From 49777fdf8d5fa117ff915a96f944f9b71b1cf313 Mon Sep 17 00:00:00 2001 From: Geir Ertzaas Date: Wed, 30 Oct 2024 15:48:50 +0100 Subject: [PATCH] Update NMOS With MPEG TS.md --- docs/NMOS With MPEG TS.md | 43 +++++---------------------------------- 1 file changed, 5 insertions(+), 38 deletions(-) diff --git a/docs/NMOS With MPEG TS.md b/docs/NMOS With MPEG TS.md index 8b0e0bc..5e0bc1a 100644 --- a/docs/NMOS With MPEG TS.md +++ b/docs/NMOS With MPEG TS.md @@ -45,46 +45,27 @@ The Source is therefore unaffected by the use of MPEG TS or the encapsulated con ### Flows The Flow resource **MUST** indicate `video/MP2T` in the `media_type` attribute, and `urn:x-nmos:format:mux` for the `format`. -This has been permitted since IS-04 v1.1. - -For Nodes implementing IS-04 v1.3.x or higher, the following additional attributes defined in the [Flow Attributes register][Flow-Attributes] of the NMOS Parameter Registers are used for MPEG TS: +For Nodes implementing IS-04 v1.3 or higher, the following additional attributes defined in the [Flow Attributes register][Flow-Attributes] of the NMOS Parameter Registers are used for MPEG TS: - [Bit Rate][Flow-Bit-Rate] This attribute **MUST** be present in the flow resource definition. -- [Mux Video Media Type][Flow-Mux-Video-Media-Type] - The `mux_video_media_type` attribute **MUST** be included for streams encapsulating TR-01 JPEG 2000 or TR-07 JPEG XS. The `mux_video_media_type` **SHALL** use media types from the [IANA Media Types Registry][IANA-MIME-Types]: `video/jpeg2000` and `video/jxsv`. - 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`. - -Sender resources provide no indication of media type or bit-rate since this is described by the associated Flow resource. - -#### Sender SDP Usage -This section is **REQUIRED** for RTP transports with SDP. +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] -Additionally, the SDP transport file needs to convey, so far as the defined format-specific parameters allow, the same information about the stream as conveyed by the Source, Flow and Sender attributes defined by this specification and IS-04, unless such information is conveyed through in-band parameter sets. - -- The `bit_rate` attribute **MUST** be included to signal the max bit rate allocated to this sender. -- For streams encapsulating TR-01 JPEG 2000 or TR-07 JPEG XS, the `mux_video_media_type` attribute **MUST** be included as defined above. - -The sender attributes described above **MUST** be present in the SDP for transports where SDP is present. - An example Sender resource 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. -This has been permitted since IS-04 v1.1. - -If the Receiver supports RTP transport, it **MUST** have the `transport` attribute set to `urn:x-nmos:transport:rtp`. +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 or the encapsulated content 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][] 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. @@ -94,7 +75,6 @@ The `constraint_sets` parameter within the `caps` object can be used to describe The following parameter constraints can be used to express limitations on MPEG TS streams: - [Transport Bit Rate][Cap-Bit-Rate] -- [Mux Video Media Type][Cap-Mux-Video-Media-Type] An example Receiver resource is provided in the [Examples](../examples/). @@ -102,16 +82,7 @@ An example Receiver resource is provided in the [Examples](../examples/). Connection Management using IS-05 proceeds in exactly the same manner as for any other stream format carried over the RTP tranport type. -### Sender SDP Signalling -If an SDP file is published at the **/transportfile** end-point it **MUST** comply with the IS-05 usage guidelines for the RTP transport and [RFC 4566][RFC-4566] - -The SDP file **MUST** comply with the same requirements described for the SDP file at the IS-04 Sender `manifest_href` as described in the [IS-04 Sender SDP Usage](#sender-sdp-usage) section. - -If the Receiver is not capable of consuming the stream described by the SDP file, it **SHOULD** reject the request. - -If it is unable to assess the stream compatibility, for example when the SDP file does not include some of the optional parameters, it **MAY** accept the request. - -A `PATCH` request on the **/staged** endpoint of an IS-05 Receiver can contain an SDP file in the `transport_file` attribute. +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/). @@ -119,10 +90,6 @@ An example SDP file is provided in the [Examples](../examples/). Controllers **MUST** use IS-04 to discover MPEG TS Senders and Receivers and IS-05 to manage connections between them. -Controllers **MUST** support IS-04 v1.3.x to implement all aspects of this specification. - -Partial implementation can be achieved using IS-04 v1.2 and earlier. - 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.