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Versions: 00 01 02 03 04 05 draft-ietf-avt-rtp-mvc

Audio/Video Transport WG                                     Y.-K. Wang
Internet Draft                                      Huawei Technologies
Intended status: Standards track                             T. Schierl
Expires: August 2009                                     Fraunhofer HHI
                                                      February 18, 2009


                     RTP Payload Format for MVC Video
                       draft-wang-avt-rtp-mvc-03.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on August 18, 2009.

Copyright Notice

   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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Abstract

   This memo describes an RTP payload format for the multiview
   extension of the ITU-T Recommendation H.264 video codec that is
   technically identical to ISO/IEC International Standard 14496-10.
   The RTP payload format allows for packetization of one or more
   Network Abstraction Layer (NAL) units, produced by the video encoder,
   in each RTP payload.  The payload format has wide applicability,
   such as 3D video streaming, free-viewpoint video, and 3DTV.


Table of Contents

   1. Introduction...................................................3
   2. Conventions....................................................4
   3. The MVC Codec..................................................4
      3.1. Overview..................................................4
      3.2. Parameter Set Concept.....................................5
      3.3. Network Abstraction Layer Unit Header.....................5
   4. Scope..........................................................8
   5. Definitions and Abbreviations..................................8
      5.1. Definitions...............................................8
         5.1.1. Definitions per MVC specification....................8
         5.1.2. Definitions local to this memo.......................9
      5.1. Abbreviations.............................................9
   6. MVC RTP Payload Format.........................................9
      6.1. Design Principles.........................................9
      6.2. RTP Header Usage.........................................10
      6.3. Common Structure of the RTP Payload Format...............10
      6.4. NAL Unit Header Usage....................................10
      6.5. Packetization Modes......................................11
         6.5.1. Packetization Modes for single-session transmission.12
         6.5.2. Packetization Modes for multi-session transmission..12
      6.6. Aggregation Packets......................................12
      6.7. Fragmentation Units (FUs)................................12
      6.8. Payload Content Scalability Information (PACSI) NAL Unit for
      MVC...........................................................12
      6.9. Non-Interleaved Multi-Time Aggregation Packets (NI-MTAPs)16
      6.10. Cross-Session DON (CS-DON) for multi-session transmission16
   7. Packetization Rules...........................................16
   8. De-Packetization Process (Informative)........................18
   9. Payload Format Parameters.....................................18
      9.1. Media Type Registration..................................18
      9.2. SDP Parameters...........................................20
         9.2.1. Mapping of Payload Type Parameters to SDP...........20


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         9.2.2. Usage with the SDP Offer/Answer Model...............20
         9.2.3. Usage with multi-session transmission...............20
         9.2.4. Usage in Declarative Session Descriptions...........20
      9.3. Examples.................................................20
      9.4. Parameter Set Considerations.............................20
   10. Security Considerations......................................20
   11. Congestion Control...........................................21
   12. IANA Considerations..........................................21
   13. Acknowledgments..............................................21
   14. References...................................................21
      14.1. Normative References....................................21
      14.2. Informative References..................................22
   Author's Addresses...............................................23
   15. Open issues:.................................................23
   16. Changes Log..................................................23



1. Introduction

   This memo specifies an RTP [RFC3550] payload format for a forthcoming
   new mode of the H.264/AVC video coding standard, known as Multiview
   Video Coding (MVC).  Formally, MVC will take the form of Amendment 4
   to ISO/IEC 14496 Part 10 [MPEG4-10], and Annex H of ITU-T Rec. H.264
   [H.264]. The latest draft specification of MVC is available in [MVC].

   MVC covers a wide range of 3D video applications, including 3D video
   streaming, free-viewpoint video as well as 3DTV.

   This memo follows a backward compatible enhancement philosophy, by
   keeping as close an alignment to the H.264/AVC payload format
   [RFC3984] as possible.  It documents the enhancements relevant from
   an RTP transport viewpoint, and defines signaling support for MVC,
   including a new media subtype name.

   Due to the similarity between MVC and SVC in system and transport
   aspects, this memo reuses the design principles as well as many
   features of the SVC RTP payload draft [I-D.draft-ietf-avt-svc].



   [Ed.Note(TS):Need text on session multiplexing and on the relation of
   this draft to [I-D.draft-ietf-avt-svc] here.]






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2. Conventions

   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 BCP 14, RFC 2119
   [RFC2119].

   This specification uses the notion of setting and clearing a bit when
   bit fields are handled.  Setting a bit is the same as assigning that
   bit the value of 1 (On).  Clearing a bit is the same as assigning
   that bit the value of 0 (Off).

3. The MVC Codec

3.1. Overview

   MVC provides multi-view video bitstreams.  An MVC bitstream contains
   a base view conforming to at least one of the profiles of H.264/AVC
   as defined in Annex A of [H.264], and one or more non-base views.  To
   enable high compression efficiency, coding of a non-base view can
   utilize other views for inter-view prediction, thus its decoding
   relies on the presence of the views it depends on.  Each coded view
   itself may be temporally scalable.  Besides temporal scalability, MVC
   also supports view scalability, wherein a subset of the encoded views
   can be extracted, decoded and displayed, whenever it is desired by
   the application.

   The concept of video coding layer (VCL) and network abstraction layer
   (NAL) is inherited from H.264/AVC.  The VCL contains the signal
   processing functionality of the codec; mechanisms such as transform,
   quantization, motion-compensated prediction, loop filtering and
   inter-layer prediction.  The Network Abstraction Layer (NAL)
   encapsulates each slice generated by the VCL into one or more Network
   Abstraction Layer Units (NAL units).  Please consult RFC 3984 for a
   more in-depth discussion of the NAL unit concept.  MVC specifies the
   decoding order of NAL units.

   In MVC, one access unit contains all NAL units pertaining to one
   output time instance for all the views.  Within one access unit, the
   coded representation of each view, also named as view component,
   consists of one or more slices.

   The concept of temporal scalability is not newly introduced by SVC or
   MVC, as profiles defined in Annex A of [H.264] already support it.
   In [H.264], sub-sequences have been introduced in order to allow
   optional use of temporal layers.  SVC extended this approach by



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   advertising the temporal scalability information within the NAL unit
   header or prefix NAL units, both were inherited to MVC.

3.2. Parameter Set Concept

   The parameter set concept was first specified in [H.264].  Please
   refer to section 1.2 of [RFC3984] for more details.  SVC introduced
   some new parameter set mechanisms.  MVC has inherited the parameter
   set concept from [H.264].

   In particular, a different type of sequence parameter set (SPS),
   which is referred to as subset SPS, using a different NAL unit type
   than "the old SPS" specified in [H.264] is used for non-base views,
   while the base view still uses "the old SPS".  Slices from different
   views would be able to use either 1) the same sequence or picture
   parameter set, or 2) different sequence or picture parameter sets.

   The inter-view dependency and the decoding order of all the encoded
   views are indicated in a new syntax structure, the SPS MVC extension,
   included in each subset SPS.

3.3. Network Abstraction Layer Unit Header

   An MVC NAL unit of type 20 or 14 consists of a header of four octets
   and the payload byte string.  MVC NAL units of type 20 are coded
   slices of non-base views.  A special type of an MVC NAL unit is the
   prefix NAL unit (type 14) that includes descriptive information of
   the associated H.264/AVC VCL NAL unit (type 1 or 5) that immediately
   follows the prefix NAL unit.

   MVC extends the one-byte H.264/AVC NAL unit header by three
   additional octets.  The header indicates the type of the NAL unit,
   the (potential) presence of bit errors or syntax violations in the
   NAL unit payload, information regarding the relative importance of
   the NAL unit for the decoding process, the view identification
   information, the temporal layer identification information, and other
   fields as discussed below.

   The syntax and semantics of the NAL unit header are formally
   specified in [MVC], but the essential properties of the NAL unit
   header are summarized below.

   The first byte of the NAL unit header has the following format (the
   bit fields are the same as defined for the one-byte H.264/AVC NAL
   unit header, while the semantics of some fields have changed slightly,
   in a backward compatible way):



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         +---------------+
         |0|1|2|3|4|5|6|7|
         +-+-+-+-+-+-+-+-+
         |F|NRI|  Type   |
         +---------------+

   F: 1 bit

   forbidden_zero_bit.  H.264/AVC declares a value of 1 as a syntax
   violation.

   NRI: 2 bits

   nal_ref_idc.  A value of 00 indicates that the content of the NAL
   unit is not used to reconstruct reference pictures for future
   prediction.  Such NAL units can be discarded without risking the
   integrity of the reference pictures in the same view.  A value higher
   than 00 indicates that the decoding of the NAL unit is required to
   maintain the integrity of reference pictures in the same view, or
   that the NAL unit contains parameter sets.

   Type: 5 bits

   nal_unit_type.  This component specifies the NAL unit type.

   In H.264/AVC, NAL unit types 14 and 20 are reserved for future
   extensions.  MVC uses these two NAL unit types.  NAL unit type 14 is
   used for prefix NAL unit, and NAL unit type 20 is used for coded
   slice of non-base view.  NAL unit types 14 and 20 indicate the
   presence of three additional octets in the NAL unit header, as shown
   below.

            +---------------+---------------+---------------+
            |0|1|2|3|4|5|6|7|0|1|2|3|4|5|6|7|0|1|2|3|4|5|6|7|
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |R|I|  PRID     | VID               | TID |A|V|O|
            +---------------+---------------+---------------+

   PRID: 6 bits

   priority_id.  This flag specifies a priority identifier for the NAL
   unit.  A lower value of PRID indicates a higher priority.

   TID: 3 bits

   temporal_id.  This component specifies the temporal layer (or frame
   rate) hierarchy.  Informally put, a temporal layer consisting of view


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   component with a less temporal_id corresponds to a lower frame rate.
   A given temporal layer typically depends on the lower temporal layers
   (i.e. the temporal layers with less temporal_id values) but never
   depends on any higher temporal layer (i.e. a temporal layers with
   higher temporal_id value).

   A: 1 bit

   anchor_pic_flag.  This component specifies whether the view component
   is an anchor picture (when equal to 1) or not (when equal to 0), as
   specified in [MVC].

   VID: 10 bits

   view_id.  This component specifies the view identifier of the view
   the NAL unit belongs to.

   I: 1 bit

   idr_flag.  This component specifies whether the view component is a
   view instantaneous decoding refresh (V-IDR) picture for the view
   (when equal to 1) or not (when equal to 0), as specified in [MVC].

   V: 1 bit

   inter_view_flag.  This component specifies whether the view component
   is used for inter-view prediction (when equal to 1) or not (when
   equal to 0).

   R: 1 bit

   reserved_zero_one_bit.  Reserved bit for future extension.  R MUST be
   equal to 0.  Receivers SHOULD ignore the value of
   reserved_zero_one_bit.

   O: 1 bit

   reserved_one_bit.  Reserved bit for future extension.  R shall be
   equal to 1.  Receivers SHOULD ignore the value of
   reserved_zero_one_bit.

   This memo reuses the same additional NAL unit types introduced in RFC
   3984, which are presented in section 6.3.  In addition, this memo
   introduces one more NAL unit type, 30, as specified in section 6.8.
   These NAL unit types are marked as unspecified in [MVC] and
   intentionally reserved for use in systems specifications like this



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   memo.  Moreover, this specification extends the semantics of F, NRI,
   PRID, TID, A, and I as described in section 6.4.

4. Scope

   This payload specification can only be used to carry the "naked" NAL
   unit stream over RTP, and not the byte stream format according to
   Annex B of [MVC].  Likely, the applications of this specification
   will be in the IP based multimedia communications fields including 3D
   video streaming over IP, free-viewpoint video over IP, and 3DTV over
   IP.

   This specification allows, in a given RTP packet stream, to
   encapsulate NAL units belonging to

     o the base view only, detailed specification in [RFC3984], or

     o one or more non-base views, or

     o the base view and one or non-base views

   [Ed.Note(YkW): To be extended to allow separate carriage of different
   temporal layers in different RTP packet streams as in
   [I-D.draft-ietf-avt-svc].]

5. Definitions and Abbreviations

5.1. Definitions

5.1.1. Definitions per MVC specification

   This document uses the definitions of [MVC].  The following terms,
   defined in [MVC], are summed up for convenience:

   access unit:  A set of NAL units always containing exactly one
   primary coded picture with one or more view components. In addition
   to the primary coded picture, an access unit may also contain one or
   more redundant coded pictures, one auxiliary coded picture, or other
   NAL units not containing slices or slice data partitions of a coded
   picture. The decoding of an access unit always results in one decoded
   picture. All slices or slice data partitions in an access unit have
   the same value of picture order count.

   prefix NAL unit:  A NAL unit with nal_unit_type equal to 14 that
   immediately precedes a NAL unit with nal_unit_type equal to 1, 5,
   or 12.  The NAL unit that succeeds the prefix NAL unit is also
   referred to as the associated NAL unit.  The prefix NAL unit contains


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   data associated with the associated NAL unit, which are considered to
   be part of the associated NAL unit.

5.1.2. Definitions local to this memo

   MVC NAL unit:  A NAL unit of NAL unit type 14 or 20 as specified in
   Annex H of [MVC]. An MVC NAL unit has a four-byte NAL unit header.

   operation point:  An operation point of an MVC bitstream represents a
   certain level of temporal and view scalability.  An operation point
   contains only those NAL units required for a valid bitstream to
   represent a certain subset of views at a certain temporal level.  An
   operation point is described by the view_id values of the subset of
   views, and the highest temporal_id.

   multi-session transmission: The transmission mode in which the MVC
   bitstream is transmitted over multiple RTP sessions, with each stream
   having the same SSRC.  These multiple RTP streams can be associated
   using the RTCP CNAME, or explicit signalling of the SSRC used.
   Dependency between RTP sessions MUST be signaled according to [I-
   D.ietf-mmusic-decoding-dependency] and this memo.

   single-session transmission: The transmission mode in which the MVC
   bitstream is transmitted over a single RTP session, with a single
   SSRC and separate timestamp and sequence number spaces.

   [Ed.Note(TS):Need more definitions here.]

5.1. Abbreviations

   In addition to the abbreviations defined in [RFC3984], the following
   ones are defined.

   MVC:       Multiview Video Coding
   CS-DON:    Cross-Session Decoding Order Number
   MST:       multi-session transmission
   PACSI:     Payload Content Scalability Information
   SST:       single-session transmission

6. MVC RTP Payload Format

6.1. Design Principles

   The following design principles have been observed:

   o Backward compatibility with [RFC3984] wherever possible.



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   o As the MVC base view is H.264/AVC compatible, the base view or any
   H.264/AVC compatible subset of it, when transmitted in its own RTP
   packet stream, MUST be encapsulated using [RFC3984].  Requiring this
   has the desirable side effect that the transmitted data can be
   received by [RFC3984] receivers and decoded by H.264/AVC decoders.

   o Media-Aware Network Elements (MANEs) as defined in [RFC3984] are
   signaling aware and rely on signaling information.  MANEs have state.

   o MANEs can aggregate multiple RTP streams, possibly from multiple
   RTP sessions.

   o MANEs can perform media-aware stream thinning.  By using the
   payload header information identifying Layers within an RTP session,
   MANEs are able to remove packets from the incoming RTP packet stream.
   This implies rewriting the RTP headers of the outgoing packet stream
   and rewriting of RTCP Receiver Reports.

6.2. RTP Header Usage

   Please see section 5.1 of [RFC3984].

6.3. Common Structure of the RTP Payload Format

   Please see section 5.2 of [RFC3984].

6.4. NAL Unit Header Usage

   The structure and semantics of the NAL unit header were introduced in
   section 3.3.  This section specifies the semantics of F, NRI, PRID,
   TID, A and I according to this specification.

   Note that, in the context of this section, "protecting a NAL unit"
   means any RTP or network transport mechanism that could improve the
   probability of success delivery of the packet conveying the NAL unit,
   including applying a QoS-enabled network, forward error correction
   (FEC), retransmissions, and advanced scheduling behavior, whenever
   possible.

   The semantics of F specified in section 5.3 of [RFC3984] also applies
   herein.

   For NRI, for a bitstream conforming to one of the profiles defined in
   Annex A of [H.264] and transported using [RFC3984], the semantics
   specified in section 5.3 of [RFC3984] are applicable, i.e., NRI also
   indicates the relative importance of NAL units.  In MVC context, in
   addition to the semantics specified in Annex H of [MVC] are


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   applicable, NRI also indicate the relative importance of NAL units
   within a view.  MANEs MAY use this information to protect more
   important NAL units better than less important NAL units.
   [Ed.Note(YkW): "MVC context" to be clearly specified.]

   For PRID, the semantics specified in Annex H of [MVC] applies.  Note
   that MANEs implementing unequal error protection MAY use this
   information to protect NAL units with smaller PRID values better than
   those with larger PRID values, for example by including only the more
   important NAL units in a forward error correction (FEC) protection
   mechanism.  The importance for the decoding process decreases as the
   PRID value increases.

   For TID, in addition to the semantics specified in Annex H of [MVC],
   according to this memo, values of TID indicate the relative
   importance.  A lower value of TID indicates a higher importance for
   NAL units within a view.  MANEs MAY use this information to protect
   more important NAL units better than less important NAL units.

   For A, in addition to the semantics specified in Annex H of [MVC],
   according to this memo, MANEs MAY use this information to protect NAL
   units with A equal to 1 better than NAL units with A equal to 0.
   MANEs MAY also utilize information of NAL units with A equal to 1 to
   decide when to forward more packets for an RTP packet stream.  For
   example, when it is sensed that view switching has happened such that
   the operation point has changed, MANEs MAY start to forward NAL units
   for a new target view only after forwarding a NAL unit with A equal
   to 1 for the new target view.

   For I, in addition to the semantics specified in Annex H of [MVC],
   according to this memo, MANEs MAY use this information to protect NAL
   units with I equal to 1 better than NAL units with I equal to 0.
   MANEs MAY also utilize information of NAL units with I equal to 1 to
   decide when to forward more packets for an RTP packet stream.  For
   example, when it is sensed that view switching has happened such that
   the operation point has changed, MANEs MAY start to forward NAL units
   for a new target view only after forwarding a NAL unit with I equal
   to 1 for the new target view.

6.5. Packetization Modes

   [Ed.Note(TS): Need to add text from [I-D.draft-ietf-avt-rtp-svc] to
   this section with respect to MVC.]






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6.5.1. Packetization Modes for single-session transmission

   This section will address the issues of section 4.5.1 and 5.1 of [I-
   D.draft-ietf-avt-rtp-svc].



6.5.2. Packetization Modes for multi-session transmission

   This section will address the issues of section 4.5.2 and 5.2 of [I-
   D.draft-ietf-avt-rtp-svc].

6.6. Aggregation Packets

   This section will address the issues of section 4.7 of [I-D.draft-
   ietf-avt-rtp-svc].

6.7. Fragmentation Units (FUs)

   This section will address the issues of section 4.8 of [I-D.draft-
   ietf-avt-rtp-svc].

6.8. Payload Content Scalability Information (PACSI) NAL Unit for MVC

   A new NAL unit type is specified in this memo, and referred to as
   payload content scalability information (PACSI) NAL unit.  The PACSI
   NAL unit, if present, MUST be the first NAL unit in an aggregation
   packet, and it MUST NOT be present in other types of packets.  The
   PACSI NAL unit indicates view and temporal scalability information
   and other characteristics that are common for all the remaining NAL
   units in the payload of the aggregation packet. Furthermore, a PACSI
   NAL unit MAY include a DONC field and contain zero or more SEI NAL
   units.  PACSI NAL unit makes it easier for MANEs to decide whether to
   forward/process/discard the aggregation packet containing the PACSI
   NAL unit.  Senders MAY create PACSI NAL units and receivers MAY
   ignore them, or use them as hints to enable efficient aggregation
   packet processing.  Note that the NAL unit type for the PACSI NAL
   unit is selected among those values that are unspecified in [MVC] and
   [RFC3984].

   When the first aggregation unit of an aggregation packet contains a
   PACSI NAL unit, there MUST be at least one additional aggregation
   unit present in the same packet.  The RTP header and payload header
   fields of the aggregation packet are set according to the remaining
   NAL units in the aggregation packet.




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   When a PACSI NAL unit is included in a multi-time aggregation packet
   (MTAP), the decoding order number (DON) for the PACSI NAL unit MUST
   be set to indicate that the PACSI NAL unit has an identical DON to
   the first NAL unit in decoding order among the remaining NAL units in
   the aggregation packet.

   The structure of a PACSI NAL unit is as follows.  The first four
   octets are exactly the same as the four-byte MVC NAL unit header as
   discussed in section 3.3.  They are followed by two always present
   octet, two optional octets, and zero or more SEI NAL units, each SEI
   NAL unit preceded by a 16-bit unsigned size field (in network byte
   order) that indicates the size of the following NAL unit in bytes
   (excluding these two octets, but including the NAL unit type octet of
   the SEI NAL unit).  Figure 1 illustrates the PACSI NAL unit structure
   and an example of a PACSI NAL unit containing two SEI NAL units.

   The bits P, C, S, and E are specified only if the bit X is equal to 1.
   The T bit MUST NOT be equal to 1 if the aggregation packet containing
   the PACSI NAL unit is not an STAP-A packet.  The T bit MAY be equal
   to 1 if the aggregation packet containing the PACSI NAL unit is an
   STAP-A packet.  The field DONC MUST NOT be present if the T bit is
   equal to 0, and MUST be present if the T bit is equal to 1.

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |F|NRI|  Type   |S|   PRID    | TID |A|      VID          |I|V|R|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |X|T|RR |P|C|S|E|    RRR        |          DONC (optional)      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        NAL unit size 1        |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+         SEI NAL unit 1        |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        NAL unit size 2        |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   SEI NAL unit 2              |
      |                                                               |
      |                                               +-+-+-+-+-+-+-+-+
      |                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

         Figure 1.  PACSI NAL unit structure

   The values of the fields in PACSI NAL unit MUST be set as follows.
   The term "target NAL units" are used in the semantics of some fields.
   The target NAL units are such NAL units contained in the aggregation



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   packet, but not included in the PACSI NAL unit, that are within the
   access unit to which the first NAL unit following the PACSI NAL unit
   in the aggregation packet belongs.

   o The F bit MUST be set to 1 if the F bit in at least one of the
   remaining NAL units in the aggregation packet is equal to 1.
   Otherwise, the F bit MUST be set to 0.

   o The NRI field MUST be set to the highest value of NRI field among
   all the remaining NAL units in the aggregation packet.

   o The Type field MUST be set to 30.

   o The S bit MUST be set to 1.

   o The PRID field MUST be set to the lowest value of the PRID values
   of all the remaining NAL units in the aggregation packet.

   o The TID field MUST be set to the lowest value of the TID values of
   all the remaining NAL units with the lowest value of VID in the
   aggregation packet.

   o The A bit MUST be set to 1 if the A bit of at least one of the
   remaining NAL units in the aggregation packet is equal to 1.
   Otherwise, the A bit MUST be set to 0.

   o The VID field MUST be set to the lowest value of the VID values of
   all the remaining NAL units in the aggregation packet.

   o The I bit MUST be set to 1 if the I bit of at least one of the
   remaining NAL units in the aggregation packet is equal to 1.
   Otherwise, the I bit MUST be set to 0.

   o The V bit MUST be set to 1 if the V bit of at least one of the
   remaining NAL units in the aggregation packet is equal to 1.
   Otherwise, the A bit MUST be set to 0.

   o The R bit MUST be set to 0.  Receivers SHOULD ignore the value of R.

   o If the X bit is equal to 1, the bits P, C, S, and E are specified
   as below. Otherwise, the bits P, C, S, and E are unspecified, and
   receivers MUST ignore these bits.  The X bit SHOULD be identical for
   all the PACSI NAL units involved in all the RTP sessions conveying an
   MVC bitstream.

   o The RR field MUST be set to '00' (in binary form).  Receivers
   SHOULD ignore the value of RR.


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   o If the T bit is equal to 1, the OPTIONAL field DONC MUST be present
   and specified as below. Otherwise, the field DONC MUST NOT be present.

   o The P bit MUST be set to 1 if all the remaining NAL units in the
   aggregation packet are with redundant_pic_cnt higher than 0, i.e. the
   slices are redundant slices.  Otherwise, the P bit MUST be set to 0.

      Informative note: The P bit indicates whether the packet can be
      discarded because it contains only redundant slice NAL units.
      Without this bit, the corresponding information can be concluded
      from the syntax element redundant_pic_cnt, which is buried in the
      variable-length coded slice header.

   o The C bit MUST be set to 1 if the target NAL units belong to an
   access unit for which the view components are intra coded.  Otherwise,
   the C bit MUST be set to 0.  The C bit SHOULD be identical for all
   the PACSI NAL units for which the target NAL units belong to the same
   access unit.

      Informative note: The C bit indicates whether the packet contains
      intra slices which may be the only packets to be forwarded for a
      fast forward playback, e.g. when the network condition is
      extremely bad.

   o The S bit MUST be set to 1, if the first VCL NAL unit, in
   transmission order, of the view component containing the first NAL
   unit following the PACSI NAL unit in the aggregation packet is
   present in the aggregation packet.  Otherwise, the S bit MUST be set
   to 0.

   o The E bit MUST be set to 1, if the last VCL NAL unit, in
   transmission order, of the view component containing the first NAL
   unit following the PACSI NAL unit in the aggregation packet is
   present in the aggregation packet.  Otherwise, the E field MUST be
   set to 0.

      Informative note: The S or E bit indicates whether the first or
      last slice, in transmission order, of a view component is in the
      packet, to enable a MANE to detect slice loss and take proper
      action such as requesting a retransmission as soon as possible,
      as well as to allow an efficient playout buffer handling
      similarly as the M bit in the RTP header.  The M bit in the RTP
      header still indicates the end of an access unit, not the end of
      a view component.

   o The RRR field MUST be set to '00000000'(in binary form).  Receivers
   SHOULD ignore the value of RRR.


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   o When present, the field DONC indicates the CL-DON value for the
   first NAL unit in the STAP-A in transmission order.

   SEI NAL units included in the PACSI NAL unit, if any, MUST contain a
   subset of the SEI messages associated with the access unit of the
   first NAL unit following the PACSI NAL unit within the aggregation
   packet.

      Informative note: Senders may repeat such SEI NAL units in the
      PACSI NAL unit the presence of which in more than one packet is
      essential for packet loss robustness.  Receivers may use the
      repeated SEI messages in place of missing SEI messages.

   An SEI message SHOULD NOT be included in a PACSI NAL unit and
   included in one of the remaining NAL units contained in the same
   aggregation packet.

6.9. Non-Interleaved Multi-Time Aggregation Packets (NI-MTAPs)

   This section will address the issues of section 4.7.1 of [I-D.draft-
   ietf-avt-rtp-svc].

6.10. Cross-Session DON (CS-DON) for multi-session transmission

   This section will address the issues of section 4.11 of [I-D.draft-
   ietf-avt-rtp-svc].

7. Packetization Rules

   [Ed.Note(TS): We need to adjust this section with respect to [I-
   D.draft-ietf-avt-rtp-svc].]

   Section 6 of [RFC3984] applies.  The following rules apply in
   addition.

   All receivers MUST support the single NAL unit packetization mode to
   provide backward compatibility to endpoints supporting only the
   single NAL unit mode of RFC 3984.  However, the single NAL unit
   packetization mode SHOULD NOT be used whenever possible, because
   encapsulating NAL units of small sizes, e.g. small NAL units
   containing parameter sets, SEI messages or prefix NAL units, in their
   own packets is typically less efficient because of the relatively big
   overhead.

   All receivers MUST support the non-interleaved packetization mode.




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      Informative note: The non-interleaved mode allows an application
      to encapsulate a single NAL unit in a single RTP packet.
      Historically, the single NAL unit mode has been included into
      [RFC3984] only for compatibility with ITU-T Rec. H.241 Annex A
      [H.241].  There is no point in carrying this historic ballast
      towards a new application space such as the one provided with MVC.
      More technically speaking, the implementation complexity increase
      for providing the additional mechanisms of the non-interleaved
      mode (namely STAP-A and FU-A) is minor, and the benefits are
      great, that STAP-A implementation is required.

   A NAL unit of small size SHOULD be encapsulated in an aggregation
   packet together with one or more other NAL units. For example, non-
   VCL NAL units such as access unit delimiter, parameter set, or SEI
   NAL unit are typically small.

   A prefix NAL unit SHOULD be aggregated to the same packet as the
   associated NAL unit following the prefix NAL unit in decoding order.

   When the first aggregation unit of an aggregation packet contains a
   PACSI NAL unit, there MUST be at least one additional aggregation
   unit present in the same packet.

   When an MVC bitstream is transported in more than one RTP session,
   the following applies.

   o Interleaved mode SHOULD be used for all the RTP sessions.

   o An RTP session that does not use interleaved mode SHOULD be
   constrained as follows.

     - Non-interleaved mode MUST be used.

     - STAP-A MUST be used, and any other type of packets MUST NOT be
   used.

     - Each STAP-A MUST contain a PACSI NAL unit and the DONC field MUST
   be present in the PACSI NAL unit.

      Informative note: The motivation for these constraints is to
      allow the use of non-interleaved mode for the session conveying
      the H.264/AVC compatible view, such that RFC 3984 receivers
      without interleaved mode implementation can subscribe to the base
      view session.

   Non-VCL NAL units SHOULD be conveyed in the same session as the
   associated VCL NAL units.  To meet this, SEI messages that are


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   contained in scalable nesting SEI message and are applicable to more
   than one session SHOULD be separated and contained into multiple
   scalable nesting SEI messages.  The DON values MUST indicate the
   cross-layer decoding order number values as if all these SEI messages
   were in separate scalable nesting SEI messages and contained in the
   beginning of the corresponding access units as specified in [MVC].

8. De-Packetization Process (Informative)

   For a single RTP session, the de-packetization process specified in
   section 7 of [RFC3984] applies.

   For receiving more than one of multiple RTP sessions conveying a
   scalable bitstream, an example of a suitable implementation of the
   de-packetization process is to be specified similarly as what will be
   finally included in [I-D.draft-ietf-avt-svc].

9. Payload Format Parameters

   This section specifies the parameters that MAY be used to select
   optional features of the payload format and certain features of the
   bitstream.  The parameters are specified here as part of the media
   type registration for the MVC codec.  A mapping of the parameters
   into the Session Description Protocol (SDP) [RFC4566] is also
   provided for applications that use SDP.  Equivalent parameters could
   be defined elsewhere for use with control protocols that do not use
   SDP.

9.1. Media Type Registration

   The media subtype for the MVC codec is allocated from the IETF tree.

   The receiver MUST ignore any unspecified parameter.

      Informative note: Requiring ignoring unspecified parameter allows
      for backward compatibility of future extensions.  For example, if
      a future specification that is backward compatible to this
      specification specifies some new parameters, then a receiver
      according to this specification is capable of receiving data per
      the new payload but ignoring those parameters newly specified in
      the new payload specification.  This sentence is also present in
      RFC 3984.

   Media Type name:     video

   Media subtype name:  H264-MVC



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   The media subtype "H264" MUST be used for RTP streams using RFC 3984,
   i.e. not using any of the new features introduced by this
   specification compared to RFC 3984.  For RTP streams using any of the
   new features introduced by this specification compared to RFC 3984,
   the media subtype "H264-MVC" SHOULD be used, and the media subtype
   "H264" MAY be used.  Use of the media subtype "H264" for RTP streams
   using the new features allows for RFC 3984 receivers to negotiate and
   receive H.264/AVC or MVC streams packetized according to this
   specification, but to ignore media parameters and NAL unit types it
   does not recognize.

   Required parameters: none

   OPTIONAL parameters: to be specified.

   Encoding considerations:

       This type is only defined for transfer via RTP (RFC 3550).

   Security considerations:

       See section 10 of RFC XXXX.

   Public specification:

       Please refer to RFC XXXX and its section 14.

   Additional information: none

   File extensions: none

   Macintosh file type code: none

   Object identifier or OID: none

   Person & email address to contact for further information:

   Intended usage: COMMON

   Author: NN

   Change controller:

       IETF Audio/Video Transport working group delegated from the IESG.





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9.2. SDP Parameters

9.2.1. Mapping of Payload Type Parameters to SDP

   The media type video/H264-MVC string is mapped to fields in the
   Session Description Protocol (SDP) as follows:

   The media name in the "m=" line of SDP MUST be video.

   The encoding name in the "a=rtpmap" line of SDP MUST be H264-MVC (the
   media subtype).

   The clock rate in the "a=rtpmap" line MUST be 90000.

   The OPTIONAL parameters, when present, MUST be included in the
   "a=fmtp" line of SDP.  These parameters are expressed as a media type
   string, in the form of a semicolon separated list of parameter=value
   pairs.

9.2.2. Usage with the SDP Offer/Answer Model

   TBD.

9.2.3. Usage with multi-session transmission

   If multi-session transmission is used, the rules on signaling media
   decoding dependency in SDP as defined in
   [I-D.draft-ietf-mmusic-decoding-dependency] apply.

9.2.4. Usage in Declarative Session Descriptions

   TBD.

9.3. Examples

   TBD.

9.4. Parameter Set Considerations

   Please see section 10 of [RFC3984].

10. Security Considerations

   Please see section 11 of [RFC3984].





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11. Congestion Control

   TBD.

12. IANA Considerations

   Request for media type registration to be added.

13. Acknowledgments

   The author Thomas Schierl of Fraunhofer HHI is sponsored by the
   European Commission under the contract number FP7-ICT-214063, project
   SEA.

   This document was prepared using 2-Word-v2.0.template.dot.

14. References

14.1. Normative References

   [H.264]   ITU-T Recommendation H.264, "Advanced video coding for
             generic audiovisual services", 3rd Edition, November 2007.

   [I-D.draft-ietf-avt-rtp-svc] Wenger, S., Wang, Y. -K., Schierl, T.
             and A. Eleftheriadis, "RTP payload format for SVC video",
             draft-ietf-avt-rtp-svc-13 (work in progress), July 2008.

   [I-D.draft-ietf-mmusic-decoding-dependency] Schierl, T., and Wenger,
             S., "Signaling media decoding dependency in Session
             Description Protocol (SDP)", draft-ietf-mmusic-decoding-
             dependency-02 (work in progress), May 2008.

   [MPEG4-10]
             ISO/IEC International Standard 14496-10:2005.

   [MVC]     Joint Video Team, "Joint Draft 7 of MVC ", available from
             http://ftp3.itu.ch/av-arch/jvt-site/2008_04_Geneva/JVT-
             AA209.zip, Geneva, Switzerland, April 2008.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data
             Encodings", RFC 3548, July 2003.





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   [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and Jacobson,
             V., "RTP: A Transport Protocol for Real-Time Applications",
             STD 64, RFC 3550, July 2003.

   [RFC3984] Wenger, S., Hannuksela, M., Stockhammer, T., Westerlund, M.,
             and Singer, D., "RTP Payload Format for H.264 Video", RFC
             3984, February 2005.

   [RFC4566] Handley, M., Jacobson, V., and Perkins, C., "SDP: Session
             Description Protocol", RFC 4566, July 2006.

14.2. Informative References

   [DVB-H]   DVB - Digital Video Broadcasting (DVB); DVB-H
             Implementation Guidelines, ETSI TR 102 377, 2005.

   [H.241]   ITU-T Rec. H.241, "Extended video procedures and control
             signals for H.300-series terminals", May 2006.

   [IGMP]    Cain, B., Deering S., Kovenlas, I., Fenner, B., and
             Thyagarajan, A., "Internet Group Management Protocol,
             Version 3", RFC 3376, October 2002.

   [McCanne] McCanne, S., Jacobson, V., and Vetterli, M., "Receiver-
             driven layered multicast", in Proc. of ACM SIGCOMM'96,
             pages 117--130, Stanford, CA, August 1996.

   [MBMS]    3GPP - Technical Specification Group Services and System
             Aspects; Multimedia Broadcast/Multicast Service (MBMS);
             Protocols and codecs (Release 6), December 2005.

   [MPEG2]   ISO/IEC International Standard 13818-2:1993.

   [RFC3450] Luby, M., Gemmell, J., Vicisano, L., Rizzo, L., and
             Crowcroft, J., "Asynchronous layered coding (ALC) protocol
             instantiation", RFC 3450, December 2002.













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Author's Addresses

   Ye-Kui Wang
   Huawei Technologies
   400 Somerset Corporate Blvd
   Bridgewater, NJ 08807
   USA

   Phone: +1-908-393-4758
   EMail: yekuiwang@huawei.com


   Thomas Schierl
   Fraunhofer HHI
   Einsteinufer 37
   D-10587 Berlin
   Germany

   Phone: +49-30-31002-227
   EMail: schierl@hhi.fhg.de


15. Open issues:

   -  The use of CL-DON for session reordering allows also for
     interleaved transmission with non-interleaved packetization mode.
     There should be a clear separation between both tools.  This issue
     should be handled the same way as for the SVC payload draft.

   -  Since SVC session multiplexing (multi source transmission(MST)) is
     cleared, it would be great to just reference the MST sections in
     [I-D.draft-ietf-avt-rtp-svc]. Since the text in sections 6 and 7
     of [I-D.draft-ietf-avt-rtp-svc] is currently very SVC specific,
     the authors would have to try to rewrite these sections in a more
     generic way. If this is not possible, we need to copy text from
     [I-D.draft-ietf-avt-rtp-svc] with respect to MVC.



16. Changes Log

   Initial version 00

      10 November 2007: YkW
         Initial version




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      12 November 2007: TS
         - Added definition of "Session multiplexing"
         - Added the reference of [I-D.draft-ietf-mmusic-decoding-
   dependency], and its reference in section 9.2.3

      12 November 2007: YkW
         - Added the reference of [I-D.draft-ietf-avt-svc] and its
   reference in section 1.
         - Added in sections 3.1 and 3.2 paragraphs regarding inter-view
   prediction


   From draft-wang-avt-rtp-mvc-00 to draft-wang-avt-rtp-mvc-01

      18 February 2008: YkW
         - Alignment to the latest MVC draft in JVT-Z209 and version 07
   of [I-D.draft-ietf-avt-svc].

      25 February 2008: TS

   -  Minor modifications and updates throughout the document

   -  Added open issue on clear separation between "decoding order
     recovery" and "interleaving"

   From draft-wang-avt-rtp-mvc-01 to draft-wang-avt-rtp-mvc-02

      09 July 2008: TS

   -  Minor modifications and updates throughout the document

   -  Added open issue

   -  NAL unit header alignment with MVC spec

   -  Section 6. References corresponding sections in [RFC3984] and [I-
     D.draft-ietf-avt-svc].

   -  TBD: Section 7, we may align [I-D.draft-ietf-avt-svc] in a way
     that SVC is not mentioned in this paragraphs, so that we can
     reference them from this document.

     21 August 2008:

   -  Minor modifications, editing and adding notes throughout the
     document.



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   -  Updated references

   From draft-wang-avt-rtp-mvc-02 to draft-wang-avt-rtp-mvc-03

      04 February 2009: YkW

   -  Updated author's address.

      04 February 2009: YkW

   -  Updated the boiler template.






































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