DE4015626A1 - Digital video recording and playback system - uses digital audio tape with memories and control circuitry to store full or part picture frames - Google Patents

Abstract

The recording and playback system comprises an A/D converter (101), a digital interface (104) to record the signals through the record head (106) on to the DAT (105), a further digital interface (108) to receive signals from the DAT (105) via the playback head (107) and convert through D/A converter (111), memory controllers (115,119) to organise data through memories (113,114,117,118), digital switches (116,120) controlled by selection signals, and variable gain amplifiers (112,121). Preferably, the memory (113) stores a part picture or a number of complete picture frames, and the number of memories (113,114...) can be increased. USE/ADVANTAGE - Fully electronic digital picture storage.

Description

The invention relates to digital video drawing and reproducing device, and relates in particular digital video recording and playback advises using a digital audio tape device (below referred to as "DAT") as a storage device for stand or Still pictures is used.

Fig. 6 shows an example of a configuration of a DAT. The DAT comprises an analog / digital converter 1 (hereinafter referred to as A / D converter), a data memory 2 , a nesting circuit arrangement 3 , a digital recording part 4 , which are connected in series, and one with the digital recording part 4 connected and in contact with the audio tape 5 recording head 6 . Furthermore, the DAT comprises a playback head 7 which is in contact with the digital audio tape 5 and is connected in series with a digital playback section 8 , a data memory 9 , a deinterleaving circuit arrangement 10 and a digital / analog converter 11 (hereinafter referred to as D / A converter).

The mode of operation of the device is explained below. The recording of a signal on the digital audio tape 5 is described first.

An analog audio signal is fed to the A / D converter 1 for conversion into a digital audio signal. The digital audio signal generated by the A / D converter 1 is stored in the data memory 2 . The data memory 2 has a storage capacity of 128 kbit, for example.

The digital audio signal stored in the data memory 2 is fed to the interleaving circuit arrangement 3 . The interleaving circuit arrangement 3 subjects the digital audio signal to an interleaving process. An interleaving process generally records a pair of digital signals in batches to avoid spatially concentrated recording of the signals. Such a process enables, for example, during the reproduction of digital signals a correction and compensation of the continuous errors caused by defects and defects in a digital audio tape used for recording (corresponding to audio tape 5 according to FIG. 6).

The digital audio signal subjected to the interleaving process is fed to the digital recording part 4 and recorded by the recording head 6 onto the digital audio tape 5 .

The reproduction of a digital audio signal from the digital audio tape 5 will now be described.

When playing the digital audio signal from the digital audio tape 5 through the playback head 7 and the playback part 8 , the digital audio signal is stored in the data memory 9 . The data memory 9 , like the data memory 2, has a memory capacity of 128 kbit.

The digital audio signal stored in the memory 9 is supplied to the deinterleaving circuit arrangement 10 . The deinterleaving circuit arrangement 10 cancels the interleaving process carried out during recording by the interleaving circuit arrangement 3 in the digital audio signal. The digital audio signal is fed to the D / A converter 11 for conversion into an analog audio signal after the deinterleaving circuit arrangement 10 and is output to an analog signal processing computer, not shown in FIG. 6.

If such a DAT is used as a storage device for still images, the storage capacity of the data memory 2 and of the data memory 9 is not sufficient. For example, an NTSC standard image with a resolution of 640 points horizontally and 480 lines vertically is stored in the data memory 2 . The image read from the data memory 2 is recorded on the digital audio tape 5 . The storage capacity of the data memory 2 is not sufficient for storing the digital signal for the image.

5 different formats are usually used when recording digital signals from images on the digital audio tape, but it is unclear whether the structure of the device according to FIG. 6 can process the large number of formats.

If digital signals of a still picture are reproduced by the digital audio tape 5 and fed to an external device for producing a copy, the picture quality must be reduced to a certain extent in order to meet the social requirements with regard to copyright or the like. Conventional devices do not offer such possibilities.

It is therefore an object of the invention mentioned above to avoid the disadvantages of the prior art and the Use of a DAT as a storage device for still images too enable by providing the storage capacity of the Data storage, ensure the adaptability to difference formats and the possibility of low quality an image to be output if necessary. Invention Ge According to a digital video recording and replay includes dispenser:

• a) an analog / digital converter to deliver a analog signal in the form of a digital signal,
• b) a data storage on the recording side for Splitting that originating from the analog / digital converter Signal in predetermined blocks and storing the up shared digital signal,
• c) a memory access control on the recording page for controlling the read / write function of the recording side, so that the blocks of digital signals in the Data storage of the recording side in a predetermined manner be registered and read out,
• d) a digital recording part for recording a digital signal on a digital tape,
• e) a digital reproduction part for the delivery of the digital signal reproduced on the digital audio tape and
• f) a digital / analog converter to implement a digital signal into an analog signal.

This structure, especially the structure for storing the digital signals in the data storage on the recording side enables the recording of digital signals on a digital tape, the storage capacity of the data storage effectively ensured and thus the use DAT as storage device for still images light becomes.

The control of the read / write function, especially the Control the order of the read / write function the memory access control on the recording side provides the Adaptation of the DAT to various types of recordings mate with digital audio tapes.

A digital video recording and playback device further includes:

• g) memory access control on playback page for controlling the read / write function of the data memory on the playback side so that the blocks of the digital signals in the data storage of the playback side registered and read in a predetermined manner will.

This structure increases the storage capacity of the data memory of the playback page for the playback effect fully secured.

A digital video recording and playback device also includes:

• h) an amplifier for amplifying the from the Implementation of the digital / analog converter formed analog Signal by a value that depends on a permitted or unauthorized operation can be changed.

According to this structure, the values vary around the analog Signals are amplified depending on whether a permitted or unauthorized operation. So that's it external output signal in unauthorized operation a ver strengthened or reduced analog signal compared to the analog signal in permitted operation. Therefore, at for example, an external device that was copied such analog signals formed in illegal operation be supplied, no analog signals of the same quality maintain, especially not the image quality of a Still image corresponding to that on the digital tape recorded digital signals. In this way the necessary deterioration in image quality, for example wise for copying, realized.

A data block when it is saved in the data memory of the The recording side is the amount of data of a digital signal  Field or full screen. Signals are in the data store stored in a data block on the playback side, the data block in the data storage on the recording side corresponds.

It is especially for recording or playback digital signals of a still picture makes sense that the Data storage on the recording side has a capacity for storage one frame or field or several frames has images or fields. The same applies to the Playback data storage. The data storage of the Playback page preferably has a storage capacity corresponding to that of the data storage on the recording side.

It is also possible to have a variety of data stores the recording and / or playback side. Consequently the storage capacity can be provided more easily will.

If there is a large number of data and / or playback page is digital Switches are provided at the respective outputs. A digi taler switch selects digital signals from a data storage device the recording or playback side from the out of the lot Number of digital signals read out from the data store Recording and playback page, and executes the chose digital signals the digital recording part or to the digital / analog converter.

The gain of the Digi tal / analog converter connected amplifier is at for example, set to 1 for permitted operation and to an integer greater than 1 for the case of the un leafy operation. Preferably the gain factor set to 2 for unauthorized operation.  

It is also possible to use the Ver strengthening factor on the reciprocal of an integer to be set larger than 1. In this case the preferred one Gain factor 1/2.

The invention is illustrated below with reference to embodiments play with reference to the drawing he purifies.

Show it:

Fig. 1 is a block diagram of the structure of a first embodiment of the digital video recording and playback device in which two data memories, a digital switch and a memory access controller are provided on the recording and playback side.

Fig. 2 shows the position of the recorded signals on a digital tape according to the embodiment of Fig. 1,

Fig. 3 is a frame, wherein the block of data recorded on the digital band digital signals is a field according to the embodiment of Fig. 1,

Fig. 4 shows the effect of the gain of the amplifier on the reproducing side according to the embodiment of Fig. 1,

Fig. 5 is a frame, wherein the block of data recorded on the digital band digital signals is a frame according to a second exporting approximately example of the invention,

Fig. 6 is a block diagram as an example of a structure of a conventional DAT.

The structure of a first embodiment of the digital video recording and reproducing apparatus FIG. 1.

Referring to FIG. 1, an amplifier 112 is 114. the input of a Ana log / digital converter 101 (hereinafter A / referred to as AD converter) and a data memory A 113 and a Datenspei cher B at the output of A / D converter 101. A memory access controller 115 is connected to data memory A 113 and data memory B 114 , both of which are connected to a digital switch 116 . The digital switch 116 is further connected to a digital acquisition part 104 .

A data memory C 117 and a data memory D 118 are connected to the output of a digital reproduction part 108 according to FIG. 1. A memory access controller 119 is connected to data memory C 117 and data memory D 118 , both of which are connected to the input of a digital switch 120 . The output of the digital switch 120 is connected to a digital / analog converter 111 (hereinafter referred to as a D / A converter), which is connected to an amplifier 121 .

The operation of this embodiment is shown in described above, starting with the description of the How the recording works.

In this embodiment, an analog video signal (hereinafter referred to as an analog signal), for example an NTSC standard analog signal, is first fed to the amplifier 112 .

The amplifier 112 is a variable gain amplifier, the gain being adjusted by a gain control signal. The gain factor of the amplifier 112 is set in accordance with the gain control signal, for example, to match an analog signal in its dynamic range to the A / D converter 101 .

The analog signal supplied to the A / D converter 101 is converted into a digital video signal (hereinafter referred to as a digital signal), for example with 8-bit quantization.

The digital signal converted from the analog signal by the A / D converter 101 is stored in the data memory A 113 or the data memory B 114 . The data storage A 113 and the data storage B 114 are both dynamic read / write memories, for example.

In this embodiment, digital signals for each field are stored in data memory A 113 or data memory B 114 . If according to FIG. 3, the digita len signals of the odd-numbered scanning lines with P (1), P (2). . . P (n) and the even-numbered scan lines with Q ( 1 ), Q ( 2 ),. . . Q (n) are designated, in the data memory A 113 P ( 1 ), P ( 2 ),. . . P (n) and in the data memory B 114 Q ( 1 ), Q ( 2 ) ,. . . Q (n) saved.

The memory functions of the data memory A 113 and the data memory B 114 are realized via the control of the write addresses of the data memory A 113 and the data memory B 114 by the memory access controller 115 .

The digital signals stored in data memory A 113 and data memory B 114 are read out and fed to digital switch 116 .

The digital signals, which are read from the data memory A 113 and supplied to the digital switch 116 , are, for example, in the ascending order of the scanning lines, ie in the order P ( 1 ), P ( 2 ),. . . P (n) . This reading process of the digital signals from the data memory A 113 in the predetermined sequence is carried out via the control of the read address of the data memory A 113 by the memory access controller 115 .

In the same way, the digital signals are read out from the data memory B 114 and supplied to the digital switch 116 in a predetermined order via the control of the read address of the data memory B 114 by the memory access controller 115 .

In this case, the order of reading is, for example, the descending order of the scanning lines, ie the order Q (n) , Q (n -1),. . . Q ( 1 ).

The digital switch 116 is supplied with a selection signal. The selection signal is a signal for selecting digital data which is read out either from the data memory A 113 or from the data memory B 114 for output by the digital switch 116 . Thus, the digital switch 116 selects the digital signal either from the data memory A 113 or from the data memory B 114 depending on the selection signal and outputs the selected digital signal.

If the selection signal assumes values which are changed synchronously with the control of the read addresses of the data memory A 113 and the data memory B 114 by the memory access controller B 115 , then the digital signals emitted by the digital switch 116 are in the order of, for example, P ( 1 ), Q (n) , P ( 2 ), Q (n -1),. . . P (n) and Q ( 1 ) delivered.

The digital signals emitted by the digital switch 116 in the predetermined sequence described are supplied to the digital recording part 104 . The digital recording part 104 records the digital signals via the recording head 106 on the digital audio tape 105 .

Since the digital signals are supplied to the digital recording part 104 in the predetermined order of the scanning lines, the digital signals according to FIG. 2 are recorded on the digital audio tape 105 in the predetermined order.

According to the example described above, the order of recording is P ( 1 ), Q (n) , P ( 2 ), Q (n -1),. . . P (n) and Q ( 1 ).

The operation of the reproduction of digital signals drawn in this way from a digital audio tape 105 is described below.

When digital signals are reproduced from the digital audio tape 105 by the playback head 107 and the digital playback part 108 , these digital signals are fed to the data memory C 117 and the data memory D 118 and stored there.

The digital signals are stored in the data memory C 117 and the data memory D 118 for each field in the same way as in the data memory A 113 and the data memory B 114 of the recording side. For example, data memory C 117 stores the digital signals P ( 1 ), P ( 2 ),. . . P (n) , while the data memory D 118 the digital signals Q (n) , Q (n -1),. . . Q ( 1 ) saves.

The memory access controller 119 controls the read / write addresses of the data memory C 117 and the data memory D 118 . The digital signals are read out from the data memory C 117 and the data memory D 118 in the order determined by the memory access controller 119 .

The digital signals read out from the data store C 117 and the data store D 118 are fed to the digital switch 120 . In the same way as in the case of the digital switch 116 , the digital switch 120 is supplied with a selection signal, so that the digital signals 120 read out from the data memory C 117 and the data memory D 118 by the digital switch 120 in a predetermined order as the order corresponds the NTSC standard signal.

The digital signal output by the digital switch 120 is supplied to the D / A converter 111 for conversion into an analog signal.

The analog signal output by the D / A converter 111 is fed to the amplifier 121 with a variable gain factor, the gain factor being set as a function of the gain factor control signal. The amplifier 121 amplifies the analog signal with a preset gain factor and outputs the amplified signal to an analog signal processor.

Control of the gain of the amplifier 121 will now be described. An example of the control is shown in FIG. 4.

For example, if the amplitude of the synchronous signal component of the analog signal has the value B ₀ and the amplitude of the video signal component has the value A ₀ , then the analog signal, which in this case is a composite signal, has the amplitude value A ₀ + B ₀ . In particular, with the NTSC standard signal A ₀ = 0.71 V and B ₀ = 0.29 V.

The gain factor of amplifier 121 set for permitted operation is different from the gain factor set for unauthorized operation.

The permitted operation is an operating state that one external device copying signals without reduction the picture quality allowed while the illegal operation is an operating state in which analog signals one external device after reducing the image quality leads.

For example, the amplification factor of the amplifier 121 is set to 1 for the permitted operation and to the integer A ₂ , which is greater than 1, for the illegal operation. Therefore, the analog signal output from the amplifier 121 to an external device in the case of unauthorized operation has a low picture quality compared to the original analog signal.

The same effect can also be achieved by setting the amplification factor of the amplifier 121 to a reciprocal value A _{1 of} an integer greater than 1, for example 1/2.

The block of digital signals P (i) , Q (i) to be processed . . . (i: integer) can be a plurality of scan lines or a vertical line in the area of a field. The data record to be processed can be a full image, as shown in FIG. 5 in a second exemplary embodiment.

In Fig. 5, P (i) and Q (i) belong to one frame, respectively.

This embodiment produces the same effects like the first embodiment.

A record is not limited to a full screen and can be a variety of frames.

The three systems can be used as a composite video signal RGB-TTL, RGB-analog and the Y / C-separated signal as ana log signal can be used.

The data storage device A 113 , the data storage device B 114 , the data storage device C 117 and the data storage device D 118 are provided in an integrated form.

In the above-described embodiments of the digital video recording and playback device thus an analog signal by a for recording A / D converter converted into a digital signal and the implemented digital signals in a data storage with  control by memory access control the recording side in data blocks for full and partial images saved. The stored digital signals are with the help of a digital recording part to a digital one Audio tape recorded. When playing the digital signals from the digital audio tape through a digital playback part reproduced and in a data memory with control by memory access control on the playback side stored in data blocks for full and partial images. The saved digi tal signals are recorded using a D / A converter in front of the Output converted into analog signals.

Claims (19)

1. Digital video recording and playback device, characterized by :
an A / D converter ( 101 ) for delivering an analog signal in the form of a digital signal,
a digital recording part ( 104 ) for recording the digital signal on a digital audio tape ( 105 ),
a digital recording part ( 108 ) for delivering the digital signal reproduced by the digital audio tape ( 105 ),
a D / A converter ( 111 ) for converting the digital signal into an analog signal,
a data memory ( 113 ) on the recording side for dividing the digital signals output by the A / D converter ( 101 ) into predetermined data blocks and storing the divided digital signals, and
a memory access controller ( 115 ) on the recording side for controlling the write / read function on the recording side, so that the data blocks of the digital signals can be written and read into the data memory ( 113 ) in a predetermined order. 2. Digital video recording and playback device according to claim 1, characterized in that the data block for storage in the data memory ( 113 ) of the recording side comprises the amount of digital signals corresponding to one frame. 3. Digital video recording and playback device according to claim 1, characterized in that the data block for storage in the data memory ( 113 ) of the recording side comprises the amount of digital signals corresponding to a field. 4. Digital video recording and reproducing device according to claim 1, characterized in that the data memory ( 113 ) of the recording side has a storage capacity for storing digital signals of a frame. 5. Digital video recording and playback device according to claim 1, characterized in that the data memory ( 113 ) of the recording side has a storage capacity for storing digital signals of a plurality of frames. 6. Digital video recording and playback device according to claim 1, characterized in that a plurality of data memories ( 113 , 114 , ... ) Is seen on the recording side. 7. Digital video recording and playback device according to claim 6, characterized by a digital switch ( 116 ) for selecting digital signals related to a data memory ( 113 ) of the recording side from among the plurality of data memories ( 113 , 114 , ... ) Recording page read digital signals and supplying the selected digital signal to the digital recording part ( 104 ). 8. Digital video recording and playback device, characterized by:
an A / D converter ( 101 ) for emitting an analog signal in the form of a digital signal,
a digital recording part ( 104 ) for recording the digital signal on a digital audio tape ( 105 ),
a digital reproduction part ( 108 ) for delivering the digital signal reproduced by the digital audio tape ( 105 ),
a D / A converter ( 111 ) for converting the digital signal into an analog signal,
a data memory ( 113 ) on the recording side for dividing the digital signal output by the A / D converter ( 101 ) into predetermined data blocks and storing the divided digital signal,
a memory access controller ( 115 ) on the recording side for controlling the read / write function of the recording side, so that the data blocks of the digital signals are written into and read from the data memory ( 113 ) on the recording side in a predetermined order,
a data memory ( 117 ) on the playback side for dividing the digital signal output from the digital playback part ( 108 ) into predetermined data blocks and storing the divided digital signal, and
a memory access controller ( 119 ) on the reproduction side for controlling the write / read function of the data memory ( 117 ) of the reproduction side so that the data blocks of the digital signals are written into the data memory ( 117 ) of the reproduction side in a predetermined order and be read out. 9. A digital video recording and reproducing apparatus according to claim 8, characterized in that the data block for storage in the data memory ( 113 ) of the recording side comprises the amount of digital signals corresponding to one frame, and that the data block for storage in the data memory ( 117 ) the playback side comprises the amount of digital signals corresponding to one frame. 10. A digital video recording and playback device according to claim 8, characterized in that the data block for storage in the data memory ( 113 ) of the recording side comprises the megne of the digital signals corresponding to a field, and that the data block for storage in the data memory ( 117 ) on the playback side comprises the amount of digital signals corresponding to one field. 11. A digital video recording and playback device according to claim 8, characterized in that the data memory ( 113 ) of the recording side has a storage capacity for storing digital signals of a frame, and that the data memory ( 117 ) of the playback side has a storage capacity for storing digital signals Full frame. 12. A digital video recording and playback device according to claim 8, characterized in that the data memory ( 113 ) of the recording side has a storage capacity for storing digital signals of a plurality of frames, and the data memory ( 117 ) of the playback side has a storage capacity for storing digital signals of a variety of frames on. 13. A digital video recording and reproducing apparatus according to claim 8, characterized in that a plurality of data memories ( 113 , 114 , ... ) Are provided on the recording side, and in that a plurality of data memories ( 117 ) are provided on the reproduction side. 14. A digital video recording and playback device according to claim 13, characterized by a digital switch ( 116 ) for selecting digital signals relating to a data memory ( 113 ) on the recording side from among the plurality of data memories ( 113 , 114 , ... ) Digital signals read out on the receiving side and supplying the selected digital signals to the digital recording part ( 104 ), and a digital switch ( 120 ) for selecting digital signals relating to a data memory ( 117 ) of the playback side from the plurality of data memories ( 117 , 118 ,...) Of the playback side digital signals read out and supplying the selected digital signals to the D / A converter ( 111 ). 15. Digital video recording and playback device characterized by
an A / D converter ( 101 ) for outputting an analog signal in the form of a digital signal,
a digital recording part ( 104 ) for recording the digital signals on a digital audio tape ( 105 ),
a digital reproducing part ( 108 ) for outputting a digital signal reproduced from the digital audio tape ( 105 ),
a D / A converter ( 111 ) for converting a digital signal into an analog signal,
a data memory ( 113 ) on the recording side for dividing digital signals output by the A / D converter ( 101 ) into predetermined data blocks and storing the divided digital signals,
a memory access control ( 115 ) of the recording side for controlling the read / write function of the data memory ( 113 ) of the recording side, so that the data blocks of the digital signals in a predetermined order in the data memory ( 113 ) on the recording side and read out ,
a data memory ( 117 ) on the playback side for dividing digital signals output by the digital playback part into predetermined data blocks and storing the divided digital signals,
a memory access controller ( 119 ) of the playback side for controlling the read / write function of the data memory ( 117 ) of the playback side, so that the data blocks of the digital signals are written and read out in a predetermined order in the data memory ( 117 ) of the playback side be, and
an amplifier ( 121 ) for amplifying the analog signal formed by the conversion of the digital signal by the D / A converter ( 111 ) with an amplification factor which can be changed depending on whether the operation is permitted or not. 16. Digital video recording and playback device according to claim 15, characterized in that the amplifier ( 121 ) has a gain factor of 1 in permitted operation and as a gain factor an integer greater than 1 in unauthorized operation. 17. Digital video recording and playback device according to claim 16, characterized in that the amplifier ( 121 ) has a gain factor of 2 in unauthorized operation. 18. Digital video recording and playback device according to claim 15, characterized in that the amplifier ( 121 ) has a gain factor of 1 in permitted operation and as the gain factor has the reciprocal value of an integer greater than 1 in unauthorized operation. 19. Digital video recording and playback device according to claim 18, characterized in that the amplifier ker ( 121 ) has a gain factor of 1/2 in unauthorized operation.