FR2466072A1 - Digital video and audio recording and reproducing equipment - uses tape with common audio and video track, with expansion and compression circuit stages - Google Patents

Abstract

The video tape recorder using spiral video signals, uses the same track to carry the video signals and also sound signals, consisting of four sets of signals. This leaves room for two conventional tracks along one edge and further control tracks for coding, synchronising and control along the other edge. The tape is used with digital systems for recording and reproducing the video and audio information. These systems use compression and expansion circuits respectively. A digital reproducing system can have recording heads for video and audio signals at positions spaced along the tape, connected to respective reproducing systems. Both video and audio information can be compressed so that compatible signals can be obtained for reproduction, using a switching system and memories for storing the signals, and a synchronising system for reproduction.

Description

Recording and / or playback systems are known where analog video information is recorded on longitudinal and continuous tracks on a tape, or on intermittent tracks at a prescribed angle to the direction of movement of the tape as in systems. quadruplex and helical scanning. In these tape systems, each channel of audio information is typically recorded at the baseband on a longitudinal track separate from the tape. These audio tracks are completely independent of the video tracks of the tape and therefore the audio and video information can be edited or edited independently. However, separate audio and video tracks require the use of separate audio and video transducers to record and output information.

Digital recording and / or playback systems where audio and video information are recorded on independent tracks are also possible.

In general, video information will be digitized and recorded at the wavelength limit in the required number of tracks with a rotary transducer as in current quadruplex or helical analog machines. Each audio channel will be digitized and recorded longitudinally in the required number of parallel tracks. Since it is desirable to decrease the use of the belt, however, such machines generally operate at relatively slow linear speeds of the belt. The wavelength recorded on the tape is equal to the relative speed between the recording transducers and the tape, divided by the recording frequency. The minimum recorded oncial length is determined by the size of the space in transducers and the limit frequency at which the polarization of the magnetic particles in the strip can be changed. Consequently, if the headband speed decreases for a given channel bandwidth, the minimum wavelength criterion can be exceeded and more parallel tracks operating at a lower frequency are required.

Separate audio and video heads, and all associated electronic recording and playback circuits can be avoided by multiplexing audio information in digital form with video information in digital form during the recording process. However, the individual audio channels and the video channel will no longer be separated and therefore there will no longer be any possibility of independently editing or editing these channels.

The audio and video information can also be recorded simultaneously on the same tracks of the band, the audio information being recorded in the form of an FM modulation of a carrier, the audio information being directly recorded on the base band. In such an arrangement, however, the FM carrier cannot be used at saturation to obtain a maximum video signal-to-noise ratio because such saturation can distort the audio signal. Of course, this system also does not allow channels that can be mounted or edited independently.

According to a preferred embodiment of the invention, compatible audio and video information is formed to be in separate locations along the same tracks of the tape. An essentially traditional head and an electronic recording / restoring circuit can be used to accomplish multiplexing while obtaining the capacity to independently mount this information. Space is obtained on the tracks by compressing the audio and video information over time before recording it on the tape and by expanding the audio and video information over time when it is restored from the tracks on the tape.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating several modes. of the invention and in which:
- Figure 1 illustrates the format of the tracks of the strip according to a preferred embodiment of the invention;
- Figure 2 gives a block diagram of a tape recording and playback system (not shown in its entirety) to use the format of Figure 1
- Figure 3 gives a block diagram of a more specific embodiment of the compression means in the system of Figure 2
- Figure L gives a block diagram of a more specific embodiment of the expansion means in the system of Figure 2; and
- Figure 5 gives a block diagram of a television recording and playback system where the number of tracks in a sequence in relation to an individual image is not equal to the number of audio channels.

As previously indicated, compatible segments of separate video and audio information are recorded on separate tracks in most of the traditional tapes which are used in current recording and / or playback systems.

In the tape format according to the invention, compatible audio and video information is recorded at separate locations along the same tracks of the tape.

Although this format can be used in recording and / or playback systems for scanning or longitudinal scanning or quadruplex scanning, FIG. 1 shows a preferred embodiment for use in recording and / or playback systems using helical exploration or scanning. the format of the tracks of figure 1 differs from the traditional format (as in the society of the engineers of cinema and television to the fats
United States of America, type C), because information from a number of separate audio channels is incorporated with compatible video information on the same tracks in the band that are normally reserved for video information only. Consequently, the space along the edge of the tape which is normally reserved for audio information is available for other purposes and can be designated by CODE INDICATION / TIME "(a), TRACK SYNCHRONIZED
SATION "(b)," TRACK CONTROL "(c), and" SPACE FOR TWO
LONGITUDINAL TRACKS "(d) in figure 1; in this figure also the letter e indicates the video tracks and a letter f indicates the audio channels n0 1, 2, 3 and 4.

Those skilled in the art will of course note, without further explanation, that the format of the tracks according to the invention is not limited to that shown in Figure 1.

To use the tape format according to the invention, digital means for recording audio and video information at separate locations along the same tracks is incorporated in the recording system, while digital means for reproducing the video information and audio from separate locations along the same tracks is incorporated into the playback system,
Figure 2 shows preferred embodiments of such digital recording and playback means, in the form of separate parts of a recording and playback system which is not shown in its entirety.

The digital recording means comprises a compression means 10 for condensing the audio and video information relative to their value in real time according to the length of the tracks of the tape so that compatible audio and video information can be recorded on separate parts. along each track. The digital restitution means comprises a dilation means 12 for extending the audio and video information restored from the separate parts along each track in order to restore their value in real time. The actual number of audio information channels recorded with video information on each track is limited by the magnetic wavelength of the tape; however, the magnetic characteristics of the tape continuously improve and the tape-to-head speeds decrease , so more than the four audio information channels shown in Figure 1 can be recorded.

In FIG. 2, the video and audio information are recorded on the tape and / or are restored by a scanner or exploration means 14 which traditionally comprises a wheel with heads (not shown) having transducers arranged around its periphery. The scanner 14 operates in cooperation with a tape transport system (not shown) in order to explore the tracks on the tape in recording, playback or erasing mode.

Separate memories are used in the compression means 10 in order to condense the audio and video information before recording it on the tape. The video information is put in digital form as an 8-bit parallel format and is applied to a video recording memory 16. Each channel of the audio information is also put in digital form as a 14-bit parallel format and is applied to an audio recording memory 18. A video recording sampling clock 20 and a video compression clock 22 respectively, determine the paces at which the real-time information is written and the information condensed in the time is read relative to the video recording memory 16. An audio recording sampling clock 24 and an audio compression clock 26, respectively, determine the rates at which the real-time information is written and the information condensed in time is read in relation to each audio recording memory 18. The video and audio inputs are also applied to the sampling clocks 20 and 24, respectively, for synchronization purposes.

The paces or frequencies of the sampling clocks 20 and 24 are lower than the paces or frequencies of the compression clocks 22 and 26 respectively, thus the durations of the video and audio information passing from the memories 16 and 18 are condensed relative to the values in real time. . These clock speeds or frequencies will depend on the frequency of the video and audio information, as well as on the number of audio channels to be used. For convenience, only one audio memory 18 is shown in Figure 2, however three other similar memories will also be required for the tape format of Figure 1, which incorporates four audio channels. All audio channels will normally use the same 24 and 26 sampling and compression clocks; however, individual clocks for each channel may be used where particular information compression ratios are desired to accommodate data discontinuous or burst type
The time-condensed video and audio information at the output of memories 16 and 18 is applied to a recording switching means 28 to sequentially trigger this information towards each track of the tape through at least one transducer on the scanner 14. Means 30 for synchronizing the video and audio recording memories 16 and 18 with the position of the scanner 14 are also incorporated in the compression means 10.

This synchronization means 30 applies a signal of
control by means of record switching 28 and force the video information to other recorded on a part
and audio information on another part of each track on the tape.

Separate memories are also used in the expansion or extension means 12 to extend the
time-condensed audio and video information at
their value in real time. Condensed video information
in time is applied to a restoring memory
32 and each channel of audio information condensed in
time is applied to individual memory of
restitution 34 by a restitution switch means 36
in order to sequentially trigger information from
each track of the strip through at least one transducer
on the scanner 14. A means 38 for synchronizing the memories
32 and 34 video and audio playback with position
of the scanner 14 is also incorporated in the dilation means 12 and applies a control signal to the restitution switching means 36, yes separates each zest of the strip into parts of the time-condensed information relating to the video channel and at each audio channel.

A video playback sampling clock Lo and a video expansion clock 42, respectively, determine the frequencies or paces at which the time-condensed information is written and the real-time information is read relative to the playback memory video 32. An audio playback sampling clock 44 and an audio expansion clock 46, respectively, determine the paces or frequencies at which time-condensed information is written and real-time information is read relative to The audio pace or frequencies of the sampling clocks 40 and 44 are greater than the frequencies of the expansion clocks h2 and 46 respectively, thus the durations of the video and audio information passing from the memories 32 and 34 are extended to restore their value in real time.

These clock frequencies will also depend on the frequency of the video and audio information as well as the number of audio channels to be used. For ease of reference, only one audio reproduction memory w4 is illustrated in FIG. 2, however, three other of these memories will also be required for the tape format of FIG. 1 oh 4 audio channels are reproduced. All audio channels can use the same sampling and expansion clocks 24 and 26 or individual clocks for each channel can be used when particular information expansion reports are desired.

In recording and / or playback systems for helical scanning television, each successive Xm chaawue or predetermined segment of the video information is recorded on a number of sequential tracks of the tape. Such recording and / or restitution systems can also be adapted to the tape format according to the invention. Digital means for recording video and audio information at separate locations along each track in each sequence of a track will be incorporated into the recording unit, while digital means for rendering video information and audio from separate locations along each track in each track sequence will be incorporated into the playback unit. Figure 3 shows an embodiment of the digital recording means where a compression means 50 is provided for condensing the information audio and video relative to their real-time value along the length of the tape tracks so that compatible audio and video information can be recorded on separate parts along each # p1s # of each sequence. FIG. A shows a preferred embodiment of the digital reproduction means, which comprises a dilation means 52 for spreading the audio and video information condensed in time on the parts separated along each track in each sequence at their time value real.

For each track of the tape in each sequence, the compression means 50 of FIG. 3 condenses the video information and each channel of the audio information by means of a separate memory. Real-time video information for each track in each sequence is applied to a video recording memory 54 by video multiplexing means 56 to distribute information from a digital video input to each track in each sequence by memories video recording 54. The nature of the recording memories 54 depends on the processing format chosen, for example, only one input and output terminal will be necessary for the serial information or a certain number of terminals d input and output will be required for parallel information. A clock 58 and a divider 60 attacked by it, are connected by means of multiplexing 56 and cooperate with it to distribute digital video information to the number of tracks in each sequence .

The frequency of the clock 58 is the same as that at which the digital video information is sampled and the divider 60 divides the frequency of the clock 58 by the number of tracks in each sequence. The divider 60 is also provided for writing the information in real time in the recording memory 54, three times a time transition clock 62 is provided for reading the information condensed in time in the recording memory 54 The frequency of the time transition clock 62 is higher than that of the divider 60 and therefore the information passing through the memories 54 is condensed with respect to the value in real time. The information condensed in time goes from each video recording memory 54 to a coding and digital formatting means 6E to effect correction or concealment of the error. The clock 62 is moreover connected to a training clock 66 and cooperates with it to let the information pass by the coding and digital formatting means 64 towards a recording switching means 68 for introduction of the video information. and audio in the tape scanner 70.

It will be noted that a synchronization signal is applied to the clock 58 and to the time transition clock 62 to reference the video information recorded at its source.

Furthermore, for convenience, only a combination of recording video memory 54 and recording switching means 68 is illustrated in Figure 3 for a single track in the sequence and similar combinations for each other track in the sequence will be required.

Each channel of the digital audio information in real time for each track in the sequence is applied to an audio recording memory 72 by a coding means 7h in order to effect correction or concealment of the error. The nature of each memory 72 also depends on the processing format chosen, for example a single input and output terminal will be necessary for information in series or else a certain number of input and output terminals will be necessary for information in parallel. The real-time information passes through the coding means 74 and is written in the recording memory 72 at a frequency or pace determined by a clock 76 having the same frequency as that at which the digital audio information is sampled. time transition clock 82 is provided for reading the time-condensed information from the recording memory 72.

The frequency of the clock 82 is higher than that of the clock 76 and therefore the information leaving the audio recording memories 72 is condensed with respect to the value in real time, in proportion to the ratio of these clocks. The time-condensed information is applied to the recording switching means 68 by digital formatting means 84 to distribute the audio information of the channel in series to the number of tracks in the sequence and to produce a format in serial when a parallel processing format is used.

The output signals from a speedometer 78 of the scanner and of the clock 76 are applied to an audio trigger signal generator 80 whose output is connected to the recording switching means 68 and to the transition clock 82. The information passes through the digital shaping means 84 at a frequency determined by the transition clock 82 and an audio shaping clock 86 which is thus attacked.

Note that the synchronization signal is also applied to the time transition clock 82 to reference the audio information recorded on its source.

Furthermore, for convenience, only one audio recording memory 72 for a single audio channel is shown in Figure 3 and additional audio channels will require an additional audio recording memory 72, while each track in the sequence will have a separate input to the record switching means 68 as previously explained.

For each track of the tape in the sequence, the expansion means 52 of FIG. 4 * indicates the video information and each channel of the audio information by means of a separate memory. The time-condensed video information for each track of the tape in the sequence is applied to a video playback memory 90 for coding and digital formatting means 92 in order to produce a correction or concealment of the error. . The nature of the playback memories 90 depends on the processing format chosen in the same way as described above for the video memories 54. The video information condensed in time is applied by means of coding and formatting. digital 92 by a switching switching means 9 for the passage of video and audio information from the tape scanner 70. The output signals of the time transition clock 62 and the shaping clock 66 are applied for determining the frequency or pace at which the information condensed in time passes through the coding and digital formatting means 92 and is written in the playback memory 90.

The signal at the output of the clock divider 60 is applied to determine the frequency or rate at which the real-time information is read from the playback memory 90 for application to a multiplexing video means 100 in order to accumulate the video information of each track in the sequence to a digital video output. As the frequency of the time transition clock 62 is higher than that of the divider 60, the time condensed information which enters the video playback memories 90 is extended in proportion to the ratio of these clocks, so the time value audio information is restored. The signal at the output of the clock 58 and that at the output of the divider 60 are applied by means of multiplexing 100 for passage of the video information in real time in series of the number i tracks from sequence to digital video output.

As the expansion means 52 must extend the video information inversely in proportion to the amount of condensation by the compression means 50, the clocks 58, 60, 62 and 66 are common to the expansion and compression means 52 and 50. Furthermore, for the facility, only a combination of a memory 90 for video reproduction and a switching switching means 94 is shown in the figure, for a single track of 7 sequence and similar combinations for each of the other tracks of the sequence se # required. Each channel of the audio information condensed in time of each zest of the sequence is applied to an audio playback memory 104 by a digital formatting means 106 to accumulate the audio information in series of this channel. , coming from the number of tracks in the sequence. The nature of the playback memories 104 depends on the processing format chosen as described above for the audio recording memories 72. The time-condensed audio information is applied by means of digital formatting 106 by the means switching switching 94. The signals at the output of the shaping clock 85 and the time transition clock 82 are applied to determine the frequency at which the information condensed in time passes by means of digital formatting 106 and is written in the playback memory 104. The signal at the output of the clock 76 is applied to determine the frequency at which the real-time information is read from the playback memory 10h by an output digital for the channel by a decoding means 108 in order to allow correction or concealment of the error. As the frequency of clock 82 is higher than that of clock 76, the information condensed in time s which enters the audio reproduction memories 10 ′ is extended in proportion to the ratio of these clocks, so the real-time value of the audio information is restored. The signal at the clock output 76 is also applied by means of decoding 108 to pass the passage of the audio information in real time in series towards the digital output for the audio channel.

As the expansion means must extend the audio information inversely proportional to the amount of onpntion by the compression means 50, the clocks 76, 82 and 86 are common to the expansion and compression means 52 and 50. Furthermore, for ease , only one audio playback memory 104 for a single audio channel is shown in Figure 4, and additional audio channels will require additional playback memories 104, while each track in the sequence will have separate playback switching means 94 as we explained it previously.

In FIGS. 3 and 4, the number of tracks of the tape which is incorporated in each sequence relating to an individual image is not determined by the number of audio channels. To illustrate this, Figure 5 gives a block diagram of a television recording and playback system using a sequence of two tracks per picture but with three audio channels. Each audio channel is distributed across all available tracks in the sequence, whether that sequence has only one track or ten tracks. In FIG. 5, the letter a designates a video input, b the video output, c the recording switch, d the playback switch, e the audio channel input 1, f the audio channel input 2, g l ' audio channel 3 input, h audio channel 1 output, i audio channel 2 output, j audio channel output s and k the scanner.

Of course, the invention is in no way limited to the embodiments described and shown which have been given only? as an example. In particular it includes all the means constituting technical equivalents of the means described as well as their combinations if these are executed according to the spirit and implemented in the context of protection as claimed.

Claims (10)

RESELL T CATIONS 1. Tape for a recording and / or playback system, characterized by audio and video information arranged in separate locations along the same tracks. 2. A tape recording system using a tape format according to claim 1, characterized by digital means (50) for recording the video and audio information at separate locations along the same tracks of the tape. 3. System according to claim 2, characterized in that the aforementioned digital means (50) comprises means (54, 60, 62; 72, 76, 82) for compressing the audio and video information relative to their value in real time along the length of the tracks on the tape so that compatible audio and video information can be arranged on separate parts along each track. 4. Tape rendering system using a # tape format according to claim 1, characterized by digital means (52) for rendering audio and video information from separate locations along the same tracks of the tape. 5. System according to claim 4, characterized in that the video and audio information on the tracks of the tape are compressed with respect to their value in real time and in that the aforementioned digital reproduction means comprises a means (82, 76 , 104; 60, 62, 90) to expand the audio and video information to restore their value in real time. 6. A tape recording and playback system using a tape format according to claim 1, characterized by digital means (10, 12) for recording the video and audio information at separate locations along the same tracks of the tape and to restore audio and video information. 7. System according to claim 6, characterized in that bare the aforementioned digital means comprises: a compression means (16, 18, 20, 22, 24, 26, 18) for condensing the audio and video information with respect to their value in real time according to the length of the tracks of the tape so that compatible audio and video information of each track: and a means of expansion (36, 32, 34, 40, 42, 44, 46) to extend the audio and video information received separate parts along each track to restore their value in real time. 8. System according to claim 7, characterized in that the aforementioned compression means comprises a recording switching means (28) for triggering the video and audio information from separate digital inputs to at least one recording transducer (14 ), the time condensed video information being applied to said recording switching means (28) by a video recording memory (16), while the time condensed audio information is applied to said recording switching means (28) recording (28) tar an audio recording memory (18), and a means (s0) is incorporated to synchronize said recording transductaurs on said recording switching means: and the aforementioned expansion means comprises a means of playback switching (36) to trigger video and audio information from at least one playback transducer (14) to separate digital outputs, time-condensed video information as long as said playback switching means (76) n a video playback memory (72) while the time-condensed audio information is used by said playback switching means (36) to an audio playback memory (34), said memories (32, 34) restore the values in real time during reading, and means (38) are incorporated for synchronizing said reproduction transducers with said reproduction switching means. 9. System according to claim 8, characterized in that determined segments of editable video and audio information are recorded, each segment being recorded on a certain number of sequential tracks of the tape, in that the aforementioned compression means (50) has input means (56) for distributing digital video information to each track of said sequence by a separate combination of video recording memory and recording switching means and also includes formatting means ( 84) for distributing the digital information from said audio recording memory (72) each track of said sequence, individually, by said separate recording switching means and in that predetermined segments of compatible video and audio information are restored, each segment being restored from said sequential tracks, the aforementioned expansion means (52) comprising an output means (100) for triggering information at the digital video output of each track in said sequence through a separate combination of a video playback memory (90) and a playback switching means (91), and also comprising a means of shaping (106) for accumulating digital information of each track in said secuence ". Individually through said separate playback switching means (94) for application to the aforementioned audio playback memory (104) 10. System according to claim 9, characterized in that the audio information for a certain number of channels is recorded on each track of the aforementioned sequence the aforementioned compression means (#o) comprising a combination of the audio recording memory (72) above and the above formatting means (84) for each audio channel; and in this case audio information for a certain number of channels is restored from the sequential tracks of the tape, the aforementioned expansion means (52) comprising a separate combination of the aforementioned output shaping means (106) and the memory of aforementioned audio reproduction (104) for each audio channel