1、 Copyright 2009 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue., White Plains, NY 10601 (914) 761-1100 Approved November 2, 2009 Table of Contents Page Foreword . 2 Intellectual Property 2 Introduction 2 1 Scope . 3 2 Conformance Notation . 3 3 Normative References . 3 4 V
2、C-2 Levels 4 5 Generalized Level Definitions 4 5.1 Level 0: Reserved 4 5.2 Levels 1 to 7: The Default Levels . 4 Annex A Catalogue of Specialized VC-2 Levels (Informative) . 7 Annex B Bibliography (Informative) . 8 Page 1 of 8 pages SMPTE ST 2042-2:2009 SMPTE STANDARD VC-2 Level Definitions SMPTE ST
3、 2042-2:2009 Page 2 of 8 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headquartered and incorporated in the United States of America, SMPTE has members in over 80 countries on six continents. SMPTEs
4、Engineering Documents, including Standards, Recommended Practices, and Engineering Guidelines, are prepared by SMPTEs Technology Committees. Participation in these Committees is open to all with a bona fide interest in their work. SMPTE cooperates closely with other standards-developing organization
5、s, including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in Part XIII of its Administrative Practices. SMPTE ST 2042-2 was prepared by Technology Committee 10E. Intellectual Property At the time of publication no notice had been received by SMPTE clai
6、ming patent rights essential to the implementation of this Standard. However, attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. SMPTE shall not be held responsible for identifying any or all such patent rights. Introduction This sec
7、tion is entirely informative and does not form an integral part of this Engineering Document. This standard defines levels for the VC-2 video coding standard. Level values, along with profile values, provide a fast look-up for decoders to establish whether they can decode a VC-2 stream. Profile valu
8、es are defined in the VC-2 specification. VC-2 levels are divided into generalized and specialized categories. Generalized levels are defined to provide identification of a range of encoded video parameters and are defined in this document. Specialized levels are defined for specific applications wh
9、ere other VC-2 level specifications do not suffice. SMPTE ST 2042-2:2009 Page 3 of 8 pages 1 Scope VC-2 is a video codec that includes parameter values to identify the complexity of the coded VC-2 bit-stream through the use of profiles and levels. These values provide a fast assessment for a decoder
10、 to establish whether it has the capability to decode the VC-2 bit-stream. Profiles are defined in the VC-2 standard (SMPTE ST 2042-1). This standard defines the coding constraints for generalized level values lying in the range 0 to 63. This standard also informatively registers the values of speci
11、alized levels with values exceeding 63. 2 Conformance Notation Normative text is text that describes elements of the design that are indispensable or contains the conformance language keywords: “shall“, “should“, or “may“. Informative text is text that is potentially helpful to the user, but not ind
12、ispensable, and can be removed, changed, or added editorially without affecting interoperability. Informative text does not contain any conformance keywords. All text in this document is, by default, normative, except: the Introduction, any section explicitly labeled as “Informative“ or individual p
13、aragraphs that start with “Note:” The keywords “shall“ and “shall not“ indicate requirements strictly to be followed in order to conform to the document and from which no deviation is permitted. The keywords, “should“ and “should not“ indicate that, among several possibilities, one is recommended as
14、 particularly suitable, without mentioning or excluding others; or that a certain course of action is preferred but not necessarily required; or that (in the negative form) a certain possibility or course of action is deprecated but not prohibited. The keywords “may“ and “need not“ indicate courses
15、of action permissible within the limits of the document. The keyword “reserved” indicates a provision that is not defined at this time, shall not be used, and may be defined in the future. The keyword “forbidden” indicates “reserved” and in addition indicates that the provision will never be defined
16、 in the future. A conformant implementation according to this document is one that includes all mandatory provisions (“shall“) and, if implemented, all recommended provisions (“should“) as described. A conformant implementation need not implement optional provisions (“may“) and need not implement th
17、em as described. Unless otherwise specified, the order of precedence of the types of normative information in this document shall be as follows: Normative prose shall be the authoritative definition; Tables shall be next; followed by formal languages; then Figures; and then any other language forms.
18、 3 Normative Reference The following standard contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this standard are enc
19、ouraged to investigate the possibility of applying the most recent edition of the standard indicated below. SMPTE ST 2042-1:2009, VC-2 Video Compression SMPTE ST 2042-2:2009 Page 4 of 8 pages 4 VC-2 Levels The VC-2 profile and level values are present in the parse info header of every VC-2 sequence
20、to provide a fast look-up for decoders to establish their suitability for a given VC-2 sequence. The profile and level values are mutually independent and decoders need both values to determine if a given VC-2 sequence is decodable. Profile values shall be as defined in SMPTE ST 2042-1, the VC-2 spe
21、cification. Level values identify constrained parameter values in a given VC-2 bitstream. Generalized levels allow some parameters to be within a range of values. Generalized levels require that decoders claiming compliance with a given level are able to decode VC-2 bitstreams encoded with the corre
22、sponding range of parameter values. Generalized level definitions do not overlap. Level values 063 inclusive shall be reserved for generalized level definitions that use the video formats defined in SMPTE ST 2042-1 Annex C. Section 5 of this document defines all generalized levels and their values.
23、All generalized level values that are not defined in this document shall be reserved values. Specialized levels are used to further constrain a VC-2 bitstream in order to satisfy the requirements of a specific application. A particular application domain may impose additional constraints on the requ
24、irements for a decoder, for example, to support a specific video interface with real-time decoding. Specialized level definitions may overlap. Level values =64 shall be reserved for specialized applications of the VC-2 codec. The VC-2 bitstream constraints shall be defined by an application specific
25、ation which shall assign a unique VC-2 specialized level value. A VC-2 bitstream identified by a specialized level value may be a specifically constrained sub-set of a generalized level definition with restrictions as defined by the application specification. This document provides informative Annex
26、 A that catalogues all known specialized level values and their defining documents. This annex should be updated as needed to maintain the accuracy of the catalogue through revisions of this document. 5 Generalized Level Definitions This standard defines the parameters applicable to conformant bit-s
27、treams for level values 0 to 7 inclusive. Other generalized level values up to 63 may be defined in future revisions of this document. Unless otherwise specified, custom flags shall be False. 5.1 Level 0: Reserved Level 0 shall be reserved. 5.2 Levels 1 to 7: The Default Levels Levels 1 to 7 shall b
28、e used to identify a VC-2 bit-stream that complies with one of the base video formats with an index value 0 as defined in SMPTE ST 2042-1 annex C and where: the default video parameters of the base video format shall not be overridden unless otherwise defined in this document. Decoders claiming conf
29、ormance to Levels 1 to 7 shall be able to decode a specific sub-set of the VC-2 bit-streams that comply with the base video formats defined in SMPTE ST 2042-1 annex C as follows: Level 1 decoders shall be able to decode VC-2 bit-streams that comply with the base video formats 16 inclusive. SMPTE ST
30、2042-2:2009 Page 5 of 8 pages Level 2 decoders shall be able to decode VC-2 bit-streams that comply with the base video formats 7, 8 or 22. Level 3 decoders shall be able to decode VC-2 bit-streams that comply with the base video formats 914 inclusive or 21. Level 4 decoders shall be able to decode
31、VC-2 bit-streams that comply with the base video format 15 only. Level 5 decoders shall be able to decode VC-2 bit-streams that comply with the base video format 16 only. Level 6 decoders shall be able to decode VC-2 bit-streams that comply with the base video formats 17 or 18. Level 7 decoders shal
32、l be able to decode VC-2 bit-streams that comply with the base video formats 19 or 20. In addition, for Levels 2, 3 and 4 only, decoders shall be able to decode the additional streams specified below which are extensions to the base video formats: Level 2 decoders shall be able to decode streams com
33、pliant with base video format 7 where the frame size has been over-ridden by a frame size of up to 486 lines (see below for details). Note: this provision supports the carriage of component video carried on interfaces defined in SMPTE 125M, SMPTE 259M, and SMPTE 293M. Levels 2 and 3 decoders shall b
34、e able to decode streams compliant with base video formats 7, 8, 11, 12 and 22, where the scan format has been over-ridden to signal progressive video (see below for details). Note: This provision supports the common practice of carrying progressive (“film mode”) video over an interlaced format. Lev
35、el 4 decoders shall be able to decode streams compliant with base video format 15 and where the Frame Rate index only has been overridden with the value of 11 (48fps). Decoders may claim compliance with any one or more level numbers as defined above. 5.2.1 Sequence Header Parameters The following co
36、nstraints shall apply to the sequence header parameters (see SMPTE ST 2042-1, Section 11): custom_dimensions_flag shall be False with the exception that, for base video format 7 only, the custom_dimensions_flag may be set to True. If the custom_scan_format_flag is True, then frame_width shall be ove
37、r-ridden with a value of 720 and the frame_height shall be over-ridden with a value between 480 and 486. custom_chroma_format_flag shall be False custom_scan_format_flag shall be False with the exception that for base video formats 7, 8, 11, 12 and 22 only, the custom_scan_format_flag may be set to
38、True. If the custom_scan_format_flag is True, then default source_sampling value of 1 (interlaced) may be overridden with the value of 0 (progressive). custom_frame_rate_flag shall be False with the exception specified above for Level 4. SMPTE ST 2042-2:2009 Page 6 of 8 pages custom_pixel_aspect_rat
39、io_flag be False custom_clean_area_flag shall be False custom_signal_range_flag shall be False custom_color_spec_flag shall be False picture_coding_mode, defined in SMPTE ST 2042-1 Section 11.4, shall correspond to the specified source format. That is, if the source format is signaled to be progress
40、ive then pictures shall correspond to frames, else if the source format is signaled as interlaced pictures shall be fields. 5.2.2 Picture Header Parameters The following constraints shall apply to picture header parameters: wavelet_index shall be as defined in SMPTE ST 2042-1, Table 12.3.1 and shall
41、 be less than, or equal to 4. dwt_depth shall be between 0 and 4 inclusive for core syntax pictures: o codeblocks_x and codeblocks_y shall be such that there is at least one coefficient in each codeblock. for low delay syntax pictures: o slices_x and slices_y shall be such that there is at least one
42、 DC (0-LL) coefficient per slice. o values in the quantizer matrix shall lie between 0 and 127 inclusive 5.2.3 Transform Data The following constraints shall apply to transform data elements (SMPTE ST 2042-1, Section 13): for core syntax pictures: o quantization indices for both subbands and codeblo
43、cks shall lie between 0 and 68 inclusive o The codeblock_mode (SMPTE ST 2042-1, Section 12.3.3), where used, shall be True. This means that the same quantization index applies to all wavelet transforms within a subband. SMPTE ST 2042-2:2009 Page 7 of 8 pages Annex A Catalogue of Specialized VC-2 Lev
44、els (Informative) The table below identifies those specialized levels defined in other SMPTE documents through the level value and its defining document (or documents). Specialized Level Value Defining Document 64 SMPTE RP 2047-1 (Mezzanine Compression of 1080P High Definition Video Sources) SMPTE S
45、T 2042-2:2009 Page 8 of 8 pages Annex B Bibliography (Informative) SMPTE 125M-1995, Television Component Video Signal 4:2:2 Bit-Parallel Digital Interface SMPTE 259M-2008, Television SDTI Digital Signal/Data Serial Digital Interface SMPTE 293M-2003, Television 720 x 483 Active Line at 59.94-Hz Progressive Scan Production Digital Representation SMPTE RP 2047-1:2009, VC-2 Mezzanine Level Compression of 1080P High Definition Video Sources
