EN 62356-2:2004
(Main)Video recording - 12,65 mm type D-11 format - Part 2: Picture compression and data stream
Video recording - 12,65 mm type D-11 format - Part 2: Picture compression and data stream
specifies the compression of a high-definition source format to a dual-channel packetized data stream format which is suitable for recording on disc and tape storage devices including the Type D-11 tape recorder
Videoaufzeichnung - D-11-Format mit 12,65 mm - Teil 2: Bildkompression und Datenstrom
Enregistrement Vidéo - Format 12,65 mm de type D11 - Partie 2: Flux de données et compression d'image
specifies the compression of a high-definition source format to a dual-channel packetized data stream format which is suitable for recording on disc and tape storage devices including the Type D-11 tape recorder
Video snemanje – Format vrste D-11 z magnetnim trakom s širino 12,65 mm – 2. del: Komprimiranje slike in podatkovni tok (IEC 62356-2:2003)
General Information
Standards Content (Sample)
SLOVENSKI SIST EN 62356-2:2006
STANDARD
januar 2006
Video snemanje – Format vrste D-11 z magnetnim trakom s širino 12,65 mm –
2. del: Komprimiranje slike in podatkovni tok (IEC 62356-2:2003)
(istoveten EN 62356-2:2004)
Video recording – 12,65 mm type D-11 format – Part 2: Picture compression and
data stream (IEC 62356-2:2003)
ICS 33.160.40 Referenčna številka
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
EUROPEAN STANDARD EN 62356-2
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2004
ICS 33.160.40
English version
Video recording –
12,65 mm type D-11 format
Part 2: Picture compression and data stream
(IEC 62356-2:2003)
Enregistrement Vidéo – Videoaufzeichnung –
Format 12,65 mm de type D11 D-11-Format mit 12,65 mm
Partie 2: Flux de données et compression Teil 2: Bildkompression und Datenstrom
d'image (IEC 62356-2:2003)
(CEI 62356-2:2003)
This European Standard was approved by CENELEC on 2004-09-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62356-2:2004 E
Foreword
The text of the International Standard IEC 62356-2:2003, prepared by IEC TC 100, Audio, video and
multimedia systems and equipment, was submitted to the formal vote and was approved by
CENELEC as EN 62356-2 on 2004-09-01 without any modification.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2005-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-09-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62356-2:2003 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 62356-2:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
SMPTE 292M 1998 BIT-serial digital interface for high- - -
definition television systems
SMPTE 274M 1998 Television - 1920 x 1080 scanning and - -
analog and parallel digital interfaces for
multiple picture rates
SMPTE RP 211 2000 Implementation of 24P, 25P and 30P - -
segmented frames for 1920 x 1080
production format
SMPTE 12M 1999 Television, audio and film - Time and - -
control code
SMPTE RP 188 1999 Transmission of time code and control - -
code in the ancillary data space of a
digital television data stream
INTERNATIONAL IEC
STANDARD
62356-2
First edition
2003-11
Video recording –
12,65 mm type D-11 format –
Part 2:
Picture compression and data stream
IEC 2003 Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale
XA
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue
– 2 – 62356-2 IEC:2003(E)
SOMMAIRE
FOREWORD . 4
1 Scope . 6
2 Normative references. 6
3 Introduction. 7
4 Encoding . 7
4.1 Overview . 7
4.2 Pre-processing . 9
4.3 Shuffling .13
4.4 Field-frame decision .15
4.5 Discrete Cosine Transform (DCT) .17
4.6 Rate control.18
4.7 Quantization .19
4.8 Entropy coding .19
4.9 Picture data packing .23
4.10 Auxiliary data.29
5 Decoding .32
5.1 Overview .32
5.2 Unpacking .32
5.3 Entropy decoding.32
5.4 Inverse quantization .32
5.5 Inverse DCT .33
5.6 De-shuffling .33
5.7 Post-processing.33
Annex A (normative) Subsampling filter.34
Annex B (normative) Channel shuffling.36
Annex C (normative) .39
Annex D (normative) VLC tables .42
Bibliography.55
Figure 1 – Encoding block diagram . 9
Figure 2 – Sampling relationships for 1 080/I and 1 080/PsF source and subsampled
systems .11
Figure 3 – Channel division of subsampled 1 080/I and 1 080/PsF signals .12
Figure 4 – Channel distribution.13
Figure 5 – Code blocks and basic blocks in channel.14
Figure 6 – Shuffle block format .14
Figure 7 – Shuffle block header byte descriptions .15
Figure 8 – Frame-mode chrominance DCT block reformat.16
Figure 9 – Field-mode DCT block reformat .17
Figure 10 – DCT coefficient encoding example.22
62356-2 IEC:2003(E) – 3 –
Figure 11 – Basic block format .23
Figure 12 – Frame-mode luminance and chrominance cells .23
Figure 13 – Field-mode luminance and chrominance cells.24
Figure 14 – Framemode placement for Offset Mode and Offset Index bits .26
Figure 15 – Fieldmode placement for Offset Mode and Offset Index bits .26
Figure 16 – Packing when quantizer base = 61 or less .27
Figure 17 – Packing when quantizer base = 63 .28
Figure 18 – Auxiliary basic block format .29
Figure 19 – Auxiliary data words .31
Figure 20 – Decoding block diagram .32
Figure A.1 – Template for insertion-loss frequency characteristic (Y) .34
Figure A.2 – Passband ripple tolerance (Y) .34
Figure A.3 – Template for insertion-loss frequency characteristic (C ,C ).35
B R
Figure A.4 – Passband ripple tolerance (CB,CR).35
Figure B.1 – 8*8 block segmentation in each channel.36
Figure B.2 –Block allocation within a segment.37
Table 1 – Data rates associated with source picture rates . 7
Table 2 – Definition of signal sampling parameters .10
Table 3 – Data representation .17
Table 4 – DC quantization divisors .19
Table 5 – AC quantization divisors .19
Table 6 – Offset mode and offset index .20
Table 7 – DC coefficient fixed precision .20
Table 8 – Example luminance a.c. coefficient encoding.21
Table 9 – Auxiliary basic block data .29
Table 10 – MSB inversion .33
Table B.1 – Equation for TMP1 .37
Table B.2 – Values of START_OFFSET for luminance planes .38
Table B.3 – Values of START_OFFSET for chrominance planes .38
Table C.1 – Dynamic range of coefficients .40
Table C.2 – Coefficients for d.c. only transforms .40
Table C.3 – 8 × 8 zigzag scan .40
H V
Table C.4 – 4 × 8 zigzag scan .41
H V
Table C.5 – 8 × 4 zigzag scan .41
H V
– 4 – 62356-2 IEC:2003(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
VIDEO RECORDING – 12,65 MM TYPE D-11 FORMAT −−−−
Part 2: Picture compression and data stream
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62356-2 has been prepared by IEC technical committee 100:
Audio, video and multimedia systems and equipment.
It was submitted to the national committees for voting under the Fast Track Procedure as the
following documents:
CDV Report on voting
100/630/CDV 100/700/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
62356-2 IEC:2003(E) – 5 –
The committee has decided that the contents of this publication will remain unchanged until
2008-11. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 6 – 62356-2 IEC:2003(E)
VIDEO RECORDING – 12,65 MM TYPE D-11 FORMAT −−
−−
Part 2: Picture compression and data stream
1 Scope
This International Standard specifies the compression of a high-definition source format to a
dual-channel packetized data stream format which is suitable for recording on disc and tape
storage devices including the Type D-11 tape recorder. The specification includes a number
of basic packetizing operations including the shuffling of the source data prior to compression,
both to aid compression performance and to allow error concealment processing in the
decoder. The standard also includes the processes required to decode the compressed Type
D-11 packetized data format into a high-definition output signal.
This standard supports high-definition source formats using 1 920 × 1 080 pixels and the
sampling structures as specified in SMPTE 274M and RP 211 at the following picture rates:
• 24/1,001/PsF;
• 24/PsF;
• 25/PsF;
• 30/1,001/PsF;
• 50/I;
• 60/1,001/I
where 'PsF' indicates Progressive segmented Frame and 'I' indicates Interlaced.
The data packet format specified by this standard is used as the source data stream for the
associated document which maps this Type D-11 packetized data-stream format together with
AES3 data over SDTI.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
SMPTE 292M:1998, Television – Bit-Serial Digital Interface for High-Definition Television
Systems
SMPTE 274M:1998, Television – 1920 × 1080 Scanning and Analog and Parallel Digital
Interfaces for Multiple Picture Rates
SMPTE RP 211:2000, Implementation of 24P, 25P and 30P Segmented Frames for 1920 ×
1080 Production Format
SMPTE 12M:1999, Television, Audio and Film-Time and Control Code
SMPTE RP 188:1999, Transmission of Time Code and Control Code in the Ancillary Data
Space of a Digital Television Data Stream
62356-2 IEC:2003(E) – 7 –
3 Introduction
This standard specifies the encoding and decoding of high-definition source formats via
compression into a bit rate in the range 112~140Mb/s for recording on a Type D-11 digital
tape recorder. The recorded bit rate is related to the source picture rate according to Table 1.
Table 1 – Data rates associated with source picture rates
Base data rate
Picture rate
Mb/s
24/1,001/PsF 111,863
24/PsF 111,975
25/PsF 116,640
30/1,001/PsF 139,828
50/I 116,640
60/1,001/I 139,828
In common with other compression systems, the Type D-11 encoding process uses intra-
frame coding (i.e. the coding is bound by the frame period) using the Discrete Cosine
Transform (DCT) to provide the data de-correlation required for efficient compression. The
coefficients are quantized and variable length coded (VLC) to produce the basic output data
format.
The source pictures are subsampled prior to compression coding. This reduces the number of
coded pixels and allows the number of bits-per-pixel value to be raised in proportion. The
luminance source sampling grid of 1 920 × 1 080 pixels is reduced to 1 440 × 1 080 pixels.
For each chrominance channel, the source sampling grid of 960 × 1 080 pixels is reduced to
480 × 1 080 pixels. In the decoder, the output pixel sample grid is restored back to the source
format of 1 920 × 1 080 pixels by interpolation following the compression decoding process.
The compressed data format specified by the output of the compression encoder is of a form
which allows direct mapping into the basic block structure as defined in the Type D-11 digital
recorder document.
4 Encoding
4.1 Overview
Type D-11 source data for compression shall comprise only the production aperture area as
defined by SMPTE 274M.
NOTE DCT coding uses a data block size which allows exactly 1 080 lines to be coded.
The source formats comprise luminance (Y) and chrominance (C , C ) component signals as
B R
defined by SMPTE 274M and SMPTE RP 211.
Type D-11 source picture rates for compression shall be constrained to the following values:
• 24/1 001 frames per second in the segmented format as defined by SMPTE RP 211;
• 24 frames per second in the segmented format as defined by SMPTE RP 211;
• 25 frames per second in the segmented format as defined by SMPTE RP 211;
• 30/1 001 frames per second in the segmented format as defined by SMPTE RP 211;
• 50 fields per second in the interlaced format (a.k.a. 50/I) as defined by SMPTE 274M;
– 8 – 62356-2 IEC:2003(E)
• 60/1 001 fields per second in the interlaced format (a.k.a. 60/I) as defined by SMPTE
274M.
The active picture data for compression shall be pre-filtered and then subsampled from a
source representation to a subsampled representation.
The reduced active data shall then be split into two identical channels for processing as
shown in Figure 1 and Table 2.
The total picture data in each channel shall be divided into 20 250 8*8 blocks, each formed
from eight samples of eight consecutive lines in a frame.
The 8*8 blocks for each channel shall then be shuffled within the frame boundary to produce
270 code blocks each comprising 45 luminance (Y) 8*8 blocks and 30 chrominance 8*8 blocks
(15C and 15 C ).
B R
The picture data in each code block shall be compressed by the application of the DCT,
quantization and VLC encoding. Each code block shall be separately encoded, and there
shall be no data-sharing between code blocks. The data from the compression output shall be
packed into the code block space of 1 080 bytes.
Each code block shall be segmented into five basic blocks each comprising 216 compressed
data bytes. Each basic block nominally contains the compressed data for nine luminance 8*8
blocks and six chrominance 8*8 blocks (3 C and 3 C ). Data overflow from one basic block
B R
can be shared with other basic blocks in the same code block.
NOTE The 8*8 blocks may be coded by a single 8*8 DCT block, by two 8*4 DCT blocks or by two 4*8 DCT blocks
depending on the mode of operation (see 4.4).
The 270 code blocks for each channel shall be divided into six equal segments of 45 code
blocks per segment. Each segment shall contain one auxiliary basic block prior to the
compressed data basic blocks. All auxiliary basic blocks in one channel shall be identical with
the exception of the segment identification number. The auxiliary basic block shall contain
utility data for the segment. The distribution of a channel into code blocks and basic blocks is
illustrated in Figure 5.
All basic blocks shall have a total length of 219 bytes. The data for the basic blocks in a code
block shall be 216 bytes in length, allowing 3 bytes for the basic block header. The data for
the auxiliary basic block in each segment shall be 217 bytes in length, allowing 2 bytes for the
basic block header.
NOTE The ‘*’ symbol is used to denote multiplication.
62356-2 IEC:2003(E) – 9 –
AUX
data
Channel 0: even samples
Entropy
Field-
DCT Quantize Pack
coding
frame
decision
Shuffle
Channel 0: encoded picture
and AUX data
Rate Control
AUX
data
Sub-
sample
Source
picture
Entropy
DCT Quantize Pack
coding
Channel 1: encoded picture
Shuffle
and AUX data
Field-
frame Rate control
decision
Channel 1: odd samples
Figure 1 – Encoding block diagram
4.2 Pre-processing
4.2.1 Source picture
The source picture shall be the production aperture as defined in SMPTE 274M having a
luminance structure of 1 920*1 080 pixels and a multiplexed chrominance structure of 960*1
080 pixels for each chrominance component.
The source interface has a sample resolution of 10 bits which shall be reduced to 8 bits after
the horizontal subsampling process.
4.2.2 Vertical sampling process
For 1 080/I systems, 540 lines for Y, C , C signals from each interlaced field shall be
B R
processed. The coding lines for each interlaced field are illustrated in Figure 2.
For 1 080/PsF systems, 1 080 lines for Y, C , C signals from each whole frame shall be
B R
processed. The coding lines for the segmented frame are illustrated in Figure 2.
4.2.3 Horizontal subsampling process
For the luminance component, all the 1 920 active samples per line shall be subsampled to 1
440 samples per line after a bandwidth limitation filtering process.
For each of the two chrominance components, all the 960 active samples per line shall be
subsampled to 480 samples per line after a bandwidth limitation filtering process.
The basic sample parameters for luminance (Y) and the two chrominance signals (C , C ) of
B R
the source and sub-sampled component signals are described in Table 2.
– 10 – 62356-2 IEC:2003(E)
Figure 2 depicts the re-sampled spatial positions of the subsampled components for 1 080/I
and 1 080/PsF line-scanning systems.
The subsampled data in each frame shall be divided into two identical channels: an even
sample channel and an odd sample channel as illustrated in Figure 3.
Let r be the horizontal sample position number in the subsampled Y, C , C source.
B R
For Y samples r = 0, 1, 2, 3, …. , 1 439
For C , C samples r = 0, 1, 2, 3, …. , 479
B R
Those samples that have 'r' as an even number, depicted as a white circle in Figure 3, shall
be distributed to channel 0.
Those samples that have 'r' as an odd number, depicted as a grey circle in Figure 3, shall be
distributed to channel 1.
Each luminance (Y) sample channel has rectangular area of 720 samples by 1 080 lines.
Each chrominance (C , C ) sample channel has a rectangular area of 240 samples by 1 080
B R
lines respectively as illustrated in Figure 4.
Figure 3 shows the overall structure of the subsampling process.
To avoid alias artifacts, the source format shall be pre-filtered with a filter operating in the
horizontal dimension only. The templates for the overall filtering characteristics of the sub-
sampling process are defined in Annex A .
NOTE The filtering and subsampling processes are implemented as one combined operation.
Table 2 – Definition of signal sampling parameters
Parameter Source sampling Subsampling Channel division
Y 1 920 1 440 720
Number of samples per
line
C , C 960 480 240
B R
Number of active lines
1 080 1 080 1 080
per frame
Quantization 10-bit (0.1 023) 8-bit (0.255) 8-bit (0.255)
Peak
4 to 1 019 1 to 254 1 to 254
range
Peak white level: 940 Peak white level: 235 Peak white level: 235
Sample levels
Y Black level: 64 Black level: 16 Black level: 16
Total levels: 877 Total levels: 220 Total levels: 220
Signal level: 512 ± 448 Signal level: 128 ± 112 Signal level: 128 ¦ 112
C , C
B R
Total levels: 897 Total levels: 225 Total levels: 225
62356-2 IEC:2003(E) – 11 –
T/3
T
Source luminance (Y)
Line 21
st
1 Line field 1
Line 584
st
1 Line field 2
Line 22
Line 585
Sub-sampled
4T/3
luminance (Y)
1st Line field 1 Line 21
1st Line field 2 Line 584
Line 22
Line 585
Source
2T
chrominance (C , C )
B R
1st Line field 1 Line 21
1st Line field 2 Line 584
Line 22
Line 585
Sub-sampled
4T
chrominance (C , C )
B R
1st Line field 1
Line 21
1st Line field 2
Line 584
Line 22
First pixel in active
Line 585
period
NOTE 'T' is the period of the luminance horizontal sampling.
Figure 2 – Sampling relationships for 1 080/I and 1 080/PsF source
and subsampled systems
– 12 – 62356-2 IEC:2003(E)
r for Y in field 1
012345678910 11
4T/3
Subsampled
luminance (Y)
Line 21
1st Line field 1
Line 584
1st Line field 2
Line 22
Line 585
r for C , C in field 1
B R
01 23
4T
Subsampled
chrominance (C , C )
B R
Line 21
1st Line field 1
Line 584
1st Line field 2
Line 22
Line 585
:Evenpixels
First pixel in active period
: Odd pixels
Figure 3 – Channel division of subsampled 1 080/I and 1 080/PsF signals
62356-2 IEC:2003(E) – 13 –
1 440 samples
480 samples 480 samples
Y Cb Cr
720 samples 240 samples 240 samples
Y Cb Cr
EVEN EVEN
EVEN
ODD ODD ODD
90 blocks 30 blocks 30 blocks
Y Cb Cr
EVEN EVEN
EVEN
ODD ODD ODD
Figure 4 – Channel distribution
4.3 Shuffling
Each subsampled input picture shall be split into two channels each comprising 12 150
luminance (Y) and 8 100 chrominance (C and C ) 8*8 blocks, as shown in Figure 4. The 12
B R
150 luminance blocks are taken from the array of 135*90 8*8 blocks. The 8 100 chrominance
blocks are taken from the array of 135*30*2 8*8 blocks.
The input format prior to shuffling for both channels shall be as shown in Figure 4. The
shuffling re-arranges the 8*8 blocks according to the algorithm defined in Annex B. After
shuffling, the blocks for each channel shall be allocated to six segments each containing 45
code blocks. Each code block shall be subdivided into five shuffle blocks as shown in Figure
5.
1 080 lines
1 080 lines
135 blocks
– 14 – 62356-2 IEC:2003(E)
Channel
Segment 0 Segment 1 Segment 2 Segment 3 Segment 4 Segment 5
Segments
0 1 44
Code Block
0 1 2 3 4 5 219 220 221 222 223 224
Shuffle Block
Encode
Encode
AUX
0 1 2 3 4 5 219 220 221 222 223 224
Basic Block
(255)
Figure 5 – Code blocks and basic blocks in channel
NOTE The contents of the five shuffle blocks are uncompressed signal data. The data in the five shuffle blocks
which form a code block are then compressed and packed into five corresponding basic blocks as described in 4.9.
Each shuffle block, defined at the output of the shuffle algorithm, comprises three header
bytes, nine luminance 8*8 blocks and six chrominance 8*8 blocks, as shown in Figure 6.
963 bytes
961 bytes
576 bytes 384 bytes
1 1
(9 Y 8*8 blocks) (3 C + 3 C 8*8 blocks)
B R
8 bit BID HD Luminance Chrominance
BID
Figure 6 – Shuffle block format
The first header byte, BID , shall define the shuffle block number from Figure 5 as an 8-bit
unsigned integer in the range 0 to 224. Figure 7a defines the bit allocation for the shuffle
block number.
The second byte (BID ) defines the shuffle block mode information as shown in Figure 7b.
Bit 7 (SPF) defines the shuffle pattern flag which identifies the two states specified in
Annex B.
Bit 6 shall be '0'.
Bit 5 defines the field-frame mode flag as described in 4.4.
Bits 4 to 2 define the 3-bit segment number (values '0' to '5') with SG as the MSB.
Bit 1 defines even channel (value '0') or odd channel (value '1').
62356-2 IEC:2003(E) – 15 –
Bit 0 shall be '0'.
The third byte (HD) defines encoding information as shown in Figure 7c.
Bit 7 shall have a default value of '0'.
Bit 6 defines the overflow flag described in 4.9.
Bits 5 to 0 define the 6-bit quantizer base described in 4.6 with QB as the MSB.
a) BID byte
LSB 0 1 234567 MSB
SB SB SB SB SB SB SB SB
0 1 2 3 4 5 6 7
Shuffle block number
b) BID byte
LSB 0 1 2 34 567 MSB
0CH SG SG SG FRM 0 SPF
0 1 2
Fixed Chan Segment number Mode Fixed Pattern
c) HD byte
LSB 0 1 2 34 567 MSB
QB QB QB QB QB QB OVF 0
0 1 2 3 4 5
Quantizer base Over Fixed
Figure 7 – Shuffle block header byte descriptions
4.4 Field-frame decision
4.4.1 Overview
The picture data in each channel shall be processed to select field- or frame-mode encoding,
indicated by bit 5 of the BID byte. Every shuffle block of any one channel comprising six
segments shall be formatted as either field mode or frame mode as specified in 4.4.2 and
4.4.3.
– 16 – 62356-2 IEC:2003(E)
4.4.2 Frame-mode reformat
In frame-mode encoding, bit 5 of BID shall be set to the value '1'. The nine luminance 8*8
blocks in each basic block shall not be reformatted and shall remain as nine 8 8 DCT
H × V
blocks. The six chrominance 8*8 blocks shall be reformatted into three pairs of 4 8 C
H × V B
DCT blocks and three pairs of 4 8 C DCT blocks.
H × V R
The splitting of 8*8 blocks into 4 8 block pairs is shown in Figure 8.
H × V
2nd 4×8 DCT
Input 8*8 C or C block
B R
1st 4×8 DCT block block
Samples 0.3 Samples 4.7 Samples 0.3 Samples 4.7
LN 0a LN 0b LN 0a LN 0b
LN 1a LN 1b LN 1a LN 1b
LN 2a LN 2b LN 2a LN 2b
LN 3a LN 3b LN 3a LN 3b
LN 4a LN 4b LN 4a LN 4b
LN 5a LN 5b LN 5a LN 5b
LN 6a LN 6b LN 6a LN 6b
LN 7a LN 7b LN 7a LN 7b
Figure 8 – Frame-mode chrominance DCT block reformat
4.4.3 Field-mode reformat
In field-mode encoding, bit 5 of BID shall be set to the value '0'. The nine luminance 8*8
Blocks in each shuffle block shall be reformatted into nine pairs of 8 4 luminance DCT
H × V
blocks. This is achieved by placing the lines from Field 1 in the first of a pair of 8 4 DCT
H × V
blocks, and lines from Field 2 in the second of the pair. The six chrominance 8*8 blocks shall
be reformatted into three pairs of 8 4 C DCT blocks and three pairs of 8 4 C DCT
H × V B H × V R
blocks.
The splitting of 8*8 blocks into 8 4 block pairs is shown in Figure 9.
H × V
62356-2 IEC:2003(E) – 17 –
1st 8×4 DCT block (Field 1)
Input 8*8 block LN 0
LN 0 LN 2
LN 1 LN 4
LN 2 LN 6
LN 3
LN 4 2nd 8×4 DCT block (Field 2)
LN 5 LN 1
LN 6 LN 3
LN 7 LN 5
LN 7
Figure 9 – Field-mode DCT block reformat
4.5 Discrete Cosine Transform (DCT)
Prior to the DCT process, the MSB of each input sample shall be inverted.
This changes the luminance data from offset binary to 2’s complement form and the
chrominance from 2’s complement with MSB inversion to 2’s complement, as shown in
Table 3.
Table 3 – Data representation
Luminance in Luminance out Chrominance in Chrominance out
0 to +255 –128 to +127 –128 to +127 –128 to +127
+255 1111 1111 +127 0111 1111 +127 1111 1111 +127 0111 1111
+129 1000 0001 +1 0000 0001 +1 1000 0001 +1 0000 0001
+128 1000 0000 0 0000 0000 0 1000 0000 0 0000 0000
+127 0111 1111 –1 1111 1111 –1 0111 1111 –1 1111 1111
0 0000 0000 –128 1000 0000 –128 0000 0000 –128 1000 0000
The DCT process defined in Annex C transforms each DCT block of luminance or
chrominance samples to a single d.c. coefficient and a number of a.c. coefficients depending
on the DCT block size.
– 18 – 62356-2 IEC:2003(E)
Following the DCT process, the output coefficients shall be scaled to lie within the maximum
range defined by a 16-bit 2’s complement number (see Annex C).
4.6 Rate control
4.6.1 Overview
Each code block, comprising five shuffle blocks, shall be used to provide the basic unit for
rate control.
The rate control process selects a quantizer base which is defined for each shuffle block in a
code block and an individual quantizer offset which is defined for each DCT block.
The rate control process aims to fill, but not exceed, the available bit space of 8 640 bits for
each code block after compression encoding (see 4.9).
4.6.2 Quantizer base
Each shuffle block shall be allocated a 6-bit quantizer base as an unsigned integer which
shall be stored in the third header byte (HD) as described in 4.3.
The quantizer base value 63 shall be selected when the target bit budget for the compressed
data in a code block is exceeded and data must be discarded as described in 4.9. In this
case, all shuffle blocks in the code block must take the quantiser base value of 63.
The quantizer base value 62 is reserved and shall not be used.
Otherwise, the quantizer base may take values between 0 and 61.
4.6.3 Quantizer offset
The quantizer base for each shuffle block may be modified for each DCT block by a quantizer
offset value.
The decision to apply quantizer offsets shall be made on a per frame basis for each channel
independently. Thus, for both channels for a frame duration, quantizer offsets are either
applied to every DCT block or to no DCT blocks.
If quantiser offsets are used, each offset value shall be a 6-bit signed 2’s complement number
having the range –32 and +31.
4.6.4 Quantizer index
The quantizer index for each DCT block is the sum of the quantizer base for the shuffle block
and the quantizer offset for the DCT block.
If the result of this sum is less than 0, the quantizer index value shall be set to 0.
The quantizer offset value shall be limited to ensure that the quantizer index value does not
exceed 89.
If quantizer offsets are not used, then the quantizer index value shall be equal to the
quantizer base.
62356-2 IEC:2003(E) – 19 –
4.7 Quantization
The 16-bit DCT coefficients from the DCT process shall be divided by a divisor value. It is
recommended that the division process includes rounding.
The divisor value for d.c. coefficients shall be defined from the quantizer index value
according to Table 4.
The divisor value for a.c. coefficients shall be defined from the quantizer index value
according to Table 5.
Table 4 – DC quantization divisors
Quantizer index value (QI) Divisor value
2 to 9 16
10 to 17 32
18 to 25 64
26 to 33 128
34 and above 256
Table 5 – AC quantization divisors
Quantizer index value (QI) Divisor value
((QI-2)/8)
2 and above 16 * 2
In frame mode only (see 4.4) and following the quantization process, the chrominance d.c.
coefficients from the second DCT block of each chrominance pair shall be DPCM coded as
follows:
(2nd C d.c. coefficient for encoding) = (1st C d.c. coefficient) – (2nd C d.c. coefficient)
B B B
(2nd C d.c. coefficient for encoding) = (1st C d.c. coefficient) – (2nd C d.c. coefficient)
R R R
4.8 Entropy coding
4.8.1 Overview
DCT blocks containing quantized DCT coefficients shall be entropy encoded using a Variable
Length Code (VLC) to produce variable length compressed data for each DCT block.
Quantizer offset information shall be encoded for each DCT block.
4.8.2 Quantizer offset encoding
The quantizer index of each DCT block is as described in 4.6. Any quantizer offset data for
each DCT block shall be encoded before the associated DCT coefficients. In each channel of
a frame containing up to eight separate Y quantizer offset values, up to eight C quantizer
B
offset values and up to eight C quantizer offset values shall be selected from the total range
R
of –32 to 31. Both channels of a frame shall use the same selected quantizer offset values.
– 20 – 62356-2 IEC:2003(E)
The selected quantizer offset values shall be assigned a 3-bit offset index value in the range
0 to 7 for each Y, C and C component separately. The offset index values shall be assigned
B R
from 0 up to the number selected with a maximum value of 7. These selected offset index
values and their corresponding quantizer offset values shall be defined for each component of
each channel in the auxiliary basic blocks, as described in 4.10.
In frames where quantizer offset values are used, each DCT block shall be assigned an offset
index value that defines the matching quantizer offset value. Each shuffle block shall be
assigned three independent 2-bit offset mode values for Y, C and C respectively. In frames
B R
where quantizer offsets are used, an offset mode value between 1 and 3 shall be selected
depending on the number of offset index values. In frames where quantizer offsets are not
used, the offset mode shall be 0. Table 6 shows the relationship between the offset mode
value and the number of offset index values supported. The first DCT block of each type (Y0,
C 0 and C 0 in Figures 11 and 12) shall include the associated 2-bit offset mode value as its'
B R
first encoded data, MSB first.
Table 6 – Offset mode and offset index
Offset mode Offset index bits Offset index values
00 0 Not used
01 1 0 to 1
10 2 0 to 3
11 3 0 to 7
Table 6 shows that an offset mode of 0 requires no offset index bits; a mode of 1 requires one
index bit; a mode of 2 requires two index bits and a mode of 3 requires three index bits in
each DCT block.
Each DCT block includes the number of bits that define the offset index value (MSB first). In
the case of the first DCT block of each type (Y0, C 0 and C 0), these bits shall immediately
B R
follow the offset mode bits. In all remaining DCT blocks in a shuffle block, these bits shall be
the first encoded data in the block.
4.8.3 Luminance d.c. coefficient encoding
Luminance d.c. coefficients shall be encoded using a fixed number of bits, depending on the
quantization index of the DCT block selected by the rate control process (see 4.6). Any
excess sign extension bits of the quantized d.c. coefficient value shall be discarded.
The number of bits allocated is shown in Table 7.
Table 7 – DC coefficient fixed precision
Quantizer index value Number of d.c. bits
2 to 9 12
10 to 17 11
18 to 25 10
26 to 33 9
34 and above 8
The luminance d.c. bits shall be presented MSB first and shall immediately follow any offset
mode or offset index bits where present.
62356-2 IEC:2003(E) – 21 –
4.8.4 Luminance a.c. coefficient encoding
Luminance a.c. coefficients shall be coded using one of 22 VLC table groups, defined in
Clause D.1. These VLC table groups provide for several VLC options including
• provision for an End of Block (EOB) code;
+
• collapsing runs of zero coefficients with a terminating value of / 1 into single codes;
-
• collapsing other runs of zero coefficients into single codes;
• provision of codes for single coefficient values.
The first luminance a.c. coefficient (or coefficient run) in each DCT block shall be coded using
the appropriate VLC table group as defined in Clause D.1.
Any subsequent luminance a.c. coefficient (or coefficient run) shall then be encoded using the
appropriate VLC table group (called the current group) together with the VLC table group of
the previous coefficient or coefficient run (called the previous group).
The current and previous group values shall be used to identify a VLC as defined in the
luminance VLC tables in Clause D.2. In the case of the first luminance a.c. coefficient (or
coefficient run), the previous group shall be assigned the default value of 0.
Each VLC may be followed by a Fixed Length Code (FLC) where the number of FLC bits for
each group is defined in Clause D.1
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