SMPTE RDD 19-2011 Television Guidelines on the Use of Dolby E with Video Signals at Frame Rates Greater than 30 Hz《电视 音频信号帧率超过30 Hz时杜比E的使用指南》.pdf

1、 The attached document is a Registered Disclosure Document prepared by the proponent identified below. It has been examined by the appropriate SMPTE Technology Committee and is believed to contain adequate information to satisfy the objectives defined in the Scope, and to be technically consistent.

2、This document is NOT a Standard, Recommended Practice or Engineering Guideline, and does NOT imply a finding or representation of the Society. Errors in this document should be reported to the proponent identified below, with a copy to engsmpte.org. All other inquiries in respect of this document, i

3、ncluding inquiries as to intellectual property requirements that may be attached to use of the disclosed technology, should be addressed to the proponent identified below. Every attempt has been made to ensure that the information contained in this document is accurate. Dolby Laboratories is, howeve

4、r, not responsible for the action, effect, consequences, etc. of any non-Dolby implementation of any device(s) based on this document. If any errors, inconsistencies, or any points that require clarification are found, contact Dolby Laboratories at the address below as soon as possible. Proponent co

5、ntact information: Dolby Laboratories Inc. 100 Potrero Avenue San Francisco, CA 94103 Attention: Broadcast Services and Support Page 1 of 11 pages SMPTE RDD 19:2011 Approved February 4, 2011 SMPTE REGISTERED DISCLOSURE DOCUMENT for Television Guidelines on the Use of DolbyE with Video Signals at Fr

6、ame Rates Greater than 30 Hz Copyright 2011 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 SMPTE RDD 19:2011 Page 2 of 11 pages Table of Contents Page 1 Scope . 3 2 Related Documents 3 3 Introduction 3 4 Terms and Definitions 4 5 Sync

7、hronization of Dolby E and Progressive Video, Operating at 50, 59.94 and 60 Frames Per Second 4 6 Switching of Dolby E with Progressive Video, Operating at 50, 59.94 and 60 Frames Per Second 7 7 Dolby E Detection 7 8 The Medium and Long Term View . 10 9 Guidelines for MPEG encoding 10 10 Dolby E Pas

8、s-Through . 11 SMPTE RDD 19:2011 Page 3 of 11 pages 1 Scope This document describes how DolbyE audio codecs can be used in conjunction with Television signals operating at frame rates higher than 30 Hz. Because the Dolby E encoded audio data is normally carried in an AES3 stream, wrapped per SMPTE S

9、T 337, it may be transported separately, or embedded in a video signal. It also provides advice to equipment designers and manufacturers on the requirements of associated equipment and to systems integrators engaged in building complete systems. 2 Related Documents Note: All references in this docum

10、ent to other SMPTE documents use the current numbering style (e.g. SMPTE ST 318:1999) although, during a transitional phase, the document as published (printed or PDF) may bear an older designation (such as SMPTE 318M-1999). Documents with the same root number (e.g. 318) and publication year (e.g. 1

11、999) are functionally identical. SMPTE ST 318:1999, Television and Audio Synchronization of 59.94- or 50-Hz Related Video and Audio Systems in Analog and Digital Areas Reference Signals SMPTE RP 168:2009, Definition of Vertical Interval Switching Point for Synchronous Video Switching. SMPTE ST 12-2:

12、2008, Transmission of Time Code in the Ancillary Data Space SMPTE ST 302:2007, Mapping of AES3 Data into an MPEG-2 Transport Stream SMPTE ST 337:2008, Format for Non-PCM Audio and Data in an AES3 Serial Digital Audio Interface SMPTE ST 2051:2010, Two-Frame Marker for 50-Hz and 60(/1.001)-Hz Progress

13、ive Digital Video Signals on 1.5 Gb/s and 3 Gb/s Interfaces 3 Introduction Dolby Laboratories has developed Dolby E, a method of reducing the data rate of PCM (baseband) audio signals while preserving the subjective quality of the audio through up to ten encode decode cycles. The data rate reduction

14、 ratio allows up to eight audio signals to be carried in a single AES3 digital audio stream. Further, the Dolby E encoded audio data is transmitted as a sequence of blocks of data, separated by guard band intervals containing null data. Dolby E encoders generate data blocks that are synchronized wit

15、h video frame rates of up to 30 frames per second. The guard bands between blocks are co-located with the Vertical Interval Switch points of the associated video signal, so that the Dolby E data stream and the video may be switched without causing any disruption of the encoded data and hence no disr

16、uption of the decoded audio signals. The Dolby E data blocks cannot be generated at higher than a 30-Hz rate, thus cannot be switched at higher rates without corrupting the data. If a Dolby E stream is to be switched simultaneously with a progressive video signal operating at 50 or 60 frames per sec

17、ond, then the Dolby E data stream may only be switched on a Progressive frame (or P Frame See Terms and Definitions) boundary that occurs during the Dolby E guard band intervals, or in other words, on every second P Frame boundary. SMPTE RP 168 states that “with both interlaced video at a specific f

18、rame rate and progressive video at double that frame rate, devices handling the progressive video should be referenced to a signal derived from an interlaced format at the interlaced frame rate. Having established this referencing relationship, progressive video devices should switch using the recom

19、mended line during Field 1 of the reference signal”. As can be seen in Figure 1, since the Dolby E guard band intervals are aligned with Field 1, the Dolby E data will not be harmed by an audio-follow-video switch of a progressive signal operating at greater than 30-Hz rate as long as the switch hap

20、pens during P Frame one. SMPTE RDD 19:2011 Page 4 of 11 pages DE 1DE DE 1DE 2 DE 1DE 3 DE 1DE 4DE 1DE 1 DE 1DE 2 DE 1DE 3 DE 1DE 4DE 1 DE 1 DE 1 DE 1Guard bandorGuard band625/25/I1125/25/I1125/50/P750/50/PPossible switch points ( Dolby E OK ) Possible switch points ( 50 % chance Dolby E OK)Video 1Fi

21、eld 1(Odd) Video 1Field 2(Even) Video 2Field 1(Odd) Video 2Field 2(Even) Video 3Field 1(Odd) Video 3Field 2(Even) Video 4Field 1(Odd) Video 4Field 2(Even) Video 1Field 1(Odd) Video 1Field 2(Even) Video 2Field 1(Odd) Video 2Field 2(Even) Video 3Field 1(Odd) Video 3Field 2(Even) Video 4Field 1(Odd) Vi

22、deo 4Field 2(Even) 1DE 2DE 3DE 4DE Video 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 8Figure 1 - Interlaced video with co-timed Dolby E (left) and Progressive video with Dolby E (right). Unless the Audio follow Video switch occurs at the switch point of the first P Frame, the first part

23、of the Dolby E data stream will be taken from the audio associated with the first source, and the second part from the audio associated with the second source, making the checksum incorrect. The decoder will mute for one frame, or until it receives a Dolby E data block with a correct checksum. 4 Ter

24、ms and Definitions Television System notation: References to television systems in this document will follow the conventions used by documents such as SMPTE RP 168, which state the total number of lines, the total number of complete images per second and whether the serial interface structure is Int

25、erlaced or Progressive. Examples are 525/59.94/I, 1125/50/I, 750/60/P. Note that other notation systems state the number of active lines, the serial interface structure and the number of complete pictures per second. Examples are 1080I/25 and 1080P/50. An Interlaced raster structure consists of a pa

26、ir of Fields, called Fields 1 and 2, or the Odd and Even fields. The complete image is called a Frame (or an I Frame) and consists of Fields 1 and 2. A Progressive raster structure consists of a sequence of complete images, called P Frames. Notionally, each P Frame can be temporally related to one F

27、ield of an Interlaced television system operating at half the frame rate of the progressive system. The P Frame temporally related to Field 1 is called P Frame 1 or the Odd P Frame, and the P Frame temporally related to Field 2 is called P Frame 2, or the Even P Frame. DE is an abbreviation of Dolby

28、 E. DE 1, DE 2 seen in the Figures refer to Dolby E data block 1, Dolby E data block 2, etc. 5 Synchronization of Dolby E and Progressive Video, Operating at 50, 59.94 and 60 Frames Per Second As frame synchronizers are used to synchronize incoming signals with the “house sync”, it is essential that

29、 the frame synchronizer to operate in a “Dolby E safe” mode, allowing clean downstream switching. Two points must be considered in designing such a frame synchronizer: 1) Any frame synchronizer must drop (or repeat) two P Frames, instead of one. The benefit of keeping Dolby E aligned by this method

30、is considered to be worthwhile given the potential small motion artifact observed when dropping 2 progressive frames. 2) The P Frames to be dropped (or repeated) must be a P Frame 1 and P Frame 2 pair (in that order) and must be aligned with the start of the Dolby E block. SMPTE RDD 19:2011 Page 5 o

31、f 11 pages Standard Interlaced frame synchronizers that drop or repeat an entire I Frames worth of audio samples during a video frame drop or repeat handle Dolby E well (Figure 2). Dropped I FrameVRef VRef VRef VRef VRef VRef VRef VRefVideo 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 8Vi

32、deo 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 9Video 9House ReferenceIncoming VideoFrame Aligned VideoVRefVideo 10DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 10Incoming DolbyEFrame Aligned DolbyEDE 811 11 211 2 31 11 2 3 41 1 211 211 DE 21 Guard ban

33、dFigure 2 An Interlaced Frame Synchronizer locking incoming video and Dolby E to an Interlaced house reference Dolby E data blocks will be corrupted if only a single P Frame is dropped or repeated by a progressive frame synchronizer. VRef VRef VRef VRef VRef VRef VRefVideo 1Video 2 Video 3 Video 4 V

34、ideo 5 Video 6 Video 7Video 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 9Video 9House ReferenceIncoming VideoFrame Aligned VideoVideo 10DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 10Incoming DolbyEFrame Aligned DolbyEDE 811 11 211 2 31 11 2 3 41 1 211

35、 2181 DE 21 Guard bandVideo 2Video 3Video 4Video 52Video 6Video 7Video 8Video 92 3Video 10Video 11Video 12Video 13Video 14Video 167 83Video 17Video 18Video 19Video 20Video 1Video 21Video 3Video 4Video 5Video 61 2 3Video 7Video 9Video 10Video 111Video 12Video 13Video 14Video 1531Video 13717Video 18Dr

36、opped P framesVRef VRef VRef VRef VRef VRef VRef VRefVRef VRef VRef VRef VRef VRefVideo 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 9VRef1 1 2 31 31Video 137VRefVideo 15DE 6319VRefCorrupted Dolby EFigure 3 A Progressive Frame Synchronizer locked to a progressive house reference signal No

37、te that the single P Frames dropped correspond to half of a Dolby E data block. Just having a progressive frame synchronizer lock to a 25 or 30 Frames per second (fps) signal, and dropping two P Frames instead of one is not enough to ensure undamaged Dolby E. The synchronizer must drop (or repeat) a

38、 P Frame 1, P Frame 2 pair (in that order) to avoid the 50% risk of starting the two P Frame drop sequence incorrectly, with a P Frame 2. This would also mean that downstream equipment relying on the same 25 or 30 fps reference to correctly switch Dolby E cannot guarantee error-free switching. SMPTE

39、 RDD 19:2011 Page 6 of 11 pages VRef VRef VRef VRef VRef VRef VRef VRefVideo 1Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 8Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 9Video 9House ReferenceIncoming VideoFrame Aligned VideoVRefVideo 10DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 1 D

40、E 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 10Incoming DolbyEFrame Aligned DolbyEDE 811 11 211 2 31 11 2 3 41 1 211 2181 DE 21 Guard bandVideo 2Video 3Video 4Video 52Video 6Video 7Video 8Video 92 3Video 10Video 11Video 12Video 13Video 14Video 15Video 167 83Video 17Video 18Video 19Video 20Video 21Video 3Vide

41、o 4Video 5Video 61 2 3Video 7Video 8Video 9Video 101Video 11Video 12Video 13Video 1431Video 13715Video 18DE 71DE 10DE 8 DE 9Corrupted Dolby EVideo 931Video 13719Video 20Dropped P framesFigure 4 A frame synchronizer correctly dropping a progressive frame pair, but incorrectly aligned with the interla

42、ced reference and the P Frame One, P Frame Two cadence The solution is to lock the frame synchronizer to a 25 or 30 fps reference signal, and to detect the Dolby E header to determine where the P Frame One, P Frame Two cadence begins, and hence where to start the two P Frame drop sequence, as shown

43、in Figure 5. See Section 7 - Dolby E. Detection. Frame synchronizers could also re-align the Dolby E on the incoming HD-SDI signal to the appropriate position. This would add the benefit of ensuring all embedded Dolby E outputs are not only error-free during frame drops, but also correctly aligned f

44、or further processing / switching, etc. The realignment results in a two P Frame delay with a 0.5 to 1.5 Dolby E data block delay. VRef VRef VRef VRef VRef VRef VRef VRefVideo 1Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 8Video 1 Video 2 Video 3 Video 4 Video 5 Video 6 Video 7 Video 9Video

45、 9House ReferenceIncoming VideoFrame Aligned VideoVRefVideo 10DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 1 DE 2 DE 3 DE 4 DE 5 DE 6 DE 7 DE 9DE 10Incoming DolbyEFrame Aligned DolbyEDE 811 11 211 2 31 11 2 3 41 1 211 211 DE 21 Guard bandDropped P frames Video 2Video 3Video 4Video 52Video 6Video 7Video

46、 8Video 92 3Video 10Video 11Video 12Video 13Video 14Video 15Video 167 83Video 17Video 18Video 19Video 20Video 1Video 21Video 3Video 4Video 5Video 61 2 3Video 7Video 8Video 9Video 101Video 11Video 12Video 13Video 1431Video 13717Video 18Figure 5 “Dolby E safe” P Frame synchronizer locked to an interla

47、ced reference, and the correct P Frame cadence. By searching for the end of a Dolby E data block as well as the beginning, a frame synchronizer could eliminate the kind of errors shown in Figure 3, caused by dropping single P Frame, or a switch during the P Frame 2, P Frame 1 transition. Pairs of P

48、Frames would be dropped (or repeated) only when aligned with complete Dolby E data blocks, and the latency adjusted to align the Dolby E data blocks to the interlaced house reference signal. SMPTE RDD 19:2011 Page 7 of 11 pages 6 Switching of Dolby E with Progressive Video, Operating at 50, 59.94 an

49、d 60 Frames Per Second SMPTE RP 168, (Definition of Vertical Interval Switching Point for Synchronous Video Switching) states, in Section 6, that “for a system with both interlaced video at a specific frame rate and progressive video at double that frame rate, devices handling the progressive video should be referenced to a signal derived from an interlaced format at the interlaced frame rate. Having established this referencing relationship, progressive video devices shou