SMPTE ST 326M-2000 Television - SDTI Content Package Format (SDTI-CP).pdf

1、_ - STD-SMPTE 32bM-ENGL 2000 I8357LiOL 0004020 T2T M SMPTE STANDARD for Television - SDTI Content Package Format (SDTI-CP) SMPTE 326M-2000 1 Scope This standard specifies the format for the transport of content packages (CP) on the serial digital transport interface (SDTI). This format is abbreviate

2、d to the term SDTI-CP. The format is a packaging structure for the assembiy of system, picture, audio, and auxiliary data items as follows: - A system item assembled as a group of timing and control elements, plus any metadata associ- ated with the picture, audio, and auxiliary data items; - A pictu

3、re item assembled as a group of up to 255 picture stream elements; - An audio item assembled as a group of up to 255 audio stream elements: - An auxiliary item assembled as a group of up to 255 auxiliary data elements such as ancillary data lines, teletext, and other data. This standard defines the

4、structure of the content package mapped onto the SDTI transport. All element and metadata formats are defined by SMPTE 331 M. An SDTI-CP compliant receiver shall be capable of receiving and parsing the structure of the SDTI-CP format. An SDTI-CP compliant decoder is defined by the ability to both re

5、ceive and decode a defined set of elements and metadata according to an associ- ated decoder template document. Page 1 of 19 pages The baseline operation of this standard is defined by the transport of content packages locked to the SDTI transport frame rate. This standard additionally de- fines for

6、mat extension capabilities as follows: - Allow content package transfers at higher and lower than the specified rate through isochronous and asynchronous transfer modes; - Provision of a timing mode to reduce delay and provision for two content packages in each SDTI transport frame; - Carriage of co

7、ntent packages in a low-latency mode; and - Multiplexing of content packages from different sources onto one SDTI transport. This standard is limited to SDTI Operating at a bl rate of 270 Mb/s and 360 Mb/s as defined by SMPTE 305M. 2 Normative references The following standards contain provisions wh

8、ich, through reference in this text, constitute provisions of this standard. At the time of publication, the edilions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recen

9、t edition of the standards indicated below. ANSVSMPTE 298M-1997, Television - Universal Labels for Unique Identification of Digital Data SMPTE 12M-1999, Television, Audio and Rlrn - Time and Control Code Copyrigh192ooO byMESOCIETYOF MOTION PICTURE AND TELOIISION ENGINEERS 595 W. Hatsdale Ave., White

10、 Plains, NY 10607 (914) 761-1100 Appmved January 31,2000 STD*SMPTE 32bM-ENGL SMPTE 326M-2OW SMPTE 305M-1998, Television - Serial Data Trans- pori Interface SMPTE 331M-2000, Television - Element and Metadata Definitions for the SDTI-CP SMPTE RP 168-1993, Definition of Vertical Interval Switching Poin

11、t for Synchronous Video Switching SMPTE RP24-2000, SDTI-CP MPEG DecoderTem- plates 3 General specification Figure 1 shows the basic layered structure of a content package. A shall be constructed of up to four items where each item is constructed of one or more elements. The system item carries conte

12、nt package metadata and may contain a control element. The system item also carries metadata which is related to elements in the other items, The picture item can consist of up to 255 picture stream elements. The audio item can consist of up to 255 audio stream elements. The auxiliary item can consi

13、st of up to 255 auxiliaty data elements. A content package contains the associated contents of one content package frame period starting with a system item and optionally containing picture, audio, and auxiliaty items. Element and metadata formats aredefined in SMPTE 331M. New element and metadata t

14、ypes may be added as new requirements are defined. An SDTI-CP decoder shall be specified by its ability to receive and decode an element or set of elements together with associated metadata defined by an associated decoder template document. The MPEG decoder template is SMPTE RP 204. Other decoder t

15、emplate recommended practices may be defined as required for other applications of the SDTI-CP. An SDTI-CP encoder which creates a content package with greater capabilities than those defined by a decoder template may risk undocumented decoder effects. The term baseline operation is used throughout

16、this standard and has a specific meaning defined as the combination of synchronous transfer mode operating in normal timing mode. Transfer and timing modes are defined in clauses 8 and 9. This standard first describes baseline operation. Later parts of this standard define the methods by which the S

17、DTI-CP format may: - allow content package transfers at higher and lower than the specified rate through isochronous and asynchronous transfer modes; - provide a timing mode to reduce delay and provide for two content packages in each SDTI transport frame; - cary content packages in a low-latency mo

18、de; and I I Content Package Items pq / Metadata /Eleme“ts rj+l Metadata Metadata Metadata Figure 1 - Basic content package structure Metadata to Element Linking Page 2 of 19 pages STD. SrlPTE 32bM-ENGL 2000 - multiplex content packages from different sources onto one SDTI transport. In general, spec

19、ial decoders are required to support these modes and the level of support provided shall be indicated in an associated decoder template docu- ment. 4 SDTI block structure The system, picture, audio, and auxiliary items are each formatted as SDTI variable blocks beginning with the separator word and

20、terminating with the end code word. Each variable block shall start immedi- ately following the SAV sequence. Thus, the starting point of a content package can be found through the detection of a system item type code. The format of each variable length block is shown in figure 2. The input format i

21、s 8-bit data entered into bits bo to b7 of the 10-bit word. Bits b8 and b9 are both set to 1 for the separator and end code words. For the item type, word count, and data block words, bit 8 is set to be the even parity of bits bO to b7 and bit 9 is set to be the odd pari of bits bo to b7. These spec

22、ifications follow those of SMPTE 305M. The SDTI data type word values are as follows: - Systemitem: 04h - Pictureitem: 0% - Audioitern: 6h - Auxiliaryitem: 0711 These data type values shall be registered in SMPTE 305M. 4.1 SDTI line and address numbers Since the data in each SDTI variable block cont

23、inue through as many lines as necessary until the block b7 bO SMPTE 326M-2 end, it isnecessarythatthe SDTI header linenumbers are contiguous. It is also necessary that the SDTI header source and destination address values are constant throughout the transmission of all lines associated with any one

24、content package. 4.2 SDTI switching The arbitrary switching of SDTI data streams, although at the picture frame boundary, mayaff ect the to successfully decode picture, audio, and aux- iliary data without the useof special processing equip ment to mitigate the switching effects. The lines affected b

25、y a picture switch are defined in SMPTE RP 168. A continuity count is provided in the system item which can be used to indicate content packages affected by a switch. 5 Content package structure Each content package shall consist of a minimum of the system item together with any, all, or none of the

26、 picture, audio, and auxiliary items. The system item shall appear first in any sequence of items within a content package. The order of the picture, audio, and auxiliaiy items may be restricted in an associated decoder template document. There shall be only one item of any type in any one content p

27、ackage. Asystem item shall be present in the content package. The presence of the other items in the content pack- age is optional depending upon the transmission requirements. In baseline operation, the content package staft ref- erence is defined by the switching point of SMPTE RP 168. The system

28、data marks the first item of the content package and, for baseline operation, starts on the following reserved line for current television systems: 525/60: Line 13 625150: Line 9 DATA BLOCK UI n o O z W II Figure 2 - Format of the SDTI variable block Page 3 of 19 pa(iee STD-SMPTE 32bM-ENGL 2000 = 83

29、57403 OOOLiO23 739 SMPTE 326M-2000 Field 1 CDTI H-ANC Header Data Field 2 U SAU C 525 Line 13 625: Line 9 Figure 3 - Arrangement of system, picture, audio and auxiliary items in the content package The general arrangement of system, picture, audio, and auxiliary data is given in figure 3. The system

30、 item is provided to give content package metadata and control information together with metadata of the associated picture, audio, and auxil- iary items. A picture item is an assembly of up to 255 picture stream elements. An audio stream item is an assembly of up to 255 audio stream elements. An au

31、xiliary data item is an assembly of up to 255 auxiliary data elements. Assignment of an element to an item type is defined in SMPTE 331M. An element shall be placed in its defined item type. The content package formed by the system, picture, audio, and auxiliary items shall represent the associ- ate

32、d contents of one content package frame period defined by the content package rate variable in the system item. The content package shall not exceed the frame period of the SDTI except where specifically provided by the special transfer modes described later in this standard. The content package dis

33、tribution for an example 12- frame MPEG-2 GOP is shown in figure 4. In the case of special transfer modes, a content package may overiap the interaceframe period. In some optional modes, there may be more than one content package per interface frame period. Details of these modes are available in la

34、ter clauses of this standard. 5.1 Timing considerations Each content package shall be regarded as a potentdb editable unit, so time alignment of the items and elements within a content package is recommended. There may be occasions where time alignment is impractical, but it should be noted that the

35、 specification of timing misalignment between items, or elements within an item, is not automatically supported. The transmission order for all elements in a content package is the order of transmission at the output o each respective element encoder. This may be differ- ent for each element (notabl

36、y in the case of MPEG-2 Page 4 of 19 pages STD-SMPTE 32bM-ENGL 2000 8357401 000402Lt b75 m + SMPTE 326M-2Ooo I B B P B B P B B P 8 First Field Second Field Key: = Content Package location Figure 4 - Content package distribution over an example MPEG-2 GOP encoding using B frames). Users of this stand

37、ard should be aware that the elements of a content pack- age may not be time aligned on a frame-by-frame basis and should take appropriate action to avoid timing errors. Metadata for any element within a content package shall maintain accurate frame association with the element data. 6 Picture, audi

38、o, and auxiliary item structure The picture, audio, or auxiliary item type value is followed by a 4-byte word count and a 1-byte item header word which defines the number of elements in the item. The item word count value for each item may be set to the length of the data block as defined by SMPTE 3

39、05M. However, when not known in advance, the word count value may be set to zero to indicate an undefined block length as defined by SMPTE 305M. The value of the item header word is the element count and has the range 1 to 255 as shown in figure 5. An element count value of O is not a valid value an

40、d shall not be used. The maximum number of elements will be typicaliy restricted by an associated decoder template document. The element data block structure is shown in figure 6. Each element data block starts with a 1 -byte element type value, followed by a 4-byte word count of the element data bl

41、ock size, a 1-byte element number, and the element data. The element word count has the same format as specified in SMPTE 305M and its value shall be the length of the element number and element data words. However, where the element word count value is not known at the point of transmission, it may

42、 be set to zero to indicate an undefined data block length. The value of the element number shall lie in the range O to 255 and shall be unique among the elements within any item. It is recommended that the element number increment by one for each element in sequence in the item. The element type an

43、d element data formats shall be as defined in SMPTE 331 M. 7 System item structure The system item contains content package metadata and control data together with metadata for each element of the picture, audio, and auxiliary items. The system item structure is defined in figure 7. It shall start w

44、ith a 7-byte system item header and may be followed by an SMPTE universal label, timing, pack- age, picture, audio, and auxiliary metadata sets, and control as indicated by the system item bitmap word. The seven bytes of the system item header def ne: - a system item bitmap word; - a content package

45、 rate word; - a content package type word, including stream status flags; - a channel handle word: - a continuity count word. Page 5 of 19 pages Figure 5 - Structure of picture, audio and auxiliary items Element Data Figure 6 - Structure of element data blocks -Item Bibnap - FEC Adive Flag - SMPTE L

46、abel - Creation Datame - User Datame - Picture - Audio - Auxiliary - control Contemn Package Rate Resewed but - not defined Package Rate - 1.001 flag - conteg Package Type Stream Status Sub-package Flag Transfer Mode Timing Made - - - - Channel Handle Figure 7 - System item structure Page 6 of 19 pa

47、ges STI)*SMPTE 32bM-ENGL 2000 8357401 000402b 11118 SYPTE 326M-2ooo 7.1 System tem bitmap 7.2 Content package rate The system item bitmap word is 1 byte in which bits bo-b7 have a defaull value of O indicating no data presence for the respective component. When a bit is set to 1, the corresponding p

48、ari is present in the The content package rate word is 1 byte which shall be used to identify the rate of content packages in baseline operation. It shall not be used to identify the frame rate Of the SDTI tmnsPfl structure. system item. Bits b7 and b6 are not defined, but are reserved for future us

49、e. Bits b5 to bl shall define the content package rate per second in baseline operation. These 4 bits identify 16 states defined as follows: If bit b7 = 1, then forward error correction (FEC) shall be present and active; If bit b6 = 1, then an SMPTE universal label shall be present; If bit b5 = 1, then a creation datehime stamp shall O = undefined value be present; 1 =24 2 =25 3=30 4=48 5=50 6=60 7 =72 8 =75 9 =90 10 = 96 11 =loo 12 = 120 13-31 = reserved, but not defined. If bit b4 = 1, then a user datehime stamp shall be present; If bit b3 = 1, then a pict