DD148431A1 - Method for redundancy-coding television signals - Google Patents

Method for redundancy-coding television signals Download PDF

Info

Publication number
DD148431A1
DD148431A1 DD21811478A DD21811478A DD148431A1 DD 148431 A1 DD148431 A1 DD 148431A1 DD 21811478 A DD21811478 A DD 21811478A DD 21811478 A DD21811478 A DD 21811478A DD 148431 A1 DD148431 A1 DD 148431A1
Authority
DD
German Democratic Republic
Prior art keywords
information
line
correction information
period
bits
Prior art date
Application number
DD21811478A
Other languages
German (de)
Inventor
Werner Zuehlke
Original Assignee
Werner Zuehlke
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Werner Zuehlke filed Critical Werner Zuehlke
Priority to DD21811478A priority Critical patent/DD148431A1/en
Publication of DD148431A1 publication Critical patent/DD148431A1/en

Links

Abstract

Method for low-redundancy coding of television picture signals for digital transmission and storage with the aim of low signal deviations after demodulation and technically simple coding, decoding and recoding. The object of the invention is to achieve a frame design when adapting the Kodewortlaenge to the waveform, which can be transmitted via synchronous transmission links or stored in line memory fixed length. For this purpose, coded combinations of fixed length of e.g. 3 bits for the brightness DPCM signal and e.g. 2 bits formed with the appropriate sampling frequency for the coded color information and output in the image line time. In addition, e.g. in places of extreme signal changes, further e.g. 2 bits formed as correction information and output in the order of their occurrence in the associated Zeilausustastluecke. The correction information is used to correct the relevant sample and not the further demodulation. They are expediently output in the line blanking line in front of the actual image line, are filled up to their maximum length by fill bits and suppressed in the event of overzealousness.

Description

, 218 114

V experienced for low-redundancy coding of television picture signals

A field of application of the invention

The invention relates to methods for low-redundancy coding of television picture signals to be transmitted or stored digitally.

Characteristic of the known technical solutions

To reduce the resulting in the PCM coding of image signals, in particular color image signals, high bit rate there are first method for signal redundancy reduction and secondly the possibility of exploiting the line blanking interval of the analog television signal, of which in the digital coding of the television signal only a small part for the Line synchronization and the sound transmission is needed.

As a technically simple yet effective method for redundancy reduction proved the Differenzpulscodemodulationsverfahren, called DPCM. In the simplest case, the differences are formed by consecutive samples and encoded with a fixed word length of 3 bits or 4 bits per sample for the brightness difference signal X and about 2 bits per sample for the color difference signals R-X and B-X or I and Q respectively.

For digital transmission, all signals must be staggered in time. These were procedures with the framework

1 (Y 1 , I 1 , Q 1 , X 2 JI 2 JQ 2 , ·· "Y n , I n , Q n ) and with the frame

2 (Y 1, X 2 , ... X n , I 1 , I 2 , .. "I n , Q 1 , Q 2 , ... Q) with different Y / ortlängen for the Y., I. and Q. words, resp.

JL JL JL

21 8 114

Y., Β.-Ϊ. and B.Y.-words are under / 1, 2, 3 /. The available

JL JL. JL JL JL

time is an active image line (line without ZA gap), when recoding of analog television signals (NTSC, PAL, SECAM) into digital signals or vice versa are provided, and can, if such recoding is not or be provided only with greater effort, up to 1.2 times the image line length. For frame 2, in addition to the image line time and the additional time from the line blanking gap, there is still a further time gain possible in that the I and Q signals or other color information are sent alternately in successive lines of output, similar to the SECAM principle / 2 / ,

Lack of these methods are that the DPCM method due to their short word length used can not follow rapid signal changes (slope overload) or small signal changes · can not encode accurately enough (granular noise) and with the frame 1, the line blanking gap can only be used if greater effort in the transcoding of or in analog signals is taken into account, while in the second frame time information is pulled apart, the receiver must again collapse on cache. In the case of methods with different word lengths, an asynchronous bit stream arises which must be buffer-converted into a synchronous bit stream via buffer memory / 4 / o If the line blanking gap is used only for the color information, the temporal utilization is poor for black-and-white television and for color transmissions Relationship of brightness to color information determined by the ratio of line time to line blanking gap and not by visual aspects.

Z iel the invention

in the

It is the object of the invention to match the signal profile at the receiver as well as possible at the transmitter with the means of a few bits and to make the decoding and recoding of and into other methods technically simple.

- 3 - 218 1 14

Presentation of the essence of the invention

It is an object of the invention to achieve an adaptation of the code word length to the waveform and to make the frame so that the resulting asynchronous bit stream can be transmitted by a synchronous transmission method and stored in line memory of fixed length »The DPCM method with fixed word lengths use for the coding of pixels in areas and areas of small details as much Bitraster as in areas of gross details and sudden changes in brightness and can not be adapted to the waveform over the Bitrasterzahl. By utilizing the line blanking gap for information transfer and the necessary transcoding to and from analogue methods where the line blanking interval is needed for synchronization, the technical overhead increases due to the necessary time shifts or time compressions.

According to the invention (for o example, difference values) are code words used with at least two different lengths, for coding the information of which the short words and the equally long part of the long code words in the image row time and remaining words, referred to as correction information are transferred to the associated horizontal blanking , For clear decoding, the correction information carries address information or the subcode words in the image line time carry features. For example, the differences in the luminance signal course are coded by a 3-bit assignment, and further 2-bit correction information is then sent in the associated line blanking interval if the 3-bit DPCM word identifies the codable maximum value. ! Color information is corrected in the same way, and for, whose correction information can also be used shorter word lengths than for the brightness corrections. 'If the available time in the line blanking gap is filled with correction information, in the simplest case the remaining ones still accumulate in the associated line

218 114

simply suppressed. Therefore, the extreme codewords or other characteristic code combinations, such as two consecutive extreme codewords or an extreme, difficult-to-code sequence of information, should be chosen so that the sum of all corrections does not often take more than the available time. If the process with a plurality of coding modes, z o 0 B different encodings for surfaces, details and edges, coupled to the correction can be limited to extreme values of individual modes.

Too little correction information is padded to its normal amount by fill bits

Due to the splitting into information of the same length, which is transmitted in the line time, and into the residual lengths of some code words designated as correction information, it is achieved that, despite different word lengths for the coding, a synchronous transmission of the essential line information ensues.

As an associated line blanking interval, it is expedient to use the one before the start of the line, because then the number of necessary buffer memories in the receivers is substantially lower than when the line blanking interval after the end of the line is used.

In addition, it is proposed to use only the same parts of the line frame for the formation of prediction values in the decoding and to use the residual values from the line blanking gap 'only for correction in the respective raster.' There is therefore the possibility of developing simple, inexpensive devices without correction and without Süeicher and comfortable devices with correction options. It also allows the partial or total re-clearing of the line blanking gap for later processes of stereo television and other television services.

5 - 218 ί 14

embodiment

The invention will be explained below using an exemplary embodiment.

In the accompanying drawing zeig't:

Fig. 1: Frame structure for a transmission method with correction information, which lie in the line blanking interval in front of the image line.

Fig. 2: A coding table for the 3-bit DPCM with 2 correction bits for large changes in the signal.

In Fig. 1, the correction information k ^ to k are drawn to the left in the previous line blanking interval t " A to 2 bits in an unbroken sequence and padded with Füllbit to its maximum length. This is followed by information about audio transmission and synchronization. In the image line time t.sub.n beginning after this, block-by-block information about the brightness progression, in the example selected four codewords of 3 bits each, and of color coding, here one codeword each for the color coordinates I and Q to 2 bits, are arranged. ·

The hatched rasters for Y ~ and Y n- ^ indicate that extreme changes in the signal are coded here and that correction information k k and k are to be assigned to them. The correction k o

Im- 2

belongs to the hatched information Q ^ and can have another word length agreed upon for color corrections than k ^ and

Fig. 2 shows a possible coding table for the 3-bit DPCM with 2 correction bits, where correction bits are always allocated when the code words LLL or 000 occur for the DPCM. These correction bits indicate different corrections for the positive and negative signal changes in this example.

Claims (3)

  1. " 6 " 218 1 14
    Claim for invention
    1. Method for low-definition coding-of television pictures. Nalen, characterized in that in a time interval (t "), which expediently corresponds to the image line time, code combinations of fixed length as coded brightness information (T-) and code combinations with not necessarily the same but also fixed length as encoded color information (Z 1 , Q ^) and in an associated period of time (t 7A ), which expediently corresponds to a line-end gap, additional fixed-length code combinations are arranged as correction information with which some of the brightness and color information occurring in the former period (t 7 ) are corrected during the decoding, and from the information Ϋ. t I and Q. of the former period (t 7 ) and the order of correction information (k.) Apart
    j v ^ ird, which correction information (k.) belongs to which information.
  2. 2. The method according to item 1, characterized in that in the associated period (W.) correction information (k ·) occur when in the period (t ") occur code combinations that characterize an extreme signal change.
    Method according to item 1, characterized in that said associated period (^ Ζ λ) is prior to the period (t 7 ) and in particular the television line blanking interval is used to transmit the correction information (k.) For the next image line.
  3. 4. The method according to item 1, characterized in that the correction information k. in demodulation only for the sake of
    J
    is used to correct the associated sample value.
    For this 1 page drawings
DD21811478A 1978-12-27 1978-12-27 Method for redundancy-coding television signals DD148431A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DD21811478A DD148431A1 (en) 1978-12-27 1978-12-27 Method for redundancy-coding television signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DD21811478A DD148431A1 (en) 1978-12-27 1978-12-27 Method for redundancy-coding television signals

Publications (1)

Publication Number Publication Date
DD148431A1 true DD148431A1 (en) 1981-05-20

Family

ID=5521986

Family Applications (1)

Application Number Title Priority Date Filing Date
DD21811478A DD148431A1 (en) 1978-12-27 1978-12-27 Method for redundancy-coding television signals

Country Status (1)

Country Link
DD (1) DD148431A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3342373A1 (en) * 1983-11-21 1985-05-30 Wolfram Dipl Ing Liebsch Digital transmission method for analog signals
DE3602825A1 (en) * 1986-01-30 1987-08-06 Siemens Ag Method and arrangement for synchronisation
DE3724544A1 (en) * 1987-07-24 1989-02-02 Bosch Gmbh Robert Method and circuit arrangement for transmitting television signals

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3342373A1 (en) * 1983-11-21 1985-05-30 Wolfram Dipl Ing Liebsch Digital transmission method for analog signals
DE3602825A1 (en) * 1986-01-30 1987-08-06 Siemens Ag Method and arrangement for synchronisation
DE3724544A1 (en) * 1987-07-24 1989-02-02 Bosch Gmbh Robert Method and circuit arrangement for transmitting television signals

Similar Documents

Publication Publication Date Title
US6067119A (en) Hierarchical low latency video compression
DE69333742T2 (en) Method and apparatus for image data coding
US5434623A (en) Method and apparatus for image data compression using combined luminance/chrominance coding
US5021879A (en) System for transmitting video pictures
EP0910213B1 (en) Coding and decoding of digital video signals
JP2547233B2 (en) Coded television signal decoding apparatus
US6400767B1 (en) Communication of HBI data in digital television data streams
JP2670259B2 (en) High-efficiency coding device
CA2060380C (en) Method and apparatus for communicating compressed digital video signals using multiple processors
EP0394332B1 (en) SYMBOL CODE GENERATION PROCEEDING FROM INTERFRAME DPCM OF TDM'd SPATIAL-FREQUENCY ANALYSES OF VIDEO SIGNALS
US5253053A (en) Variable length decoding using lookup tables
EP0744869B1 (en) Image processing apparatus
US5216503A (en) Statistical multiplexer for a multichannel image compression system
EP0778703A2 (en) Variable length code recording/playback apparatus
US20020080875A1 (en) Coded stream splicing device and method, and coded stream generating device and method
CA1227867A (en) Image transmission
US5485211A (en) Multiple encoder output buffer apparatus for differential coding of video information
EP0084270B1 (en) Video bandwidth reduction system employing interframe block differencing and transform domain coding
JP2532712B2 (en) How and transmitting encoded as global motion vector and the local motion vectors video signal
EP0562419A2 (en) Variable length code word decoder for use in digital communication systems
US5295203A (en) Method and apparatus for vector coding of video transform coefficients
US5694170A (en) Video compression using multiple computing agents
US5136371A (en) Digital image coding using random scanning
DE69934616T2 (en) Device and method for predictive motion-compensated coding
US5781561A (en) Encoding apparatus for hierarchically encoding image signal and decoding apparatus for decoding the image signal hierarchically encoded by the encoding apparatus

Legal Events

Date Code Title Description
ENJ Ceased due to non-payment of renewal fee