SMPTE ST 258M-2004 Television - Transfer of Edit Decision Lists.pdf

1、 1 Scope This standard describes the data format for the interchange of a list of audio/video content decisions which specify an audio/video product. Exchange of this information allows the audio/video product to be reproduced on a compatible editing system. Such a list is commonly referred to as an

2、 edit decision list. The transfer medium and storage format are not specified in this standard. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were val

3、id. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. ANSI X3.4-1986 (R1992), Information Processing Coded Character Set - 7-Bit American National

4、 Standard Code for Information Interchange (7-Bit ASCII) SMPTE 12M-1999, Television, Audio and Film Time and Control SMPTE RP 162-1993, Storage of Edit Decision Lists on 3-1/2 in Disks 3 Definitions alphanumeric: The term refers to any alphabetic character or the digits 0 through 9. ASCII: American

5、National Standard Code for Information Interchange Coded Character Set 7-Bit, ANSI X3.4, which describes the character encoding used by this practice. auto-assembly: Recording one or more edits automatically under system control from data in an edit decision list. drop frame time code: A time code n

6、umbering system which omits frame numbers to compensate for the variance between nominal fields per second and actual fields per second. For NTSC (field rate approximately 59.94 fields per second), frames 0 and 1 are omitted at the start of each minute, except minutes 0, 10, 20, 30, 40, and 50. See

7、also non-drop frame time code. edit: One or more interrelated elements treated as a unit. edit decision list: One or more edits. Page 1 of 37 pages SMPTE 258M-2004 Revision of ANSI/SMPTE 258M-1993 Copyright 2004 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White P

8、lains, NY 10607 (914) 761-1100 Approved April 6, 2004 SMPTE STANDARD for Television Transfer of Edit Decision Lists SMPTE 258M-2004 Page 2 of 37 pages editing mode: Specification of whether or not video is to be recorded on this edit and which audio tracks, if any, are to be recorded. effect: An aud

9、io/video action which is used to combine two or more sources into a single source. element: A series of printable ASCII characters, terminating in the ASCII characters CR LF. Elements contain information specifying audio/video content decisions in an audio/video product. field: A syntactical unit wi

10、thin an element that contains a functional grouping of data. Fields are delineated within an element by separators. hexadecimal: A notation for representing numbers in base 16. Each 8-bit byte is represented by two ASCII characters. The first character represents the 4 high-order bits, and the secon

11、d character represents the 4 low-order bits. The range of values of each of the 4-bit nibbles is 0 to 15, which is represented by the ASCII characters 0 through 9 for values 0 through 9, and ASCII characters A through F for values 10 through 15. mix: A method of combining two or more sources to prod

12、uce a single source. nondrop frame time code: A time code numbering system in which the number of frames per second is constant. See also drop frame time code. separator: Character(s) used to delineate fields within an element. source: A reference to video or audio program material. submaster: A sub

13、master is a medium, other than the master record medium, on which material is recorded for later use as source material. A typical use of a submaster would be the creation of a multiple mix effect on a system with only one mix effect bank. virtual edit: Specification of an effect that is not to be r

14、ecorded directly, but can be referenced later as a source. virtual source reference: A reference to a virtual edit defined earlier in the edit decision list. 4 Notation The syntax of the edit decision list format is specified using a notation commonly used in the software industry called BNF (Backus

15、-Naur form). The use of this notation allows precise, yet easy to understand, syntactic specification of the edit decision list format. A BNF grammar consists of a list of rules which define grammatical terms. The first term defined is typically the highest level construct in the grammar, in this ca

16、se, an EDL. As there are many variations of the notation known as BNF, the following is a formal definition of the notation used in this practice: Grammatical terms are capitalized, with an underscore ( _ ) separating words. Grammatical rules consist of: the name of the grammatical term being define

17、d, followed by a colon (:), followed by a list of grammatical terms, BNF operators, and/or literals, and terminated with a semi-colon (;). Literal strings are enclosed within double-quotes (). Literal characters are enclosed by single-quotes (). SMPTE 258M-2004 Page 3 of 37 pages Nonprintable charac

18、ters are represented by their name as shown in annex A. Comments begin with /* and end with */. The logical OR operation is specified with a vertical bar (|). Use of square brackets ( and ) indicates that zero or one occurrence of the items in the brackets is allowed. Use of braces ( and ) indicates

19、 that one or more occurrences of the items in the braces are allowed. The complete grammar is defined in annex B. 5 Edit decision list structure 5.1 General information The information in an edit decision list (EDL) consists of 8-bit data bytes. The low-order 7 bits are interpreted as characters fol

20、lowing the ASCII character set. The high-order bit is ignored. No distinction is made between uppercase and lowercase alphabetic characters when interpreting source elements, trigger elements, device control elements, playback elements, and system directives. Uppercase and lowercase alphabetic chara

21、cters are considered distinct in comment elements and user elements. The EDL consists of one or more SMPTE_DIRECTIVEs, followed by a FRAME_RATE_DIRECTIVE, followed by one or more EDIT_SEQUENCEs or PLAYBACK_SEQUENCEs. Both EDIT_SEQUENCEs and PLAYBACK_SEQUENCEs consist of one or more ELEMENTs. The end

22、 of an edit decision list is indicated by either: the end of the storage medium; a CONTROL-Z (SUB) character. The physical order of edits on the transfer medium determines the order in which the edits are to be executed. Note that this may result in later edits recording over portions of prior edits

23、. 5.2 Elements There are eight types of elements: INITIAL_DIRECTIVE; SYSTEM_DIRECTIVE; COMMENT_ELEMENT; USER_ELEMENT; TRIGGER_ELEMENT; DEVICE_CONTROL_ELEMENT; SOURCE_ELEMENT; PLAYBACK_ELEMENT. An element consists of a PRINTABLE_STRING, as defined by the grammar in annex B. Each element is terminated

24、 by a TERMINATOR (CR LF). The basic unit of information in an element is the field, consisting of one or more characters. A field is delineated from the following field by a SEPARATOR. If a TERMINATOR (CR LF) is preceded by a backslash (), the TERMINATOR is treated as a SEPARATOR. Zero or more separ

25、ators, followed by a TERMINATOR, is legal but has no semantic meaning in an EDIT_LIST. SMPTE 258M-2004 Page 4 of 37 pages Each element, except for INITIAL_DIRECTIVEs and SYSTEM_DIRECTIVEs, begins with an EDIT_NUMBER. The element type is determined by an optional element type character immediately fo

26、llowing the EDIT_NUMBER field. The absence of this character indicates that the ELEMENT is a SOURCE_ELEMENT. INITIAL_DIRECTIVEs and SYSTEM_DIRECTIVEs are easily identified, as they are the only elements that do not begin with an EDIT_NUMBER. 5.2.1 Initial directives The following directives must occ

27、ur at the start of the EDL, and cannot be used later in the EDL: SMPTE_DIRECTIVE: SMPTE SEPARATOR STD NUMBER M | SMPTE SEPARATOR STD NUMBER M - NUMBER | SMPTE SEPARATOR RP NUMBER | SMPTE SEPARATOR RP NUMBER - NUMBER | SMPTE SEPARATOR EG NUMBER | SMPTE SEPARATOR EG NUMBER - NUMBER /* Indicates that t

28、his list is compatible with the specified standard, recommended practice, or engineering guideline. At least one of these directives must be used at the start of the list to identify the documents that the list conforms to. */ ; FRAME_RATE_DIRECTIVE: TIME_CODE_MODULUS SEPARATOR NUMBER /* Specifies t

29、he nominal number of frames per second for time code arithmetic. One and only one shall immediately follow the SMPTE directive(s) at the head of the list. */ ; 5.2.2 System directive A SYSTEM_DIRECTIVE does not have an EDIT_NUMBER. Its purpose is to provide additional information to the editing syst

30、em, or to the operator, for edit(s) subsequent to the directive. SYSTEM_DIRECTIVEs are described in clause 6. 5.2.3 Element type The element type character indicates the type of ELEMENT. Element type identifiers are as follows: * COMMENT_ELEMENT; ? USER_ELEMENT; # TRIGGER_ELEMENT; % DEVICE_CONTROL_E

31、LEMENT; SOURCE_ELEMENT; = PLAYBACK_ELEMENT. The absence of this character indicates a SOURCE_ELEMENT. 5.2.4 Edit sequence An EDIT_SEQUENCE consists of one or more of the following element types, each terminated by a TERMINATOR: COMMENT_ELEMENT; USER_ELEMENT; TRIGGER_ELEMENT; SMPTE 258M-2004 Page 5 o

32、f 37 pages DEVICE_CONTROL_ELEMENT; SOURCE_ELEMENT. An EDIT_SEQUENCE need not contain all five types, but must contain at least one. All ELEMENTs of an EDIT_SEQUENCE have the same EDIT_NUMBER. The end of an EDIT_SEQUENCE is indicated by a change in EDIT_NUMBER on the next ELEMENT, or by the end of th

33、e EDL. 5.2.5 Playback sequence A PLAYBACK_SEQUENCE consists of one or more PLAYBACK_ELEMENTs, each terminated by a TERMINATOR. It is used to specify dynamic source motion in a manner which allows speed variation to be precisely duplicated. 6 System directive specification System directives are as fo

34、llows: SYSTEM_DIRECTIVE: INFORMATIONAL_DIRECTIVE | AUTO_ASSEMBLE_DIRECTIVE | CONTROL_DIRECTIVE | MISCELLANEOUS_DIRECTIVE | MOTION_DIRECTIVE ; INFORMATIONAL_DIRECTIVE: * PRINTABLE_STRING /* List Comment (Information for the Operator) */ | TITLE SEPARATOR PRINTABLE_STRING /* Indicates that all subsequ

35、ent edits until another TITLE directive are to be associated with the specified title string. */ ; AUTO_ASSEMBLE_DIRECTIVE: WAIT /* Stop auto-assembly when the following edit is encountered. */ | SKIP“ /* Do not perform the following edit. */ | BELL /* Sound an audible indicator before performing th

36、e following edit.*/ ; CONTROL_DIRECTIVE: RECORD SEPARATOR MODE_FIELD SEPARATOR MEDIUM_IDENTIFIER = TIME_CODE /* Identifies a reel or other medium upon which subsequent edits will be recorded. The video and/or audio tracks specified in both this mode field and in a subsequent edits mode field will be

37、 recorded for that edit. The TIME_CODE indicates the offset to be added to the sync entry and sync exit times of each edit to determine that edits record times for this record medium. Note that more than one record directive can be active at any time. */ | NORECORD SEPARATOR MODE_FIELD SEPARATOR MED

38、IUM_IDENTIFIER /* Terminates any RECORD directive for the specified video and/or audio tracks on the specified record medium. */ SMPTE 258M-2004 Page 6 of 37 pages | SYNC SEPARATOR SOURCE_IDENTIFIER = TIME_CODE /* A sync group is established, comprised of the indicated sources. The members of the sy

39、nc group roll synchronously, based on the time code associated with each source, whenever any member of the sync group rolls. Establishing a sync group cancels any previous master/slave links between the members of the sync group. If more than one source in a sync group has a SOURCE_ELEMENT in an ed

40、it, only the first source specified in the edit will be used to determine synchronization of unspecified members of the sync group. Time code values explicitly stated in a SOURCE_ELEMENT will take precedence over any SYNC relationships for the duration of the given edit. */ | NOSYNC SEPARATOR SOURCE

41、_IDENTIFIER /* Removes the indicated sources from all prior sync groups. */ | SLAVE SEPARATOR MASTER_SRC_ID = TIME_CODE SEPARATOR SLAVE_SRC_ID = TIME_CODE /* Establishes master/slave link(s) between the master source and each indicated slave source. All slaves roll synchronously with the master sour

42、ce, whenever the master source is rolled, based on the time codes in the SLAVE directive. Establishing a master/slave link cancels any previous master/slave links between the indicated sources. Time code values explicitly stated in a SOURCE_ELEMENT will take precedence over any master/slave links fo

43、r the duration of the given edit. */ | NOSLAVE SEPARATOR MASTER_SRC_ID SEPARATOR SLAVE_SRC_ID /* Breaks the master/slave link between the indicated master source, and each listed slave source. */ ; MISCELLANEOUS_DIRECTIVE: AUDIO SEPARATOR MODE_AUDIO_SUBFIELD /* The track(s) indicated are the ones th

44、at are used by the MODE_FIELD when all audio is called for. A range of audio tracks can be specified by separating two audio track numbers with a dash (-). */ | INCLUDE SEPARATOR FILENAME = TIME_CODE /* This directive causes the contents of the specified file to replace the include directive in the

45、edit decision list. The time code specifies an offset which will be added to all sync entry and sync exit times of source elements in the included file. The filename is a PRINTABLE_STRING enclosed in quotes. */ | MEDIUM SEPARATOR SOURCE_IDENTIFIER SEPARATOR MEDIA_TYPE /* Allows specification of the

46、media type for a source. Options include LIVE, TAPE, and OTHER. Each media type can be optionally followed by a printable string to give more details as to media type. */ | WIPES SEPARATOR SMPTE /* Wipe patterns are defined by figure 1. */ | WIPES SEPARATOR PRINTABLE_STRING /* Wipe patterns are not

47、defined by figure 1. The PRINTABLE_STRING specifies the name of the switcher that the wipe patterns conform to. */ ; MOTION_DIRECTIVE: MOTION_CURVE SEPARATOR MOTION_TYPE /* The motion curve directive indicates how motion changes from one source speed to the next. Motion is made to fit a curve: BEST,

48、 SPLINE, or Nth order. Refer to 7.7.4 for details of the meanings of the MOTION_TYPEs. */ ; SMPTE 258M-2004 Page 7 of 37 pages 7 Edits 7.1 Edit number The first field of an ELEMENT is the EDIT_NUMBER. It consists of up to three subfields, concatenated without separators: EDIT_NUMBER_SUBFIELD (required) VIRTUAL_EDIT_INDICATOR_SUBFIELD (optional) RECORDED_INDICATOR_SUBFIELD (optional) The EDIT_NUMBER may be preceded by a separator, but embedded separators are not permitted. The ELEMENT type is determined by an optional element type character immediately following the EDIT_