SMPTE ST 339-2015 Format for Non-PCM Audio and Data in AES3 - Generic Data Types.pdf

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1、 Approved March 27, 2015 Copyright 2015 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Table of Contents Page Foreword 2 Intellectual Property . 2 Introduction. 2 1 Scope 3 2 Conformance Notation 3 3 Normative References 3 4 Null Data

2、 (data_type = 0) 4 4.1 Null Data burst_preamble . 4 4.2 Null Data burst_payload 4 5 Time Stamp (data_type = 2) . 4 5.1 Time Stamp burst_preamble . 4 5.2 Time Stamp burst_payload . 5 6 Pause (data_type = 3) . 7 6.1 General 7 6.2 The burst_preamble 8 6.3 Pause data_burst_payload . 9 6.4 Burst Spacing

3、10 6.5 Multiplexed Data Streams . 10 7 Utility (data_type = 26) 11 7.1 Utility Data burst_preamble . 11 7.2 Utility Data burst_payload . 11 8 User Defined (data_type = 30) 14 8.1 User Data burst_preamble 14 8.2 User Data burst_payload 14 Annex A Bibliography (Informative) 15 SMPTE ST 339:2015 Revisi

4、on of SMPTE 339-2008 SMPTE STANDARD Format for Non-PCM Audio and Data in AES3 Generic Data Types Page 1 of 15 pages SMPTE ST 339:2015 Page 2 of 15 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headqua

5、rtered and incorporated in the United States of America, SMPTE has members in over 80 countries on six continents. SMPTEs Engineering Documents, including Standards, Recommended Practices, and Engineering Guidelines, are prepared by SMPTEs Technology Committees. Participation in these Committees is

6、open to all with a bona fide interest in their work. SMPTE cooperates closely with other standards-developing organizations, including ISO, IEC and ITU. SMPTE Engineering Documents are drafted in accordance with the rules given in its Standards Operations Manual. SMPTE ST 339 was prepared by Technol

7、ogy Committee 32NF. Intellectual Property At the time of publication no notice had been received by SMPTE claiming patent rights essential to the implementation of this Engineering Document. However, attention is drawn to the possibility that some of the elements of this document may be the subject

8、of patent rights. SMPTE shall not be held responsible for identifying any or all such patent rights. Introduction This section is entirely informative and does not form an integral part of this Engineering Document. This standard specifies data type specific format requirements for null data, time s

9、tamp data, user defined data, pause data and utility data which may include video frame synchronization information that may be carried within an AES3 interface according to SMPTE ST 337. SMPTE ST 339:2015 Page 3 of 15 pages 1 Scope This standard specifies data type specific format requirements for

10、several types of data bursts that may be carried within an AES3 interface according to SMPTE ST 337. Included are descriptions of the data type (defined in SMPTE ST 338), the format of the burst_payload for the data type, the coding of data type dependent fields in the burst_preamble, and additional

11、 data burst and bitstream formatting requirements not defined in SMPTE ST 337. This includes specific synchronization methods which may affect formatting. This standard covers generic data types which include null data, time stamp data, user defined data, pause data, and utility data which may inclu

12、de video frame synchronization information. 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

13、 indispensable, 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 individu

14、al paragraphs 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 recommende

15、d as 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 cour

16、ses 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 def

17、ined 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 implemen

18、t them 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; then formal languages; then figures; and then any other language forms. 3

19、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 valid. All standards are subject to revision, and parties to agreements based on this recommended pra

20、ctice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. SMPTE ST 12-1:2014, Time and Control Code SMPTE ST 309:2012, Transmission of Data and Time Zone Information in Binary Groups of Time and Control Code SMPTE ST 339:2015 Page 4 of

21、15 pages SMPTE ST 337:2015, Format for Non-PCM Audio and Data in an AES3 Serial Digital Audio Interface SMPTE ST 338:2015, Format for Non-PCM Audio and Data in AES3 Data Types SMPTE RP 168:2009, Definition of Vertical Interval Switching Point for Synchronous Video Switching 4 Null Data (data_type =

22、0) The null data type is provided so that the preamble sync codes may be intentionally inserted into the data stream. Null data bursts can be inserted in an AES3 transport stream to help receivers detect the fact that the stream is carrying non-PCM audio data. Null data bursts shall obey the burst s

23、pacing requirements specified by SMPTE ST 337, Section 7.3. The Null data burst should not be used as a sync run in sequence. The Pause data type should be used instead. 4.1 Null Data burst_preamble The burst_preamble for a null data burst shall set the length_code, error_flag, and data_type_depende

24、nt values to 0. The data_stream_number shall be set to any valid number other than 0x7. The data_type shall be set to 0 as defined in SMPTE ST 338. 4.2 Null Data burst_payload The null data burst shall not contain a burst_payload (a payload of length 0). 5 Time Stamp (data_type = 2) The time stamp d

25、ata type is used to convey time synchronization information associated with a specific data burst. This information shall include SMPTE ST 12-1 time code information and/or specific delay information. The use of time stamp bursts is optional. When present, the time stamp information shall apply to t

26、he data burst (which immediately follows in the AES3 interface). When time code information is present, the time stamp may contain date and time zone information coded in the time code binary groups according to SMPTE ST 309. 5.1 Time Stamp burst_preamble The burst_preamble for a time stamp data bur

27、st shall include a data_type_dependent field set to a value of 0. The data_stream_number shall be set to 0x7. The data_mode parameter shall be set to 0. The data_type shall be set to 2 as defined in SMPTE ST 338. When time code information is conveyed within time stamp data bursts, data stream numbe

28、r 7 should not be interpreted as a single data stream of time code information. Note: Time stamp data bursts are independent and apply only to the data burst that immediately follows in the AES3 interface; therefore time code information from multiple time code sources can be contained within data s

29、tream number 7. Within an individual data burst time code information from at most one time code source will be present. SMPTE ST 339:2015 Page 5 of 15 pages 5.2 Time Stamp burst_payload The time stamp burst_payload shall always be packed in the 16 bit data mode and shall have a length of six to nin

30、e 16-bit words. The burst_payload shall be in the format shown in Table 1. The flag bit f2 in word 5 shall indicate the status of all SMPTE ST 12-1 LTC time code fields in words 0-5. If this bit is set to 0, SMPTE ST 12-1 time code information is present. If this bit is set to 1, SMPTE ST 12-1 time

31、code information is not present and all bit fields in words 0 to 5 other than bit f2 are not defined. In Table 1, numbers in brackets (e.g., 63) shall refer to the corresponding bit numbers of the SMPTE ST 12-1 LTC time code words. The time code hours field is denoted by bit fields H20-H1, which cor

32、respond to the SMPTE ST 12-1 BCD coded hours bits (e.g., H20 corresponds to 20s of hours). The minutes, seconds, and frames address fields are indicated in a similar fashion by the bit fields M40-M1, S40-S1, and F20-F1 respectively. The flag bit f1 in word 5 shall indicate the status of the binary g

33、roup and flag bit fields in words 0 to 3. If this bit is set to a 1 the binary group and flag bit fields in words 0 to 3 have been copied from a source of SMPTE ST 12-1 time code. If this information has not been provided, flag bit f1 shall be set to a 0, and these binary group and flag bit fields s

34、hall be set to 0. Bit fields a3-a0 of word 5 carry a 4 bit frame rate code. The frame rate code shall be encoded as shown in Table 2. Bit 0 of word 5 shall carry the drop-frame flag bit from bit 10 of the SMPTE ST 12-1 time code word. If the f1 bit (word 5, bit 1) is set to 1, bit 6 of word 3 shall

35、also carry the drop-frame flag. Reserved bits (R) in word 5 shall not be used and shall be set to 0. Note: The interpretation of the SMPTE ST 12-1 time code flag bits is dependent on the time code frame rate and whether or not the codeword is LTC or VITC. Word 4 of the time stamp shall be used to as

36、sociate the time code carried in words 0 to 3 with a specific sample of the linearly coded audio recovered from the data burst carrying (low bit rate) encoded audio immediately following the time stamp burst. The sample number is carried as an unsigned integer. For example, if an audio data burst re

37、presents 1536 linear PCM samples and the sample number is set to 1007, then the SMPTE ST 12-1 time code applies to sample 1007 of the 1536 samples of the linearly coded audio. If the sample number contained in a time stamp is greater than the number of samples represented by the corresponding encode

38、d audio data burst, then the time code shall be associated with a sample of the linearly coded audio recovered from the following data burst having the same stream number. As an example of this case, and again using an audio data burst that represents 1536 linear PCM samples, if word 4 is set to 154

39、6, then the SMPTE ST 12-1 time code applies to sample 10 of the 1536 samples recovered from the next data burst with the same stream number. In such cases, the same SMPTE ST 12-1 time code information may be repeated more than once with different sample numbers in each case. In all cases, the sample

40、 number shall be accurate to within 0.5 ms of the ideal value. When the time stamp is followed by a data burst that does not contain encoded audio, word 4 is not used, and shall be set to a value of 0. SMPTE ST 339:2015 Page 6 of 15 pages Table 1 Time stamp burst_payload Time Stamp MSB Bit Number LS

41、B Payload Word 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 Usr8, Usr7, flags, hours 63 62 61 60 55 54 53 52 59 58 H20 H10 H8 H4 H2 H1 1 Usr6, Usr5, flag, minutes 47 46 45 44 39 38 37 36 43 M40 M20 M10 M8 M4 M2 M1 2 Usr4, Usr3, flag, seconds 31 30 29 28 23 22 21 20 27 S40 S20 S10 S8 S4 S2 S1 3 Usr2, Usr1

42、, cf, df, frames 15 14 13 12 7 6 5 4 11 10 F20 F10 F8 F4 F2 F1 4 Sample number s15 s14 s13 s12 s11 s10 s9 s8 s7 S6 s5 s4 s3 s2 s1 s0 5 Reserved, flags R R R R R R R R R f2 a3 a2 a1 a0 f1 10 6 User private (optional) U U U U U U U U U U U U U U U U 7 User private (optional) U U U U U U U U U U U U U

43、U U U 8 Delay (optional) D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Figure 1 Sample number indication in time stamp data bursts Table 2 Frame rate code frame rate code frame rate a3 a2 a1 a0 0 0 0 0 not indicated 0 0 0 1 24 1.001 (23.98) 0 0 1 0 24 0 0 1 1 25 0 1 0 0 30 1.001 (29.97) 0 1

44、0 1 30 0 1 1 0 50 0 1 1 1 60 1.001 (59.94) 1 0 0 0 60 - - - - reserved 1 1 1 1 reserved TSn d a ta b u r s t nTSn + 1 d a ta b u r s t n + 1S a m p l e s (n) S a m p l e s (n+ 1 )T im e S ta m p n c o n ta in s t h etim e in fo r m a tio n f o r s a m p les ( n ) in d a ta b u r s t nT im e S ta m p

45、 n + 1 c o n ta in s t h etim e in fo r m a tio n f o r s a m p les ( n + 1 ) in d a ta b u r s t n + 1In c r e a s in g Ti m eSMPTE ST 339:2015 Page 7 of 15 pages Words 6 and 7 are optional words that may contain user private data; however their presence is required when the optional delay field (w

46、ord 8) is present. Word 8 is optional. If present, it shall contain a delay indication denoted by bit fields D15-D0. The delay field is a signed integer (in 2s complement format) that indicates the offset, in terms of AES3 frames, of the reference point of the corresponding data burst from the defin

47、ed reference position for that data burst. A positive value shall indicate the reference point is advanced (in time) from the reference position, while a negative value shall indicate the reference point is delayed (in time) from the reference position. For instance a delay setting of +2037 indicate

48、s that the reference point of the corresponding data burst is present in the AES3 bitstream 2037 frames ahead of the reference position for the burst. An exception is the value 0x8000 which shall be used to indicate no delay information is provided even though word 8 is present. This gives a range o

49、f 32767 AES3 frames, equivalent to approximately 682 msec with an AES3 reference sample rate of 48 kHz. The definitions of the reference point and reference position are relative to the data_type setting of the corresponding data burst. The definitions may vary between data types and may not exist for some data types, in which case the meaning of the delay field is undefined. 6 Pause (data_type = 3) 6.1 General The Pause data type is provided to fill gaps in streams of