

Senders

The Sender resource MUST indicate urn:x-nmos:transport:rtp or one of its subclassifications for the transport attribute. Sender resources provide no indication of media type or format, since this is described by the associated Flow resource.

The SDP file at the manifest_href MUST comply with the requirements of RFC 9134. If the Sender meets the traffic shaping and delivery timing requirements specified for ST 2110-22, the SDP file MUST also comply with the provisions of ST 2110-22.

Flows

The Flow resource MUST indicate video/jxsv in the media_type attribute, and urn:x-nmos:format:video for the format. This has been permitted since IS-04 v1.1.

Nodes implementing IS-04 v1.3 or higher MUST indicate the color (sub-)sampling in the Flow resource using the components attribute defined in the Flow Attributes register of the NMOS Parameter Registers. The components array value corresponds to the sampling, width and height values in the SDP format-specific parameters defined by RFC 9134.

Nodes implementing IS-04 v1.3 or higher MUST indicate the stream bit rate in the Flow resource using the bit_rate attribute also defined in the Flow Attributes register. The bit rate value also appears in the SDP file, per RFC 9134.

An example Flow resource is provided in the Examples.

Sources

The Source resource MUST indicate urn:x-nmos:format:video for the format. Source resources can be associated with many Flows at the same time. The Source is therefore unaffected by the use of JPEG XS compression.

JPEG XS IS-05 Senders and Receivers

Connection Management using IS-05 proceeds in exactly the same manner as for any other stream format carried within RTP. The SDP file at the /transportfile endpoint on Senders MUST comply with the requirements of RFC 9134 and, if appropriate, ST 2110-22.

An SDP file provided in the transport_file attribute of a PATCH request on the /staged endpoint of Receivers MUST also comply with RFC 9134 and, if appropriate, ST 2110-22.

An example SDP file is provided in the Examples.

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