DE3310824A1 - Video processor - Google Patents

Abstract

A video processor, particularly for digital video recorders, characterised in that both the coder and the decoder, of which the video processor consists, can be used completely separately. In the coder, only the image information about the parts of the frame which are new or not sufficiently similar compared with the last frame is output during a period, for example the duration of one frame. In addition, an information item is output which determines the parts. The degree of similarity can be easily adjusted in the coder. In the decoder, the additional information is received at the beginning of each period, stored in a memory CS and it is determined whether the new picture signals or the picture signals delayed in the same delay section by the duration of one frame (the period) are received in a delay section VD and output. See Figure 2. The quality of reproduction is considerably enhanced. The consumption of a storage medium can be reduced by a multiple. <IMAGE>

Description

Video processor

The invention relates to a video processor, particularly for digital ones V-ideorecorder. The video processor significantly improves the playback quality a video recording.

The file rate of the image information is also higher than conventional Methods, drastically throttled. That means a considerable decrease in required amount of storage medium, e.g. B. magnetic tape.

The video processor is thus an important step in this direction the video recorder with semiconductor storage media (no mechanics).

By using the encoder in a transmitter and the decoder in a receiver e.g. for television, the reception can be improved and a freely available Time, z.n.

for sending additional information, there are obtained scr few electronic methods to improve the playback quality of a video recording to improve.

The signal processing used in analog video recorders caused by the cosine equalization or the crispening technique a subjective Impression of an artificial image. Saving the image information from one line is used to correct errors. Very brief failures of the reproduced Image information can be corrected. The reduction in the consumption of the storage medium is bought at the price of a drastic reduction in the amount of information, e.g. in the field Skip system where only every other field is recorded.

The playback quality is improved with digital video recorders by encrypting the ni I riinforrnn t i on, reducing the amount of stored Information is enlarged additionally. Using a special coding D-PCM, the data rate is reduced to around a third without any noticeable loss of image.

Since the expansion of the electronics brings dubious results, have the developers focus almost exclusively on the mechanical side of the video recorder concentrated. Our quality is bought at the price of precise and complicated mechanics.

Reducing the consumption of the storage medium, which in practice the extension of the playing time means is also bypassed. You set new ones Technologies for storage media and new systems, e.g. lasers.

All of this has led to a mess in the video market, The Invention the task is based on an electronic way, both the reproduction quality to improve as well as to reduce the consumption of the storage medium.

According to the invention, this object is achieved in that the image information is encoded and decoded, taking into account the content of the image information will.

As an example, a cartoon can be cited, where often several For seconds only a tiny part of the entire picture is changed, the background however remains unchanged. The unchanged parts of the image information are after the coding is only output once.

This unique information is received and stored in the decoder and then played back from memory.

The advantages achieved: 1. Considerable improvement in playback quality.

2. Reducing the consumption of the storage medium.

3. Possibility of using the time that dulell the failure of the unnecessary image information is created.

4. Error correction due to a lack of reproduction in the principle of the Video processor included.

5. Several identical components in the coder and decoder.

6. Possibility of a complete separation of the encoder and decoder.

7. Compatibility.

3. Clarity.

9. D-PCM coding can be used.

10. Great flexibility by changing a comparison value N (in Coder), which determines the degree of similarity of the images.

11. The level of the comparison value N is automatically taken into account in the decoder. Full compatibility.

The functioning of the video processor is illustrated using the example of a digital Video recorder with longitudinal track recording and with a magnetic tape as Storage medium shown. For the sake of simplicity, a, converted into digital form, Usual black and white TV signal processed.

An image signal is defined as electrical information about it a sample of the image.

An embodiment of the coder is shown in FIG.

The current applied to input (i) and the one in the delay element VC image signals delayed by the duration of one frame (one period) are received in the PartDIF subtracted.

No distinction is made here as to which signal is larger. That The result of the subtraction is compared with a comparison value N in the comparator KOM. A bit is thus assigned to each image signal and stored in the memory AS.

At the beginning of a period, the content of the memory AS becomes the memory BS transferred. The content is also output at output (2) and onto the magnetic tape recorded. This is followed by the output of the to the duration of the period in Delay element VC delayed image signals. At the same time at the other output (3) the bits assigned to them in the comparator KOM in the last period are output.

The respective bit indicates that the recording can take place if the value of the respective silver fraction was greater than the value N. Otherwise the recording is interrupted, e.g. the progress of the magnetic tape is stopped. During this process, the memory AS is loaded with new values, just like in the last period.

In a special case, if the previous and the current full screen are identical are, the new recording consists only of the content of the memory AS, where all of its bits are the same.

An embodiment example 1 of the decoder is shown in FIG.

At the beginning of each period, the magnetic tape at input (4) reads the content of the memory AS received and stored in the memory CS. Then appears each individual i3it of the memory at the output (6) of the decoder and determines whether in the delay element VD, either the one received or that in the same delay element image signal delayed by the duration of one frame (period) and is output at the same time at the output (5). In the first case it will be playback continued. Otherwise it will be interrupted, e.g. the progress of the magnetic tape will be stopped.

The association created in the coder between an image signal and the respective bit of the memory BS can be produced in this way.

In a special case, if the previous and the current full screen are identical are, only the content of the memory AS is received in the delay element VD the old content pushed through again and output at output (5).

The error correction is carried out in the decoder. A Felller can E.g. in a level detector when the input signal level is sufficient be recognized. A repetition of the corresponding part of the E.ingal) e is possible be.

In this case, they are stored in the delay element Image signals output.

Special codes can also be used for error detection and correction can be applied.

The amount of data recorded on the magnetic tape can be further reduced are1 if in the coder not each, but several image signals, e.g. line by line, a bit is assigned. Depending on the comparison value N, the bit would then say that the current line is identical or arbitrarily similar to the previous one. In the Method, the storage capacities of the storage systems AS, BS and CS also decrease.

If the code and the decoder are made as one inseparable unit The delay elements can be, and this is the case with a video recorder VC, VD and the memories BS, CS are only executed once.

What savings in the required storage capacities compared to Conventional methods can be achieved 1 show the following numerical examples. Typical values are assumed: number of lines 500, 25 frames per second, one 100,000 image signals, each 8 bits in size, describe full images.

The picture changes completely within an average Second. A 10 minute image information is processed. The required storage capacities: 1. Coding of each picture signal Without coding: 600 x 25 x 100,000 x 8 = 12 gigabits With coding: 600 x 25 x 1.32 x 100000 = 1.98 gigabits six times the profit 2nd line coding Without coding: 12 gigabits With coding: 600 x 25 x 0.32 x 100000 = 0.48 gigahit 25x profit Profits can be made by using the D-PCM Coding can be enlarged. The content of the AS memory can also be added be coded. By specifying the addresses, its individual digits or Areas are named where the content has the same value.

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Claims (7)

Patent pending video processors, especially for digital video recorders, characterized in that both coder and decoder from those of the video processor can be used completely separately, with those at the input of the coder applied image signals in a delay element by the duration of one or more Fields, i.e. one period, are delayed with a difference between the delayed image signal and the input signal is compared with a value N. and each is stored in the form of a bit in a memory-A, where at the beginning each period the content of the memory A zii a memory B transferred and on Output of the encoder is output, with the subsequent in the delay element image signals delayed by the duration of the period and at another output the Bits assigned to them by comparison with the value N in the previous period <Jes memory n are output, whereby in the decoder of the originally in Coders encoded image information, the content of the memory at the beginning of each period A is received and stored in a memory C, with each bit subsequently of the memory can be output at an output of the decoder and determine can, whether in a delay element, either the input signal of the decoder or the image signal delayed in the same delay element by the duration of the period recorded and output at another output, whereby the generated in the coder Assignment between an image signal and the respective bit of the memory B established can be. 2. Video processor according to claim i, characterized in that daX in the coder several image signals of one period, e.g. an image line, only one bit is assigned, the value of which is the individual The results of the comparisons with the value N indicate where in the decoder each bit of the Memory C can determine the output of several, respective image signals, whereby the assignment can be reproduced. 3. Video processor according to claim l, characterized in that the A / D or D / A converter can be added to the coder and / or decoder at any point, whereby the processing can also be done in an analogous way. 4. Video processor according to claim 1, characterized in that the Coder and / or decoder can be supplemented by buffer memory at any point, whereby the image signals at the respective locations at the desired times for unification can stand. 5. Video processor according to claim 1, characterized in that at a corrupted input signal of the decoder the corresponding part of the input is repeated and / or the image signals stored in the delay element of the decoder are issued. 6. Video processor according to claim 1, characterized in that the im Coder the comparison value N depends on the input signal and / or is influenced by the user can be. 7. Video processor according to claim 1, characterized in that several Coder are combined in one, with the common memory each A and D, whereby one bit each can be assigned to several image signals occurring in parallel and / or several decoders are combined in one, with the common memory C, whereby Several image signals are assigned to each bit of the memory and output in parallel can.