1、Information technology Coding of audio-visual objects Part 11: Scene description and application engine AMENDMENT 6Amendment 6:2010 (IDT) toNational Standard of CanadaCAN/CSA-ISO/IEC 14496-11-07(ISO/IEC 14496-11:2005, IDT)NOT FOR RESALE.PUBLICATION NON DESTINE LA REVENTE.CSA Standards Update Service
2、Amendment 6:2010 toCAN/CSA-ISO/IEC 14496-11-07December 2010Title: Information technology Coding of audio-visual objects Part 11: Scene description and application engine AMENDMENT 6Pagination:22 pages (iii preliminary and 19 text)To register for e-mail notification about any updates to this publicat
3、iongo to www.shopcsa.caclick on E-mail Services under MY ACCOUNTclick on CSA Standards Update ServiceThe List ID that you will need to register for updates to this publication is 2418653.If you require assistance, please e-mail techsupportcsa.ca or call 416-747-2233.Visit CSAs policy on privacy at w
4、ww.csagroup.org/legal to find out how we protect your personal information.Reference numberISO/IEC 14496-11:2005/Amd.6:2009(E)ISO/IEC 2009INTERNATIONAL STANDARD ISO/IEC14496-11First edition2005-12-15AMENDMENT 62009-03-15Information technology Coding of audio-visual objects Part 11: Scene description
5、 and application engineAMENDMENT 6 Technologies de linformation Codage des objets audiovisuels Partie 11: Description de scne et moteur dapplication AMENDEMENT 6 ISO/IEC 14496-11:2005/Amd.6:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing polic
6、y, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central S
7、ecretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to
8、 ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2009 All rights reserved. Unless otherwise specified, no part of this p
9、ublication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 G
10、eneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org ii ISO/IEC 2009 All rights reservedAmendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) ISO/IEC 2009 All rights reserved iiiForeword ISO (the International Organization for Sta
11、ndardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organiz
12、ation to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology
13、, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards ado
14、pted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject o
15、f patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Amendment 6 to ISO/IEC 14496-11:2005 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia info
16、rmation. Amendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) ISO/IEC 2009 All rights reserved 1Information technology Coding of audio-visual objects Part 11: Scene description and application engine AMENDMENT 6 After 8.13, add the following new subclause: 8.14 Scene Pa
17、rtitioning 8.14.1 Overview In 3D streaming applications, a server often holds a compressed binary representation of the whole scene data. At the time a client connects, it receives a coarse version of the environment that suits more or less its actual location and requested precision. For the rest o
18、f the navigation, refinement data will be sent according to the observer trajectory within the scene. At this stage, two scenarios are possible. The first one is called server-driven scenario; in this case, the server is assumed to be able to cope with the necessary computations for deciding exactly
19、 what refinements the client needs. Usually, the client has already sent his position and some hints of what he already has in his cache. According to this information, the server extracts a subset of the compressed binary representation, using some kind of MPEG-21 gBSD file. The second possible sce
20、nario is the so-called client-based one. In this case, it is the client task to compute and request the necessary refinement data. In a perfect world, the server would have enough capability to constantly remain in server-driven mode. But in practical applications, when the number of clients grows,
21、often reaching several thousands of terminals, the server can not cope anymore and has to cast to the most effective clients the task of identifying the needed refinements. Another important thing to note, also raised after our practical implementations, is that this becomes general rule when dealin
22、g with peer-to-peer applications, i.e. when terminals can arbitrarily be considered as servers as well. While the client-driven mode reduces the amount of information to send to the server (namely the hints on the cache content), one noticeable difference is that the client does not know exactly wha
23、t could or should be sent in function of his position and orientation. What was known on the server side in the server-driven mode is unknown by the client in the client-driven mode. The schema is based on an extensible syntax, such as the AFX backchannel. The purpose of this framework is to be able
24、 to any space partitioning conception, including the most general ones, as well as the most specific. The partitioning types considered so far are: 1) BSP: this had already been proposed at the Fairfax meeting, but the activity had not followed up at that time by lack of support and efficient design
25、 of the node. However, the technology itself has proved to be useful for adaptive transmission and rendering of large scenes, and applies to the most arbitrary scenes, independently on the tools used to compress the objects. 2) Cells / Portals: another widely used representation for selective transm
26、ission / rendering of large interior scenes is the Cell / Portal paradigm. This representation is a graph in which the nodes figure the various rooms in the building and the edges denote the possible visibility from one room to another. Amendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11
27、:2005/Amd.6:2009(E) 2 ISO/IEC 2009 All rights reserved3) PVS (Potentially Visible Sets): also very widely used for exterior scenes, the purpose of PVS is the same as Cells and Portals with the difference that areas are not related to other visible areas but instead linked to the set of objects that
28、are visible from this area. 4) WaveletSubdivisionSurfaces: this is a specific partitioning design, suited to the accommodation of geometric wavelet coefficients. This is based on bounding volumes that are strongly dependent on the shape of the base mesh. 5) FootPrints: this is the specific design th
29、at was originally demonstrated and that showed significant gain in both bandwidth and reconstruction time. Generic tools, such as BSP, Cells and Portals and PVS are supposed to handle portions of scenes independently of the encoding scheme. This can be used for VRML scenes, or with objects for which
30、 the partitioning does not have to have finer granularity than the object itself, namely because its encoding does not provide multiresolution. 8.14.2 Node interface PROTO SpacePartition #%NDT=SFWorldNode,SF3DNode %COD=N eventIn MF3DNode addChildren eventIn MF3DNode removeChildren exposedField MF3DN
31、ode children exposedField SFUrl SPStream NULL 8.14.2.1 Semantics and functionality children: this is the target node. The partitioning information may apply to the children nodes and to its descent. SPStream: this is the stream containing the Scene Partitioning information. NOTE The partitioning nod
32、es obey the following criteria: Each partitioning node is attached to a rendered node; The partitioning node influences the descent of the rendered node it is attached to; The partitioning nodes combine themselves according to the hierarchy of the scene graph; Figure AMD6.1 shows an example illustra
33、ting these points. Amendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) ISO/IEC 2009 All rights reserved 3Figure AMD6.1 example of organization of space partitioning nodes within a scene graph In this example, one can see various space partitioning nodes (the SPs) occur
34、ring at various depth in the scene hierarchy. The type of each SP node is suited to the type of the object it is linked to. For example IndexedFaceSets representing the Earth and the Boat are partitioned using BSP and PVS. The museum, which is an interior subscene, is partitioned with Cells and Port
35、als. The statue inside the museum, represented by WaveletSubdivisionSurfaces, is partitioned with the according declination of the node. Each SP node is dependent on every other SP node upper in the hierarchy. For instance the rendering of the statue is subject to adaptation lead by SP4, but is cons
36、trained by the visibility induced by SP3 and SP1, that are linked to parent nodes. 8.14.3 Scene Partitioning stream definition 8.14.3.1 SpacePartitionDecoderConfig 8.14.3.1.1 Syntax class SpacePartitionDecoderConfig int (8) DSItag; int (8) type; switch(type) 0: BSPDecoderConfig; 1: CellPortalDecoder
37、Config; 2: PVSDecoderConfig; 3: SPFootprintDecoderConfig; 4: WaveletDecoderConfig; ) Earth Boat Museum Plane Visitor Statue SP1 SP2 SP3 SP4 IndexedFaceSet IndexedFaceSet IndexedFaceSet NURBSWaveletSubdivision WaveletSubdivision Partitioning Cells / Portals PVS BSP Amendment 6:2010 to CAN/CSA-ISO/IEC
38、 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) 4 ISO/IEC 2009 All rights reserved8.14.3.1.2 Semantics DSItag: Space Partition tag (0x0C) type: space partition type 8.14.3.2 BSPDecoderConfig 8.14.3.2.1 Syntax class BSPDecoderConfig int(6) indexNbBits; int(6) coefNbBits; int(6) objCountNbBits; int(1)
39、 is3D; 8.14.3.2.2 Semantics indexNbBits: number of bits used to encode BSP plane IDs coefNbBits: number of bits used to encode BSP plane coefficients objCountNbBits: number of bits used to encode the number of objects is3D: identifier of the 2D (value 0) or 3D (value 1). 8.14.3.3 CellPortalDecoderCo
40、nfig 8.14.3.3.1 Syntax class CellPortalDecoderConfig int(6) cellCountNbBits; int(6) totalCountNbBits; int(6) cellGeomNbBits; int(1) is3D; 8.14.3.3.2 Semantics cellCountNbBits: number of bits used to encode number of cells in the stream totalCountNbBits: number of bits used to encode total number of
41、cells as well as cell IDs cellGeomNbBits: number of bits used to encode cell geometry parameters is3D: identifier of the 2D (value 0) or 3D (value 1). Amendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) ISO/IEC 2009 All rights reserved 58.14.3.4 PVSDecoderConfig 8.14.3
42、.4.1 Syntax class PVSDecoderConfig int(6) cellCountNbBits; int(6) objCountNbBits; int(6) pvsGeomNbBits; 8.14.3.4.2 Semantics cellCountNbBits: number of bits used to encode the total number of cells objCountNbBits: number of bits used to encode the total number of objects 8.14.3.5 SPFootprintDecoderC
43、onfig 8.14.3.5.1 Syntax class SPFootprintDecoderConfig int(8) type; unsigned int(5) rootChildrenRadiusNbBits; unsigned int(5) nbChildrenNbBits; unsigned int(5) nbSubTreesNbBits; float(32) acquisitionPrecision; float(32) minMetricError; float(32) maxMetricErrorEncodingFunction; unsigned int(16) nbRoo
44、tChildren; unsigned int(5) indexNbBits; unsigned int(5) nbNodesInSubTreeNbBits; unsigned int(5) nbNodesOnFirstLevelOfSubTreeNbBits; unsigned int(5) nbSubTreesChildrenNbBits; unsigned int(5) nbNodesOnLastLevelNbBits; unsigned int(5) networkType; switch(networkType) 0: / no additional information; 1:
45、int(5) subTreeSizeNbBits; Int(5) geometryNodesSizeNbBits; 8.14.3.5.2 Semantics type: type of the description structure rootChildrenRadiusNbBits: number of bits used to decode the radius of the children (i.e. the bounding sphere) nbChildrenNbBits: number of bits used to decode the number of hierarchi
46、cal description nodes children nbSubTreesNbBits: number of bits used to decode number of sub-trees in a packet. acquisitionPrecision: precision used during data acquisition. Amendment 6:2010 to CAN/CSA-ISO/IEC 14496-11-07ISO/IEC 14496-11:2005/Amd.6:2009(E) 6 ISO/IEC 2009 All rights reservedminMetric
47、Error: smallest metric error that is greater than 0. maxMetricErrorEncodingFunction: maximum metric error used in the encoding function. nbRootChildren: number of children nodes for current node. indexNbBits: number of bits used to decode description node indices. nbNodesInSubTreeNbBits: number of b
48、its to used to decode the number of sub-tree nodes. nbNodesOnFirstLevelOfSubTreeNbBits: number of bits used to decode the number of nodes included in the first level sub-tree. NbSubTreesChildrenNbBits: number of bits used to decode the number of current sub-tree childrens. nbNodesOnLastLevelNbBits:
49、number of bits used to decode the number of nodes in the sub-tree first level. networkType: communication type. Type 0: client - server Type 1: P2P -subTreeSizeNbBits: number of bits used to decode the sub-tree size. -geometryNodeSizeNbBits: number of bits used to decode the geometry size. 8.14.3.6 WaveletDecoderConfig 8.14.3.6.1 Syntax class WaveletDecoderConfig int(6) unitCountNbBits; int(6) faceCountNbBits; int(6) geomNbBits; 8.14.3.6.2 SpacePartitionNodeMess
