Television systems; Enhanced 625-line Phased Alternate Line (PAL) television; PALplus

PALplus is an enhanced 625-line PAL transmission system allowing broadcasting of 16:9 wide-screen picutes with greately reduced levels of conventional PAL artefacts, whilst retaining a high level of compatibility with existing PAL transmission infrastrucutre and receivers.

Televizijski sistemi – Izboljšana televizija s fazno spreminjajočo se vrstico (PAL) s 625 vrsticami – PALplus

General Information

Status
Published
Publication Date
30-Nov-2003
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2003
Due Date
01-Dec-2003
Completion Date
01-Dec-2003

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SLOVENSKI STANDARD
SIST ETS 300 731 E1:2003
01-december-2003

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Television systems; Enhanced 625-line Phased Alternate Line (PAL) television; PALplus

Ta slovenski standard je istoveten z: ETS 300 731 Edition 1
ICS:
33.160.25 Televizijski sprejemniki Television receivers
33.170 Televizijska in radijska Television and radio
difuzija broadcasting
SIST ETS 300 731 E1:2003 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 731 E1:2003
EUROPEAN ETS 300 731
TELECOMMUNICATION March 1997
STANDARD
Source: EBU/CENELEC/ETSI JTC Reference: DE/JTC-PALplus
ICS: 33.020
Key words: Broadcasting, analogue, TV, wide screen
Union Européenne de Radio-Télévision
European Broadcasting Union
Television Systems;
Enhanced 625-line Phased Alternate Line (PAL) television;
PALplus
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification:

No part may be reproduced except as authorized by written permission. The copyright and the

foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1997.
© European Broadcasting Union 1997.
All rights reserved.
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ETS 300 731: March 1997

Whilst every care has been taken in the preparation and publication of this document, errors in content,

typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to

"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents

Foreword .......................................................................................................................................................7

1 Scope ..................................................................................................................................................9

2 Normative references..........................................................................................................................9

3 Abbreviations.......................................................................................................................................9

4 Basic PALplus system description ....................................................................................................10

4.1 Introduction ........................................................................................................................10

4.2 Normative features of a PALplus transmission..................................................................11

5 The PALplus signal ...........................................................................................................................12

5.1 Input picture signal to the PALplus encoder ......................................................................12

5.2 The encoded composite PALplus signal............................................................................12

6 The PALplus encoding processes.....................................................................................................15

6.1 Vertical conversion.............................................................................................................16

6.1.1 Encoder vertical conversion of luminance.....................................................16

6.1.2 Encoder vertical conversion of chrominance ................................................16

6.1.3 430-line letterbox...........................................................................................17

6.2 Vertical helper encoding ....................................................................................................20

6.2.1 Helper amplitude ...........................................................................................20

6.2.2 Modulation.....................................................................................................20

6.2.3 Description of helper processing...................................................................21

6.2.4 Baseband helper ...........................................................................................25

6.3 Motion Adaptive Colour Plus..............................................................................................25

6.3.1 Pre-processing in the encoder ......................................................................26

6.3.2 Motion detector operation..............................................................................29

6.3.3 Non-PALplus use of Motion Adaptive Colour Plus ........................................32

6.4 PAL encoding.....................................................................................................................32

6.4.1 Luminance.....................................................................................................33

6.4.2 Chrominance.................................................................................................33

6.5 Reference signals ..............................................................................................................33

6.5.1 Helper reference signals with baseband helper ............................................35

6.6 Signalling ...........................................................................................................................35

Annex A (normative): Filter and look-up table coefficients....................................................................37

A.1 General rules for filter descriptions ...................................................................................................37

A.1.1 General rules for horizontal filters......................................................................................37

A.1.2 General rules for vertical filters ..........................................................................................37

A.2 Vertical conversion............................................................................................................................37

A.2.1 ENC_Y_QMF (camera mode) ...........................................................................................37

A.2.2 ENC_Y_QMF (film mode)..................................................................................................42

A.2.3 ENC_UV_C_VSRC............................................................................................................45

A.2.4 ENC_UV_F_VSRC ............................................................................................................47

A.3 Helper encoding ................................................................................................................................49

A.3.1 ENC_BB_US......................................................................................................................49

A.3.2 ENC_BB_PRE_MOD_LPF_SS .........................................................................................49

A.3.3 ENC_BB_POST_MOD_NYQ.............................................................................................50

A.3.4 LUT_BB_ENC (film mode).................................................................................................50

A.3.5 LUT_BB_ENC (camera mode) ..........................................................................................51

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A.4 Motion Adaptive Colour Plus ............................................................................................................ 52

A.4.1 Y_BSPLIT.......................................................................................................................... 52

A.4.2 ENC_Y_IFA....................................................................................................................... 52

A.4.3 ENC_UV_LPF ................................................................................................................... 53

A.4.4 VERT_IFA ......................................................................................................................... 54

A.4.5 ENC_MD_UV_LPF............................................................................................................ 55

A.4.6 ENC_M_US....................................................................................................................... 55

A.4.7 LUT_IFD_U_CLIP .............................................................................................................56

A.4.8 LUT_IFD_V_CLIP .............................................................................................................57

A.4.9 LUT_MD_M....................................................................................................................... 58

A.4.10 LUT_ENC_MD_YL............................................................................................................ 59

A.4.11 LUT_ENC_MD_CS ........................................................................................................... 59

A.5 PAL encoding ................................................................................................................................... 59

A.5.1 ENC_UV_US..................................................................................................................... 59

Annex B (informative): Encoder filter plots ............................................................................................. 60

Annex C (informative): The PALplus decoder ........................................................................................ 65

C.1 General............................................................................................................................................. 65

C.1.1 Composite PALplus input signal........................................................................................ 65

C.1.2 Decoder output signal ....................................................................................................... 65

C.2 Overview of the PALplus decoding process .....................................................................................66

C.2.1 PAL decoding.................................................................................................................... 66

C.2.2 MACP post-processing ..................................................................................................... 67

C.2.2.1 Motion detector operation ............................................................................. 70

C.2.3 Helper processing ............................................................................................................. 73

C.2.4 Vertical conversion of luminance ...................................................................................... 74

C.2.5 Vertical conversion of chrominance .................................................................................. 74

C.2.6 Use of the Line 23/623 reference signals to assist vertical conversion............................. 77

Annex D (informative): Reference PALplus decoder: filter and look-up-table coefficients ..................... 78

D.1 General rules for filter descriptions................................................................................................... 78

D.1.1 General rules for horizontal filters ..................................................................................... 78

D.1.2 General rules for vertical filters .........................................................................................78

D.2 Vertical conversion ........................................................................................................................... 78

D.2.1 DEC_Y_QMF (camera mode)........................................................................................... 78

D.2.2 DEC_Y_QMF (film mode) ................................................................................................. 81

D.2.3 DEC_UV_VSRC................................................................................................................83

D.2.4 DEC_UV_VSRC_NDL....................................................................................................... 85

D.3 Helper decoding................................................................................................................................ 88

D.3.1 DEC_BB_PRE_MOD ........................................................................................................ 88

D.3.2 DEC_BB_POST_MOD_LPF_ISS ..................................................................................... 88

D.3.3 LUT_BB_DEC (film mode)................................................................................................ 89

D.3.4 LUT_BB_DEC (camera mode) ......................................................................................... 90

D.4 Motion Adaptive Colour Plus, decoder ............................................................................................. 91

D.4.1 Y_BSPLIT.......................................................................................................................... 91

D.4.2 DEC_Y_VAA ..................................................................................................................... 91

D.4.3 DEC_UV_LPF ................................................................................................................... 92

D.4.4 VERT_IFA ......................................................................................................................... 93

D.4.5 DEC_MD_UV_LPF............................................................................................................ 94

D.4.6 DEC_M_US....................................................................................................................... 94

D.4.7 LUT_IFD_U_CLIP .............................................................................................................95

D.4.8 LUT_IFD_V_CLIP .............................................................................................................96

D.4.9 LUT_MD_M....................................................................................................................... 97

D.4.10 LUT_DEC_MD_YL............................................................................................................ 98

D.4.11 LUT_DEC_MD_CS ........................................................................................................... 98

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D.5 PAL decoding ....................................................................................................................................98

D.5.1 DEC_UV_DS_LPF.............................................................................................................98

D.5.2 DEC_CHROM_BPF...........................................................................................................98

Annex E (informative): Decoder filter plots..............................................................................................99

Annex F (informative): Receivers for the PALplus system ...................................................................103

F.1 General............................................................................................................................................103

F.2 Receiver IF characteristics..............................................................................................................103

F.3 Features included in a PALplus receiver.........................................................................................103

F.4 Receiver switching time in response to changes signalled by the WSS.........................................104

F.5 Use of Wide Screen Signalling (WSS)............................................................................................104

F.5.1 PALplus............................................................................................................................104

F.5.2 Non-PALplus Motion Adaptive Colour Plus .....................................................................105

F.5.3 Conventional PAL ............................................................................................................105

F.5.4 Conventional PAL with helper..........................................................................................105

F.5.5 Transmissions transcoded into SECAM ..........................................................................105

Annex G (informative): Application of ghost cancellation ......................................................................106

Annex H (informative): Studio production requirements .......................................................................107

H.1 General............................................................................................................................................107

H.2 Limitations of the composite PALplus signal...................................................................................107

H.3 Camera mode and film mode..........................................................................................................108

H.4 Programme junctions between transmissions in PALplus and PAL ...............................................108

H.5 Open subtitles and logos.................................................................................................................109

H.6 Non-PALplus use of Motion Adaptive Colour Plus..........................................................................109

History........................................................................................................................................................110

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Foreword

This European Telecommunication Standard (ETS) has been produced by the Joint Technical Committee

(JTC) of the European Broadcasting Union (EBU), Comité Européen de Normalisation ELECtrotechnique

(CENELEC) and the European Telecommunications Standards Institute (ETSI).

NOTE: The EBU/ETSI JTC was established in 1990 to co-ordinate the drafting of ETSs in the

specific field of broadcasting and related fields. Since 1995 the JTC became a tripartite

body by including in the Memorandum of Understanding also CENELEC, which is

responsible for the standardization of radio and television receivers. The EBU is a

professional association of broadcasting organizations whose work includes the co-

ordination of its Members' activities in the technical, legal, programme-making and

programme-exchange domains. The EBU has Active Members in about 60 countries
in the European Broadcasting Area; its headquarters is in Geneva *.
* European Broadcasting Union
Case Postale 67
CH-1218 GRAND SACONNEX (Geneva)
Switzerland
Tel: +41 22 717 21 11
Fax: +41 22 717 24 81
Transposition dates
Date of adoption: 28 February 1997
Date of latest announcement of this ETS (doa): 31 May 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 November 1997
Date of withdrawal of any conflicting National Standard (dow): 30 November 1997
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1 Scope

This European Telecommunication Standard (ETS) is applicable to 625-line PAL systems B, G, H, I, D

and K.

It specifies an enhanced transmission system which allows PAL broadcasters to offer wide-screen

pictures in the 16:9 aspect ratio format, maintaining compatibility with existing PAL receivers.

This ETS specifies the transmitted signal. It specifies the method of coding for accommodating wide

aspect ratio signals, and the method of coding for reducing conventional PAL cross-effects and for making

optimal use of the video signal spectrum. The method for reduction of PAL artefacts may also be used for

studio contribution or distribution purposes. Annex C provides details of a reference PALplus decoder that

makes full use of the picture enhancements offered by PALplus. Annex F gives rules of operation for the

minimum requirements for a PALplus receiver.
2 Normative references

This ETS incorporates by dated and undated reference, provisions from other publications. These

normative references are cited at the appropriate places in the text and the publications are listed

hereafter. For dated references, subsequent amendments to or revisions of any of these publications

apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest

edition of the publication referred to applies.
[1] ITU-R Recommendation BT.601-5: "Studio Encoding Parameters of Digital
Television for Standard 4:3 and Wide-screen 16:9 Aspect Ratio".
[2] ITU-R Recommendation BT.470-4: "Television Systems".
[3] EBU Technical Recommendation R62: "Recommended dominant field for
625-line 50-Hz video processing".
[4] ETS 300 294: "Television Systems; 625-Line television Wide Screen Signalling
(WSS)".
3 Abbreviations

For the purpose of this ETS, the following abbreviations apply in the construction of system coefficient

names:
BB Black Bands
BPF Band-Pass Filter
BSPLIT Band-SPLITing filter
C Camera mode
CHROM Modulated PAL CHROMinance
CLIP CLIPping
CS motion detector Chrominance Switching control
CVBS Composite Video, Blanking and Sync
DEC DECoder
DS Down-Sampling
ENC ENCoder
F Film mode
HDTV High-Definition TeleVision
IFA Intra-Frame Averaging
IFD Inter-Frame Difference
ISS Inverse Spectrum Shaping
L motion detector Luminance level control signal
LPF Low-Pass Filter
LUT Look-Up Table
M Motion detector chain chrominance motion signal
MAC Multiplexed Analogue Components
MACP Motion Adaptive Colour Plus
MD Motion Detector chain
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NDL Not incorporating PAL Delay Line function
NYQ NYQuist
PAL Phased Alternate Line
POST_MOD POST-(de)MODulation
PRE_MOD PRE-(de)MODulation
QMF Quadrature Mirror Filter
S motion detector chrominance Switching control signal
SS Spectrum Shaping
U present in C path
US Up-Sampling
UV present in both colour-difference signal (C and C ) paths
B R
V present in C path
VAA Vertical Anti-Aliasing
VERT VERTical
VSRC Vertical Sample-Rate Conversion
Y luminance signal
YL motion detector luminance Level control
4 Basic PALplus system description
4.1 Introduction

PALplus is an enhanced transmission system which has been designed to allow PAL broadcasters to offer

wide-screen pictures with greatly reduced levels of conventional PAL artefacts, whilst retaining a high level of

compatibility with the PAL transmission infrastructure and with existing PAL receivers. The system is

intended to co-exist with both MAC and digital television services in a complementary fashion, enabling

viewers to receive enhanced quality wide-screen pictures originated in component form. The objective of the

PALplus project has not been to design an HDTV system. The expected cost of PALplus receivers is

therefore lower than that of HDTV receivers.

The format of the primary input and output signals for PALplus shall be 625/50/2:1, with 16:9 aspect ratio.

HDTV 1250/50/2:1 sources can be used after down-conversion to 625/50/2:1.

The wide-screen picture shall be transmitted in letterbox format to achieve compatibility with existing 4:3

receivers. Loss of vertical resolution (as compared to the 576 active line source picture) is minimized in the

PALplus receiver by making use of a vertical helper signal transmitted in the black bands above and below

the letterbox picture.

The PALplus system has two modes of operation. These are called "film mode", which should be used only

with film sources, and "camera mode" which should be used with normal 50 Hz video sources. Both the

vertical conversion (to the letterbox picture) and the Motion Adaptive Colour Plus (MACP) method of

improved chrominance/luminance separation make use of a camera mode and a film mode to give optimum

system performance.

Starting from a 625/50/2:1 4:2:2 digital component input signal (in accordance with ITU-R Recommendation

BT.601-5 [1], based on 13,5 MHz sampling) with 576 active lines per frame and an aspect ratio of 16:9, a

conversion to 430 active picture lines shall be first carried out.

NOTE: All references to ITU-R Recommendation BT.601-5 [1] refer to the 13,5 MHz sampling

rate variant specified in part A thereof.

In "camera mode" (when the source provides 50 Hz motion), this conversion shall be performed intra-field

in order to avoid motion artefacts but, in "film mode" (when the source is known to have only 25 Hz

motion), then an intra-frame conversion shall be used. The letterbox picture signal used for transmission

has only three quarters of the number of active picture lines as the source; in order to minimize loss of

vertical resolution in the PALplus display, the black bands shall be used to transmit a vertical helper signal.

An enhanced PAL encoding and decoding technique known as "Motion Adaptive Colour Plus" shall be

used to reduce PAL luminance/chrominance cross-talk artefacts and to maximize horizontal resolution. In

film mode, the system takes advantage of the known temporal redundancy of the signal and uses an

intra-frame PAL encoding technique ("fixed" Colour Plus). In camera mode, the same technique shall be

applied to appropriate areas of each picture frame. However, in areas containing moving saturated colour

(usually representing only small parts of typical pictures), there is likely to be a significant amount of

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movement between the adjacent fields of a source picture frame, which could lead to occasionally visible

colour judder if fixed Colour Plus processing were applied. To minimize this problem, in such areas of the

picture the system shall revert adaptively to a simpler form of PAL encoding, making use of motion

detectors in both the encoder and decoder to identify areas of fast colour motion between adjacent

frames.

Ghost cancellation is an optional enhancement. The parameters of the ghost cancellation reference signal

are given in ITU-R Recommendation BT.1 124, annex 1, section 1.3.
4.2 Normative features of a PALplus transmission

A PALplus signal shall be derived according to the processes illustrated in figure 1. These are summarized

below and detailed descriptions of each process are given in clause 6. The signal at the output of the

encoder shall be described as "PALplus" only when all of the following processes are implemented:

a) Vertical conversion (QMF process) to 430-line letterbox;

- this is the conversion of the 16:9 aspect ratio source picture with 576 active lines to a 16:9

aspect ratio letterbox picture with 430 active lines. The QMF (Quadrature Mirror Filter) format

conversion process also yields vertical luminance resolution information that shall be

encoded and transmitted in the black bands.
b) Vertical helper encoding;

- this is the method of processing and modulating the vertical luminance information derived

from the QMF format conversion process, resulting in the "vertical helper" signal that shall be

transmitted in the black bands above and below the active letterbox picture.
c) Motion Adaptive Colour Plus (MACP);

- this is the encoding technique that makes possible improved separation of chrominance and

luminance in the PALplus receiver.
d) Wide Screen Signalling (WSS);

- this shall be used to convey essential information about the content of the transmitted signal

to the decoder. The system used is defined in ETS 300 294 [4].
e) Reference signals;

- the transmission shall contain reference signals in lines 23 and 623 that may be used by the

PALplus receiver for the accurate setting of the levels of the incoming luminance and vertical

helper signals. Details are given in subclause 6.5.

The PALplus signal at the output of the encoder shall consist of the combination of the PAL-encoded MACP

pre-processed letterbox picture, the modulated helper signal resulting from the QMF conversion process, the

reference signals, and the signalling bits, as shown in figure 1.

The features of a PALplus transmission are summarized in table 1. Compensating delays should be included

in associated audio paths prior to transmission, so as to match the vision processing time in the PALplus

encoder.
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Table 1: The enhancement features incorporated in a PALplus transmission
Enhancement Normative for PALplus?
Format conversion (QMF) from ITU-R YES
Recommendation BT.601-5 [1] source with 16:9
aspect ratio to central 430-line letterbox
Vertical helper encoding YES
...

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