1、 Copyright 2011 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 3 Barker Avenue, White Plains, NY 10601 (914) 761-1100 Approved May 25, 2011 Table of Contents Page Foreword . 2 Intellectual Property 2 Introduction 2 1 Scope . 3 2 Conformance Notation . 3 3 Normative References . 3 4 Genera
2、l Description . 4 4.1 Acronyms and Terms 4 5 Coding Constraints 4 5.1 Video Source Parameters . 5 5.2 Coding Parameters . 5 5.2.1 Sequence Header . 5 5.2.2 Picture Syntax . 7 5.2.3 Transform Parameters 7 5.3 Entropy Coding . 8 6 Syntax Constraints 8 Annex A Byte Values of Stream Components (Informat
3、ive) . 10 A.1 Parse Info 1 10 A.2 Sequence Header 11 A.2.1 Parse Parameters . 11 A.2.2 Base Video Format . 12 A.2.3 Source Parameters . 12 A.2.4 Picture Coding Mode 12 A.2.5 Sequence Header Bytes . 13 A.3 Parse Info 2 13 A.4 Picture Number 14 A.5 Transform Parameters . 14 A.6 Transform Data 15 A.7 E
4、nd of Sequence 16 Annex B Filter Coefficients for 1920 to 1440 Conversion (Informative) . 17 B.1 1920 to 1440 Conversion (Down-conversion) . 17 B.2 1440 to 1920 Conversion (Up-conversion) 18 Annex C Bibliography (Informative) 20 Page 1 of 20 pages SMPTE RP 2047-3:2011 SMPTE RECOMMENDED PRACTICE VC-2
5、 Level 65 Compression of High Definition Video Sources for Use with a Standard Definition Infrastructure SMPTE RP 2074-3:2011 Page 2 of 20 pages Foreword SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards developing organization. Headquartered a
6、nd 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 open to a
7、ll 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 Part XIII of its Administrative Practices. SMPTE RP 2047-3 was prepared by Tec
8、hnology Committee10E. Intellectual Property At the time of publication no notice had been received by SMPTE claiming 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
9、rights. SMPTE shall not be held responsible for identifying any or all such patent rights. Introduction The transition from standard definition to high definition television production is well advanced. Yet many television production facilities still have a substantial legacy of a standard definitio
10、n infrastructure that is impractical, or uneconomic, to immediately upgrade to a high definition infrastructure. There is therefore a need to compress high definition signals so that high definition production may continue to use a standard definition infrastructure. Standard definition infrastructu
11、re components that may be re-used by such compression include cabling, routers, uncompressed video links and uncompressed video recorders. This recommended practice defines constraints on the VC-2 specification (SMPTE ST 2042-1) such that high definition source video images can be compressed to stan
12、dard definition data rates. The bit rate of the resulting VC-2 stream is such that it can be carried over a standard definition serial digital interface (SDI) operating at 270Mbit/s. This document defines constraints on the coding and syntax. It does not define a mapping to any specific transport la
13、yer. The constraints defined herein are designed to support low latency, low complexity implementations suitable for television production environments. SMPTE RP 2047-3:2011 Page 3 of 20 pages 1 Scope This recommended practice defines constraints on the VC-2 video compression specification such that
14、 10-bit high definition video signals may be compressed to only occupy the bit rate of 8-bit standard definition signals. Specifically, it defines constraints for compressing interlaced source video having 1920 or 1440 pixels/line by 1080 lines/frame at 25 or 30/1.001 frames/s, or progressive source
15、 video having 1280 pixels/line by 720 lines/frame at 50 or 60/1.001 frames/s, using 4:2:2 sampling in all cases. This document defines a VC-2 bit-stream for video compressed according to this practice. It also defines an application specific level for VC-2 compression. 2 Conformance Notation Normati
16、ve 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 indispensable, and can be removed, changed, or added editorially without
17、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 paragraphs that start with “Note:” The keywords “shall“ and “shall not“
18、 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 particularly suitable, without mentioning or excluding others; or tha
19、t 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 of action permissible within the limits of the document. The keyword “
20、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 in the future. A conformant implementation according to this document
21、 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 them as described. Unless otherwise specified, the order of precedence o
22、f 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. 3 Normative References Note: All references in this document to other
23、 SMPTE documents use the current numbering style (e.g. SMPTE ST 274:2008) although, during a transitional phase, the document as published (printed or PDF) may bear an older designation (such as SMPTE 274M-2008). Documents with the same root number (e.g. 274) and publication year (e.g. 2008) are fun
24、ctionally identical. 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, SMPTE RP 2074-3:2011 Page 4 of 20 pages and parties to
25、agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. SMPTE ST 274:2008, Television 1920 x 1080 Image Sample Structure, Digital Representation and Digital Timing Reference Sequences for Multiple Picture R
26、ates SMPTE ST 296:2001, Television 1280 720 Progressive Image Sample Structure Analog and Digital Representation and Analog Interface SMPTE ST 2042-1:2009, VC-2 Video Compression 4 General Description The VC-2 compression standard defines a compression system that uses Wavelet coding as the basis fo
27、r image de-correlation with a number of compression tools including: A choice of Wavelet transform filters, A choice in the number of levels of Wavelet decimation, A choice between standard and low-delay operation, A choice of entropy coding. The VC-2 compression standard defines various coding para
28、meters that are needed by a decoder to successfully decode and present the output video signal. This practice defines coding constraints to provide the interoperability of VC-2 streams coded for compatibility with a standard definition infrastructure. This practice also constrains the stream syntax
29、to ensure that coded streams can be mapped in an interoperable fashion onto a transport layer. The constraints defined here are signaled in the stream as the specialized VC-2 level number 65 (as indicated in Section 5.2.1.1). That is, VC-2 streams conformant to this practice ensure compliance by spe
30、cifying specialized level 65 in the stream. This practice does not define how the VC-2 stream is mapped to any specific transport layer. Note: Such VC-2 stream transport specifications are defined in other SMPTE documents, such as SMPTE ST 2047-4 for the carriage of VC-2 Level 65 Compressed Video ov
31、er SDI. 4.1 Acronyms and Terms Lists of acronyms and terms are defined in SMPTE ST 2042-1. They are not replicated here to avoid any divergence of meaning. 5 Coding Constraints This section defines the VC-2 coding constraints that ensure conformance to this application. In summary, this application
32、has the following key coding constraints: 1. The video sources are limited to 4:2:2 sampling with the following picture formats: 1920 pixels by 1080 interlaced lines with frame rates of 25 frames/sec or 29.97 frames/sec, 1440 pixels by 1080 interlaced lines with frame rates of 25 frames/sec or 29.97
33、 frames/sec, 1280 pixels by 720 progressive lines with frame rates of 50 frames/sec or 59.94 frames/sec. SMPTE RP 2047-3:2011 Page 5 of 20 pages 2. The codec uses only the low delay profile. 3. The codec uses only the LeGall (5,3) wavelet kernel. 4. The wavelet depth is exactly 3. 5. Slices are kept
34、 as small as possible, consistent with the wavelet depth, to minimize latency and implementation complexity. 5.1 Video Source parameters The video sources shall be: 1. as defined by SMPTE ST 274 for the field rates of 50 fields/sec and 59.94 field/sec only; and 2. as defined by SMPTE ST 296 for the
35、frame rates of 50 frames/sec and 59.94 frames/sec only. The image sampling shall be: 1. as defined by SMPTE ST 274 systems 5 and 6 only; 2. as defined by SMPTE ST 274 systems 5 and 6 only, in which the horizontal sample rate has been reduced to 1440 pixels; and 3. as defined by SMPTE ST 296 systems
36、2 and 3 only. Note: In the second case, the horizontal sampling structure of SMPTE ST 274 systems 5 and 6 is reduced in the ratio 3 output pixels for every 4 input pixels prior to compression. The sampling structure needs to be restored in a complementary fashion after decompression. Thus the overal
37、l system (sample rate changing plus compression) can maintain compatibility with SMPTE ST 274. The provision to support 1440 pixel video is provided for compatibility with other video compression systems that use 1440 pixel video sub-sampling (such as Type D-11, SMPTE ST 367). Failure to support 144
38、0 pixel video compression would result in increased compression artifacts and noise in systems with concatenated compression. To summarize, the text in Section 5.1 normatively provides for the sub-sampling of 1920 pixels to 1440 pixels for the purpose of compression coding. Since the sub-sampling is
39、 a part of the compression process, there is no externally accessible presence of the 1440 pixel format so there is no requirement to document a standardized method for the down and up conversions. Filter coefficients suitable for sample rate changing using FIR filters are provided in informative An
40、nex B. The bit depth shall be limited to the 10 most significant bits. The video sampling format shall be 4:2:2 as defined by SMPTE ST 274. Only the active picture area shall be coded. For the 1080 line video formats only, each field of 540 lines shall be padded to 544 lines as part of the compressi
41、on process, as defined in SMPTE ST 2042-1, Section 13.1.2. These extra four lines shall be added to the end of the picture and shall be removed as part of the VC-2 decoding process. Note: These extra 4 lines are needed to pad the number of lines to be divisible by 8 in order to support the transform
42、 depth value of 3. 5.2 Coding Parameters The codec shall use only the low delay syntax. The coding syntax structure shall be as defined in SMPTE ST 2042-1. 5.2.1 Sequence Header The Sequence Header comprises the parse parameters, base video format, source parameters and picture coding mode and is de
43、fined as follows. SMPTE RP 2074-3:2011 Page 6 of 20 pages 5.2.1.1 Parse parameters The major version and minor version numbers shall be as defined in SMPTE ST 2042-1, Section 11.1. The profile value shall be the low delay profile as defined in SMPTE ST 2042-1, Annex D.1.1. The level value shall be a
44、 specialized level value with the value of 65. This level value shall be used only for the VC-2 coding constraints that comply with this practice. 5.2.1.2 Base video format The base video format shall be one of format numbers 9, 10, 11 or 12 (HD 720P-60, HD 720P-50, HD 1080I-60 or HD-1080I-50) as de
45、fined in SMPTE ST 2042-1. Video formats with 1440 horizontal pixels use the base video format 11 or 12 and override the frame width to be 1440 using the source parameter values as defined in Section 5.2.1.3. Notes: 1. Per SMPTE ST 2042-1, the format names for 30/60 frames/sec systems ignore the 1.00
46、1 divisor for simplicity. Thus HD 1080I-60 means that the default field rate is 60/1.001 fields/sec, not 60 fields/sec. 2. The format is thus defined as follows: The picture size is one of 1920 x 1080, 1440 x 1080 or 1280 x 720. The sampling format is 4:2:2. The scanning is interlaced for 1920 x 108
47、0 and 1440 x 1080 video sources, and progressive for 1280 x 720 video sources. The frame rate is 30/1.001Hz or 25Hz for 1920 x 1080 and 1440 x 1080 video sources, and 60/1.001Hz or 50Hz (for 1280 x 720 video sources). The pixel aspect ratio is 1:1 (aspect ratio index 1, SMPTE ST 2042-1, Table 11.4)
48、or 4:3 for 1440 video sources (aspect ratio index 6, reduced horizontal resolution systems). The clean picture area is the same as the picture size, i.e. 1920 x 1080, 1440 x 1080 or 1280 x 720. The video depth is 10 bits. The color primaries and color matrix are as defined in ITU-R BT.709. The trans
49、fer function is as defined in ITU-R BT.709. 5.2.1.3 Source parameters The source parameters allow the video parameters pre-defined by the base video format to be overridden with custom values. To comply with this document, the pre-defined video parameters shall not be overridden with the single exception as follows: Source video formats with 1440 horizontal pixels shall use base video format 11 or 12 and shall override the frame width to be 1440 as specified in SMPTE ST 2042-1, Section 11.3.2. 5.2.1
