NL8101952A - DEVICE FOR RECORDING AND / OR PLAYING DIGITIZED VIDEO INFORMATION. - Google Patents

Description

T ** i C / Ca / lh / 1255

Device for recording and / or displaying digitized video information.

The invention relates to a device for recording and / or reproducing digitized video - information, more particularly on such a device, with which a color video signal in digital form is provided. and is recorded in a time-saving manner on a recording medium by means of a number of rotatable magnetic heads, respectively. is displayed from it.

As is well known, a video signal prior to recording on a tape magnetic tape is usually subjected to frequency modulation and again read out of the magnetic tape in frequency modulated form. For some time now digital video signal processing has become fashionable especially with studio equipment, which means that a video tape apparatus 15 used for this purpose must also be suitable for processing information in digital form.

Without going into further detail, ·. .here. suffice to note that the use of a digital video tape device offers several advantages.

Characteristic of the use of a video tape apparatus, however, is the need for a high recording density, for which several proposals have already been made.

For some time, attention has focused in particular on the digitization aspects of such a mode of video signal recording and reproduction.

As is well known, the digitized video information is usually divided into a number of 30 information blocks prior to recording on a recording medium, each of which contains, in addition to the digitized video information, a synchronization word, identification information, address information and CRC information .

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In order to achieve a good recording and reproducing quality, a careful choice of the number of information blocks to be used and of the number of rotatable magnetic heads to be used for recording these information blocks appears to be of great importance. Considerations aimed at obtaining the simplest possible system also play an important role. Can be made - .; ··. ··. ·. «·. /·-/.·· · ', that' these 'considerations with' hitherto * known 'schemes and systems of the type considered here have yielded insufficient results.

The present invention aims to improve upon this and to provide a new type of apparatus for recording and / or reproducing digitized video information, which better reflects the aforementioned considerations.

Another object of the invention is to provide such a device which enables both recording and reproduction of both audio and video information by means of a number of rotatable magnetic heads.

20 Starting from a device for recording and / or reproducing digitized video information, using a number of rotatable magnetic heads, which ........ t. Attached to a one-band guide drum with an outer peripheral surface along which a magnetic tape can be helically conveyed over a predetermined winding angle, and furthermore signal processing means for distributing a digitized scanning interval relating to one image line. In addition, video information in a plurality of information blocks, the invention requires that such a device be provided with means for assigning each equally numbered information block of one such image control scan interval to each of the rotatable magnetic heads for recording thereon.

The invention will be elucidated in the following description with reference to the accompanying drawing of some embodiments, to which the invention is not, however, limited. Show in the drawing:

Figure 1 shows a block diagram of an entire system 8101952-3 for application of an embodiment of the device according to the present invention,

Figure 2 shows a principle block diagram of an embodiment of a digital processing circuit on the recording side of the system,

Figure 3 shows a principle block diagram of an embodiment of the digital processing circuit on the. · Reflective side of the system, "· .. ·, ·

Figures 4 and 5 are schematic representations for clarifying the signal format used when recording a color video signal in digital form.

Figure 6 shows a principle block diagram of another embodiment of a digital processing circuit on the recording side of the system, Figure 7 shows a principle block diagram of another embodiment of a digital processing circuit on the display side of the system,

Figure 8 shows schematic representations of an embodiment of a rotatable magnetic head unit of a videotape device,

Figure 9 shows a schematic representation of an embodiment of a recording track pattern, *. . :; Figure 10 is a schematic representation of an embodiment of error visualization or mapping and Figure IX is a schematic representation of another embodiment of a recording track pattern.

The block diagram of Figure 1 relates to an entire system for recording and / or reproducing digitized video and audio information, including the possibility of "editing" using an apparatus according to the invention.

The system of Figure 1 is grouped around a digital video editing unit 1, consisting of a first DVP-1 editing unit with an analog / digital 35 converter, a digital / analog converter, and a signal generator for generating and outputting different types of clock. and time-determining signals, a second processing unit DVP-2 for processing digitized 8101952 -4- * * t · * - L—. * video signals before recording, a third processing unit DVP-3 for processing displayed or read video signals in digital form, and from an information research unit ANA for error indication or 5 mapping.

Furthermore, the system comprises a television camera 2 and two videotape devices 3 and 4, which are of normal video. w; .. tape devices. " differences for what -with regard to huri nragagnet head-. Mechanism and the associated sub-circuits.

A monitor television receiver 5 serves for visualization of read-out video information, while a monitor television receiver 6 serves for visualization of an error determined by the information research unit ANA. Furthermore, the system comprises a digital audio processing unit 7 in the form of a slightly modified pulse code modulation adjusting unit for converting an audio signal into a pulse code modulated signal suitable for recording by means of a video tape apparatus.

Between the audio editing unit 7 and the digital video tape devices 3 and 4 there is an audio switching unit 8. In the embodiment described here. .... v t .. one, .. number. .from. 16. ^ udip channels CHj-rCHjg :: applied, with pairs of microphones M ^ -M ^ g and speakers SP ^ SP. ^. In signal recording, the digitized audio information output from the digital audio processing unit 7 is selectively fed to the video tape device 3 or the video tape device 4, while during signal playback the signal read out by one of the two video tape devices is switched on via the audio switching unit 8. the digital audio processing unit 7 is supplied.

Finally, the system includes a remote control device 9 for supplying control signals for controlling the digital video editing unit 1, the video tape devices 3 and 4 and the digital audio editing unit 7 remotely.

Next, the recording and / or reproduction of a color video signal with an associated audio signal will be described in more detail.

When the television camera 2 records an object not shown in the drawing, the color video signal output from the camera is supplied to the first time processing unit DVP-1 of the digital processing unit 1, and then sampled and brought into digital form. Each picture line of the color video signal with the exception of the horizontal synchronizing pulse HD and the color burst signal BS is sampled as an effective picture information area. In addition, the vertical synchronization pulse and the equalization pulses of the color video signal of each image frame are also not considered effective image information areas and are therefore not included. However, since a test signal, such as a signal VIR, VIT or the like, is inserted in the vertical retrace period of the video signal, the total number of effective video picture lines including the corresponding picture lines is determined. For example, in the case of an NTSC type color video signal, the effective number of picture lines per television picture frame period is chosen as 256 picture lines, starting from the 10th picture line of each picture frame.

- \ ··. In the embodiment of the invention described herein, the sampling frequency fyg, with which the color video signal is sampled, is selected to be four times that of the color subcarrier frequency fg ^. For this purpose, the horizontal synchronizing signal HD and color burst signal BS separated from the received color video signal are applied to a signal generator 30 for generating and outputting clock pulses synchronized with the color burst signal BS with a frequency of 4 fgC *.

A sampling pulse is delivered on the basis of these clock pulses.

The aforementioned effective image information area or part of the color video signal is sampled by means of this sampling pulse and subsequently subjected to analog / digital conversion to, for example, an 8-bit 8101952-6 digital signal in parallel form.

Since the sampling frequency is equal to 4 fgc and the color subcarrier frequency fgc for an NTSC type color video signal can be expressed by 5. 155 f ^ SC 2 IHf where the picture line scan frequency is, the number of.:. Y - »*. · - samples per *; picture adjustment period r 910 amount and. "" Note:: - - - -. see, as already explained, sampling the signal during the picture suppression period is pointless, the number of effective video samples per picture line will be less than 910. , for example, 768.

The video signal thus digitalized is supplied to the second video processing unit DVP-2, 15 to which the clock pulse is also supplied.

The second video processing unit DVP-2 is essentially in the form shown in Figure 2. In the embodiment described here, the digital video signal and clock pulse 20 output from the first processing unit DVP-1 are supplied to a video coupling unit 11, in which the digital video signal is still further to describe, time scissors mode is further processed. Respectively on the picture -... ... line., The picture frame ,, the: video picture and the. recording, track-related identification signals and various time-rhythm signals generated and output by the processing unit DVP-1 are applied to predetermined partial circuits of the processing unit DVP-2.

As already noted, the digitized video information is divided over a number of channels prior to recording. According to the invention, the two video tape devices 3 and 4 for recording (and / or reproducing) the video information are equipped with n rotatable magnetic heads? when the digitized video information is distributed over n channels, the signal information about one picture line is separated into 2n information blocks, each channel being allocated two such information blocks. In the embodiment described here, n = 4. As shown in Figure 4A, the video information relating to one picture line is separated into the information about a first 1/2 picture line and the information about a second 1/2 picture line, after which it is both information are divided by 4, resulting in 8 information groups D1 -Dg with 96 samples each. Subsequently, the information groups D ^ -D ^ relating to a first 1/2 picture line are distributed over 4 channels A, B, C and D - - - -; associated recording tracks are recorded, while the 4 information groups Dg-Dg relating to the last 1/2 picture line are also distributed over channels A, B, C and D and are respectively arranged according to FIG. associated registration tracks are recorded. The information groups D1 and Dg are thereby recorded according to a recording track added to channel A, while in a similar manner the information groups Dg, D1; DDg and D ^, Dg according to resp. recording tracks Τβ, Tc and added to channels B, C and D are recorded.

If the information divided over four channels in each channel were subjected to a separate signal processing, this would require four separate signal processing systems, which would require a relatively large amount of material and cause high costs.

. ; .1ηΛ related, with it, channels A, B and channels C and D are respectively. combined into two systems AB and CD with 25 own signal processing. To this end, in the video coupling unit 11, the information rate is reduced by half, while on the channel AB side, the information groups D1 and Dg are multiplexed and combined in a time-sharing manner (see Figure 4B) so that the samples 30 of the information group D1 and that of the information group Dg become alternately available, while the information groups Dg and such are multiplexed and combined in a time-sharing manner so that the samples of both groups Dg and D1 are alternately available.

On the side of the channel CD, the information groups D2 and D1 are multiplexed and time-shared, after which the information groups Dg and Dg are multiplexed and time-shared.

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The output signal of the channel AB thus formed is supplied by the video coupling unit 11 to a time base compression circuit 12AB, while the output signal thus formed of. the channel CD is applied to a time base compression circuit 12CD. The time base compression performed by these circuits is at a predetermined compression ratio and is on - - *. : focused / v ƒ space · '! ,to. obtain for. possible insertion;

digitized audio information, error correction codes 10 and for format conversion aimed at the final signal recording.

The time-compressed digital information which for the channels AB and CD by the resp. time compression circuit 12AB and 12CD are outputted, 15 are applied to respective error correction encoders 13AB and 13CD, the output signals of which are supplied to the resp. recording processing units 14AB and 14CD are supplied. In the error correction coding units 13AB, 13CD and the recording processing units 14AB, 14CD, the video signal information multiplexed with each 20 sample is processed in a time-sharing manner for each sample. That is, the samples of the same of the different information. .. groups D ^ -D ^ within the appropriate sample unit.

one, while decreasing the information rate to half, that is, to a 1/4 of the original information rate. As shown in Figures 4D, 4E, 4P and 4G, the signal processing for the different channels A, B, C and D takes place separately.

As described above, the 30. video signal information by the error correction coding units 13AB, 13CD and subsequent recording processing units 14AB, 14CD is processed in a time-sharing manner and converted into signals, the format of which is respectively. is shown in Figures 4H and 5.

From this it appears that in the embodiment described here, one information block B is always added to the 8 information groups D1-Dg (with 96 samples each) the size of an eighth picture line of the video information 8101952-9-9. As shown in Figure 4H, such an information block D contains a block synchronizing signal SYNC of three samples (24 bits), an identification signal ID and an address signal AD of together four samples (32 bits) and a block of parity information BPC of four samples ( 32 bits).

The synchronization signal SYNC is for extracting ... the signals ID, AD, the: signal information and the block parity "· *" * "" information at "the signal display." Λ. · "

The identification signal ID serves to identify the resp. corresponding channel A, B, C or D and of the resp. associated video image and video image frame, as well as the address of the relevant information block B. The block parity information BPC serves for error detection and correction of the information belonging to one block at 15 s signal display.

For each image frame of each channel, the information is processed to obtain the information structure or information format of Figure 5.

This figure shows the one channel information structure 20 of the video information for one image frame, two information blocks B containing the information about 1/4 of one image line of the video signal. In the embodiment described here, the two different information blocks B numbers correspond to the above-mentioned address signal AD.

In the case of an NTSC type color video signal, if the number of effective picture lines 256 is chosen, the number of blocks of one picture frame per channel will be 512. This results in a matrix-30 distribution with 16 block columns and 32 block rows, as shown in Figure 5, to which parity information in the horizontal or row direction in the 17th and 18th columns, respectively, as well as parity information in the vertical or column direction in the 33rd row is added to obtain a matrix-35 compound of 18 x 33 blocks.

If it is thereby assumed that the information locks B are designated in the order as Bj-B ^ ^, the following modulo-2 additions 8101952 t> J * -10-L - - - can be performed for the first row, the information blocks always being horizontally combined every other to form the following two horizontal partial information and the first row: 5:

Bi ® B3 ^ Bj 0 - 0 s B17

Similarly, the horizontal parity information for the second through the 33rd rows can be formed.

For the first column of the matrix distribution, the following modulo-2 additions are performed in the vertical direction to obtain the vertical parity information B ^ 77 for the first column: B1 ® B19 ® B37 ® * * * ® B559 = B557

Similarly, the vertical parity information for the second through the 16th columns is generated.

The horizontal and vertical parity information and block parity information thus obtained are used to ..... (...,.; /-,./ fe3Wikfc, to increase the information error correctability during signal display.

25 The for the formation of the horizontal and vertical

parity information and signal processing necessary for adding it to the video information already obtained is performed by the error correction encoders 13ΆΒ and 13CD, while the data for producing the synchronizing signal SYNC, the identification signal ID and the address signal AD

and signal processing necessary for adding these signals to the other video information takes place in the recording processing units 14AB and 14CD.

In the latter processing units, block coding takes place such that the number of bits per sample of 8 is converted into 10. This block coding is carried out such that out of the number of (21 ^) available 10-bit codes 8, 2 codes are selected, of which the digital sum-8101952 -11 variation is equal to O or nearly 0; the original 8-bit code is added to the selected 10-g bit codes on a 1 ^ 1 basis. The selection of the 2 10-bit codes is effected such that the digital sum variation of the recorded signal comes as close to 0 as possible, which means that in that signal the binary values "0" and "1" are equally distributed. forkpmen. Such a coding takes place when digital information is recorded in order to obtain the smallest possible DC voltage signal component, since it cannot be properly reproduced by signal reproduction by means of a magnetic signal display device.

The digital encoded digital signal having the character of a 10-bit information word: 15 is then converted by the processing units 14AB and 14CD from a signal in parallel to a signal in series form, and this in sequence from the information block B1 to the information block B594 · At the beginning and end of the digital signal of one image frame period of each channel, a front-side signal, resp. added a sidewalk signal.

The serialized digital signals for the different channels are separated by the processing units 14AB, 14CD via resp. pick-up amplifiers 15A-15D supplied to resp. the output terminals 16A-16D.

The analog audio signals output from the micro are supplied to the digital audio processing unit 7. These analog audio signals are preprocessed by the recording processing circuit (see Figure 6) of the audio processing unit 7. When considering 2-channel audio signals, the corresponding signals are transmitted via resp. input terminals 70 ^, 702 and low pass filters 71712 supplied to resp. sample and hold circuits 72 ^, 722 * For sampling the audio signal, in the embodiment described herein, a sample frequency f ^ g of 50.4 / 1.001 KHz is used. In the case of a color video signal of the NTSC type, in order to avoid the occurrence of beatings between the audio sub-carrier signal and the color sub-carrier signal, a value is selected for the video frame rate, which is greater than 30 Hz 5 by an amount of 1/1000 Hz, while in the time-basic compression of the audio signal such a compression ratio should be chosen *. .that the sampling frequency after compression is an integer • - multiple of the. horizontal or picture line scan frequency *: f. This explains the aforementioned value selection 10 "for the sampling frequency f ^ g for the audio signal, whereby the said compression ratio therefore plays an important role.

Next, the relationship between the sampling frequency f applied when sampling the video signal and the Vb sampling frequency fAg applied when sampling the audio signal will be clarified: f = - f rAS 7 * 5 _ 8 14 _2_. ·

7 '5 * 255 SC

20 = _12_ f ........ (1)

2275 * rSC

= 4 'fSC ........ (2). . "·" * "* -» * fAs = '2275 * vS ........

Thus, that sample information is supplied to two analog / digital converter 73χ and 732 for converting the information into digital signals of 16 bits per sample. .

The digital signals output from the converters 73 and 732 are fed to a multiplexer 74 for a time-cutting operation such that the information of the first channel and the information of the second channel alternate with each sample at the output of the unit 74 appears. This output information is supplied to a time compression circuit 75, which contains a RAM type memory. The output information is subjected to information block-wise interleaved by the time compression circuitry and further to time compression or time base compression to provide "space" for insertion of error detection and error correction codes; after processing by the circuit 75, the information 5 is supplied thereto to an error correction coding unit 76 / which inserts error detection and error correction codes in the resulting "space", respectively. to the information received. ... .. .. · ... adds. , ...: V.:..- '. ···· · -: · - · ’. ··· .: · -. * ··.

The digital audio signal output by the error correction encoder 76 is supplied to a video amplifier 77, to which a video synchronizing signal and information synchronizing signal from a synchronizing signal generating circuit 78 are also supplied for adding to the audio information, after which the thus edited information becomes available at an output terminal 79.

The description just given relates to the case of 2-channel audio information, but it will be clear that in the case of using 16 20 channels, the 16-channel audio information obtained in digital form obtained in a time-saving manner through the multiplex unit 74 is processed.

... .... When 4-channel video information is supplied to the videotape devices 3 and 4, the audio information is supplied to the two videotape devices via the audio processing unit 7.

Video devices 3 and 4 each have, as shown in Figures 8A and 8B, four rotatable magnetic heads GA, GB, GC and GD as well as one rotatable magnetic head AH. These five magnetic heads are arranged relatively close to each other and in sequence along a axis parallel to the axis of rotation, and are driven in rotation with the image raster frequency of 60 Hz in synchronization with the color video signal. A magnetic tape T extends helically about the rotational surface of the magnetic heads GA, GB, GC and GD approximately according to Omega and is subjected to longitudinal transport at a constant speed.

For example, if the video tape device 3 is in the "signal recording" operating state, the resp. digital video signals of each image frame resp. channels belonging to channels A, B, C and D. recorded by the magnetic heads GA, GB, GC and GD on the magnetic tape T according to resp. four oblique recording tracks TA,

Tg, Tc and TD (see Figure 9). Moreover, it is shown in digi. .... audio signal brought into shape. The magnetic head AH. -According to an also ·· inclined recording register v '* ’! ·' · recorded on the magnetic tape T.

In the described embodiment, values for the scanning width of the magnetic heads GA-GD and AH and for the distance between adjacent recording tracks are chosen such that the width of one set of recording tracks TA, Tg, Tc, Tg and TAÜ corresponds to that of one. video recording track according to the "C" format of the SMPTE.

Assuming an information rate R ^. The number of 8-bit samples of the audio signal that can be used in the digital sample format of the video signal per picture frame will then be examined. The information rate R of the audio signal is first calculated.

As has already been noted, one sample of the .... signal, aixdiQ signal, includes 16, bi * ts, while 16 include audio channels. are applied. Therefore, if a value of 100% is assumed for the redundancy of the error correction code, the synchronization signal, etc., the total information speed R & can be displayed by:

Ra = (16 x 2) X 16 x fAS I

30 '. * _ 4096 ^

"2275 * •" "USA

= 25.779 M bit / s (4)

This means that the sample number NA of the digital audio signal inserted per image frame is as follows: 'i 35 • 8101952 -15- N = R x - x ~ -r WA * KA x 8 60 ^^ 96 y 4 xf X! XM01 2275 x * x rSC x 8 60 5 = 53760 (5) •. 1 * - · ¯ ·: Since the number of video windows per picture line · j is 910, as has already been explained, the number jq when converting the audio information rate into the input! rate of formation of the digitized video signal per audio samples to be inserted into television image frames are represented by: 15 591 ° = 59r0769 (picture lines) (6)

This means that about 60 image lines are required.

Since the number of effective video image rules is 256, it is stated that the audio information takes up about 20% of the total of video and audio information.

As a result, the application of one audio recording track to four video recording tracks per image frame period is sufficient. ·. .

In practice, it has been found to be problematic to accurately align the five magnetic heads, while the effect of leakage flux from adjacent magnetic heads cannot be completely neglected, so that the five magnetic heads GA, GB, GC, GD and AH successively arranged slightly offset in their rotational direction relative to each other. As a result, the starting positions of the various recording tracks T ^ -T ^ and during signal recording are not entirely aligned. However, if the four-channel (A-D) digital video signals and the digital audio signal are recorded at 35, that is, at their input to the resp.

magnetic heads GA-GD and AH, respectively. delays are nevertheless obtained, a recording track distribution pattern can be obtained on the magnetic tape T corresponding to 8101952 -16-U- · "with the magnetic heads arranged for five in one (parallel to the axis of rotation) line drawn in FIG. strate tracks distribution pattern.

As described above, the digitized color video signal and the associated audio format, also digitized. - signal, both recorded as digital signals. vj - voj-vo'igijis “will be described for displaying or reading a digital signal recorded in the manner described above.

When the videotape device 3 is switched to the "signal display" operating state, the digital video information is read from the recording tracks ΤΑ ~ Τβ by the resp. magnetic heads GA-GD practically simultaneously take place with reading of digital audio information from the recording track by the magnetic head AH. If the magnetic heads GA-GD and AH are arranged successively in their rotational direction relative to each other, as described above, the signals read out from the various recording tracks will become available in a sequential delay. However, the delays in question can easily become. undone. or 'corrected, for example by means of' a buffer memory.

The video signal thus read out in digital form becomes di.t. to the processing unit DVP-3 of the digital video processing unit 1, while the read-out audio signal is supplied in digital form via the audio coupling unit 8 to the digital audio processing unit 7.

First, the processing of the read out video signal will be described. The video editing unit DVP-3 has the form shown in figure 3. Thereby the

4-channel readout signals via input terminals 35 20A-20D and then resp. via display amplifiers 21A-21D

supplied to resp. display units 22A-22D for converting from the serial form into the parallel form and further for block decoding, i.e. converting 10-bit 8101952 f * -17-coded signals into (original) 8-bit coded signals. Furthermore, a clock signal is output by means of a phase-locked loop triggered by the read-out digital signal.

The parallelized 8-bit digital signals are applied to resp. time base correction circuits 23A-23D for elimination of time base fluctuations. As is well known, such basic time correction circuits 23 may contain a digital memory, the aforementioned block synchronizing signal SYNC being used to detect the beginning of a next information signal, while the reading of the obtained information takes place in the relevant memory on the basis of the clock signals obtained from the processing units 22. The readout from the digital memory always takes place on the basis of clock signals based on reference synchronization signals, such that any time base fluctuations are eliminated.

Signals output from time base correction circuits 23A and 23B are applied to a multiplexing unit 24AB, while signals output from time base correction circuits 23C and 23D are applied to. a plywood unit. 24CD. The digital signals of the channel A and the channel 25 B received by the multiplexer 24AB are processed in a time-sharing manner such that they alternately become available sample by sample, while the digital signals for the channel C supplied to the multiplexer 24CD and the channel D is processed in a time-sharing manner such that they are alternately made available sample by sample.

The digital information signals originating from the multiplex units 24AB and 24CD are supplied to a resp. error correction decoders 26AB and 26CD. In this switching unit 25, the different channels are identified on the basis of the recording track identification signals of the identification signals supplied to the different information blocks; based on this identification, the various information blocks are fed to the eligible channels. In the switching unit 25, the signal processing naturally takes place in a time-sharing manner.

The switch circuit 25 in particular operates very efficiently during special, that is to say the normal, deviating signal display. At normal signal. display, in which the position of a recording track on the - ·· -: * ·· '* •' magrtéetbènd 'inherited' by 'one' month ^ 'during' scan track 'followed by this will coincide with each other. 10 the four rotatable magnetic heads have only the out resp. read out associated recording tracks. On the other hand, during special signal reproduction, such as signal reproduction with a fast-moving image, where the tape transport speed is several tens of times higher than during normal signal-15 reproduction, the rotatable magnetic heads scan each time a number of recording tracks, as in figure 9 with a relatively thick drawn arrow. is indicated. The magnetic heads GA-GD will then each output a signal containing a mixture of information signals belonging to channels 20 A-D.

The switch unit 25 now examines the channel identity of the information read on the basis of the ··. The recording information signal, such that the information signals 25 for the channel AB read from the recording tracks T1 and Tg are applied to the decoding unit 26AB, while the data from the recording tracks T0 and read signals for the channel CD both are supplied to the decoding unit 26CD.

The decoding units 26AB and 26CD each contain an image frame memory of sufficient capacity for

storage of the information related to one channel of one image frame. Therefore, the information relating to channels A and B and the information relating to channels C and D are scissor-fed by the decoding units 26AB and 26CD in the following time.

edited. The information is read into the image frame memory in response to the address signal AD at each information block B, while at the same time correcting any error present in the information based on the block parity information and the horizontal and vertical parity information. Regarding this error correction, it can be stated that the error within an information block is first corrected on the basis of the block parity information, then error correction takes place on the basis of the horizontal parity information, while finally error correction is based on -of. the vertical parity information can: follow. ' ''

The information subject to error correction is supplied to resp. time base expansion circuits 27AB and 27CD for time base expansion of the information intended for the channels such that the original signal format (prior to the signal recording) is recovered.

The video signal information from the time base expansion circuits 27 is supplied to the video coupling unit 28 for conversion into original, single-channel digital information, which is then supplied to the first processing unit DVP-1 for digital-analog conversion and for combination with the synchronization pulse and the color burst signal to the original color video signal, which is, for example, sent to the monitor. . vision receiver 5 can be supplied. In addition, different time rhythm pulses, which are based on 25 reference clock pulses from the signal generator of the processing unit DVP-1, respectively. through the video coupling unit 28 to the various circuits of the signal processing units.

In the display system described here, the transmission of the information read by the video magnetic heads GA-GD to the read-in side of the time base correction circuits 23A-23D takes place on the basis of the clock pulses separated from the read-out information, but the information transmission of the read-out side of the time base correction circuits 23 to the resp. Output connections are made on the basis of clock pulses supplied by the signal generator of the processing unit DVP-1.

The audio information read out by the magnetic head AH from the recording track 8101952 -20 track TAU is fed via the switching unit 8 to the audio processing unit 7, the reproducing processing unit of which, for example, has the form shown in FIG. The read-out audio signal received via an input terminal 80 is supplied to an information extraction circuit 81, in which, on the basis of a local clock signal, the audio signal received in the received audio signals is synchronized with information-synchronization signals in addition to the desired audio format. 10 extracted.

The information thus extracted is supplied. a time base expansion circuit 82 for interleaving, resulting in the audio signals with the original time base and in the original code. These audio signals 15 are then applied to an error correction decoder 83 for correction of any errors based on the error detection code and the error correction code.

When error correction by the error correction decoding unit 83 proves to be impossible, the digital information signal is applied to an error hiding circuit 84 to replace the residual error with the mean value resulting from interpolation. preceding and subsequent information words. · '- ···

The thus error-corrected and eventual error-hiding error-replaced signal is applied to a demultiplexer 85 for distributing the signal over the two original channels.

The signal assigned to the first channel is fed to a digital / analog converter 86 ^ for conversion 30 to an analog signal, which is made available via a low-pass filter .87 ^ to an output terminal 88 ^, while the signal assigned to the second channel is supplied to a digital / analog converter 862 for conversion to an analog signal, which is made available to an output terminal 882 via a low-pass filter 872.

. The description just given relates to a two-channel case, but it will be clear that the same signal processing can be applied to 16-channel information, the digital signal then having to be transmitted by the demultiplexer unit 85 over 16 channels. divided.

5 The analog audio signals made available in this way via the various output channels of the audio processing unit 7 are fed to resp. speakers r -'or! '· speaker style SP ^ -SP ^ g supplied. "·"

As described above, with the aid of the invention, both video and audio signals can be reproduced in digital form and their resp. analog form.

In signal display, the number of information blocks containing an error is displayed on the monitor television receiver 156 by the information examining device ANA of the video processing unit 1.

Figure 10 shows the display florate of the monitor receiver 6 in the case of displaying a number of information blocks affected by error. In Fig. 10, the reference numeral 100 refers to the screen of the monitor receiver 6. In this case, for example, in each box 101 enclosed by a rectangle, some, for example, ... image 10, decimal numbers can be displayed, which, for example, represent the number of an information block affected by error. The letters shown on the left of each box 101 serve to clarify what is displayed, respectively. the display status. The following indications may appear in the boxes 101 enclosed by a rectangle.

30. (I) The symbol groups BPC11, BPC12, BPC21 and BPC22 represent the numbers of the error blocks affected which may appear in the first to fourth channels, (II) The symbol groups BPC13, BPC14, BPC23 and BPC24 represent 35 the numbers of the error blocks affected by the associated channel that cannot be corrected based on the block parity information, j 8101952 -22- ί (III) The symbol groups HPC1L, HPC12, HPC21 and HPC22 \ represent the numbers of the error blocks affected after error correction based on the horizontal parity * information, ^ 5 (IV) The symbol groups VPC11, VPC12, VPC21 and VPC22 represent the numbers of the. an error has been made, • '-4' "· · subblocks after" error correction based on the vertical parity information. "

In FIG. 10, the letters "FIELD" ... (F) "are used to indicate that the number of error-affected subblocks displayed on F video image frames has been visualized.

- If the. For example, the text reads "FIELDr ____ (60)", that is, the number of displayed information subblocks relates to information from 60 video image frames.

in the case of "editing" with the aid of the two video tape devices 3 eri 4, the digital signal is read out from the magnetic tape by means of the video tape device 3 via the reproducing processing unit DVP-3 of the digital video editing unit 1 directly to the recording device. DVP-2 processing unit, the output signal of which, for example, directly to the video tape apparatus. 4i% brd; € ove form for Rapture thereby.

In the digital audio processing unit 7, the output signal of the error hiding circuit 84 of the reproducing system is applied to the time base compression circuit 75 of the recording system, the latter of which the output signal appearing at the output connection 79 is supplied to the video tape apparatus 4.

30 During signal recording and signal reproduction, • the video tape equipment 3 eri 4 with track servo control of the usual type may suffice.

As described above, according to the present invention, the video signal information of one picture line is divided into a number of information blocks twice the number of rotatable magnetic head periods used for recording the video signal. In this case, two information blocks are always fed to each magnetic head to 81019 52 -23-w-· · "and recorded by it on the magnetic tape. This provides the following possibility. if the number of magnetic heads used for recording the video signal is chosen, the information block will become too large for good error correction, so that only a rough error correction is obtained if, in addition, a value is chosen for the said dividend. more than 10 times that of the number of magnetic heads used, too high a redundancy is obtained.

In contrast to this, the invention now provides the possibility of achieving digital signal recording and reproduction, in which both a satisfactory error correction and a suitable, ie not too high, redundancy are obtained.

According to the previously described embodiment of the invention, the information about one picture line is roughly divided over two information blocks, after which each relevant information block is divided over a number of channels, to which the information values are sequentially applied. With such supply of the information from one image frame to the channels and subsequent information processing, using a relatively small capacity delay buffer memory is sufficient to obtain a suitable information distribution over the channels.

Since in the embodiment described above, 4-channel information is processed in a four-channel manner in a time-saving manner by means of the digital processing units DVP-2 and DVP-3, a highly simplified circuit of small dimensions and costs is obtained.

Moreover, in the embodiment of the invention described above, a separate recording track is used for recording the audio information, so that in editing, the advantage of independent recording and insertion of the video signal and the audio signal is 8101952 1 -24 - is acquired.

Although the signals to be recorded are applied to the five rotatable magnetic heads with relative delays in the above-described embodiment, thereby obtaining a recording track distribution pattern similar to that used with one-line magnetic heads, it is possible that the relative delays are given to such a recording track distribution pattern 10, thereby making better use of the available width of the magnetic tape T (see FIG. 11).

The invention is not limited to the embodiment described above and shown in the drawing; various modifications can be made to the described components and in their mutual connection, without thereby: - exceeding the scope of the invention.

8101952

Claims (5)

1. Digital video and audio information recording and / or reproducing device, comprising: A) a number of rotatable magnetic heads, which are added to a tape guide drum with an outer peripheral surface, along which a magnetic tape screw tape is provided over a predetermined winding angle and B) signal processing means for distributing the digitized video information of one image control scan period over a number of information blocks, characterized by: C) distributing means for supplying an even number of information blocks of one image control scan period to each of the rotatable magnetic heads for recording thereby. Device according to claim 1, characterized in that each information block has identification information. and contains parity information for retrieving the original order and original format of the digital video information. Device according to claim 2, characterized; by at least one rotatable magnetic head for recording a digitalized audio signal according to a recording track, which extends recording tracks serving in parallel form a bundle for recording video information in digital form. Device according to claim 1, characterized in that the rotatable magnetic heads are arranged relatively close together. 30 Apparatus according to claim 1, characterized in that the digitized video information is constituted by a digitized, composite color video signal obtained by sampling at a sampling frequency which is four times the color subcarrier-35 sd signal frequency. 8101952