JPH0313087A - Picture coder - Google Patents

Abstract

PURPOSE:To attain the processing at a low speed as to each coder by using plural coders to an HDTV signal to apply parallel processing. CONSTITUTION:In the case of an HDTV signal, an input signal is split into 4 by a 1st switch 2 and written in 1st-4th buffer memories 3-6 and read from the buffer memories 3-6 simultaneously to apply parallel processing. Since dispersion (rough and minute parts) takes place into a data by each parallel processing, random processing is applied by a shuffling device 8. After DCT operation is applied to a random processing data, variable length coding is applied to each conversion data. As to the write to the buffer memories 3-6, since the data is processed at random by shuffling at readout, there is no special restriction except the changeover of a 1st switch 2 in the unit of lines specified by the size of a block.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image encoding device for image signals (HD TV signals, MUSE signals, standard TV signals).

Conventional technology HDTV signal transmission A HDTV signal with a bandwidth several times wider than the current standard TV signal.
When attempting to record on a TR, disc, etc., the required bit rate becomes extremely high. Therefore, compressing and encoding the amount of information to an extent that does not cause significant deterioration in image quality is a promising technique.However, HDTV signals have a particularly large difference from current standard TV signals, except for the fact that they are broadband. Is it possible to apply the same encoding method as the current one? The MUSE method is a method for transmitting QHDTV signals using one channel of satellite broadcasting. This method compresses the baseband of a wideband HDTV signal to 8MHz using multiple sub-Nyquist sampling.
Then, by frequency modulating the transmission band, the transmission band is reduced to 2TMH2 width, which is one channel of a broadcasting satellite, and satellite broadcasting can be performed on the same transmission channel as the current broadcasting.In this way, the MUSE method uses a narrowband H.
Since it is a signal format that can transmit DTV signals, VTR,
It can also be applied to various recording and reproducing devices such as disks.
By compressing and encoding using the UseMUSE method, even longer recording becomes possible.

About standard format TV signals The method of compressing and encoding L signals is an effective means for transmission or recording, and various methods have been devised or made into devices.

Here, it would be very efficient if the same encoding process could be applied to each of the above-mentioned HDTV signal and MU'SE standard TV signal, and the circuits could be shared. In realizing the image encoding device as described above, there are problems such as those listed below (and some techniques). It is difficult to implement a technology that sequentially encodes input signals in terms of hardware, and an encoding method that takes feasibility into account is required. V 4W
When considering sharing MUSE signals and standard TV signals, each signal has a different sampling frequency.If the circuit is simply shared, the processing frequency will differ depending on the signal, making it impossible to transmit and record at a constant rate. becomes impossible.

In view of the problems of the prior art, it is an object of the present invention to provide an image encoding device that can be used for encoding HDTV signals, MUSE signals, and standard TV signals and is suitable for shared use. It is an object.

Means for Solving the Problems The present invention (Friend) In compressing and encoding an image signal in units of blocks, it has a plurality of encoders operating in parallel,
The HDTV signal is encoded using all of the above encoders (for the MUSE signal or the standard TV signal, among the multiple encoders mentioned above,
The present invention is characterized in that it is configured to perform encoding using some encoders.

Effects The present invention has the above-described configuration, so that ζ
By using multiple encoders and processing in parallel, each encoder can process at low speed.
Is it possible to handle high-speed processing of HDTV signals with these encoders? , MUSE signal For standard format TV signals, encoding processing can be performed using some of the above-mentioned multiple encoders without using a dedicated encoder. Embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure, 1 is an input terminal, and 2 is an input terminal. The first selects and outputs the signal input from terminal 1 to one of the four buffer memories 3.4.5.6.
These 1st to 4th buffer memories 3-
Reading from 6 is performed using a clock independent of the write clock (\ Blocking is performed at the same time.) 7 is a second switch, which receives the input signal or the output of the first switch 2 as an input to the fourth buffer memory 6. Select one of the signals. 8 is a shuffling device, which randomizes the data blocked in each buffer memory 3 to 6 in block units. Also, 9, 10, 11,
12 C 1st to 4th DCT arithmetic unit Tearari, 13, 1
4, 15, and 16 are first units that perform variable length encoding on the data converted by each DcT calculation unit 9 to 12.
The operation of the image encoding apparatus in this embodiment will be explained below in the fourth variable length encoder. HDTV signal MUSE signal Power for inputting standard TV signal 3M class signal <
, HDTV signal 1 has a large amount of information compared to other signals, and the processing format is also different. For example, the table below shows the bit rate of each signal (for HDTV signals, MU
SE signal The bit rate is about 3 to 4 times that of the standard TV signal.

Therefore, in the case of an HDTV signal, the input signal is divided into four by the first switch 2 and written to the first to fourth buffer memories 3 to 6. Parallel processing is performed by simultaneously reading from each buffer memory 3 to 6. Do the following. Here, the data is read out simultaneously in blocks from each buffer memory 3 to 6, and is randomized by a shuffling device 8, which causes variations in data (coarse parts and fine parts) due to each parallel processing unit. Let's do it. Regarding shuffling, methods such as dividing one field into several blocks and randomizing within each block or randomizing within one field can be considered.It is more effective to perform it in large units. Finally, after performing DCT operation on the randomized data, a variable length encoder is applied to each transformed data. Regarding writing to buffer memories 3 to 6, the first switch 2 is switched in units of lines determined by the block size, which is randomized by shuffling when reading.
There are no particular restrictions.

In case of MUSE signal, standard TV signal (Yo 4)
Processing is performed using only one of the two parallel processing circuits. In other words, the second switch 7 switches the input signal to the fourth
Write only to buffer memory 6 After the read data is randomized by the shuffling device 8, the fourth DCT calculation device 12 performs calculation, and the fourth variable length encoder 16 performs variable length encoding. Here, as shown in the table? ,,MUSE
Signal, standard TV signal ζi Approximately 1/1 of HDTV signal
It is sufficient that the size of the fourth buffer memory 6 is 1/3 to 1/4 of the HDTV signal. MUSE signal When changing the compression rate of a standard TV signal to that of an HDTV signal, this can be easily achieved by manipulating the compression rate in the variable length encoder 16.

As explained above, in this embodiment, the encoding process of the HDTV signal signal is parallelized into four processes. Furthermore, by separating the writing clock and the reading clock using the buffer memories 3 to 6, the encoding process can always be performed with a constant clock even if the sampling frequency of the human signal is different.

In the above example, the processing is parallelized into four stages depending on the selected sampling frequency.Of course, the number of parallelizations differs depending on the sampling frequency and the encoding processing format. As a method of
In the above embodiment, another method that uses DCT and is capable of highly parallel processing may be applied.

As described in detail, according to the present invention, even a 1i HDTV signal can be processed by high-speed processing by using a plurality of low-speed encoders in parallel, and therefore has excellent hardware implementation.

In addition, since the encoding process can always be performed with a constant clock regardless of input signals with different sampling frequencies, the encoding process when compressing and encoding HDTV uMUsE signal standard TV signals can be easily shared. It is possible, and its practical effects are great.

[Brief explanation of the drawing]

The figure is a block diagram of an image encoding device according to an embodiment of the present invention.

Claims (2)

[Claims] (1) When compressing and encoding image signals in block units, HDTV has multiple encoders that operate in parallel.
For signals, all of the encoders mentioned above are used for encoding, and for MUSE signals or standard TV signals, some of the encoders among the plurality of encoders mentioned above are used. An image encoding device characterized in that it is configured to perform encoding. (2) having a memory corresponding to each of the plurality of encoders;
The image signal is once stored in the memory and the data read from the memory is compressed and encoded so that the plurality of encoders are all operated with a common clock regardless of the image signal. The image encoding device according to claim 1, characterized in that: