RTCP XR Report Block for TS Decodability Statistics Metric Reporting
draft-huang-xrblock-rtcp-xr-decodability-02

Abstract

Transport Stream is a standard container format used in the transmission and storage of multimedia data. This document defines an RTCP XR Report Block that allows the reporting of decodability statistics metrics related to transmissions in Transport Stream format.

Status of this Memo

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This Internet-Draft will expire on August 15, 2012.

Copyright Notice

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Table of Contents

• 1. Introduction
• 2. Terminology
• 2.1. Standards Language
• 2.2. Acronyms
• 3. TR 101 290 Decodability Statistics Metric Report Block
• 4. SDP Signaling
• 5. IANA Considerations
• 6. Security Considerations
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Authors' Addresses

1. Introduction

This draft defines a new block type to augment those defined in [RFC3611] for use with Transport Stream (TS) [ISO-IEC.13818-1.2007]. The new block type supports reporting on the consistency of transport streams [ETSI] by checking TS header information. This new block type can be useful for identifying the existence, and characterizing the severity, of a packet transport problem which may affect users' perception of a service delivered over RTP; it may also be useful for verifying the continued correct operation of an existing system management and providing accurate measures of TS quality for operators.

The new report block is in compliance with the monitoring architecture specified in [RFC6390]. The metric is applicable to any type of RTP application that uses the TS standard format for transmission and storage of multimedia data.

2. Terminology

2.1. Standards 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 [RFC2119].

In addition, the following terms are defined:

2.2. Acronyms

SSRC

Synchronization Source [RFC3550]

TS

Transport Stream [ISO-IEC.13818-1.2007]

3. TR 101 290 Decodability Statistics Metric Report Block

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     BT=TBD    |       rvd     |         block length          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                     SSRC of source                           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          begin_seq            |             end_seq           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         Number of TSs                         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|             Transport Stream Synchronization Losses           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      Sync byte errors                         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                  Continuity count errors                      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                      Transport errors                         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         PCR errors                            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                   PCR repetition errors                       |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|            PCR discontinuity indicator errors                 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                         PTS errors                            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

This block reports decodability statistics metrics beyond the information carried in the standard RTCP packet format. Information is recorded about basic monitoring parameters necessary to ensure that the TS can be decoded including the number of Transport Stream Synchronization Losses, Sync byte errors, Continuity count errors, and continuous monitoring parameters including Transport errors, Program Clock Reference (PCR) errors, PCR repetition errors, PCR discontinuity indicator errors, and Presentation Time Stamp (PTS) errors [ETSI]. Such information can be useful for network management and real time application quality monitoring.

Note that this metric report block is not only applicable to MPEG-2 transport streams [RFC2250], but is also applicable to any other codec data encoded using the TS format.

The Decodability Metrics Block has the following format:

block type (BT): 8 bits

A TR 101 290 decodability metrics report block is identified by the constant <TDM>.

rvd: 8 bits

This field is reserved for future definition. In the absence of such a definition, the bits in this field MUST be set to zero and SHOULD be ignored by the receiver.

block length: 16 bits

The constant 11, in accordance with the definition of this field in Section 3 of RFC 3611 [RFC3611].

SSRC of source: 32 bits

As defined in Section 4.1 of [RFC3611].

begin_seq: 16 bits

As defined in Section 4.1 of [RFC3611].

end_seq: 16 bits

As defined in Section 4.1 of [RFC3611].

Number of TSs: 32 bits

Number of Transport Streams in the above sequence number interval.

Transport Stream Synchronization Losses: 32 bits

Number of TS Synchronization Losses in the above sequence number interval.

Sync byte errors: 32 bits

Number of TS sync byte errors in the above sequence number interval.

Continuity count error: 32 bits

Number of Transport Continuity count errors in the above sequence number interval.

Transport errors: 32 bits

Number of Transport errors in the above sequence number interval.

PCR errors: 32 bits

Number of PCR errors in the above sequence number interval.

PCR repetition errors: 32 bits

Number of Transport PCR repetition errors in the above sequence number interval.

PCR discontinuity indicator errors: 32 bits

Number of PCR discontinuity indicator errors in the above sequence number interval.

PTS errors: 32 bits

Number of PTS errors in the above sequence number interval.

4. SDP Signaling

rtcp-xr-attrib =  "a=rtcp-xr:" 
                  [xr-format *(SP xr-format)] CRLF

   xr-format = decodability-metrics

      decodability-metrics = "decodability-metrics" 

One new parameter is defined for the report block defined in this document to be used with Session Description Protocol (SDP) [RFC4566] using the Augmented Backus-Naur Form (ABNF) [RFC5234]. It has the following syntax within the "rtcp-xr" attribute [RFC3611]: RFC 3611 [RFC3611] for a detailed description and the full syntax of the "rtcp-xr" attribute.

5. IANA Considerations

Rachel Huang
rachel.huang@huawei.com
101 Software Avenue, Yuhua District 
Nanjing, JiangSu 210012 China

New report block types for RTCP XR are subject to IANA registration. For general guidelines on IANA allocations for RTCP XR, refer to Section 6.2 of [RFC3611].

This document assigns one new block type value in the RTCP XR Block Type Registry: [RFC4566] parameter for the "rtcp-xr" attribute in the RTCP XR SDP Parameters Registry:

The contact information for the registrations is:

• Name:

  TDM

  Long Name:

  TR 101 290 Decodability Metrics

  Value

  <TDM>

  Reference:

  section 3
  
  

This document also registers one SDP

• • “decodability-metrics”

6. Security Considerations

This proposed RTCP XR report block introduces no new security considerations beyond those described in [RFC3611].

7. References

7.1. Normative References

7.2. Informative References

Authors' Addresses