This file is raw output from pdftotext and may not be ideal for distribution. If you are a maintainer for Hackipedia, please sit down when you have time and clean this text version up. Source PDF: /mnt/fw-js/docs/ATSC/A-71 ATSC Parameterized Services Standard.pdf Like all conversions the text below should be fully readable as UTF-8 unicode text. --------------------------------------------------------------- ATSC Standard: ATSC Parameterized Services Standard Document A/71, 26 March 2007 Advanced Television Systems Committee, Inc. 1750 K Street, N.W., Suite 1200 Washington, D.C. 20006 Advanced Television Systems Committee Document A/71 The Advanced Television Systems Committee, Inc., is an international, non-profit organization developing voluntary standards for digital television. The ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. Specifically, ATSC is working to coordinate television standards among different communications media focusing on digital television, interactive systems, and broadband multimedia communications. ATSC is also developing digital television implementation strategies and presenting educational seminars on the ATSC standards. ATSC was formed in 1982 by the member organizations of the Joint Committee on InterSociety Coordination (JCIC): the Electronic Industries Association (EIA), the Institute of Electrical and Electronic Engineers (IEEE), the National Association of Broadcasters (NAB), the National Cable Television Association (NCTA), and the Society of Motion Picture and Television Engineers (SMPTE). Currently, there are approximately 140 members representing the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. ATSC Digital TV Standards include digital high definition television (HDTV), standard definition television (SDTV), data broadcasting, multichannel surround-sound audio, and satellite direct-to-home broadcasting. Contact information is given below. Mailing address Advanced Television Systems Committee, Inc. 1750 K Street, N.W., Suite 1200 Washington, D.C. 20006 Telephone 202-872-9160 (voice) 202-872-9161 (fax) Web site http://www.atsc.org E-mail standards@atsc.org The revision history of this document is given below. A/71 Revision History A/71 approved 26 March 2007 2 ATSC Parameterized Services Standard 26 March 2007 Table of Contents 1 SCOPE 5 1.1 Introduction and Background 5 1.2 Organization 5 2 REFERENCES 6 2.1 Normative References 6 2.2 Informative References 6 3 DEFINITION OF TERMS 6 3.1 Compliance Notation 6 3.2 Treatment of Syntactic Elements 6 3.3 Acronyms and Abbreviations 7 4 COMPONENT LIST DESCRIPTOR (NORMATIVE) 7 4.1 Additional Constraints 9 Annex A: Example of Stream Information Details (Informative) 11 A1 NEW CODEC PROFILE 11 3 Advanced Television Systems Committee Document A/71 Table Index Table 4.1 Bit Stream Syntax for the Component List Descriptor 8 4 ATSC Standard: ATSC Parameterized Services Standard 1. SCOPE This supplementary standard defines a general purpose method to enable announcement of the technical attributes of program elements that must be supported in a receiving device to render the programming on a particular virtual channel. It is not a replacement for fully-defined and optimized combinations of program elements defined for a particular service type, such as those established by A/53 and A/97. 1.1 Introduction and Background This standard establishes a tool intended to help manage technological change and reduce the impact of evolutionary changes to the ATSC Digital Television Standard. As time goes on, broadcast service providers may desire to introduce new structures and formats of program elements. Some may be alternative methods for compressing audio or video, others that are less central to the broadcast service may include such things as providing for secure use of broadcast content within a home, or the signaling of IPTV-related services. In contrast, the base set of standards provides an enumerated set of standardized techniques with detailed constraints agreed-upon and established prior to the deployment of receiving devices. The particular technological element of control that is relevant to the signaling of the structure of service offerings is the service_type, which is a construct to explicitly define the exact match of transmit and receive capabilities required for successful rendering of digital content found on the virtual channel associated with the given service_type value. For collections of program elements that are to be presented in a specific predetermined and predictable manner, especially for mass- market optimized products, well known sets of enumerated characteristics are valuable. Traditionally, a change is made to the base set (defined by specific values of service_type) when the need arises to make a major improvement in delivery formats. Special-purpose combinations that need to be unknown to the consumer also have justified the establishment of new service_type values. This standard introduces a different approach designed to establish, for products supporting it, a uniform and controlled way to enable new components to be transmitted without impacting legacy devices and products that are unable to support the identified codecs or program elements. This approach is similar to the device discovery and control profiles in the Digital Living Network Alliance (DLNA) guidelines [4]. The fundamental element of the new approach is a descriptor that specifies characteristics of the critical parameters for each service element of a particular virtual channel. The descriptor is placed in the A/65 [2] VCT and lists the stream_type and other details describing capabilities that need to be supported in the receiver to render all content in the associated virtual channel. 1.2 Organization This document is organized as follows: Page 5 Advanced Television Systems Committee Document A/71 • Section 1 – Outlines the scope of this document and provides a general introduction. • Section 2 – Lists references and applicable documents. • Section 3 – Provides a definition of terms, acronyms, and abbreviations for this document. • Section 4 – Component List Descriptor specification (normative). 2. REFERENCES At the time of publication, the editions indicated below were valid. All standards are subject to revision, and parties to agreement based on this standard are encouraged to investigate the possibility of applying the most recent editions of the documents listed below. 2.1 Normative References The following documents contain provisions which, through reference in this text, constitute provisions of this standard. [1] IEEE: “Use of the International Systems of Units (SI): The Modern Metric System”, Doc. IEEE/ASTM SI 10-2002, Institute of Electrical and Electronics Engineers, New York, N.Y. [2] ATSC: “Program and System Information Protocol for Terrestrial Broadcast and Cable, Revision C, with Amendment No. 1,” Doc. A/65C, Advanced Television Systems Committee, Washington, D.C., 2 January 2006 (Amendment No. 1 dated 9 May 2006). 2.2 Informative References [3] ISO: “ISO/IEC IS 13818-1:2000 (E), International Standard, Information technology – Generic coding of moving pictures and associated audio information: systems.” [4] Digital Living Network Alliance: DLNA Networked Device Interoperability Guidelines expanded: March 2006. 3. DEFINITION OF TERMS With respect to definition of terms, abbreviations, and units, the practice of the Institute of Electrical and Electronics Engineers (IEEE) as outlined in the Institute’s published standards [1] shall be used. Where an abbreviation is not covered by IEEE practice or industry practice differs from IEEE practice, the abbreviation in question will be described in Section 3.3 of this document. 3.1 Compliance Notation As used in this document, “shall” denotes a mandatory provision of the standard. “Should” denotes a provision that is recommended but not mandatory. “May” denotes a feature whose presence does not preclude compliance, which may or may not be present at the option of the implementer. 3.2 Treatment of Syntactic Elements This document contains symbolic references to syntactic elements used in the audio, video, and transport coding subsystems. These references are typographically distinguished by the use of a different font (e.g., restricted), may contain the underscore character (e.g., sequence_end_code) and may consist of character strings that are not English words (e.g., dynrng). 6 ATSC Parameterized Services Standard 26 March 2007 3.3 Acronyms and Abbreviations The following acronyms and abbreviations are used within this specification. ATSC Advanced Television Systems Committee CVCT Cable Virtual Channel Table DLNA Digital Living Network Alliance IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronics Engineers IPTV Internet Protocol television ISO International Standards Organization MPEG Moving Picture Experts Group TVCT Terrestrial Virtual Channel Table VCT Virtual Channel Table 4. COMPONENT LIST DESCRIPTOR (NORMATIVE) The component_list_descriptor() is used in the A/65 [2] TVCT and/or the CVCT to signal the combination of components (stream types, etc.) associated with a particular virtual channel. Each instance of the component_list_descriptor() shall identify the set of stream types that, if supported in a receiving device, allow that device to properly render and present all programming on the channel. Some or all of the identified stream types may be absent at any given time. The component_list_descriptor() shall be present in the descriptor loop following the descriptors_length field of any terrestrial_virtual_channel_table_section() or cable_virtual_channel_table_section() in which the value of the service_type field is 0x07 in the enclosing “for” loop. Receiving devices can use the combination of parameterized services and the Component List Descriptor to identify and discard channels for which processing support for all identified components is not available. Up to two instances of the Component List Descriptor may appear in the TVCT/CVCT descriptor loop, a “primary” and an “alternate.” A second instance is appropriate when content carried within a particular program element is simulcast on a second program element, where the simulcast stream is encoded using a different codec. This situation reflects the case that support in the receiver for either of two different sets of stream types is sufficient to guarantee support for encoding formats for the content on the channel. This standard establishes no constraints or relaxations on the contents of the TVCT or CVCT other than those explicitly stated herein. The bit-stream syntax for the component_list_descriptor() shall be as shown in Table 4.1. 7 Advanced Television Systems Committee Document A/71 Table 4.1 Bit Stream Syntax for the Component List Descriptor Syntax No. of Bits Mnemonic component_list_descriptor() { descriptor_tag 8 uimsbf descriptor_length 8 uimsbf alternate 1 bslbf component_count 7 uimsbf for (i=0; i