JPH0993140A - Digital data multiplxer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To send pair data of plural channels at a high speed into one data string consecutive timewise by reading selectively EOB data in succession to selectively read of pair data. SOLUTION: The multiplexer is made up of run length coders 13, 14 of quantizers 11, 12, FIFOs 15, 16, significant/insignificant judgement circuits and significant data counters 17, 18,a multiplexer 19, a control means 20, an EOB data generator 21, and a Huffman coder 22. Pair data coded respectively by the run length coders 13, 14 are stored entirely to FIFOs 15, 16 at the end of block. In the data processing cycle of succeeding block, the multiplexer 19 is controlled to read selectively the pair data. In succession to selective reading of the pair data, EOB data are selectively read under the control of the multiplexer or the control of the multiplexer 19 by the control means 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data multiplexer for run-length coding and multiplexing digital data such as image data and audio data of a plurality of channels. Furthermore, the digital data multiplexing apparatus of the present invention is particularly effective in the case of component-length image data composed of luminance and chrominance signals, which are run-length coded for multiplex transmission or multiplex recording.

[0002]

2. Description of the Related Art Conventionally, in a digital data multiplexer, paired data (zero run length data and non-zero data) in which EOB (End Of Block) data representing a channel section or a block section is added to the end of a data string. (Comprising and) is output from the run-length encoder for each channel, and its encoded output (encoded data) is FI
After the data is once stored in the storage means composed of FO (First-In-First-Out), etc., the stored data is sequentially selected in the channel in the multiplexer that multiplexes the encoded data of each channel during the signal processing period of the next block. Are read out and multiplexed.

When selectively reading the accumulated data, the EO added to the end of the data of each channel
The B data is detected, and the process proceeds to the reading of the data of the next channel. That is, in this case, EO
Since the B data means that the paired data of that channel has ended, the read channel is transferred to the next channel by using the EOB data as an identification code, and thereby multiplexing (time division multiplexing) is performed.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention A multiplexer as described above, that is, EOB data is added and stored after signal-processed (run-length encoded) data of each channel, and then EOB data is added at the time of multiplexing. The method of multiplexing by switching the read channel while detecting data is not a problem if the signal processing speed is extremely low, but the target data requires a high processing speed like image data. If the data is
OB data detection time or processing time after detection becomes a problem, and it is not possible to secure a time for reading data from the storage means at the time of multiplexing, so that data of a plurality of channels can be continuously multiplexed and output. The problem of becoming difficult arises.

In order to solve the above problem, an object of the present invention is to selectively read out sequential channels from a plurality of channel pair data stored in a storage means.
It does not require time-consuming detection of EOB data or selection processing of the next channel after detection,
Therefore, it is an object of the present invention to provide a digital data multiplexing apparatus capable of collectively transmitting paired data of a plurality of channels into one data string which is continuous at high speed.

[0006]

In order to achieve the above object, a digital data multiplexing device of the present invention is a device for run-length encoding and multiplexing digital data of a plurality of channels. A run-length encoder that receives the digital data and encodes the received digital data into paired data consisting of zero-run length data and non-zero data, and the run-length encoder that is cascade-connected to the paired data. For each channel, and a storage means for storing, a significant / insignificant determination circuit that receives the digital data of the current block, and counts non-zero data of the received digital data, and a significant data counter, EOB data that generates EOB data representing a channel division or block division And generator, said pairs data and EOB data for each respective channel from the storage means and the EOB data generator for each channel,
A multiplexer for selectively reading and generating multiplexed data in the data processing cycle of the next block, receiving the output at the end of the block of the significant / insignificant decision circuit and the significant data counter of the successive channels, and receiving the next block In the data processing cycle, the control unit controls the multiplexer so as to selectively read the paired data of a corresponding channel for the number of data corresponding to the counter output at the end of the received block. Subsequent to the selective reading of data, the EOB data is selectively read out by the control in the multiplexer or the control of the multiplexer by the control means.

Further, in the digital data multiplexing apparatus of the present invention, the EOB data which is selectively read out after the selective reading of the paired data continues to the data of the non-last channel among the data of the plurality of channels in the same block. The EOB data read out represents a channel division, and the EOB data subsequently read out from the data of the last channel among the data of the plurality of channels in the same block is data representing a block division.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the accompanying drawings. Before describing the digital data multiplexing apparatus of the present invention, the above-mentioned conventional digital data multiplexing apparatus will be briefly described to clarify the difference from the apparatus of the present invention.

FIG. 4 is a block diagram showing a conventional digital data multiplexer. In FIG. 4, 2-channel digital data CH1 and CH2 are encoded by run-length encoders 1 and 2, respectively, and become paired data of zero run length data and non-zero data. As described above, this paired data is added with EOB data at the end of each data string encoded in the block in the run-length encoders 1 and 2, and serves as a storage unit indicated by reference numerals 3 and 4. It is output to FIFO-I and II.

The output sides of the FIFO-I and II are connected to a multiplexer 5 so that one of the outputs is selectively read out by the control described below and sent to the transmission line. That is, the control for selection is the CH1 data string as it is until the EOB data is detected from the output of the FIFO-I (CH1 data string) shown by 3 in FIG. After the detection, the multiplexer 5 controls so that the CH2 data string is selected as a target for selective reading. In addition,
The EOB detector 7 is for detecting EOB from the data string of CH2.

C shown in FIGS. 5A and 5D, respectively.
The data of H1 and CH2 are supplied to the run-length encoders 1 and 2 shown in FIG. 4 and are shown in FIGS. 5B and 5E, which are discontinuous in time (indicated by − in the figure). It is encoded into a paired data string consisting of zero run length data and non-zero data. It is assumed that EOB data is added to the end of the encoded data string. These CH1 and CH2
Of the paired data strings of FIFO-I and II as storage means
(3 and 4 in FIG. 4, respectively) for storage.

With respect to these accumulated data strings, a multiplexer (see FIG. 4) is used in the data processing cycle of the next block.
In step 5), the reading and multiplexing are selectively performed. The first data string read by the multiplexer is the CH1 data string, which is shown in FIG.
The discontinuous portion indicated by-in (b) is filled, and the data is read out as a continuous data string that is short in the time direction. Next, when the CH1 EOB detector (6 in FIG. 4) detects the EOB data of the CH1 data string, the multiplexer switches the data reading from FIFO-I to FIFO-II. As a result, the CH2 data string is read as a short continuous data string in the time direction (FIG. 5 (f)), and is transmitted to the transmission line as time division multiplexed data.

However, in the above-mentioned digital data multiplexer, a delay of, for example, about 2 data periods occurs after the EOB data is detected by the EOB data detector until the reading of the FIFO-II is started. There are cases in which a blank appears in the multiplexed data string as indicated by x in g), or the multiplexing process does not end within the period of one block cycle as shown in FIG.

Next, the present invention will be described. FIG.
1 is a block diagram showing an embodiment of a digital data multiplexing device of the present invention. In addition, (a) to (h) in the figure,
This figure and the time chart for explaining the operation of the multiplexer (Fig. 3)
It is added to correspond to and. In FIG. 1, CH1 and CH2 digital data are as follows.
The quantizers 11 and 12 are quantized by a known method in such a manner that zeros are likely to continue. here,
Quantization divides the data by a certain constant and rounds down the number after the decimal point. The larger the constant, the easier it is for zeros to continue. On the other hand, the outputs of the quantizers 11 and 12 become paired data via the run length encoders 13 and 14, respectively, and are stored in FIFO-I and II as storage means, which are shown as 15 and 16. Regarding the operation of the FIFO-I and II, the difference from the conventional example described with reference to FIG.
In the present invention, the EOB data is not added to the end of the data string of the pair data in the run length coding.

On the other hand, the outputs of the quantizers 11 and 12 are supplied to the significant / insignificant decision circuit and the significant data counters 17 and 18, respectively. These counters 17, 18 are
In short, the number of data of non-zero data (significant data) in the input data is accumulated. For example, as shown in FIG. 2, it is composed of a zero determination circuit 23 and a significant data number counting circuit 24. As circuit operation,
The zero determination circuit 23 determines whether the input data is zero for each data period, and generates a count enable signal when the input data is not zero. Further, the significant data number counting circuit 24 counts up by +1 when receiving the count enable signal from the zero determination circuit 23, and outputs the count result at the end of one block period (16 data periods) shown in FIG. 3 or 5. It is adapted to be supplied to the control means 20 described later. Further, the significant data number counting circuit 24 has a reset input terminal and is adapted to reset the count value to zero when receiving a counter clear signal from the control means 20.

Referring again to FIG. The multiplexer 19 allows the FIFO-I and II (15,
When the data string is read from 16), the data string is output as a continuous data string that is short in the time direction, as described in the conventional example. It goes without saying that this output data string also does not include EOB data, unlike the conventional example. The significance data count output (the number of significance data) from the significance / insignificance determination circuit and the significance data counters 17 and 18 described above is the control means 20.
To control the multiplexer 19. An EOB data generator 21 is also connected to the multiplexer 19 so that the EOB data can be selectively read out by the control in the multiplexer 19 or the control by the control means 20.

Now, it is assumed that the significant / insignificant judgment circuit and the significant data counter 17 output a count value of certain significant data at the end of the block. This count value is used by the multiplexer 19 to selectively read the data accumulated for the period corresponding to the number of the output count value from the FIFO-I indicated by 15 in FIG. 1 in the signal processing period of the next block. used.

The operation of the control means 20 will be described more specifically as follows. CH1 and C encoded by the run-length encoders 13 and 14, respectively
All H2 pair data is 1 at the end of the block.
The data is stored in FIFO-I and II indicated by reference numerals 5 and 16.
Further, the count outputs (the number of significant data) of the significant / insignificant judgment circuit and the significant data counters 17 and 18 at the end of the block are all fetched by the control means 20 at the end of the block. At this time, the start time and the duration of reading the data string from the FIFO-I and II indicated by 15 and 16 are immediately calculated, and can be predicted in advance. Further, the multiplexer 19 is a FIFO-
It is in the data processing cycle of the next block that the data string is selectively read from I and II as continuous data.

That is, as soon as the data processing cycle of the next block is reached, the multiplexer 19 causes the FIFO-
The reading of the data string is started from I (15 in FIG. 1), but the reading duration is determined by the counter output value of the counter 17 at the end of the block, and is controlled by the control means 20 which takes in this value. . FIFO-I
Immediately after the period of reading data from the EOB data generator 12 ends, EOB data representing the channel division is read from the EOB data generator 12. The reading of the EOB data may be performed by the control in the multiplexer 19 or the control by the control means 20.

Reading EOB data (1 data period)
Immediately after the above, the reading of the data string is started from the FIFO-II (16 in FIG. 1). At this time, the starting point is
FIFO-II shown at 16 because it is known in advance
It is possible to perform control in consideration of the processing time required for reading. Further, the duration of this reading is also controlled by the control means 20 which takes in the counter output value of the counter 18 at the end of the block. When the reading of the data from the FIFO-II is completed, the EOB data representing the block division is immediately read from the EOB data generator 12.

The case where two channels of digital data are run length encoded and multiplexed has been described above with reference to FIG. 1, but the same can be done when the number of channels is increased to three or more. Further, after the count output of the significant / insignificant determination circuit and the significant data counters 17 and 18 at the end of the block is fetched by the control means 20, the counter 17.18 does not need to hold the counter output value, and The count value is reset to zero in order to prepare for counting the significant data of the block. The connection from the control means 20 to the counters 17, 18 is the supply line for this reset signal.

The CH1 data string, the EOB data string, the CH2 data string and the EOB data selectively read by the multiplexer 19 as described above are sent to the Huffman encoder 22. By the Huffman encoder, Further, the variable length coded data string is sent to the transmission line as a variable length code output.

The overall operation will be described below with reference to the drawings. FIG. 3 is a time chart showing a specific operation of the digital data multiplexing apparatus of the present invention described above. In FIG. 3, the data string display method is the same as that of FIG. 5 described in the related art. Further, FIG. 3 shows in which part of the multiplexer each data string shown in (a) to (i) is generated in correspondence with FIG. First, (a) and (e) show the data strings of CH1 and CH2 which are quantized by the quantizers 11 and 12 so that zeros are likely to continue. These data strings are supplied to the run length encoders 13 and 14, respectively, and the obtained pair data (zero run length data, non-zero data)
For the run-length encoder 13 for CH1, the data string (b), that is, (0,1) (0,8) (3,
5) (2, 2) (1, 4) (0, 7) (2, 3) (0,
6) (however, (-,-) are omitted), and for the run-length encoder 14 for CH2, the data string (f), that is, (0, 2) (4, 8) (2, 3).
(4, 4) (0, 9) ((-,-) are omitted here as well). These data strings are immediately written to the FIFO-I and II indicated by 15 and 16 in FIG. 1, respectively.

At the same time, in the significant / insignificant judgment circuit and the significant data counter 17, the effective paired data (that is, the data strings (b) and (f) are (-,
Since the counter is incremented by +1 each time the data portion that does not become −) is counted, the count is as shown in (c) for CH1, and the count value at the end of the block is 8
Becomes Similarly, in the case of CH2, the count becomes (g) by the data counter 18, and the count value at the end of the block becomes 5. Both of these values (8 and 5) are fed to the control means, respectively FIFO-I, II.
It is used for selective data reading from (15, 16 in FIG. 1).

In the signal processing cycle of the next block (block period shown in the right half of FIG. 3), the control means 20 first selects the CH1 side, and the significant / insignificant determination circuit and the significant circuit at the end of the block. The data is read from the FIFO-I up to 8 which is the count result of the data counter 17. The discontinuous paired data (b) which is the output data of the run-length encoder 13 has been stored in the FIFO-I once, so here (d).
Pair data as continuous data as shown in can be read. When this reading is completed, for example, the control means 20 sends a reset signal to the significant / insignificant determination circuit and the significant data counter 17 to prepare for the signal processing of the next block.

When the output of the multiplexer 19 finishes outputting the pair data from the FIFO-I of CH1, the data reading is switched to the EOB data generator 21 to output the EOB data. In addition, here EOB
The data is (0,0).

After the EOB data is output in this way, the CH2 side is selected, and data is output from the FIFO-II up to 5 (the value at the end of the block) which is the count result of the significant / insignificant judgment circuit and the significant data counter 18. Read out. At this time, the start point of reading the data from the FIFO-II is calculated as 8 + 1 = 9 from the results of the significant / insignificant judgment circuit and the significant data counter 17, and it is sufficient to start the reading from the next number of 9. Since it is predicted in advance, it is controlled in consideration of the processing time required for reading the FIFO-II. Again, the data is FIF
Since the data is once stored in O-II, it is possible to read the paired data as continuous data as shown in (h). After reading, the counter 1 is the same as CH1.
8 is reset.

Then, when the output of the multiplexer 19 finishes outputting the pair data from the FIFO-II of CH2, the read is switched to the EOB data generator 21 to switch the EOB.
Output the data.

From the above, valid pair data (0, 1) is output from the output side of the multiplexer 19 as shown in (i).
(0,8) (3,5) (2,2) (1,4) (0,7)
(2,3) (0,6) (0,0) (0,2) (4,8)
(2, 3) (4, 4) (0, 9) (0, 0) are continuously output, that is, the paired data of CH1 and CH2 are time-division multiplexed as continuous data.

In the embodiment described above, the data to be multiplexed has two channels, but if the number of consecutive zeros is sufficiently large, the data of two or more channels can be multiplexed. Further, the number of digital data per block, which is 16 in the above embodiment, is not limited to this.

Also, regarding the circuit configuration of the digital data multiplexing apparatus of the present invention, the circuit element used may be replaced with another circuit element as long as it has a function equivalent to that, for example, as a storage means. The FIFO can be realized by replacing it with another type of storage device.

[0032]

According to the present invention, it is in the signal processing cycle of the next block that the data of a plurality of channels is multiplexed, and the time when the channel at the time of entering the processing cycle should be switched to the next channel. Since it is known (can be predicted), it is possible to set the data read time from the data storage means (for example, to perform read control in anticipation of the read delay of the FIFO), and thus the EOB data detection There is no longer a situation in which, like a conventional multiplexer which reads the FIFO later, a wasteful time is taken for multiplexing and processing cannot be performed within one block period (see FIG. 5).

Further, by implementing the present invention, even if the pair data which is run-length coded is continuously stored regardless of the channel or the block for storing the pair data in the storage means, the delimiter information is stored. As a result, since the number of significant data at the end of the block in the channel or block is detected by the significant data counter, consideration such as inserting delimiter information between channels or blocks becomes unnecessary.

In addition, since the EOB data is inserted after the transmission of the last pair data of the channel or block is completed at the time of multiplexing, as in the conventional case, the EOB data is inserted at the end of the pair data for each channel or block. It is no longer necessary to add EOB data and store it in the pair data storage means. Therefore, referring to the stored pair data, E
It is not necessary to detect OB data and switch multiplexing.

Further, generally, in multiplexing, if the data amount is compressed or the data amount does not change, the processing speed must be increased. However, when run-length coding is performed as in the present invention, significant data is output in a timely manner, but the amount of data is
Compared to before run-length coding, the amount of data per channel is controlled by a quantizer so that the data amount is 1 / (total number of channels) or less and compression is performed by run-length coding.

Therefore, it is only necessary to process the total number of data counted by the significant data counting means by the number of channels to be multiplexed within one block data processing cycle. At this time, it is not necessary to individually detect and multiplex the data of the number of channels in the block to be multiplexed. Therefore, it is not necessary to increase the processing speed of data, and there is an effect that the processing speed can be reduced as it is or the amount of data is reduced.

The effects described above are greatly exerted particularly when processing a high-definition image signal.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital data multiplexing device of the present invention.

FIG. 2 shows a configuration of a significant / insignificant determination circuit and a significant data counter in the configuration of FIG.

FIG. 3 is a time chart showing a specific operation of the digital data multiplexing apparatus of the present invention.

FIG. 4 is a block diagram showing a conventional digital data multiplexer.

FIG. 5 is a time chart showing the operation of the conventional digital data multiplexer.

[Explanation of symbols]

1, 2 Run-length encoder (including EOB addition function) 3 FIFO-I 4 FIFO-II 5 multiplexer 6, 7 EOB data detector 11, 12 quantizer 13, 14 Run-length encoder 15 FIFO-I 16 FIFO-II 17, 18 Significant / insignificant decision circuit and significant data counter 19 Multiplexer 20 Control means 21 EOB data generator 22 Huffman encoder 23 Zero decision circuit 24 Significant data number counting circuit

Claims (2)

[Claims] 1. An apparatus for run-length encoding and multiplexing multiple channels of digital data, wherein the apparatus receives the digital data of a current block, and receives the received digital data as zero run length data and non-zero data. A run-length encoder for encoding paired data, storage means for storing the paired data in cascade connection to the run-length encoder, and receiving the digital data of the current block, Each channel is provided with a significant / insignificant judgment circuit that counts non-zero data of the digitized digital data and a significant data counter, and further, an EO representing a channel division or a block division
The pair data and EOB data for each channel are selectively read from the EOB data generator for generating B data, the storage means for each channel, and the EOB data generator in the data processing cycle of the next block. A multiplexer for generating multiplexed data, receiving the end-of-block output of the significant / insignificant decision circuit and the significant-data counter of successive channels, and receiving the end-of-block counter in the data processing cycle of the next block And a control means for controlling the multiplexer so as to selectively read the paired data of a corresponding channel for the number of data corresponding to the output, and, following the selective reading of the paired data, in the multiplexer. Control or by the control means Digital data multiplexing apparatus characterized by being configured such that the EOB data is selectively read out under the control of the multiplexer. 2. The digital data multiplexing apparatus according to claim 1, wherein the EOB data which is selectively read out after the selective reading of the paired data is of a channel which is not the last among the data of the plurality of channels in the same block. Digital data characterized in that the EOB data read subsequently to the data represents a channel division, and the EOB data continuously read out from the data of the last channel among the data of the plurality of channels in the same block is data showing the block division. Multiplexer.