GB2230130A

GB2230130A - Controlling data recording medium apparatus

Info

Publication number: GB2230130A
Application number: GB9004345A
Authority: GB
Inventors: Kevin Downes; Keith Miller
Original assignee: VIDEO ANSWERS Ltd
Current assignee: VIDEO ANSWERS Ltd
Priority date: 1989-02-27
Filing date: 1990-02-27
Publication date: 1990-10-10
Anticipated expiration: 2010-02-27
Also published as: GB8904446D0; GB2230130B; GB9004345D0

Abstract

A method and apparatus for controlling a data recording medium apparatus, such as a laser video disc player 4, wherein the control apparatus 10 interrogates the video disc player prior to carrying out any instructions, to identify the player type. If the video disk player is not identified as being on a list of compatible players stored by the apparatus, an error is indicated. Once the video disc player has been identified, commands are supplied to the apparatus in barcode form by a barcode reader 14. The barcode commands are then converted into commands appropriate to the particular type of video disc player identified using look-up tables, and then transmitted to the video disc player. If a barcode has an equivalent command which is not compatible with the video disc player being used, the nearest approximate command is transmitted to the player. The method and apparatus may be used with digital video tape players and other similar apparatus. <IMAGE>

Description

Method and Apparatus for Controlling Data Recording Medium Apparatus The present invention relates to a method and apparatus for controlling data medium apparatus which is preferably, but not exclusively, in the form of a laser disc player, whereby control is effected in response to inputs from a scanning device, scanning a printed code. The code is preferably a bar code. The data medium apparatus may be also a CD ROM or any other audio/visual storage medium.

It has been previously proposed to control laser disc player by response to the output of a bar code reader, see for example US 4,481,412 and GB 2,201,028. One difficulty which has been encountered is that commercially available laser disc players vary from one manufacturer to another and this has necessitated unique control equipment for translating the output of the bar code reader into control signals which are meaningful to the laser disc player. This in turn has restricted the usefulness of such equipment.

It is an object of the present invention to overcome the disadvantages of the previously proposed system by providing control equipment which is capable of interrogating a laser disc player connected thereto and for modifying the control signals generated by the control equipment whereby to permit one of a plurality of different laser disc players to be connected thereto.

The present invention also seeks to provide control equipment capable of processing codes corresponding to both interruptable and noninterruptable control signals or commands, and codes which cause the system to mark time for a predetermined interval (i.e. waiting a specified time between the completion of one control command and the commencing of the next command).

The present invention further provides control equipment which includes a facility for indefinitely repeating the actions or commands corresponding to a given code.

There is no single parameter or characteristic associated with video disc players which can be used to distinguish one from another.

This has resulted in it being necessary to carry out a number of interrogations before being able to identify the particular laser disc player connected to the control equipment.

In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a view of a video display system incorporating a control unit according to the present invention for controlling a data recording medium apparatus; Figure 2 shows a block diagram of the control apparatus according to the present invention; Figure 3 illustrates a block diagram of the system memory of the control apparatus of Figure 2; Figure 4 is a flow chart illustrating the operation of the control apparatus of Figure 2.

The following description will be given on the basis that the recording medium playback apparatus is a video disc player. it is conceived that at some stage in the future digital video tape may provide equivalent characteristics to laser discs and it is anticipated that the present control equipment could be utilized with such a tape playback apparatus rather than a disc playback apparatus. Not all the features of a laser disc may be reproduced however.

Referring to Figure 1, the apparatus for controlling a data recording medium apparatus according to the invention forms part of a video display system designated 2. The video display system 2 consists of a laser video disc player 4 which drives a CRT display 6. The video disc player 4 has a conventional slot 8 for receiving a video disc. A barcode control unit 10 is coupled to the video disc player 4 via a multi-conductor cable 12 and to a barcode reader pen 14 via a flexible cable 16. A book 18 containing a number of barcodes 20 representing instructions or data lies on top of the control unit 10 to facilitate selection and entry of barcode commands by a user by wiping the barcode reader pen 14 across one or more barcodes 20.

Figure 2 shows a block diagram of the control unit 10 of Figure 1 which includes a processor-based control signal generator for translating the signals generated by the barcode reader pen 14 into control signals for application to the video disc player 4 connected to the control unit.

The input port 22 receives barcode signals from the barcode reader pen 14 via input line 16. The system memory includes a pen handler section 28 which is coupled to the input port 22 and receives barcode data via data line 30. Similarly, a communications handler section 32 is coupled to an input/output (I/O) port 36 via data line 34 which carries command signals and data te and from the I/O port 36. The I/O port 36 comprises an asynchronous serial communications interface (enabling two-way communication between the video disc player 4 and the control unit 10) such as an RS232 serial interface or similar interface. The use of such an interface enables the control unit 10 to implement software to interrogate a video disc player connected thereto, as described in more detail below. The interface 36 is coupled to I/O line 12.

The system memory 26 is coupled to a processor (CPU) 40 via a two-way data line 42. The interface is connected to the communications handler section 32 which is under the control of the operating system 46 (described below) of the processor 40 but which receives data from look-up tables in a manner which will now be described having regard to the operation of the control unit 10.

In Figure 3 a block diagram of the organisation within the system memory 26 of Figure 2 is shown. (In the diagram software communications between elements are indicated by arrows). The main components of the system memory are defined by the operating system software 46 and the video disc player control section 48. The pen handler software section 28 is linked to the barcode reader (decode) section 50 which is in turn linked to the video disc player control section 48 and the operating system software 46. The barcode reader (decode) section 50 and the video disc player control section 48 may be implemented as software and/or hardware and may take the form of circuitry and software conventionally used in existing video disc player control equipment. The video disc player control software 48 contains software appropriate to control one, preselected, video disc player.In this view of the fact that this software is basically unique to a particular type of video disc player, for that software to be useful for a different type of video disc player it is necessary to modify one or more of the control and decode functions so as to render the control commands output from the control unit 10 via the interface 36 in an appropriate form for the particular disc player connected to the interface 36. For this purpose the video disc player control software 48 has associated table containing data relating to various commands and to different types of video player, which are used in processing barcode commands: the tables are barcode command (decode) tables 52, generalized function tables 54, and function tables for specific players 56.The communications handler software section 32 and the system timer software are each linked both to the operating system software 46 and the video disc player control software 48.

Figure 4 shows a flow chart of the operation of the control unit 10. For the video disc player control software to be able to work, the control unit 10 must be "initialized" and, this is done either by the operation of a manual control on unit 10 or by reading a particular barcode using the barcode reader pen 14. The control unit 10 therefore checks first of all for initialization (steps S1, S2). When it has been initialized, the control unit 10 attempts to identify the particular type of video disc player connected to the interface 36, initially by checking to see whether a parameter has been set (e.g. by setting a dial control on unit 10) indicating the video player type (S3). If a parameter has been set the software jumps to a later stage in the processing indicated by (A). If no parameter has been set, the interrogation of the video disc player proceeds as described below. First of all it is to be appreciated that not all video disc players have the same capabilities and indeed not all video disc players are capable of two-way communications with the control equipment. The software in the control unit which performs the interrogation of the video disc players does so based on the knowledge of the unique characteristics of a particular range of video disc players. These unique characteristics are utilized by the control unit 10 to identify particular types of video disc player either by the features individually or in combination. There is thus no single characteristic or parameter which can be observed by the control unit 10: rather, it is a combination of various parameters which are used by the control equipment to determine the type of video disc player to which it is connected.With reference to Figure 4(a), for each video disc player which can be connected to and supported by the control unit 10 according to the present invention, the interrogation proceeds as follows. Provided that the control unit 10 has not already selected all makes (manufacturer types) of video player, a new make of video player is selected (steps S4, S5). If all makes of player have already been selected then an audible warning is sounded and a "video Error" sign is displayed. If all the possible formats have not already been selected then a new format is selected (steps S7, S8).

Referring to Figure 4(b), in step S9 format data is transmitted to the video player 4 by the control unit 100 which then detects the response sent back (if any). If the response does not correspond to a predetermined regime then the software jumps to an earlier stage in the processing indicated by (C). If the response is as expected, the type of video player is identified and stored (steps S10, S11). Once the video disc player 4 has been identified, the reading of any barcode 20 by the barcode reader pen 14 will result in the corresponding command being carried out by the control unit 10, as described below, for the particular video disc player. If the connection between the video disc player 4 and the control equipment 10 is broken at any time, for example by unplugging, the control unit 10 must be "initialized" once more.

Depending on the result of the interrogation of the video disc player, the output of the video disc player control section 48 is fed via the look-up tables 52,54,56 which are conditioned in response to the result of the interrogation to provide appropriate control command signals through the communications handler section 32 and the interface 36 to the video disc player 4. The processing of the barcode commands is described in more detail below. The next stage involves identifying the disc type and whether or not the disc is arranged in chapters (steps S12,S13,S14 and S15). If the type of disc is not CLV- or CAVtype then "Video Error" is displayed and an audible warning is sounded. The disc type information is stored in memory (step S16).

The start of the processing of the commands in barcode form is shown in Figure 4(c). Once a barcode 20 has been scanned by a user wiping the barcode reader pen 14 over a barcode 20, the barcode is received by the input port 22 on input line 16.

The input port 22 then transmits the barcode to the pen handler section 28 via data line 30. On receiving a barcode, the pen handler software converts the barcode into data in the form required for processing and outputs the barcode data. Referring to Figure 4(d), the barcode reader (decoder) software 50 loads the barcode data and decodes the barcode data into data corresponding to control commands, and outputs the decoded data (steps S20 to S22).

The operation of the video disc player control software 48 and operating system software 46 is shown in Figure 4(e). The software first checks for any data from the video disc player through the input/output port (step S23); and if the response is negative the software checks that the barcode is read and stored by the decode software (step S24). If there is such data passing through the I/O port, the data is received and validated with the expected results (step S25). If the data is found to be valid (step S26), step S24 is executed. If the data is invalid, and 'error" is indicated and an audible warning sounded (step S27).

If on executing step S24 it is found that the barcode has not been read and stored by the decode software, the processing continues from the point designated (G). If on the other hand the barcode has been read and stored, the data is received from the decoder software and validated (step S28). If the data is invalid an "error" is indicated and an audible warning is sounded (steps S29 and S30). If the data is valid the software determines whether another command is in progress (step S31).

If no command is already in progress the software sets an indication that a barcode is available, flushes the barcode list and appends à new code to the list (step S32). Processing then continues from the point designated (G). If a command is already in progress the software checks (step S33) whether the command is an interruptable command and, if it is, step S32 is executed. If the command is uninterruptable, the software sets an indication that a barcode is not available (step S34), and processing continues from the point designated (G).

Referring to Figure 4(f), at the point designated (G) the software checks whether a barcode is available (step S53) and if it is not available then the software proceeds to determine whether the procedure list is empty (step S36). If there is a barcode available then the software proceeds to: point to a new barcode (step S37); look up barcode command, general function and player tables, and retrieve procedural data from the tables and add to procedure list (step 538).

The software then executes step S36 whereupon if is is found that the procedure list is empty, the software proceeds to determine whether the system timer has expired (step S39). If the procedure list is not empty the next item in the procedure list is obtained and put into action (step S40). The corresponding data is then output in the 3/0 port (step S41). Next, the timer is set, if required (step S42). The software then sets an indication of the expected results from the player, if any (step S42).

When this has been done, step S39 is executed.

If the timer has not expired, processing continues from the point designated (F) (see Figure 4(e)). If the time has expired then the timer is cleared and processing continues from the point designated (F).

It is to be understood that not all video disc players have the same range of facilities and hence some bar code commands cannot be utilized by particular video disc players. The control unit 10 will either treat such bar code commands as errors or will cause an approximate function to be performed by the video disc players. For example, if a frame search bar code is read but the video disc inside the player is not frame addressable, the software should produce an error signal which can be communicated the user by means of a visual or audible signal. if a barcode 20 is read which requires fast forward at for example four times normal speed, but the player only is capable of three times normal speed, then fast forward at three times normal speed is performed rather than producing an error.

Further features of the apparatus according to the present invention are that it has been designed to read and decode USS-128 (otherwise known ass code 128) industrial format bar code at high resolution.

In code 128, the format of each barcode is that there is a lead-in section, followed by one or more command sections, followed by a checksum section and terminated by a lead-out section. Various functions of the control equipment are also of interest.

In addition to the customary video disc player commands, it is intended that a bar code 20 is available to the user which signals to the control unit 10 that it has to repeat one or a string of subsequent commands in an order which can be determined by the user simply causing the appropriate bar codes 20 to be read in the order in which he wishes the commands to be executed. This function is particularly useful for visual displays where one wishes to show viewers a pre-selected range of material in a particular order and to change the order fairly frequently in a simple manner.

A further important function is that a timed wait of up to a pre-determined maximum delay can be provided. The timed wait may be either interruptible or non-interruptible and again the length of the delay is determined by the user causing a particular bar code 20 indicative of the length of the delay to be read subsequent to a particular bar code indicating that a timed wait is required. In addition, certain other bar codes may be encoded as interruptable or noninterruptable codes. The form of the various command sections of the barcode formats proposed for the present invention is shown in the attached Table in which the designation X indicates a unique selected alpha-numeric character which may be repeated in some instances or replaced by further selected characters so as to create unique commands.Binary and numeric data (i.e. non-printable/control characters) are printed according to code 128 standard but passed to the application decoder as data with the appropriate code 128 codes removed.

While the above description has been given on the basis that a bar code 20 is used to embody the printed code, it is to be appreciated that other printed codes could also be utilized which would simply necessitate a change in the read control and decode section as well as, possibly, a change in the type of reader 14 which is used.

The apparatus can also call up still frame audio where that function exists on the video disc player and it can also generate text where this function exists in the disc player.

The control unit 10 is capable of taking additional specific software in order to encode a complete application. For example, specific software may be supplied with a work book and video disc where the software will contain all the coding specific to do that course thereby enabling a single barcode 20, e.g. of one character to obtain a multiplicity of functions. The control letter Z could represent, for example, ten different video control actions.

CONTROL SUMMARY TABLE The following specifies the set of desired controls we would wish to have over a videodisc player.

Supporting The Command Set Because not all combinations of videodisc player and videodisc will be able to support all functions, the software should, wherever possible "do the most sensible thing". In some cases this may mean taking a similar action, in others it may be lighting up an error LED. For instance Long Play (CLV) videodiscs are NOT frame addressable, so any frame addressable command used with a CLV disc should light an error LED. However, a barcode specifying a fast played sequence at 8 times normal speed on a player which only supports 3 times normal speed, should play at 3 times normal speed and not produce an error.

Handset Video Control The following set of commands mimic their counterparts on a handset.

SEARCHTYPE FRAME

X X 0 Set software into frame addressable search mode.

See also INDEX command.

KEY number

X X < num$gt; Enter digit 0-9 as part of frame / chapter number to be searched. < num > is the ASCII number.

CORRECT

X X frame / chapter entry error. Discard current SEARCHTYPE.

Delete all previously entered numbers.

SEARCH

X X Validate & perform frame / chapter search as specified.

Chapter Search Validation Invalid chapter number should produce "videdo error" LED & beep (max. ???? chapters on disc) Disc does not have chapters.

Chapter Search Operation Start playing chapter.

Frame Search Validation Frame address < 54000 Disc is frame addressable Frame Search Operation Still frame.

Invalid search should produce "video error LED & beep.

AUDIO LEFT OFF

X X 0 AUDIO LEFT ON

X X 1 Switch left audio track (audio track 0) on / off AUDIO RIGHT OFF

+ + t t X X 0 AUDIO RIGHT ON

X X 1 Switch right audio track (audio track 1) on / off VIDEO OFF

X X 0 VIDEO ON

X X 1 Switch video picture on / off INDEX OFF

X X 0 INDEX ON

X X 1 Switch index as used by last SEARCHTYPE on / off. If no SEARCHTYPE has been requested, default to : frame address for CAV discs, chapter index for CLV discs. A SEARCHTYPE command immediately followed by INDEX command will force that type of index display on / off.

STEP REVERSE

X X 0 STEP FORWARD

X X 1 Step forward / backward from current position by 1 frame SLOW REVERSE

X X 0 SLOW FORWARD

X X 1 Play from current position at player's default slow speed to end / start of disc PLAY REVERSE

X X 0 PLAY FORWARD

X X 1 play from current position at normal speed to end / start of disc FAST REVERSE

X X 0 FAST FORWARD

X X 1 play from current position at player's default fast speed to end / start of disc.

PAUSE

X X freeze motion, picture on. To act as a toggle, continuing previous slow / fast / play motion.

EJECT

X X open lid of player (eject disc) ENHANCED VIDEO CONTROL The following commands take their origins from established computer control functions. Many commands will perform a sequence of operations. Parameters to some commands refer to tables which are listed at the end of this section.

Initialise Videodisc Player INIT (player)

±---------± - - - - - - - - -+ ! x I < player > ±---------+ - - - - - - - - - + Command to initialise videodisc software.

If no parameters autosense comms. baud rate and type of player in use.

If parameters parameter states type of player in use, by name VP831 VP835B VP835E Philips VP406 VP410 VP412 VP415 LDP1500 ) Sony LDP2000 ... - LDV6100 (??) ) Pioneer LDV4100 (??)...) autosense comms. baud rate.

Both initialisation processes should also determine type of disc in use (CAV, CLV) and whether disc has chapters or not. Failure to INITIALISE correctly will produce "video error" LED & beep. Comms.

errors should also be indicated, if any.

Frame Addressable Commands The following commands apply to CAV (active play) 'discs only.

Before actioning each command, the software should check disc is CAV frame number parameters are in valid range (1-54000) player supports command Still Frame Access STILL frame

±---------±------ ! x ! < sv > ! < frame > ! ( 7 ±---------±------ Goto frame < frame > , switch video on/ off according to < sv > . If < sv > = 0, video is OFF, if < sv > = 1, video is ON. Target frame is denoted by 5 ASCII numeric characters, with leading ASCII numeric zeros if appropriate.

Played Sequences The general barcode format is

±----------±---------±-±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ ! ! ! ! ! ! ±----------±---------±-±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ : : : : : : : :.........endframe : : : : : :........startframe : : : :......audiovisual / speedvisual state : :...........command code Where : command code is a single ASCII character denoting the operation to be performed.

If the code is UPPERCASE alphabetic, the command is interruptable, if the code is lowercase alphabetic, the command is interruptable only by a 'RESET' command.

audiovisual state is a single ASCII character (see table) denoting state of audio & video IN NORMAL PLAY MODE.

speedvisual state is a single ASCII character (see table) denoting state of video & BR< speed of play IN FAST / SLOW PLAY MODE.

In these modes there is no audio available and speedvisual replaces the audiovisual code.

startframe is 5 ASCII digits denoting the start frame of the sequence, with leading ASCII numeric zeros, range 1-54000.

endframe is 5 ASCII digits denoting the end frame of the sequence, with leading ASCII numeric zeros, range 1-54000.

N.B. if startframe > endframe, the sequence should be played in reverse.

PLAY startframe TO endframe, interruptable

±----------±-----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ ! X ! < av > ! < startframe > ! < endframe > ! (12) ±----------±-----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ play the frame sequence < startframe' > to < endframe > with audio & video in state specified by < av > .

Direction may be forward or backward depending upon frame numbers. Allow the sequence to be interrupted by other barcodes.

PLAY startframe TO endframe, non-interruptable

±----------±-----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ ! X ! < av > ! < startframe > ! < endframe > ! (12) ±----------±-----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ play the frame sequence < startframe > to < endframe > with audio & video in state specified by < av > . Direction may be forward or backward depending upon frame numbers. This command can only be interrupted by the 'RESET' barcode.

VARI-SPEED PLAY startframe TO endframe, interruptable

±-----------±----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ ! X ! < sv > ! < startframe > ! < endframe > ! (12) ±-----------±----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ play frame sequence < startframe > to < endframe > with the video in specified state & at slow / fast speed indicated by < sv > in the direction accordiny to < startframe > , < endframe > .

Audio will naturally be muted. Players which do not support variable slow speed should play at their default slow speed.

Players which do not support variable fast speed shouldplay at their default fast speed.

This command may be interrupted by other commands.

VARI-SPEED PLAY startframe TO endframe, noninterruptable

±-----------±----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ ! X ! < sv > ! < startframe > ! < endframe > ! (12) ±-----------±----------±-±-±-±-±-±-±-±-±-±-±-±-±-±-+ play frame sequence < startframe > to < endframe > with the video in specified state & at slow / fast speed indicated by < sv > in the direction according to < startframe > , < endframe > . Audio will naturally be muted.

Players which do not support variable slow speed should play at their default slow speed.

Players which do not support variable fast speed should play at their default fast speed.

This command can only be interrupted by the 'RESET' command.

Chapter Addressable Commands The following commands apply to discs which have chapters marked out on them. A disc can be either CAV or CLV (Long Play).

Before each command is actioned, the software should check disc has chapters player supports command The general barcode format is

±---------------±------------------±-------±------±--------+ ! ! ! ! ±---------------±------------------±-------±------±--------+ : : : : : : : : : : : :.........chapter number : : : :......audiovisual / speedvisual state : :.......command code Where : command code is a single ASCII character denoting the operation to be performed audiovisual state is a single ASCII character (see table) denoting state of audio & BR< video IN NORMAL PLAY MODE.

speedvisual state is a single ASCII character (see table) denoting state of video & BR< speed of play IN FAST/SLOW PLAY MODE. In these modes there is no audio available and speedvisual replaces the audiovisual code.

chapter number is 3 ASCII digits denoting the chapter number of the sequence, with leading ASCII numeric zeros, range 1 999.

PLAY chapter, interruptable

±------------±----------------±----------±-----+ ! x ! < Av > ! < chap > ! ±------------±----------------±----------±-----+ play chapter number 'chapter' with the audio & video in the specified states.

This command may be interrupted by others.

PLAY chapter, non-interruptable

±------------±----------------±----------±-----+ ! x ! < av > ! < chap > ! ±------------±----------------±-----------------+ play chapter number 'chapter' at normal speed, with the audio & video in the specified states. This command may only be interrupted by the 'RESET' command.

VARI-SPEED PLAY chapter, interruptable

±------------±----------------±----------±-----+ ! x ! < sv > ! < chap > ! ±------------±----------------±----------±-----+ play chapter number < chap > at speed & BR< video display specified by < sv > (see speedvisual table).

For those players & videodiscs which cannot support vari-speed chapter play, the software should produce an LED "video error".

For those players which support limited vari-speed capability, the default fast / slow speeds should be used.

This command may be interrupted by other commands.

VARI-SPEED PLAY chapter, non-interruptable

For those players & videodiscs which cannot support vari-speed chapter play, the software should produce an LED video error For those players which support limited vari-speed capability, the default fast / slow speeds should be used.

This command may be interrupted by other commands.

SUNDRY Send Command String Direct To Player SEND DIRECT strinyl RECEIVE string2

±------------±------±--------±------± - - - - - - --± - - - - - - -+ ! x ! < 11 > ! < 12 > 1 < stringl > ! < string2 > ±------------±------±--------±------± - - - - - - --± - - - - - - -+ where < 11 > is the length (in characters) of the string to be transmitted.

< 12 > is the length of the string to be received if no string is to be received, < 12 > = 0.

< strinyl > is the string to be transmitted.

< string2 > is the string to be received (if any) Reset ( interrupt everything RESET

±------+ ! x ! ( 1 ) ±------+ reset all barcode stacking software.

Cleanup video & comms software. Generally revert to 'clean' state immediately after initialisation of videodisc player.

Repeat Command REPEAT command(s)

±------± - - - - - - - - - - - - - - -+ ! x ! < command(s) > + ~ ~ ~ ~ ~ ~ ~ + - - - - - - - - - - all subsequent commands for the current barcode are repeated in order until interrupted by another barcode entry. All < command(s) > should be interruptable. If they are not, the application software should adjust them to their interruptable equivalents.

MPU Timer Operations Maximum time delay is 2500 seconds.

TIMED WAIT time~in~seconds, interruptable

±----- ! x ! < seconds > ! ( 5 ±----- halt the reader for the specified amount of time. If a barcode is scanned within time delay, perform 'reset' function & BR< action new barcode. If no barcode is scanned, perform any remaining, stacked commands.

TIMED WAIT time~in~seconds, non-interruptable

±----- ! x ! < seconds > ! ( 5 ±----- halt the reader for the specified amount of time. Ignore all barcodes scanned, except for 'RESET' command.

MPU Commands These commands are only acceptable BEFORE any video command has been actioned. If these commands are received at any other time, a "video error" should result. These commands cannot be used with a REPEAT command prefix.

SELF TEST

±------±------+ ! x ! x ! ( 2 ) ±------±------+ perform self test function for software & BR< MPU.

IDENTIFY

±------±------+ ! x ! x ! ( 2 ) ±------±------! get software to identify itself via output to serial printer. Display should include list of players supported, software & hardware version number(s), suitable copywrite.

PARAMETER TABLES Audiovisual~state Table The table below gives the various options for the audiovisual state of the player for frame & chapter play commands. AudioL indicates the state of the Left audio channel, AudioR the Right channel. VidS indicates the state of the video picture at the Start of the sequence, VidE gives the state at the End of the sequence. Most of the possible combinations have been listed (except for those which are nonsensical).

AudioL Audio RVidS VidE Encode ON ON ON ONA ON ON ON OFF c Z ON ON OFF ON C: ON ON OFF OFF ON OFF ON ON ON OFF ON OFF ON ON OFF OFF ON ON OFF OFF OFF OFF ON ON ON OFF ON ON OFF OFF ON OFF ON OFF ON OFF OFF OFF OFF ON ON OFF OFF ON OFF Speedvisual~state Table The following table gives the different states which may be possible for FAST/SLOW command sequences involving chapter & frame access of the video disc. VidE denotes the state of the video at the End of the sequence, Speed denotes the speed of play, relative to NORMAL SPEED. For all speeds other than normal speed, there is NO AUDIO output.

The default video start is ON.

Speed VidE Encode 1/64 ON OFF 1/32 ON c OFF H OFF ?o ( 1/16 ON w OFF OFF slow ( 1/8 ON speed OFF speed ( OFF 1/4 ON OFF 1/3 ON OFF H 1/2 ON OFF * * 2 ON OFF * 3 ON OFF C: : 4 ON w OFF C ( * 8 ON fast ( OFF C speed ( * 16 ON OFF m * * 32 ON OFF H H * 64 ON OFF

Claims

CLAIMS: 1. An apparatus for controlling a data recording medium playback apparatus, comprlsng: printed code scanner for converting optical changed produced during scanning of a printed code into an electrical coded data signal; decision means for determining control commands which are expressed by said coded signal; control means for issuing control commands for controlling said data recording medium playback apparatus in accordance with control commands determined by said decision means; input/output means, coupled to said control means and to said data recording medium playback apparatus for transmitting said control commands to said data recording medium playback apparatus;; wherein said control means identifies the type of said data recording medium playback apparatus prior to the transmission of control commands thereto, and wherein said control commands are determined by said decision means dependent upon the identity of said recording medium playback apparatus.
2. An apparatus according to claim 1, wherein: said decision means and said control means are located within a system memory, and said system memory is coupled to said printed code scanner and to a processor means.
3. An apparatus according to claim 2, wherein: said system memory means is coupled to said printed code scanner via an input means.
4. An apparatus according to claim 3 wherein: said system memory means further includes, coupled with said control means, look-up table means.
5. An apparatus according to claim 4, wherein: said look-up table means includes codes command decode means, for converting said coded data into function data.
6. An apparatus according to claim 5, wherein: said look-up table means further includes generalized function means, for converting said function data into command data.
7. An apparatus according to claim 6, wherein: said look-up table means further includes player function means, for converting said command data into said control commands in response to said received identification data.
8. An apparatus according to any of claims 1 to 7, wherein: said memory means further includes, coupled to said control means and said input/output means, communications handler means, for controlling communication of said identification data and said control commands there between.
9. An apparatus according to claim 8, wherein: said input/output means comprises an asynchronous serial communications interface.
10. An apparatus according to any of claims 1 to 9, wherein: said printed code scanner comprises a barcode reader pen and receives said coded data therefrom.
11. An apparatus according to claim 10, wherein: said system memory means includes coupled to said input means and said decode means, pen handler means, for controlling the transmission of coded data therebetween,
12. A method for controlling a data recording medium playback apparatus comprising: in a first step, identifying the type of data recording medium playback apparatus; in a second step, (a) reading in a printed code to produce a corresponding coded data signal; (b) determining from said coded data signal a control command which is expressed by said coded data signal; (c) supplying a control command to said data recording medium playback apparatus; wherein said control command is dependent on the identity of the data recording medium playback apparatus.
13. A method according to claim 12, wherein: said first step includes transmitting identification data to said recording medium apparatus and receiving identification data returned therefrom.
14. A method according to claims 12 or 13, wherein: said coded data is read by a barcode reader.
15. A method according to claim 14, wherein: said identification of the data recording medium apparatus proceeds following manual initialization by a user or by a predetermined barcode being read.
16. A method according to any of claims 12 to 15, wherein: i) converting said coded data into function data, ii) converting said function data into command data, iii) converting said command data into said control commands dependent on the identity of said data recording medium apparatus.
17. An apparatus according to any of the preceding claims, further including means for identifying whether the control command corresponding to each said coded data signal is interruptable or non-interruptable, and said control means issues control commands dependent on said identification.
18. An apparatus according to any of the preceding claims, further including means for causing the data recording medium playback apparatus to mark time for a predetermined interval.
19. An apparatus according to any of the preceding claims further including means for causing a control command corresponding to a coded data signal to be indefinitely repeated.