IE57443B1 - Process for the transcoding of a videotex image to make it compatible with several videotex systems - Google Patents

Abstract

1. Process for the transcoding of a primary videographic message describing a primary image in a first videographic language into a secondary videographic message describing a secondary image in said first videographic language and a secondary image in at least one other videographic language, said secondary images being essentially identical to the primary image, said videographic messages being formed from a sequence of binary data, each binary data item being associated, by each videographic language with a particular code, said transcoding process being characterized in that the transcoding of each data item of the primary videographic message comprises the following operations : the code of the first videographic language associated with said data item is compared with the codes of the other videographic languages associated with said data item to determine whether said code is identical to said codes or whether said code is different from at least one of said codes, A) if said code is identical to said codes, the data item is written into the secondary videographic message, B) if said code differs from at least one of said codes, it is established whether the data item is associated with a character code or a control or display code, Ba) if the data item is associated with a character code, a first predetermined data item is written in the secondary videographic message, Bb) if the data item is associated with a control or display code, it is established whether said code is transcodable, Bb**alpha ) if said code is not transcodable, a second predetermined data item is written in the secondary videographic message, Bb**beta ) if said code is transcodable, in the secondary videographic message is written a data string in such a way that the sequences of codes associated with said string have an essentially identical meaning for each videographic language.

Description

The present invention relates to a process for the transcoding of an image of one videotex system to make it compatible with several videotex systems. More . [ specifically, the invention relates to a process for transcoding a primary videographic message describing a primary image in a first videographic language into a secondary videographic message describing a secondary image in said first videographic language and a secondary image in at least one other videographic language. The aim of the invention is to obtain a secondary videographic message producing secondary images which are essentially identical to the primary image, i.ei secondary images essentially containing characteristics of the primary image, particularly regarding the shape, size and colour of the objects of said image and which may possibly only differ therefrom in the representation of detail elements.

It is pointed out that the term videography defines ’a telecommunications process making it possible to provide a user with alphanumeric or graphic messages on a display screen. In one variant of this process, called broadcast videography or teletext, the messages are systematically broadcast by a television network and the user can make a choice from among these messages. In a second variant of this process, called interactive videography or videotex, ? a telecommunications network transmits requests from the 4 . user and the messages obtained in response. The French * TELETEL system, the British PRESTEL system and the German BILDSCHIRMTEXT system (TELETEL, PRESTEL AND BILDSCHIRMTEXT being registered trademarks) are based on said second variant.

Fig.J diagrammatically shows the architecture of a videotex system, which is a network comprising a server 2, a transmission network 4, which can be the telephone -2<4 system, and a group of videotex terminals 6. Each videotex terminal 6 has at the input a modem 8, to which are connected a telephone 10 for communicating with the server, a keyboard 12 enabling the user to dial and transmit requests to the server, and a circuit 14 connected to television screen 16» The circuit comprises a decoder 18 which receives, via modem 8, the videographic messages transmitted by the server, a page memory 20, a character generator 22 and a display generator 24 supplying a video signal to the television screen 16. A time base 26 ensures the sequencing of the signals between the different means of circuit 14.

Each videotex system is defined by a videographic language, i.e. a group of character codes and control codes, and by a transmission protocol for transmitting these codes from the server to the videotex terminal. In Europe, the characteristics of videotex systems are defined by standard TCD 6-1 of CEPT (Commission Europeenne des Postes et Telecommunications). Videotex systems such a PRESTEL, TELETEL and BILDSCHIRMTEXT are secondary standards defining three different levels of the aforementioned main standard.

Each videographic language has a list of alphanumeric characters, a list of semi-graphic characters, a list of controls and a list of display attributes. These elements of the language are represented in the videotex system by codes, i.e. a particular numerical value, which is in general a binary data byte. It is important not to confuse the numerical value, which is a binary number independent of the videographic language, and the code associating one element of the videographic language with a numerical value and consequently only has a meaning for a given videographic language.

The different videographic languages are not compatible with one another, because on the one hand different codes - 3 can correspond with a particular numerical value in different videographic languages and on the other because the display attributes are not processed in the same way in all the videotex systems. (c.f. e.g. IBM Technical Disclosure Bulletin, vol.26, no.lOB, March 1984, pp.5588-5592, Mew York, US; C. Codrai et al, Multiple Line Videotex Adapter.) Thus, for example, the display attributes are in series in the PRESTEL system, occupying a character location in the screen memory, whereas they are in parallel in the TELETEL system, occupying a memory location in a memory plane arranged in parallel with the screen memory plane. Finally, in BILDSCHIRMTEXT system, the display attributes can be in series or in parallel.

These differences make it impossible to restore on a terminal of a first videotex system an image produced by a second videotex system. The object of the invention is to eliminate this limitation. This is brought about by a transcoding process, which converts a videographic message, corresponding to the coding of an image according to a first videotex system into another videographic message which, interpreted by terminals of different videotex systems, produces on each of these terminals an image which is essentially identical to the image corresponding to the initial videographic message.

This transcoding process consists of analyzing each data item of the initial videographic message and producing, as a function of the nature of said data item and the meaning of the code associated therewith in the initial videographic language, another data item or a data sequence interpretable by several videotex systems and whereof the code or sequence of codes associated therewith has a meaning identical to that of the code associated with the data item of the initial videographic message.

More specifically, the invention relates to a process for the transcoding of a primary videographic message describing a primary image in a first videographic -4language into a secondary videographic message describing a secondary image in said first videographic language and a secondary image in at least one other videographic language, said secondary images being essentially identical to the primary image, said videographic messages being formed from a sequence of binary data, each binary data item being associated, by each videographic language with a particular code, said transcoding process being characterized in that the transcoding of each data item of the primary videographic message comprises the following operations : the code of the first videographic language associated with said data item is compared with the codes of the other videographic languages associated with said data item > to determine whether said code is identical to said codes or whether said code is different from at least one of said codes, '' A) if said code is identical to said codes, the data iteoi is written into the secondary videographic message, B) if said code differs from at least one of said codes, it is established whether the data item is associated with a character code or a control or display code.

Ba) if the data item is associated with a character code, a first predetermined data item is written in the secondary j videographic message, Bb) if the data item is associated with a control or display code, it is established whether said code is transcodable, BbeC ) if said code is not transcodable, a second predetermined data videographic message, item is written in the secondary a 30 Bb£ ) if said code is transcodable, in the secondary * 4 videographic message is written a data string in such a way that the sequences of codes associated with said string have an essentially identical meaning for each videographic language.

A code of the primary videographic message is transcodable if the function which it represents exists in the secondary videographic language. In the latter language, said function -5can be represented by a single code or may only be representable by a seguence of codes. To facilitate the transcoding of the primary videographic message, all the transcodable codes can be contained in a table. By consulting this table, it is possible to rapidly know whether a code is transcodable.

The characteristics and advantages of the invention can be better gathered from the following description relative to a non-limitative embodiment and with reference to the attached drawings, wherein show s Fig 1, already described, diagrammatically a videotex system.

Fig 2, the interconnection of two videotex systems by means of an apparatus realising the inventive transcoding process.

Fig 3, the structure of the image memory of a terminal of the TELETEL videotex system.

Fig 4, the structure of the image memory of a terminal of the PRESTEL videotex.

Fig 2 shows a first videotex system 28 and a second system, videotex Λ 30. Each system has a server 32, 38, a transmission system 34, 40 and terminals 36, 42.

Each terminal can transmit requests and receive messages from its server. In the conventional case where the transmission systems or networks are telephone systems, they can be interconnected and this is symbolized by a link 43 in the drawing. This link which can exist in the prior art videotex systems is not, however, sufficient for enabling one terminal of a videotex system to communicate with the server of the other videotex system.

According to the invention, said communication is made possible by adding between the server and its transmission system, a means 44 which transcodes videographic messages supplied by said server and which -6in this way produces videographic messages which can be interpreted by the terminals of each of the two videotex systems. For example, the means 44 is shown on the first videotex system 28, which enables the terminals 36 of the second videotex system 30 to communicate with the server 32 of the first videotex system 28. Obviously, server 38 could also be equipped with a means identical to means 44. The terminals 36 of the first videotex system 28 could then communicate with server 38 of the second videotex system 30.

A description will now be given of an embodiment of the inventive process by considering, in an exemplified manner, the case where the first videotex system is the TELETEL system and where the second videotex system is the PRESTEL system. The videographic language of the TELETEL system is more particularly described in the publication Minitel M1, Specifications techniques d'utilisation, September 1984, published by the French Ministry of Postes and Telecommunications and in the Journal Radiodiffusion - Television, No 182 Didon-Antiope, Specifications techniques, by Telediffusion De France. The videographic language of the PRESTEL system is more particularly described in PRESTEL terminal specification, 1980, published by the British Ministry of Posts and Telecommunications.

The process according to the invention ensures the transcoding of a primary videographic message describing a primary image in the videographic language of the TELETEL system into a secondary videographic message describing a secondary image in said videographic language and a secondary image in the videographic language of the PRESTEL system.

For a better understanding of the process according to the invention, it is firstly pointed out that a videographic message is a data string, each data item -7e.g. having the length of one byte. This data item is a value associated with the binary profile of the byte and is represented by a group of two hexadecimal numbers, such as 5/15. The code term designates the pair constituted by an element of a videographic language and a data item representing said element. Finally, a videographic language is defined by a group of character codes, control codes and display codes or attributes.

The incompatibility between two videotex systems is due to the fact that the same data item can correspond to different codes in the videographic languages of said videotex systems. The invention proposes replacing each of these data items by another data item or by a data string compatible with the two videotex systems, i.e. which is interpretable by these two systems and which produces essentially identical images on the screens of the terminals of these systems.

Prior to describing the transcoding process according to the invention, it worth referring the basic characteristics of the TELETEL and PRESTEL videotex systems. In tables I to V and VI to VIII respectively are shown the codes constituting the videographic languages of the TELETEL and PRESTEL systems. In each of these tables, the column number and row number at the intersection of which is located a code respectively constitute the upper part and lower part of the data item representing said code. The columns are numbered 0 to 7 by means of bits b , b , and b , whilst the rows 7 6 5 are numbered 0 to 15 by means of bits b , b , b 4 3 2 and b^. The most significant data bit b& is a parity bit. The boxes in the table not corresponding to any code are tinted grey.

The videographic language of the TELETEL system is defined by a group of five sets of codes : set GO of the alphanumeric character codes (table I)« -fleet Gl of the semi-graphic character codes or mosaics (table II), auxiliary set G2 of alphanumeric character codes (table III), set CO of control codes (table IV) and — t set Cl of display codes or attributes (table V).

In the same way, the videographic language of the PRESTEL system is defined by a group of four sets of codes : set GO of alphanumeric character codes (table VI), set G1 of semi-graphic character codes or mosaics (table II), set CO of control codes (table VII) and set C1 of display codes or attributes (table VIII).

The comparison of these tables makes it possible to reveal the following differences between the videographic language of the TELETEL system and the videographic language of the PRESTEL system. For the main set GO, data items 2/3, 2/4 and 5/14 do not correspond to any code of the TELETEL system, but have a meaning in the PRESTEL system. Data items 5/11, 5/13, 5/14, 5/15, 7/11, 7/13 and 7/15 correspond to different codes in the PRESTEL and TELETEL systems. The semi-graphic character sets Gl of the TELETEL and PRESTEL systems are identical. The auxiliary character code set G2 only exists in the TELETEL system. For the control code set CO, data items 0/2, 0/3, 0/14, 0/15, 1/2, 1/8, 1/9, 1/13 and 1/15 correspond to a code only in the TELETEL system and codes 0/5, 1/5 and 1/4 only correspond to codes of the PRESTEL system. For the display attributes, the only data items corresponding to identical codes in the PRESTEL and TELETEL systems are 4/0 to 4/9, 4/12 and 4/13.

The TELETEL and PRESTEL videotex systems also differ in the manner of storing an image. Fig 3 shows the image memory of a TELETEL terminal. It comprises a first memory zone 46 or screen memory for storing 25 rows of 40 characters, which constitute the displayed image, a second zone 48 of the same size as memory zone 46 and which stores the state of the parallel display attributes -9and a memory zone 50 organized in stack form and constituted by four bytes for storing the series attributes. These series attributes are those which define the background colour, the underlining of a character, masking and transparent background.

Fig 4 shows the structure of an image memory of a PRESTEL terminal. Said memory 52 is constituted by 24 rows with 40 character locations, which either contain a character code, or a display attribute.

The differences between the videographic language of the TELETEL system and the videographic language of the PRESTEL system and between the structures of the image memories of TELETEL terminals and the PRESTEL terminals lead to an incompatibility between these two videotex systems. This incompatibility is removed as a result of the transcoding process according to the invention, which e.g. makes it possible to translate a primary video graphic message describing a primary image in the videographic language of the TELETEL videotex system into a secondary videographic message describing a secondary image in the videographic language of the TELETEL videotex system and a secondary image in the videographic language of the PRESTEL videotex system, said secondary images being essentially identical to the primary image.

The transcoding process according to the invention consists of analyzing each data item of the primary videographic message and producing a secondary videographic message, in which each data item of the primary videographic message is retained or replaced by another data item or by a data string.

In the case where the data item of the primary videographic message corresponds to the same code in the videographic languages of the TELETEL and PRESTEL systems, said data item is copied out in the secondary -10videographic message. This is the case when the data item of the primary videographic message represents a character code of the main set GO, with the exception of a very limited number of codes (see tables I and VI), when the data item represents a character code of the semi-graphic set G1 (table II) or when the data item represents a movement control code of the entry marker (data item 0/8 to 0/13, 1/1, escape code (1/11) or the clearing code (1/14), cursor or 1/4), the or when the data item represents one of the display codes (tables V and VIII) : 4/0 to 4/9, 4/12, 4/13, 5/8 and 5/13.

In the case where the data item of the primary videographic message corresponds to a code of the videographic language of the TELETEL system and to a different code of the videographic language of the PRESTEL system, the transcoding of said data item is dependent on the nature of the code associated with said data item.

If these codes are character codes, the data item of the primary videographic message is replaced by another data item, which is chosen from among the data representing the same character code in the videographic languages of the TELETEL and PRESTEL systems. This replacement data item can e.g. be the space code 2/0.

If the data item of the primary videographic message represents a control or display code, the first operation of the transcoding process consists of determining whether the function represented by the code of the videographic language of the TELETEL system associated with the data item can be expressed by means of a code or « a sequence of codes of the videographic language of the PRESTEL system. If this is not possible, the data item is eliminated or replaced by another data item having an identical meaning for the two videographic languages. This other data item can e.g. be the null control code -11(0/0) or a data item representing an inactive code for each of the two videographic languages.

If the function represented by the control code of the videographic language of the TELETEL system associated with the data item can be expressed in the videographic language of the PRESTEL system, the transcoding process according to the invention consists of writing in the secondary videographic message a data string such that the seguence of codes of the videographic language of the TELETEL system and the sequence of codes of the videographic language of the PRESTEL system associated with said data string have an essentially identical meaning to that of the code associated with the data item of the primary videographic message.

The codes of the videographic language of the TELETEL system having no equivalent or which cannot be translated into the videographic language of the PRESTEL system are as follows : control code : SS2 (call code to the auxiliary set G2 off the character code), because the PRESTEL system only has one main set of characters, display attributes : latent state (4/10) end of latent state (4/11) double width (4/14) double size (4/15) end of underlining (5/9) start of underlining (5/10) transparent background (5/14) demasking (5/15).

A videographic image of the TELETEL system can consequently only be transcoded into a videographic image compatible with the PRESTEL and TELETEL systems and A identical to the starting image if the latter has none of the aforementioned codes. -12It is obvious that if the primary image of the TELETEL system has characters of set G2, it is not possible to produce a secondary image essentially identical to the primary image, because said secondary image, to be compatible with the PRESTEL system, must have no characters of said set G2. Conversely, if the non-transcodable code of the primary image is e.g. the underlining display attribute, the elimination of this attribute in the secondary image may not fundamentally modify the appearance thereof. In this case it remains possible to produce a secondary image essentially identical to the primary image.

Finally, the control codes and display attributes of the TELETEL videographic language which can be transcoded are : control codes : REP (1/2) (0/14) (0/15) US (1/15), display attributes : background colour (5/0 to 5/7) normal background (5/12) background reverse (5/13).

Thus, the majority of the TELETEL system videographic 25 language codes are interpretable or can be transcoded in such a way as to be interpretable by a PRESTEL system. which can be data string message by videographic For each of the control an display codes transcoded, details will be given of the written in the secondary videographic replacing the data item of the primary message representing said code. 1. Code SO (0/14) The SO or shift out code permits the passage into the semi-graphic or mosaic mode, which is terminated by the -13SI or shift in code for the return to the main set GO.

Any character code between codes SO and SX designates semi-graphic characters. Data item 0/14 representing code SO in the primary videographic message is replaced, in the secondary videographic message, by the data string : 0/14, 5/2, 5/0, 4/2, 0/13, 0/9, ...., 0/9.

This data string produces an identical effect on the TELETEL and PRESTEL terminals. It controls the passage into the semi-graphic mode on the black background and defines the colour of the plot or trace. In the chosen example, the ink colour is green (indicated by the second and fourth data items of the string), but any other colour could be selected. If it is wished to have a background colour other than black, it is merely necessary to follow said data string by the data string corresponding to the background colour change to be described hereinafter. * To establish that the indicated string is interpreted in the same way by the TELETEL and PRESTEL* terminals, it will be assumed that the screen cursor is located in the character location of coordinates i and j , in which i is the row number and j the column number.

For a TELETEL terminal, the data string 0/14, 5/2, 5/0 and 4/2 correspond to the successive codes : set semi-graphic mode, green background colour, black background colour and green ink colour. This string comprises a control code followed by three display attributes in parallel, which do not modify the position of the cursor, the latter remaining in the character location of the coordinates i and j. t This same data string received by a PRESTEL terminal consists of the sole code set green mosaic mode (5/2), the other data items not corresponding to any code being Ignored. This code is a display attribute in -14series. It moves the cursor by one character location to the right. This cursor is then located in the character location of coordinates i'j+i.

The string of the first four data items of the secondary videographic message consequently produces the same function on a TELETEL terminal and on a PRESTEL terminal, but does not displace the cursor in the same way, because certain codes correspond to parallel TELETEL attributes (with no action on the cursor) and series Prestel attributes (displacing the cursor). The correct repositioning of the cursor in the character location of coordinates if j+1 is ensured by the data string 0/13, 0/9 ... 0/9. These data items correspond to identical codes for TELETEL and PRESTEL terminals. Code 0/13 (carriage return) returns the cursor to the character location of coordinates if0. Each code 0/9 (horizontal tabulation) moves the cursor by one character location to the right. To bring the cursor into the character location of coordinates ifj+1, the secondary videographic message has a sequence of j+1 codes 0/9. 2. Code SI (0/15) The SI or shift in code makes it possible to shift back from the set G1 of semi-graphic character codes to the main set GO of the alphanumeric character codes. Data item 0/15 of the primary videographic message is transcoded in the secondary videographic message by the data string : 0/15, 4/2, 0/13, 0/9, ...., 0/9.

This data string controls the passage into the alphanumeric mode and defines the colour of the in* (second data item of the string). In the chosen example, the ink colour is green, but any other colour can be selected.

The first two data items respectively correspond, in the case of a TELETEL terminal, to the return code to set GO -15and to the green ink colour. These data items have no effect on the cursor. For a PRESTEL terminal, data item 0/15 is ignored and data item 4/2 signifies the green ink colour in the alphanumeric mode. This moves the cursor by one character location.

The data string 0/13, 0/9, ..., 0/9 brings about a repositioning of the cursor identical to that of the transcoding of the SO code. 3. REP (1/2) In the primary videographic message, said repetition code is followed by a numerical argument indicating the number of times the code preceding said repetition code must be repeated. As this repetition code does not exist in the videographic language of the PRESTEL system, it is replaced in the secondary videographic message by the explicit repetition of the code preceding it. 4. US (1/15) This code permits a direct positioning of the cursor in the TELETEL system. It is followed by two arguments respectively indicating the row number and column number of the new cursor position. This code does not exist in the videographic language of the PRESTEL system and is consequently replaced in the second videographic message by a relative positioning based on the current address, which is always stored, by means of a positioning code string for the cursor (data item 0/8 to 0/13).

. Background colour (5/0 to 5/7) For a TELETEL terminal, the background colour can be directly defined by codes 5/0 to 5/7. This possibility does not exist for a PRESTEL terminal, which can only modify the background colour by the code 5/2 (black background) or by the code 5/13 (new background), which defines the current ink colour as the new background colour. -16In an exemplified manner, a description will now be given of the data string of the secondary videographic message corresponding to a yellow ink colour on a blue background. At the start of said data string, the cursor is located in the character location of coordinates i,j. The data sequence 4/3 (yellow ink colour) and 5/4 (blue background colour) of the primary videographic message is replaced by the data string : 2/0, 5/4, 2/0, 2/0 (repositioning), 4/4, 5/13 , 4/3, 5/12 (repositioning).

The first repositioning comprises a sequence of codes for returning the cursor to the character location of coordinates i,j and the secondary repositioning for returning the cursor to the character location of coordinates i+3,j. Thus, on the TELETEL and PRESTEL terminals yellow writing on a blue background is obtained, which is preceded by a black space and two blue spaces.

The second data item of the sequence (5/4 in the chosen example) and the first and third data items following the first repositioning (4/4 and 4/3) define the background colour and the ink colour which have been selected. Any combination can be defined, with the exception of the black ink colour, which is impossible in the PRESTEL system.

The data string which, in the secondary videographic message, represents the background colour change code is remarkable in that it contains data corresponding to different codes of the videographic languages of the TELETEL and PRESTEL systems. 6. Normal background! 5/12) and reverse background (5/13) These codes can be processed in the same way as a background and Ink colour change.

For reproducing a secondary image essentially identical -17to the primary image, it is also necessary to take account of the fact that all the display attributes are reinitialized at the start of the image row in the PRESTEL system - code 0/13 (carriage return) cancelling out the display attributes - whereas in the TELETEL system, only the display attributes in series (background colour, masking,underlining, and size) are made inactive on moving from one row to the next row.

A simple solution for solving this difficulty consists of 10 again writing in the secondary videographic message the value of the display attributes following each row transition and after the direct cursor positioning code US (1/15).

TABLE I 0 0 1 1 1 1 • 1 1 0 0 1 10 1 0 1 0 1 E 2 3 4 5 6 7 0 0 0 0 0 0 @ P P 0 0 0 1 1 1 1 A Q a q 0 0 1 0 2 JS 2 B R b r 0 0 1 1 3 C S c s 0 1 0 0 4 U ! - r 4 D T d t 0 1 0 1 5 % 5 E u e u L 0 1 1 0 6 & 6 F V f V 0 1 1 1 7 s 7 G w g w 1 0 0 0 8 ( 8 H X h X 1 0 0 1 9 ] 9 I Y a 1 y 1 0 1 0 10 * β Β J z • J z 1 0 1 1 11 + J K [ k 1 1 0 0 12 < L 1 1 1 0 1 13 * Ξ M ] m 1 1 1 0 14 β > N £ 1 1 1 1 ia Δ ? o - TABLE II TABLE III 0 0 1 1 1 1 ί 1. 1 0 0 1 1 0 1 0 1 0 1 2 3 4 5 6 7 leaeaiaia 0 0 0 0 0 Ii IBBi Λ K 0 0 0 1 1 β λ + % I »«** f * ·* | ΐ* /E se 0 0 1 0 2 0 2 Έ) ff 0 0 1 1 3 ε 3 Λ fV*,* ·€ ι . i a 3 0 1 0 0 4 $ X •a» .- ' ' 1 L· 1 1 n 0 1 0 1 5 ¥ Al ^~ I 0 1 1 0 6 # ΤΓ M 1 IJ • » IJ 0 1 1 1 7 • a {X * S' L· I· 1 0 0 0 8 tt 9 a R» »7 — -L t 1 0 0 1 9 s 1 Ϊ, 0 0 1 0 1 0 10 ti 99 o :+. v : 7 . u — CE ae 1 0 1 1 11 « & id-*.- j- o β 1 1 0 0 12 —T ••si.TSrT ! ··♦'♦ · V t ί 1 1 0 1 13 t .½ 99 J-*- , T Λ 1 1 1 0 14 —34 L - ~ n h 1 1 1 1 15 ♦ M 6 w ir TABLE IV 0 0 I ο 0 I 0 1 Η ΕΠ 0 1 0® 0 Θ 0 0 0 NUL • - rf 0 Θ 0 1 1 ί Coni 0 0 1 0 2 Repl 0 0 1 1 3 ’Ί 0 1 0 0 4 V” · 0 1 0 1 5 ΐϊΐ’ΐ 0 1 1 Θ 6 ..... · 0 1 1 ί 7 1 0 0 0 8 BS • ·. 1 Θ 0 1 9 ΗΤ 1 0 1 0 10 LF 1 0 1 1 11 VT Ξ 1 1 0 0 12 FF 1 1 0 1 13 CR ...., ’ i Λ β 1 1 0 14 SO RSI 1 1 1 1 Ε SI 3 TABLE V b .3 1 1 b 6 0 0 b 5 0 1 b 4 b 3 b 2 b 1 4 5 0 0 0 0 0 black iftk - black background 0 0 0 1 1 red ink red background 0 0 1 0 2 green ink green background 0 0 1 1 3 yellow ink yellow background 0 1 0 0 4 blue ink blue background 0 1 0 1 5 magenta ink magenta background 0 1 1 0 6 cyan ink cyan background 0 1 1 1 7 white ink white background Ί 0 0 0 8 flashing masking 1 0 0 1 9 fixed reset underlining 1 0 1 0 10 latent state iset underlining 1 0 1 1 11 end of latent state 1 1 0 0 12 normal size normal background 1 1 0 1 13 double height reverse background 1 1 1 0 14 double width transparent background 1 1 1 1” 15 double siaffe demasking ro to TABLE VI b7 0 0 1 1 1 1 bg 1 1 0 0 1 1b5 0 1 0 1 0 1 2 3 4 5 6 7 b4 6» hg »1 0 0 0 0 0 0 (a) P P 0 0 0 1 1 ! 1 A Q a q 0 0 1 0 2 99 2 B R b r 0 0 1 1 3 £ 3 C S c s 0 1 0 0 4 $ 4 D T d t 0 1 0 1 5 % 5 E u e u 0 1 1 0 6 & 6 F V f V 0 1 1 1 7 9 7 G w 9 w 1 0 0 0 8 I 8 H X h X 1 0 0 1 9 ) 9 I Y β 1 y 1 0 1 0 10 * • J z • J k z % 1 0 1 1 11 + K — 1 1 0 0 12 9 < \ 1 1 1 1 0 1 13 - = M m % 4 1 1 4 β 0 14 s > N I n - 1 1 1 1 15 φ 0 tt o TABLE VII m u • 0 0 0 0 0 NUL| 0 0 0 1 1 (·' 0 0 1 0 2 0 0 1 1 3 0 1 0 0 4 | 0 1 0 1 5 ενώ 0 1 1 0 6 0 1 1 1 7 1 0 0 0 8 BS 1 0 0 1 9 HT I 1 0 1 0 10 LF 1 0 1 1 11 VT 1 1 0 0 12 FF 1 1 0 1 13 CR 1 1 1 0 141 1 1 1 1 E Con Coffl ESC RS TABLE VIII b 7 1 1 6 —o-- 0 T 5 u— 1 4 5b4 3 b 2 b 1 '0 0 0 0 0 0 0 0 1 1 red ink red mosaic b 0 1 0 2 green ink green mosaic 0 0 1 1 3 yellow ink yellow mosaic ό 1 0 0 4 blue ink blue mosaic 0 1 0 1 5 magenta ink magenta mosaic 0 1 1 0 6 cyan ink cyan mosaic 0 1 1 1 7 white ink white mosaic conceal display 1 0 0 0 8 flashing 1 0 0 1 9 steady contiguous mosaic s 1 •0 1 0 10 J separated mosaics 1 0 1 1 11 b · 1 1 0 0 12 normal height black background T 1 0 Ϊ 13 double height new background 1 1 1 0 14 hold mosaics 1 1 1 1 15 release mosaics

Claims (6)

1. A process for the transcoding of a primary videographic message describing a primary image in a first videographic language into a secondary videographic message describing a secondary J image in said first 5 videographic language and a secondary image in at least one other videographic language, said secondary images being essentially identical to the primary image, said videographic messages being formed from a seguence of binary data, each binary data item being associated, by 10 each videographic language with a particular code, said transcoding process being characterized in that the transcoding of each data item of the primary videographic message comprises the following operations : the code of the first videographic language associated with said data 15 item is compared with the codes of the other videographic languages associated with said data item to determine whether said code is identical to said codes or whether said code is different from at least one of said codes, 20 A) if said code is identical to said codes, the data item is written into the secondary videographic message, B) if said code differs from at least one of said codes, it is established whether the data item is associated with a character code or a control or display code, 25 Ba) if the data item is associated with a character code, a first predetermined data item is written in the secondary videographic message, Bb) if the data item is associated with a control or display code, it is established whether said code is 30 transcodable, Bbot) if said code is not transcodable, a second predetermined data item is written in the secondary videographic message, Bb£) if said code is transcodable, in the secondary 35 videographic message is written a data string In such a way that the sequences of codes associated with said string have an essentially identical meaning for each videographic language.

2. A process according to claim .1, wherein the first predetermined data item is a data item, whose associated 5 codes of each videographic language are identical.

3. A process according to claim 2, wherein the first predetermined data item is the data item associated with the space code.

4. A process according to claim 1, wherein the second 10 predetermined data item is a data item, whose associated codes of each videographic language are identical.

5. A process according tp claim 4, wherein the second predetermined item is the data item associated with the null code.

6. A process substantially as hereinbefore described with reference to the Accompanying drawings.