JPH11205784A - Picture decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a picture decoder analyzing a fault without adding a measuring instrument at the time of generating an error during reception. SOLUTION: An error information analyzing part 3 detects kinds of error information generated at a variable length decoding part 2 by a syntax monitoring part 11, a code monitoring part 12 and the number of pixels and the number of lines monitoring part 13 to write in an analyzing memory 14 by the control of a memory control part 15. Then, writing is stopped at the time point of generating an error and the contents of the memory 14 are read to be displayed outside by an instruction from outside such as a personal computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image decoding apparatus for analyzing decoding failure detection.

[0002]

2. Description of the Related Art Generally, an image decoding apparatus uses MPEG2.
(Moving Picture Experts G
In the case of receiving a highly efficient encoded bit stream represented by loop 2) and performing variable length decoding, a decoding error may occur due to a bit error in a transmission path, a defective encoder, or the like. When these errors occur, error concealment that detects syntax violations and codes not specified in the decoding table when performing variable-length decoding and replaces erroneous data with past data remaining in memory. And so on.

[0003]

Since the conventional image decoding apparatus performs the above-described processing, the type of error can be specified. However, detailed information such as how the image is coded is not decoded by the image decoding apparatus. There is a problem that analysis cannot be performed unless a measuring instrument such as a logic analyzer is connected to a circuit inside the apparatus. In addition, there is a problem that this analysis requires a great deal of labor and time, and may lead to an unexpected failure during the measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an image decoding apparatus which can analyze a failure without adding a measuring device even when an error occurs during normal reception. The purpose is to gain.

[0005]

An image decoding apparatus according to the present invention comprises: a variable length decoding means for reading and decoding data contained in a received bit stream; The related predetermined status and the writing of the data are sequentially performed in units of a picture head pulse included in the bit stream. When an invalid status is detected, the writing is stopped, and the written status and the data are written. And error information analysis means for outputting the error information.

[0006] In the image decoding apparatus according to the present invention, the error information analysis means monitors the syntax status included in the bit stream and outputs the syntax status, and notifies an error when detecting an incorrect syntax status. , An analysis memory to which the syntax status and the data contained in the bit stream are sequentially written, and a picture head pulse contained in the bit stream to the analysis memory. Memory control means for successively writing data, and stopping the writing when an error notification output from the syntax monitoring means is received, and display control for reading the syntax status and the data written in the analysis memory. With means A.

In the image decoding apparatus according to the present invention, the error information analyzing means has a code table in which a predetermined code is defined, and the code status included in the bit stream is defined in the code table. A code monitoring unit that monitors by comparing with a code, outputs the code status, and outputs an error notification when an incorrect code status is detected, and sequentially writes the code status and data included in the bit stream. Memory control for sequentially performing writing to the analysis memory in units of a picture head pulse included in the bit stream and receiving an error notification output from the code monitoring unit, and stopping the writing. Means and written in the analysis memory It is obtained and a display control means for reading the serial code status and the data.

[0008] In the image decoding apparatus according to the present invention, the error information analysis means monitors the number of pixels / line number status included in the bit stream, outputs the pixel number / line number status, and outputs an incorrect number of pixels. A number-of-pixels / line-number monitoring means for outputting an error notification upon detection of the / number-of-lines status, an analysis memory in which the pixel number / line number status and data contained in the bit stream are sequentially written; A memory control unit for sequentially writing data to the analysis memory in units of a picture head pulse included in the image data and stopping the writing when an error notification output from the pixel number / line number monitoring unit is received; Of the pixel number / line number status and the data written in the memory for It is obtained and a display control unit.

An image decoding apparatus according to the present invention comprises: a variable length decoding means for reading and decoding data included in a received bit stream; a predetermined status relating to error information included in the bit stream; Writing of a temporal reference indicating the header information and the frame number included in the bit stream is sequentially performed in units of memory capacity of a memory to be written or in units of sequence header information included in the bit stream, and when an invalid status is detected. Error information analyzing means for stopping the writing and outputting the written status, the header information and the temporal reference.

[0010] In the image decoding apparatus according to the present invention, the error information analysis means monitors the syntax status included in the bit stream and outputs the syntax status, and notifies an error when detecting an incorrect syntax status. , An analysis memory in which the syntax status, the header information and the temporal reference included in the bit stream are sequentially written, and a memory capacity unit of the analysis memory or included in the bit stream. Memory control means for sequentially writing data to the analysis memory in units of sequence header information and receiving the error notification output from the syntax monitoring means, and stopping the writing, and writing to the analysis memory. Above Scan status, in which a display control means for reading out the header information and the temporal reference.

[0011] In the image decoding apparatus according to the present invention, the error information analysis means has a code table in which a predetermined code is defined, and the code status included in the bit stream is defined in the code table. A code monitoring unit that monitors by comparing with a code, outputs the code status, and outputs an error notification when an invalid code status is detected; and the code status, header information included in the bit stream, and temporal information. The reference memory is sequentially written to the analysis memory, and the analysis memory is sequentially written in units of the memory capacity of the analysis memory or in units of sequence header information included in the bit stream, and is output from the code monitoring unit. Is written when an error notification is received A memory control means to stop, the code status written in the memory for the analysis, in which a display control means for reading out the header information and the temporal reference.

[0012] In the image decoding apparatus according to the present invention, the error information analysis means monitors the number of pixels / line number status included in the bit stream, outputs the number of pixels / line number status, and outputs an incorrect number of pixels. A pixel number / line number monitoring means for outputting an error notification upon detection of the pixel number / line number status;
An analysis memory in which header information and a temporal reference included in the bit stream are sequentially written, and a memory capacity unit of the analysis memory or a sequence header information unit included in the bit stream to the analysis memory. Memory control means for sequentially performing writing and stopping the writing when an error notification output from the pixel number / line number monitoring means is received; the pixel number / line number status written in the analysis memory; A display control unit for reading out header information and a temporal reference included in the bit stream.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of an image decoding apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a reception buffer memory which temporarily stores a received bit stream 101 and separates a picture head pulse 102 from the bit stream 101.
Reference numeral 2 denotes a variable-length decoding unit (variable-length decoding unit) that reads the bit stream 101 from the reception buffer memory 1,
The shifter inside the variable length decoding unit 2 outputs a bit stream 104 in which data code alignment is always taken, and performs variable length decoding to output decoded data 103.

Reference numeral 3 denotes an error information analysis unit (error information analysis means), which is a bit stream 104 output from the variable length decoding unit 2, a bit stream 101 read from the reception buffer memory 1, and a picture head pulse 102.
To analyze the error information.

In the error information analysis unit 3, reference numeral 11 denotes a syntax monitoring unit (syntax monitoring unit) which monitors the syntax code of the bit stream 104,
It outputs a syntax status 105, that is, a normal syntax status or an incorrect syntax status, and outputs an error notification 106 when an incorrect syntax status is detected.

Reference numeral 12 denotes a code monitoring unit (code monitoring means) which has a code table in which prescribed codes are described, and displays a code status included in the bit stream 104 in a code described in the code table. Monitor by comparing with code status 1
07, that is, a normal code status or an incorrect code status below the slice layer not specified in the code table, and an error notification 108 is output when an incorrect code status is detected. Here, the slice layer is a set of macroblocks defined by MPEG2 and comes after the picture layer. Codes below the slice layer are not transmitted from the encoding side.

Reference numeral 13 denotes a pixel number / line number monitoring unit (pixel number /
The number of lines monitoring unit) receives the bit stream 104, monitors the number of decoded pixels and the number of lines, and monitors the number of pixels / line number status 109, that is, the normal number of pixels / line number status or the incorrect number of pixels / In addition to outputting the line number status, when an incorrect pixel number / line number status is detected, an error notification 110 is output.

Reference numeral 14 denotes an analysis memory, which is a bit stream 101, a syntax status 105 output from the syntax monitoring unit 11, a code status 107 output from the code monitoring unit 12, and a pixel / line number monitoring unit 13. , The pixel number / line number status 109 output from the CPU is sequentially written and stored.

Reference numeral 15 denotes a memory control unit (memory control means), which controls writing to the analysis memory 6 by a write enable 111 and an address 112. Reference numeral 16 denotes a display control unit (display control means), which is an address 112 from the memory control unit 15, output information 113 of the analysis memory 14,
Syntax monitoring unit 11, code monitoring unit 12, number of pixels /
Error notification 106 output from line number monitoring unit 13,
108 and 110 are input to perform control for monitoring with a personal computer or an external monitor of a display panel.

As described above, the error information analyzer 3 includes a syntax monitor 11, a code monitor 12, a pixel / line number monitor 13, an analysis memory 14, and a memory controller 15.
And a display control unit 16.

Next, the operation will be described. The received bit stream 101 is stored in the reception buffer memory 1. The bit width here, that is, the number of data bits depends on the configuration of the variable length decoding unit 2 and may be any value. The reception buffer memory 1 separates the picture start pulse 102 from the bit stream 101 and
Is output to the memory control unit 15. The bit stream 101 stored in the reception buffer memory 1 is read irregularly in accordance with an instruction from the variable length decoding unit 2, and the specified code is always aligned by the shifter in the variable length decoding unit 2. And output as a bit stream 104. The variable length decoding unit 2 repeats decoding of a header, decoding of DCT coefficients, and the like from the bit stream 104, and outputs decoded data 103.

The syntax monitoring unit 11 in the error information analysis unit 3 inputs the bit stream 104, monitors the status transition of the header information, that is, the syntax status, and checks whether the syntax status is normal or incorrect.
5 is output to the analysis memory 14. For example, in the case of MPEG2, a sequence extension should originally be input after a sequence header, but when a syntax code that violates other standards is detected, the syntax monitoring unit 11 An error notification 106 is output to the display control unit 16. For example, in the above case, a syntax status other than the sequence extension is output after the sequence header.
The output syntax status 105 is input to the analysis memory 14 and written under the control of the memory control unit 15.

The code monitoring unit 12 has a function of holding a code table in which prescribed codes are described, inputting the bit stream 104, and monitoring a code status that does not correspond to the code table. The code described in the code table is, for example, a part of MPEG2, a picture coding type.
e, picture structure, motion
n type, qscale type, Macrob
lock type, coded blockpatt
ern, DCT coefficients, and others. Each code table contains a prohibition code, a reserved code, an unspecified code, and the like.

The code monitoring unit 12 controls the bit stream 1
04, and outputs a normal or invalid code status 107 not applicable to these code tables to the analysis memory 14. The output code status 107 is written into the analysis memory 14 under the control of the memory control unit 15. When detecting an invalid code status, the code monitoring unit 12 outputs an error notification 108 to the memory control unit 15 and the display control unit 16.

The pixel number / line number monitoring unit 13 receives the bit stream 104, monitors whether the decoded pixel number and line number status has exceeded, and determines whether the pixel number / line number status 109 is normal or incorrect. Is output. The output number of pixels / number of lines status 109 is
Written under the control of the memory control unit 15. In addition, when detecting the incorrect pixel number / line number status, the pixel number / line number monitoring unit 13 outputs an error notification 110 to the memory control unit 15 and the display control unit 16.

The bit stream 101 read from the reception buffer memory 1 is also input to the analysis memory 6, and
Similarly, the data is sequentially written under the control of the memory control unit 15.

On the other hand, the picture head pulse 102 read from the reception buffer memory 1
To reset the memory address counter in the memory control unit 15 to 0.

The writing control to the analysis memory 14 is performed by the memory control unit 15. Each time the picture head pulse 102 is input, the memory address counter is reset to 0, the write enable 111 is activated, and the address of the analysis memory 14 is specified by the address 112, thereby the syntax monitoring unit 11
, The code status 107 output from the code monitoring unit 12, the pixel number / line number status 109 output from the pixel / line number monitoring unit 13, and the code status 107 read from the reception buffer memory 1. The bit stream 101 is stored in the analysis memory 1
Write to 4.

That is, in this example, a bit stream for one picture is always overwritten on the analysis memory 14. The writing unit may be a method of repeating overwriting in units of a plurality of pictures.

FIG. 2 is a diagram showing mapping of the analysis memory 14 according to the first embodiment of the present invention. Syntax status 105, code status 107, pixel count / line count status 109, and bit stream 10
1 is written to each address 0 to n one bit at a time. The head data of the picture is written at address 0, and the last data of the picture is written at address n. The bit depth indicates the number of bits of data used. For example, the syntax status 105, code status 107, and pixel / line number status 109 are each 4 bits, and the bit stream 101 is 8 bits.

The memory control unit 15 sends the error notification 1
When any of 06, 108, and 110 is input, the write enable 111 is set to false, and writing to the analysis memory 14 is stopped. This state is maintained, and a state of waiting for a read command from the display control unit 16 is established.

The error notifications 106, 108 and 110 are displayed on an external LED display or a liquid crystal panel via the display control unit 16. When the display control unit 16 receives a read command from an external personal computer or the like,
The data is sequentially read from the analysis memory 14 and displayed on a display panel such as an external personal computer monitor, a liquid crystal panel, or an LED.

As described above, the error information analysis unit 3 sequentially writes the syntax status 105, the code status 107, the pixel / line number status 109, and the bit stream 101 into the analysis memory 14, and when an invalid status occurs, The writing is stopped, the contents of the analysis memory 14 are read out by an external command such as a personal computer, and displayed externally. Unless an invalid status is detected, overwriting is repeated at a designated period, in this example, for each picture.

In the embodiment of FIG. 1, the analysis memory 14
The bit stream 101 written into the memory controller 15 and the picture head pulse 102 input to the memory control unit 15 are output from the reception buffer memory 1, but the bit stream 104 output from the variable length decoding unit 2 is And the picture head pulse separated by the variable length decoding unit 2 may be input to the memory control unit 15.

As described above, according to the first embodiment, since the bit stream is configured to be analyzed one bit at a time on a picture basis, a detailed analysis in a short cycle is possible, and an error occurs during normal reception. Is obtained, it is possible to obtain an image decoding apparatus that can perform a failure diagnostic analysis without adding a measuring device.

Embodiment 2 FIG. 3 is a block diagram showing a configuration of an image decoding apparatus according to Embodiment 2 of the present invention. In the figure, the difference from the first embodiment is that the bit stream 101 is written in the analysis memory 14 in FIG. 1 of the first embodiment, whereas the variable length decoding unit is written in FIG. 3 of the second embodiment. Header information 1 output from 2
15 and a temporal reference 116 indicating the frame number of the picture are written in the analysis memory 14.
In FIG. 1, the picture head pulse 102 read from the reception buffer memory 1 is sent to the memory control unit 15, but in FIG.
Are not separated by the reception buffer memory 1 and are not sent to the memory control unit 15. Others are the same as FIG.

Next, the operation will be described. In the first embodiment, strict analysis is performed by writing the bit stream 101 bit by bit into the analysis memory 14.
In the second embodiment, the header information 115 and the temporal reference 11 are used instead of the bit stream 101.
6 is written to enable monitoring in a long cycle.

The memory control unit 15 has a write enable 1
11 is activated, and the address of the analysis memory 14 is designated by the address 112, whereby the syntax status 1 output from the syntax monitoring unit 11 is output.
05, the code status 107 output from the code monitoring unit 12 and the pixel number / line number status 109 output from the pixel number / line number monitoring unit 13 are stored in the analysis memory 1
4 and the various header information 115 and the temporal reference 116 output from the variable length decoding unit 2 are written to each address.

FIG. 4 is a diagram showing mapping of the analysis memory 14 according to the second embodiment of the present invention. A syntax status 105, a code status 107, a pixel count / line count status 109, header information 115, and a temporal reference 116 are written to each address.

Here, the header information 115 is written and stored only when the header information is present.
hd is the sequence header information, seq-ex is the sequence extension, and gop-hd is the group of
picture header information, pic-hd indicates picture header information, pic-ex indicates picture extension, and slc-hd indicates slice header information. The sequence header information seq-hd is header information that appears in units of 30 to 40 pictures, and the slice header information slc-hd appears most frequently. By storing the header information 115, it is possible to know the lack of the header, for example, the lack of the picture header information pic-hd.

The temporal reference 116 indicating the frame number is updated each time the picture header information pic-hd appears. This temporal reference 1
By storing “16”, it is possible to detect the loss of a picture unit that cannot be detected in the first embodiment.

Syntax status 105, code status 107, pixel count / line count status 109
In the relevant header information 115, each status is written and stored. For example, the syntax status 105 is stored at the position of the sequence header information seq-hd, and the code status 1
07 stores the status of the slice header information slc-hd.

The memory control unit 15 resets the memory address counter to 0 after writing by the amount of the memory capacity of the analysis memory 14, and repeats overwriting. The writing unit may be a method in which the address is reset at the cycle of the sequence header seq-hd and the overwriting is repeated. When any of the error notifications 106, 108, and 110 is input, the memory control unit 15 stops writing to the analysis memory 14 by setting the write enable 111 to false. This state is maintained, and a state of waiting for a read command from the display control unit 16 is established.

The error notifications 106, 108 and 110 are displayed on an external LED or a liquid crystal panel via the display control unit 16. Upon receiving a command from an external personal computer or the like, the display control unit 16 sequentially reads data from the analysis memory 14 and displays the data on a display panel such as an external personal computer monitor, a liquid crystal panel, or an LED.

As described above, according to the second embodiment, since the bit stream 101 is configured to be analyzed in a long cycle, it is possible to detect a syntax violation due to an encoder failure and analyze a certain error rate. In addition, even if an error occurs during normal reception, it is possible to realize an image decoding apparatus that can perform failure diagnosis and analysis without adding a measuring device.

Further, an effect that a loss in a picture unit can be detected can be obtained.

[0047]

As described above, according to the present invention, the writing of the predetermined status and data related to the error information included in the bit stream is sequentially performed in units of the first pulse of the picture included in the bit stream. Stop writing when an invalid status is detected,
Since the written status and data are configured to be output, the bit stream is analyzed one bit at a time in picture units, thereby enabling detailed analysis in a short cycle, and an error occurs during normal reception. Even in such a case, there is an effect that it is possible to obtain an image decoding device that enables diagnosis and analysis of a failure without adding a measuring device.

According to the present invention, the writing of the predetermined status related to the error information contained in the bit stream, the header information contained in the bit stream, and the writing of the temporal reference indicating the frame number are performed by the memory for writing. It is performed sequentially in units of memory capacity or in units of sequence header information included in the bit stream, and when an invalid status is detected, writing is stopped,
It is configured to output the written status, header information and temporal reference, so by analyzing the bit stream in a long cycle, it is possible to detect syntax violation due to encoder failure and analyze error rate to some extent Even if an error occurs during normal reception, there is an effect that it is possible to realize an image decoding device that can perform failure diagnosis and analysis without adding a measuring device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image decoding device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing mapping of an analysis memory according to the first embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of an image decoding device according to Embodiment 2 of the present invention.

FIG. 4 is a diagram showing mapping of an analysis memory according to a second embodiment of the present invention;

[Explanation of symbols]

2 variable length decoding unit (variable length decoding unit), 3 error information analysis unit (error information analysis unit), 11 syntax monitoring unit (syntax monitoring unit), 12 code monitoring unit (code monitoring unit), 13 pixel number / Line number monitoring unit (pixel number / line number monitoring means), 14 analysis memories,
15 memory control unit (memory control means), 16 display control unit (display control means), 101, 104 bit stream, 102 picture head pulse, 105 syntax status, 106, 108, 110 error notification, 107 code status, 109 pixels Number / line number status, 115 header information, 116 temporal reference.

Claims (8)

[Claims] 1. A variable length decoding means for reading and decoding data included in a received bit stream, and a predetermined status relating to error information included in the bit stream and writing of the data, Error information analyzing means for sequentially performing the above operation on a picture head pulse basis included in the bit stream, stopping the writing when an incorrect status is detected, and outputting the written status and the data. Image decoding device. 2. An error information analyzing means for monitoring a syntax status included in a bit stream and outputting the syntax status, and outputting an error notification when an incorrect syntax status is detected. And an analysis memory in which the syntax status and the data included in the bit stream are sequentially written, and sequentially writing in the analysis memory in units of a picture head pulse included in the bit stream,
A memory control unit that stops the writing when an error notification output from the syntax monitoring unit is received; and a display control unit that reads the syntax status and the data written in the analysis memory. The image decoding device according to claim 1, wherein: 3. The error information analysis means has a code table in which a predetermined code is defined.
Code monitoring means for monitoring a code status included in a bit stream by comparing the code status with a code defined in the code table, outputting the code status, and outputting an error notification when an invalid code status is detected. An analysis memory in which the code status and the data included in the bit stream are sequentially written; and sequentially writing to the analysis memory in units of a picture head pulse included in the bit stream,
A memory control unit for stopping the writing when the error notification output from the code monitoring unit is received; and a display control unit for reading the code status and the data written in the analysis memory. The image decoding apparatus according to claim 1, wherein 4. The error information analysis means monitors the number of pixels / line number status included in the bit stream and outputs the number of pixels / line number status, and detects an incorrect number of pixels / line number status. A pixel number / line number monitoring unit that outputs an error notification; an analysis memory in which the pixel number / line number status and data included in the bit stream are sequentially written; a picture head included in the bit stream Writing to the above analysis memory is performed sequentially in units of pulses,
Memory control means for stopping the writing upon receiving an error notification output from the pixel number / line number monitoring means; display control for reading the pixel number / line number status and the data written in the analysis memory 2. The image decoding apparatus according to claim 1, further comprising: 5. A variable length decoding means for reading and decoding data included in a received bit stream, a predetermined status related to error information included in the bit stream, and a predetermined status included in the bit stream. The writing of the temporal reference indicating the header information and the frame number is sequentially performed in units of memory capacity of the memory to be written or in the unit of the sequence header information included in the bit stream. An image decoding apparatus, comprising: an error information analysis unit that outputs the status, the header information, and the temporal reference. 6. An error information analyzing means for monitoring a syntax status included in a bit stream and outputting the syntax status, and outputting an error notification when an incorrect syntax status is detected. And an analysis memory in which the syntax status, header information and temporal reference included in the bit stream are sequentially written, and a memory capacity unit of the analysis memory or a sequence header information unit included in the bit stream The memory control means for performing writing to the analysis memory sequentially, and stopping the writing when receiving the error notification output from the syntax monitoring means, the syntax status written to the analysis memory, The above header The image decoding apparatus according to claim 5, characterized in that a display control means for reading out distribution and the temporal reference. 7. The error information analysis means has a code table in which a predetermined code is defined,
Code monitoring means for monitoring a code status included in a bit stream by comparing the code status with a code defined in the code table, outputting the code status, and outputting an error notification when an invalid code status is detected. An analysis memory in which the code status, header information and temporal reference included in the bit stream are sequentially written, and a memory capacity unit of the analysis memory or a sequence header information unit included in the bit stream. Memory control means for sequentially writing to the analysis memory and stopping the writing when an error notification output from the code monitoring means is received; the code status and the header information written to the analysis memory And the above ten The image decoding apparatus according to claim 5, characterized in that a display control means for reading out Lal reference. 8. The error information analyzing means monitors the number of pixels / line number status included in the bit stream, outputs the number of pixels / line number status, and detects an incorrect number of pixels / line number status. A pixel number / line number monitoring unit that outputs an error notification; an analysis memory in which the pixel number / line number status, header information and a temporal reference included in the bit stream are sequentially written; and a memory of the analysis memory A memory in which writing to the analysis memory is sequentially performed in units of capacity or in units of sequence header information included in the bit stream, and when the error notification output from the pixel number / line number monitoring unit is received, the writing is stopped. Control means; and the number of pixels / line written in the memory for analysis. Down count status, the image decoding apparatus according to claim 5, characterized in that a display control means for reading the header information and the temporal reference included in the bit stream.