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Update NMOS With MPEG TS.md
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Expand Up @@ -9,12 +9,6 @@ _(c) AMWA 2024, CC Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0)_

[MPEG Transport Stream][MPEG-TS] is a standard digital container format specified in ISO/IEC 13818-1, widely used for transmission and storage of audio, video, and data.

SMPTE [ST 2022-2][ST-2022-2] defines the Unidirectional Transport of Constant Bit Rate MPEG-2 Transport Streams using RTP on IP Networks.

The [Video Services Forum][VSF] developed Technical Recommendations [TR-01][TR-01] and [TR-07][TR-07], which cover the encapsulation of JPEG 2000 and JPEG XS video respectively within MPEG TS over IP networks, compliant with ST 2022-2.

AMWA IS-04 and IS-05 have support for RTP transport and can signal the media type `video/MP2T` as defined in [RFC 3555][RFC-3555].

This BCP allows for the use of all transport types defined by IS-05 that can carry media type `video/MP2T`.

## Use of Normative Language
Expand All @@ -28,7 +22,7 @@ The NMOS terms 'Controller', 'Node', 'Source', 'Flow', 'Sender', 'Receiver' are

## MPEG TS IS-04 Sources, Flows, and Senders

Nodes capable of transmitting MPEG TS streams, including those carrying JPEG 2000 or JPEG XS content as per VSF TR-01 and TR-07, **MUST** have Source, Flow, and Sender resources in the IS-04 Node API.
Nodes capable of transmitting MPEG TS streams **MUST** have Source, Flow, and Sender resources in the IS-04 Node API.

Nodes **MUST** support IS-04 v1.3 to implement all aspects of this specification.

Expand All @@ -48,24 +42,18 @@ The Flow resource **MUST** indicate `video/MP2T` in the `media_type` attribute,
An example Flow resource is provided in the [Examples](../examples/).

### Senders
For Nodes transmitting MPEG TS over RTP transport as defined by ST 2022-2, the Sender `transport` attribute **MUST** be `urn:x-nmos:transport:rtp` or one of its sub-classifications.

The SDP file published at the `manifest_href` end-point **MUST** comply with the IS-05 usage guidelines for the specific transport and [RFC 4566][RFC-4566]

For Nodes implementing IS-04 v1.3 or higher, the following additional attributes defined in the [sender attributes register][Sender-Attributes] of the NMOS Parameter Registers are used for MPEG TS:

- [Bit Rate][Sender-Bit-Rate]
This attribute **MUST** be present as defined in equipment where the bit rate is known, and **MAY** be signaled in the sender SDP as "b=AS:bit-rate", where bit-rate is in integer units of kilobits/second.
- [Bit Rate][Sender-Transport-Bit-Rate]
This attribute **MUST** be present as defined in equipment where the bit rate is known.

An example Sender resource is provided in the [Examples](../examples/).
An example Sender JSON is provided in the [Examples](../examples/).

## MPEG TS IS-04 Receivers

Nodes capable of receiving MPEG TS streams, including those carrying JPEG 2000 or JPEG XS content as per VSF TR-01 and TR-07, **MUST** have a Receiver resource in the IS-04 Node API, which lists `video/MP2T` in the `media_types` array within the `caps` object.
Nodes capable of receiving MPEG TS streams **MUST** have a Receiver resource in the IS-04 Node API, which lists `video/MP2T` in the `media_types` array within the `caps` object.

If the Receiver supports RTP transport, it **MUST** have the `transport` attribute set to `urn:x-nmos:transport:rtp` or one of its sub-classifications..

If the Receiver has limitations on or preferences regarding the MPEG TS streams that it supports, the Receiver resource **MUST** indicate constraints in accordance with the [BCP-004-01][] Receiver Capabilities specification.
If the Receiver has limitations on or preferences regarding the MPEG TS streams that it supports, the Receiver resource **MUST** indicate constraints in accordance with the [BCP 004-01][BCP-004-01] Receiver Capabilities specification.

The Receiver **SHOULD** express its constraints as precisely as possible, to allow a Controller to determine with a high level of confidence the Receiver's compatibility with the available streams.

Expand All @@ -74,39 +62,29 @@ It is not always practical for the constraints to indicate every type of stream
The `constraint_sets` parameter within the `caps` object can be used to describe combinations of parameters which the Receiver can support, using the parameter constraints defined in the [Capabilities register][Capabilities-Register] of the NMOS Parameter Registers.

The following parameter constraints **MAY** be used to express limitations on MPEG TS streams:
- [Transport Bit Rate][Transport-Bit-Rate]
- [Transport Bit Rate][Cap-Transport-Bit-Rate]

An example Receiver resource is provided in the [Examples](../examples/).
An example Receiver JSON is provided in the [Examples](../examples/).

## MPEG TS IS-05 Senders and Receivers

Connection Management using IS-05 proceeds in exactly the same manner as for any other stream format carried over the RTP tranport type.

Any SDP file published at the **/transportfile** end-point **MUST** comply with the IS-05 usage guidelines for the RTP transport and [RFC 4566][RFC-4566].

An example SDP file is provided in the [Examples](../examples/).
Connection Management follows IS-05 for the transport type.

## Controllers

Controllers **MUST** use IS-04 to discover MPEG TS Senders and Receivers and IS-05 to manage connections between them.

Controllers **MUST** support the BCP-004-01 Receiver Capabilities mechanism and all the parameter constraints listed in this specification in order to evaluate the stream compatibility between MPEG TS Senders and Receivers.

Controllers **MUST** be capable of handling RTP transports as per the NMOS specifications indicated in the Sender and Receiver resources.

[BCP-004-01]: https://specs.amwa.tv/bcp-004-01/ "AMWA BCP-004-01 NMOS Receiver Capabilities"
[MPEG-TS]: https://www.iso.org/standard/69461.html "ISO/IEC 13818-1 Systems"
[TR-01]: https://vsf.tv/download/technical_recommendations/VSF_TR-01_2018-06-22.pdf "VSF TR-01 Transport of JPEG 2000 Broadcast Profile Video in MPEG-2 TS over IP"
[TR-07]: https://vsf.tv/download/technical_recommendations/VSF_TR-07_2020-04-01.pdf "VSF TR-07 Transport of JPEG XS Video in MPEG-2 TS over RTP"
[VSF]: https://vsf.tv/ "Video Services Forum"
[RFC-2119]: https://datatracker.ietf.org/doc/html/rfc2119 "Key words for use in RFCs"
[RFC-3555]: https://datatracker.ietf.org/doc/html/rfc3555 "MIME Type Registration of RTP Payload Types"
[ST-2022-2]: https://ieeexplore.ieee.org/document/7291602 "SMPTE ST 2022-2: Unidirectional Transport of Constant Bit Rate MPEG-2 Transport Streams on IP Networks"
[RFC-4566]: https://datatracker.ietf.org/doc/html/rfc4566 "SDP: Session Description Protocol"
[RFC-4855]: https://datatracker.ietf.org/doc/html/rfc4855 "Media Type Registration of RTP Payload Formats"
[NMOS-Glossary]: https://specs.amwa.tv/nmos/main/docs/Glossary.html "NMOS Glossary"
[Capabilities-Register]: https://specs.amwa.tv/nmos-parameter-registers/branches/main/capabilities/ "Capabilities Register"
[Sender-Attributes]: https://specs.amwa.tv/nmos-parameter-registers/branches/main/sender-attributes "Sender Attributes Register"
[Sender-Bit-Rate]: https://specs.amwa.tv/nmos-parameter-registers/branches/main/sender-attributes/#bit-rate "Sender Bit Rate"
[Sender-Transport-Bit-Rate]: https://specs.amwa.tv/nmos-parameter-registers/branches/main/sender-attributes/#bit-rate "Sender Transport Bit Rate"
[Cap-Transport-Bit-Rate]: https://specs.amwa.tv/nmos-parameter-registers/branches/main/capabilities/#transport-bit-rate "Transport Bit Rate"


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