GB2381371A

GB2381371A - Digital audio or video playback arrangement

Info

Publication number: GB2381371A
Application number: GB0302439A
Authority: GB
Inventors: Martin John Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-21
Filing date: 1998-10-21
Publication date: 2003-04-30
Anticipated expiration: 2018-10-21
Also published as: GB0302439D0; GB2343049A; GB2381371B; GB9823050D0; GB2343049B

Abstract

A digital audio or video playback arrangement for a studio broadcast system is arranged to enable tracks from CD's to be played from hard disk. Behind a mixing panel 5L is a touchscreen colour monitor 6, which has three virtual CD players VP1, VP2 and VP3 at the bottom of its screen aligned with respective physical control panels C2, C3 and C4. Uniquely, the disc jockey can see at a glance which player is operating and the state of its associated mixer channel. One or more real time output streams 404, 405 can be generated simultaneously from the same CD.

Description

Digital Audio/Video Playback Arrangement The present invention relates to a digital audio and/or video playback arrangement, particularly but not exclusively for broadcasting, and to a method of operation thereof. The invention is applicable both to audio and to video playback.

Ever since the introduction of the CD, digital recording has made a huge impact on

,.. yl-eco-'s an'1-1 NT,, B : : rg'e the broadcast radio market. Few stations still play vinyl records and the NAB jingle vl I I lu u L. LLE ji I cartridge has been replaced by digital floppy disk players and cheaper, maintenance free PC hard disk systems. Computer based music scheduling has become the norm at most stations and hard disk systems used for playing music have the advantages over CD's of instant access and the potential for automation.

In theory these developments should make systems easier to use, enabling audio material to be accessed quickly and making the disc jockey's life easier by increased automation.

In reality the situation is somewhat different.

The chief reason for this is that as components have evolved and replaced existing equipment the result is more computer keyboards, more screens to look at and more opportunities for mistakes to be made. The disc jockey can end up spending more time sorting out the sheer mechanics of the show than working on the show's content.

In the US, hard disk systems are becoming common for playing music but as stations are more specialised and play fewer tracks the disk storage requirements are not a problem.

In the UK market, stations tend to play a greater variety of music so the sheer amount of disk storage required to hold a radio station's CD collection makes the concept unworkable.

Throughout this transformation into the digital age, the mixing desk has remained largely unchanged.

In particular, in one current CD-based studio, CDs are played from conventional CD players of which there are typically three. This allows one CD to play on-air, the next track to be standing by and a third player as a spare. Commercials and jingles are commonly played from a PC based hard disk system. This gives the disc jockey quick access to material and also allows logs of which items were played to be

generated automatically. There are also various outside feeds such as Travel News, Newsroom aid other studios in the station.

All the above sources are fed through a conventional analogue audio mixer for balancing of levels. This also allows remote start of the CD players and the ability to hear a source on prefade-i. e. to hear a mixer channel without it being broadcast on air.

The above system has the advantages of ease of use and being tried and trusted.

However it is relatively expensive, has limited automation potential and the disc jockey has to locate and load all CD's to play.

Conversely, in a hard disk-based studio, all music tracks are played from a PC based hard disk system, not directly from CD. Commercials and jingles are also played from the same hard disk system. There are various outside feeds such as Travel News, Newsroom and other studios in the station.

All the above sources are fed through a conventional analogue audio mixer for balancing of levels. This allows remote start of the hard disk players and the ability to hear a source on prefade though this can be limited as the hard disk system commonly only has two or three stereo outputs.

Such a hard disk system has the advantages that music tracks are instantly available, tracks from the same CD can be played back to back, automation is easier to implement and it can be fully integrated with a scheduling system.

It has the disadvantages that all music has to be loaded into the system in advance, it can be expensive, since more storage will need to be added as the station's library grows and it is inefficient because 40% of the tracks may only get played once every six months. Furthermore because such a system is inherently computer and mouse based, it can be less satisfying to use and the disk jockey can feel out of control.

The complexity of a television studio is even greater, placing even greater demands on the presenters and technicians.

It is envisaged that the invention will be applicable particularly to broadcast arrangements where ease of use and efficient use of time are of the essence, and not only to radio and television broadcast arrangements but also cable and satellite broadcast arrangements, particularly in view of their inherently digital nature.

The invention provides a digital audio or video playback arrangement comprising at

least one physical control panel which is aligned with and controls a virtual audio or video player represented on a display.

This has the advantage that the flexibility of a hard disk based system is retained in conjunction with the ease of use of a conventional hardware-based system.

Preferably two or more fader panels are aligned with respective audio or video players represented on a common display.

Further preferred features of the invention are defined in the dependent claims.

A preferred embodiment of the invention is described below by way of example only with reference to Figures 1 to 10 of the accompanying drawings, wherein: Figure 1 is a schematic block diagram of a digital audio broadcasting arrangement in accordance with the invention; Figure 2 is a schematic block diagram of the processing, memory and storage arrangment of the arrangment of Figure 1; Figure 3A is a timing diagram showing the reading and writing of digital audio streams in the arrangement of Figure 2; Figure 3B is a timing diagram showing a variant of the reading and writing of the above digital streams in the arrangement of Figure 2 in response to the detection of a fault; Figure 4 is a view of the left hand touchscreen monitor and corresponding left hand portion of the mixer control surface of the arrangement of Figure 1; Figure 5 is a view of the right hand touchscreen monitor and corresponding right hand portion of the mixer control surface of the arrangement of Figure 1; Figure 6 is a screen shot of the left hand touchscreen monitor in"NORMAL" (default) mode; Figure 7 is a screen shot of the left hand touchscreen monitor in"LIBRARY"mode ; Figure 8 is a screen shot of the right hand touchscreen monitor in"STACKS"mode ; Figure 9 is a screen shot of the right hand touchscreen monitor in"RECORD"mode,

and Figure 10 is a screen shot of the left hand touchscreen monitor in"MASTER PFL" mode.

Referring to Figure 1, the arrangement comprises a personal computer (e. g. a Pentium II (Registered Trade Mark) ) (1) running a multi-tasking operating system such as Windows 98 (Registered Trade Mark) or Windows'Registered Trade Mark) with a keyboard (not. shown), a trackball (not shown) and two touchscreen colour monitors 6 and 7 which provide a graphical user interface.

The computer has an audio hard disk recording card (not shown) connected to an external audio interface module 4 with multiple inputs and outputs. The inputs can include a news feed, a traffic information feed, and a telephone feed for example and can include both digital and analogue sources. In order to accommodate the latter, the interface module 4 is provided with an analogue to digital converter (not shown).

The computer 1 is provided with fast hard disk storage 20 for audio (either local disks or a networked storage), a fast (e. g. 20x) CD-ROM drive 3 and a network connection to other PCs in the building (not shown) for exchanging music scheduling and log information.

A digital mixing module 5 is coupled to the computer via a data link. It should be noted that no audio signal passes through the mixing module-it is used purely as a remote control surface. Additionally the computer 1 is coupled to a master digital control panel 8 located at the right hand side of mixer control panel 5. Control panel 8 is provided with a MASTER PREFADE button 90, and RECORD, LIBRARY and STACKS mode selection buttons 80, 81 and 82 and a group of four navigation buttons N for navigating horizontally and vertically through the tracks displayed on screen. The operation of control panel 8 will subsequently be described in detail.

Before describing the user interface aspect of the arrangement in more detail, the internal operation of the PC system 1 with its associated mass storage will be described with reference to Figures 2,3A and 3B.

As shown in Figure 2, the PC 1 is provided with a high capacity hard disk 20 and is arranged to read in a digital audio stream from CD-ROM drive 3 (Figure 1) at nX real time e. g. 15X real time as indicated by input stream 100, under the control of microprocessor 500 (which is suitably a Pentium II (Registered Trade Mark) processor). The audio stream is fed into RAM 403 and checked for faults (e. g. a run

of identical sample indicative of a scratch in the CD) and for maximum level by a suitable program executed in processor 500. After checking it is written sequentially to separate files Fl, F2, F3, F4, F5, F6 (constituting one track F of the CD) and as a further sequence of files G1.... G6 (constituting another track G of the CD) only the first file G 1 having been written to disk at the stage shown in in Figure 2, each me comprising 30 seconds of audio. If a fault is detected in the audio stream before that particular 30 second portion of the audio stream has been fully written to disk, then the file is deleted and the process repeated at a lower speed (e. g. 4X) until all the separate files have been successfully written.

Once the first file Fl has been fully written to disk (i. e. has also been checked) then it will be possible to commence playback whilst the rest of the input stream from CD is still being processed and written to disk. Each separate stream of audio (whether for on-air playback or PFL) will require its own output buffer RAM memory region 401, 402, which will store approximately 5 seconds of audio. The output buffer memory regions 401, 402 may be separate memory modules (possibly located on the audio card) or may be discrete regions of a common memory e. g. the RAM associated with processor 500. to output buffer memory region 401 could already be playing back a different track which previously existed on disk. Small portions of the separate audio files Fl, F2, F3... are read at nX real time eg 15X or 20X real time to output buffer memory region 401 where they are reassembled into a continuous data stream 404 (TRACK F) which is played out in real time to external audio interface 4.

Similarly small portions of separate audio files Gl, G2, G3.... G6 which have been written to disk from another track G of the CD are read at nX real time to output buffer memory region 402 where they are reassembled into another data strream 405 which is similarly played out in real time as track G. The maximum level data (in respect of each track F and G) determined from the above processing is also fed to the audio card (not shown) of the PC and used to control the modulation levels of the respective digital signals in order to ensure optimum transmission.

Referring to Figure 3A, which shows the reading and writing operations of the CD (which generates the input stream 100), the hard disc 20, the RAM buffers 401 and 402 and the microprocessor RAM 403 at successive intervals between times tO and tl8, the above process will be described in more detail. Where a reading or writing process is faster than real time (n times real time) this is indicated by (nX). All the other reading and writing processes not qualified by" (nX)" are in real time.

As noted above, the CD is read at a rate of nX real time, eg 15 times faster than real time and this digital audio stream is read at the same rate to RAM 403 during period tO-tl. At the same time, RAM 403 is read and the resulting stream is written to hard disc 20 (after checking for data integrity and level) as an audio file Fl containing e. g.

30 seconds of audio.

In the second period tl-t2 an initial portion of audio file F1 is read from hard disk 20 to RAM buffer 401 where the resulting portions of the file reassembled and read out as real time audio stream 404. Thus playback of track F begins at tl, which may be only a few seconds after reading the input stream 100 from the CD. It should be noted that any combination of audio files (including files previously written) can be read from disk 20, distributed between the RAM buffers 401 and 402 and reassembled in any order under microprocessor control, so that, for example, tracks from the CD can be played simultaneously as separate output streams and can be played in a different order from that of the CD. During this period a further audio file F2 is written to disk 20 whilst Fl is being read. There may be a rapid alternation between reading and writing to disk during this period or the reading and writing can be truly simultaneous by virtue of the multi-tasking capability of the operating system.

In the third period (t2-13) a similar process occurs, the only difference being that a new file F3 is written to disk whilst the RAM buffer 401 still has enough data left to continue reading out the initial portion of Fl in real-time. It is assumed for the sake of simplicity that there are only six 30 second files F1 to F6, which correspond to track F on the CD.

In the fourth period (t3-t4) the next portion of audio file F1 is read from hard disk 20 to RAM buffer 401. During this period a further audio file F4 is written to disk 20.

In the fifth period (t4 - t5) a new file F5 is written to disk whilst the RAM buffer 401 still has enough data left to continue reading out the subsequent portion of Fl in realtime.

In the sixth period (15 - t6) the next portion of audio file F1 is read from hard disk 20 to RAM buffer 401 as real-time playback continues at output stream 404. During this period the final audio file F6 is also written to disk 20.

In the seventh period (t6-t7) all the separate files have been written to disk and realtime playback will continue via RAM buffer 401.

In the eighth period (t7-t8) another track from a CD is written to disk as file Gl.

Playback of file Fl continues as the next portion is read from disk and written to RAM buffer 401.

In the ninth period (t8-19) the next portion of the CD track is written to disk as file G2. Playback of file Fl continues via RAM buffer 401 and the initial portion of file G1 is written to RAM buffer 402 where it can be output in real-time. This playback of track G begins at time t9.

This process continues for the next few periods until tl3-tl4 when all files G1-G6 have been written to hard disk 20. It should be noted that due to the high speed transfer of data (assuming a transfer speed of 15 times real-time and a disk lile duration of 30 seconds) it is not until period tl5-tl6 that the initial portion of file F2 is read from disk and written to RAM buffer 401.

The sequence shown in Figure 3B is similar to that of Figure 3A except that it is assumed a scratch (corresponding to a sequence of identical samples) is detected in the CD during writing file F2 to hard disk 20 during the second period tl-t2.

Accordingly this file is re-written at a lower speed (n'X) real time (e. g. 5X) in the third period t2 to t3. It should be noted that playback of file Fl had already commenced in the period tl-t2.

It can be seen from comparing Figure 3A and 3B that as the defect was discovered in the second portion of the input stream (i. e. in file F2) playback of file F1 has not been affected at all and can still playback in real-time via RAM buffer 401. As mentioned before, it is not until period tl5-tl6 that file F2 is read from disk and written to the RAM buffer, so there is sufficient time to download file F2 without defects as shown in Figure 3B.

The main advantage of downloading to separate temporary files Fl, F2, F3... is that playback can commence once the first file (i. e. 30 second portion) has been fully written to disk thus giving only a few seconds'delay (eg about 1.5 seconds in this case) from inserting the CD to starting playback. The other advantage is if there is a scratch on the CD at 4.05 (for example) then only the affected 30 second portion (between 4.00 and 4.30) has to be downloaded again rather than the whole track. This is especially important if that track has started playback on-air before having been fully downloaded.

The peak audio levels for each file Fl, F2, F3... are stored in RAM and when all sections have downloaded the section with the highest peak audio level is used to decide whether extra gain should be introduced upon playback. If playback on-air (as opposed to PFL) has commenced before all the sections have been downloaded then default gain will be used.

The concept of downloading all CDs to hard disk introduces another preferred

innovative feature that conventional CD players will never be able to match. Because the desk's routing is effectively controlled by software, it will be possible to listen to the end of any track using the PFL (Pre Fade Listen) facility (provided by one of the buttons B shown in Figure 4) while the same track is currently playing out to air. The same will be true for commercial break stacks and jingles.

Downloading to disk whilst checking for sequences of identical samples as described above has another advantage: CDs will never skip on air. Testing has shown that even downloading at 8x real time has resulted in perfect rendition of tracks which are otherwise unplayable on some conventional CD players.

Because the system checks the peak level of the selected track, additional gain can be automatically added for quiet tracks upon playback. If the track starts to play on- air before totally downloaded (and therefore before it is fully checked for peak level) then the default gain will be used but the peak level value will still be written to the audio file generated and will be used if the track is played in the future.

Several radio stations choose to edit tracks before broadcasting (either for removing bad language or to fit in with the station's style). When the track is first edited a data file is usually generated called an EDL (Edit Decision List). In accordance with a preferred feature of the invention the new edited version is automatically recreated when the original CD track is reloaded by using the EDL data. This effectively means that tracks which require editing before playback can be treated in the same way on the system as non-edited tracks.

In accordance with a further preferred feature, when a track is loaded in from CD, the present arrangement will automatically look up the programme schedule for the next four days (or other specified time) and check whether any track (s) from the same CD are scheduled. If they are to be played and currently have a MISSING status then they are also loaded to disk immediately after the original track has been downloaded.

For example, the breakfast show disc jockey scrolls down the schedule and sees that the next track to be played is Track 5. The status column displays MISSING so he puts the requested CD into the CD-ROM drive. Track 5 immediately starts to download to hard disk 20.

Meanwhile the program loaded in computer 1 finds that in three days time the late evening show is scheduled to play track 8 from the same CD, the status on this track is also MISSING. So, once Track 5 has finished downloading, the arrangement automatically downloads Track 8 for future use. Because this process is so quick

(around 15 seconds), the breakfast show disc jockey will probably be unaware that the extra download ever happened.

A couple of days pass, and the late show disc jockey is doing his show (maybe in a different studio, maybe even on the station's alternative output). He scrolls down the schedule, sees that Track 8 is scheduled. The status of the track is AVAILABLE. He hits the LOAD button on DISC 2 and instantly plays the track to air that the breakfast show disc jockey unwittingly loaded in for him.

Even though each extra track for future use will only take about 10-15 seconds to download there is of course the option to cancel the extra loading if the on-air disc jockey needs to get on with loading his own tracks. In this case the future event will still show MISSING on the status line and will have to be loaded from CD during the show.

The preferred arrangement also features automatic track storage management. Once a track has been played out on-air, the automatic track storage facility will check the programme schedule for the following period e. g. four days and see whether that track is played again (even if it appears on the programme schedule for the station's alternative output). If it is to be played again within this specified time then the track is kept on the system and will be displayed as AVAILABLE on display area D when the disc jockey comes to play it in the future. If it is not played again then the track is deleted from the hard disk automatically. So for instance, if it is played again in two weeks time the track will have to be loaded from CD. It makes little sense to have tracks sitting around on the system and using disk space if they are rarely played.

Playlisted tracks are the exception to this; they will remain on the system until manually deleted by the system administrator.

This automatic and unique way of limiting the number of music tracks that need to be stored on the hard disk at any one time is a major advantage of the preferred embodiment. It essentially gives the station all the flexibility of a hard disk based system without the disadvantages of a member of staff required to load all the tracks onto the system and the ever increasing amount of disk storage required to hold the tracks.

It should be pointed out that the preferred embodiment allows tracks to be loaded in advance without loading into a virtual player. This can either be done on the same system or on a separate PC, which has a fast CDROM drive and is networked to the main hard disk storage. If tracks are loaded in advance in this way, each track will be directly downloaded as one complete file rather than numerous temporary files.

Differently scheduled tracks from the same CD would be loaded at the same time.

Referring now to Figures 4 and 5, the mixing module 5 is typically in the form of two mixing panels 5L and 5R (Figures 4 and 5 respectively) mounted in a desk (not shown) with space for scripts etc in the middle. The panels are ergonomically angled towards the disc jockey and are divided horizontally into channels Cl to C7 and C8 to C13 respectively as described above. Each channel has a standard fader F that is also motorised and also has illuminated pushbuttons B for LOAD, AUTO, CUE, PFL (Pre-Fade Listen) and START.

The channels are modular so different requirements can easily be accommodated.

The illuminated pushbuttons will differ according to the type of channel.

The channels Cl to C13 (Figures 4 and 5) are (from left to right): Cl EFFECTS (internal effects output from audio card) C2 DISC 1 C3 DISC 2 C4 DISC 3 C5 MIC 3 C6 MIC 2 C7 MIC 1 There is then a script space between two panels, followed by: C8 QUICKFIRE C9 AUX 1 C10 AUX 2 C11 CART 1 C12 CART 2

C13 CART 3 The function of a mixer channel C2, C3 or C4 (Figure 4) or Cl1, C12 or C13 (Figure 5) will now be described. The CD track or cart can be started by pressing the START button B which will illuminate green when in playback mode. If the CUE button B is pressed then the track will stop playback and reset to the chosen start point (which is by default the start of audio but can be changed) the CUE button will illuminate amber when reset and ready.

If a channel has its AUTO button B lit then its associated player will automatically start after the previous event finishes. Players will automatically start in order from left to right but if any carts have AUTO activated then they will take priority over discs.

For example if Disc 1 is playing and both Disc 2, Cart 1 and Cart 2 are loaded and have their AUTO buttons lit, when Disc 1 finishes, the players will automatically start in this order: Cart 1, Cart 2 followed by Disc 2.

The QUICKFIRE fader will be described subsequently.

Behind mixing panel 5L is touchscreen colour monitor 6, which has three virtual CD players VP1, VP2 and VP3 at the bottom of its screen aligned with channels C2, C3 and C4 respectively. Similarly touchscreen monitor 7 has virtual cartridge players VP4, VP5 and VP6 which correspond to and are situated directly above the CART 1- 3 channels (Cll, C12 and C13) on the right hand mixing panel 5R. Uniquely, the disc jockey can see at a glance which player is operating and the state of its associated mixer channel.

Each on screen virtual player has a current status display L at the bottom (which shows READY/PLAY/PAUSE etc) and above that is a visual display Dl of the current position (time) within the audio file. Above display Dl is a representation VI of the disc being played by each virtual player with audio file details displayed such as track title and artist. Display Dl displays either an E (for tracks that end suddenly) or an F (for tracks that fade out). Intro countdowns are displayed with tenths of a second displayed after the"seconds"display. All the above timing information is either included as part of the music schedule data or is retrieved from the station's CD library database.

As shown in Figure 4 and more clearly in Figure 6, above the virtual disk players on the left hand screen 6 are six"soft"buttons SB1 to SB6 (i. e. touch-sensitive regions

of the screen) arranged horizontally across the screen. These allow control of the 0 software and their functions will change depending on what mode the screen is in.

The following description relates to the default or"NORMAL"mode.

Above the soft buttons is the main programme schedule S (Figures 4 and 6) which can be scrolled up and down with the trackball (not shown). This central area is also where scripts which are to be read by the disc jockey will appear when required. The programme schedule area S contains information for each programmed event such as source, status and title.

The status displayed for each event will be one of the following : i) ON AIR-the event (track/cart/commercial etc) is currently being broadcast on air. ii) READY-the relevant event has been loaded into a player and is ready to be played on-air. iii) AVAILABLE-the event already exists on the hard disk/s for loading into a player. iv) MISSING-only applies to tracks downloaded from CDs-the event is NOT currently on the hard disk/s and will need to be downloaded from CD.

If the LOAD NEXT soft button SB 1 is pressed then the next AVAILABLE event, which is not either on-air or ready, is automatically loaded into the next available player of the correct type (whether disc or cart event). The event's status will change to READY and the disc/cart can be previewed on PFL (Pre-Fade Listen) or played out on air immediately.

If the LOAD NEXT soft button SB I is pressed and the next event which is not either on-air or ready is shown as MISSING then the drawer of the CD-ROM player 3 will automatically open so the correct CD (as identified under the SOURCE column) can be inserted.

The system will check that the correct CD has been inserted (by reading the CD's serial number and/or index information) and will automatically start downloading the correct track in the manner described above with reference to Figures 2,3 and 3A.

Within a few seconds the channel's CUE button will illuminate, the artist/title will be displayed on screen, relevant timings will be displayed (on Dl and D2) and when the downloading (including re-recording of any files with faults) has been completed satisfactorily the event's status will change to READY on both the programme schedule and the player's status display L.

The fact that the track title will be displayed on the player above the relevant channel

greatly reduces the chance of the disk jockey starting the wrong player by accident.

If the disc jockey wants to play a track not on the programme schedule then he presses the LOAD button B (Figure 4) on the desired player and can choose to either insert a CD for downloading or select from the library of tracks already held on hard disk. Tracks/carts are ejected from the virtual players by holding the CUE and LOAD buttons B (Figure 4) at the same time.

Above the programme schedule area S is displayed the current time in written form (e. g. twenty-five minutes past four) and also digital form with seconds. There is also a countdown in minutes and seconds until the next top of the hour (eg minutes and seconds remaining until 4. 00pm exactly).

Referring to Figures 5 and 8, the right hand portion 5R of the control panel and associated touch screen monitor 7, which are used for playing virtual cartridges, will now be described. Above the virtual cart players VP4, VP5 and VP6 (which function identically to the virtual disc players VP1 to VP3 apart from not displaying whether a track ends or fades) on the right hand screen 7 are displayed representations V2 of the virtual cartridge being played by each virtual player with audio file details displayed such as track title and artist which are analogous to the representations VI of Figures 4 and 6. Above these are displayed three"next slots"V3 which similarly represent the next cart to be played after the current cart for each player when carts have been stacked up in sequence. Above the"next slots"is displayed a virtual cart library R.

There are provided: i) Virtual carts which are light blue in colour and as their name suggests, contain a single audio file, and ii) Virtual stacks, which are green in colour and contain a group of carts. These are ideal for commercial breaks so several carts can be grouped in advance onto a single stack.

Because each cart player is virtual it can have differently routed outputs according to requirements, so catering for split-frequency stations is no problem. For instance both AM and FM commercial stacks could be played from a single cart/stack, be controlled from the same fader whilst still going to the separate respective outputs.

Additionally, the system features a MASTER PFL mode, selected by button 90 on panel 8,} which allows the disc jockey to do a completely different mix on the

prefade output without affecting what is going out on the main mixer output (i. e. on air). A screenshot of MASTER PFL mode is shown in FIGURE 10.

In the default mode, each channel's PFL button B (Figures 3 and 4) works in a conventional manner for previewing tracks and carts etc. However when the MASTER PFL mode is selected the faders F of any on air sources will physically close (all the faders are motorised for this purpose), and currently loaded players will empty. This allows the disc jockey to pre-record a telephone call, promotional script etc using any of his sources. He can even use the same players that are currently playing a track/cart to air on the main output.

In order to alert the disc jockey that MASTER PFL is on (so he does not mistakenly believe that what he is listening to is being broadcast) the layout of the schedule screen S will change. The event currently on-air will move to the top line 300 and the next three events will be displayed below. The fifth line 301 will change to a blue colour and display"Master Prefade On"which will move across the screen. This fifth line will also help separate the on-air events from every other event displayed below which can be scrolled up and down as described above.

Once the disc jockey has finished and switches MASTER PFL off, the faders return to their original position to display the on-air output.

MASTER PFL also provides the facility to record segues (in the manner of a script for controlling a program with a pre-recorded series of commands) which are further down the programme schedule. Everything that the disc jockey does will be remembered and recalled at the appropriate time when the arrangement is using the FULL AUTO facility.

In order to do this the disc jockey scrolls the schedule in region S of screen 6 (Figure 10) to a transition line TL (found between two events) and presses RX TRANS button SB5 on this screen. The desk will instantly switch into MASTER PFL mode and the players will automatically be loaded with the outgoing and incoming track plus any cart's specified in the transition.

The disc jockey will then press RECORD button 82 and the last 20 seconds or so of the outgoing track will start playing. In addition the clock displays will change to show what the time really would be at this point in the future. Thus"time checks"in the future are provided for. If the disc jockey just wants to do a straight music segue, the program will remember the point the next track was started and all the fader positions when it comes to the actual on-air time. If the disc jockey wants to do a link, then opening either mic fader F will automatically start recording the mic

output which will be later replayed as a cart. If he is not happy with the result, he can keep recording the transition until satisfied.

The above process is completely transparent and allows the disc jockey to record some of his show in advance, including links if he wishes. It is believed that no other system currently offers this degree of flexibility and ease of use.

Additionally, a FULL AUTO function can be selected by toggling a full auto/manual button 180. The system will follow the schedule in column SC of region S of the left hand screen 6 (Figure 4), load tracks and carts and automatically transition between events. The background of the clock area T of the left hand screen will change to red when full auto mode is activated.

I The right hand screen 7 operates in three basic modes: i) In LIBRARY mode as a cart library (selected by LIBRARY button 80 on the master control panel 8) to select which cart to load into the player. A screen shot of LIBRARY mode is shown in Figure 7. Each page holds 18 carts as shown in region R and pages are scrolled through using navigator buttons N. To load into a player, the LOAD button B is pressed on the desired player's channel and the required cart touched on the screen. It is also possible to load more than one cart into the same player at the same time. This is done by continuing to hold down the LOAD button B whilst the required cart is touched on the screen. If multiple carts are loaded into the same player this way, they will stack vertically (the next one to play now being visible in the"next slot"V3) and can be viewed and reordered by switching to, STACKS mode as described below.

Carts can also be played out directly from the library on the QUICKFIRE fader channel C8 just by touching the title. More than one cart can be played simultaneously in this mode but all carts will appear on the QUICKFIRE fader. Once a cart has been started on the QUICKFIRE fader, the label will change to a countdown of remaining time. A second touch on the playing cart will fade it out.

Panel 8 features four navigation buttons N which are used to navigate horizontally and vertically through the cart library screens when in LIBRARY mode. ii) In STACKS mode (as shown in Figure 8) for viewing the progress of cart stacks (selected by STACKS button 81 on the master control panel 8). This will display the stack title ST at the top (only in the case of a pre-programmed stack having a title) and below that is a pile of the carts contained within the stack. There is also a CHAIN button CH which when touched ensures that each cart in the stack will

automatically play in sequence after the previous cart finishes. The bottom cart in the stack will drop into the player and the stack will move down. Some stations like the ability to reorder the carts in a stack at anytime before playing to air, which is made possible in this mode by simply dragging the carts to a new position within the stack. iii) In RECOPT1 mode (selected by button 82) for recording to hard disk. A screenshot of RECORD mode is shown in Figure 9. It is possible to select any number of sources for recording and there are provided controls 100,101, 102,103, 104 and 105 for REWIND, STOP, PAUSE, PLAY, RECORD and FAST FORWARD respectively. It is also possible to provide an editing screen for editing the recorded audio by touching an EDIT button 106. The edit screen may be conventional and therefore is not shown. A SAVE button 107 is provided for saving the recording.

It should be noted that although an embodiment has been described in which a hard disk is used as the mass storage, any non-volatile memory of sufficent capacity for audio or video is suitable; other non-disk based memory types may become available in the future.

Claims

1. A digital audio or video playback arrangement comprising at least one physical control panel which is aligned with and controls a virtual audio or video player represented on a display.

2. A digital audio or video playback arrangement as claimed in claim 1 comprising two or more fader panels aligned with respective audio or video players represented on a common display.

3. A digital audio or video playback arrangement as claimed in claim 1 or claim 2 wherein one or more of the following items of information is arranged to be displayed in association with a virtual audio or video player on screen: operational status of the virtual player, title of track being played, timing information relating to such a track, and tracks available for playback.

4. A digital audio or video playback arrangement as claimed in any preceding claim wherein the display is a touch-screen display having virtual buttons enabling the user to control each virtual audio or video player.

5. A digital audio or video playback arrangement as claimed in claim 4 wherein two or more modes of operation of the players are selectable by the user and the controls and/or information relating to an audio or video player displayed on screen change according to the mode selected.