JP2007110376A - Moving image recoding unit, moving image coding method, and moving image recoding program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of image quality and to reduce processing time, when recoding a coded data in which deblock filtering is performed. <P>SOLUTION: A decoder 100 decodes the coded data in which deblock filtering is performed, and outputs a pre-deblock filtered decoded image and a post-deblock filtered decoded image to a decoded image switch 200. In case of deciding to perform deblock filtering at the time of recoding based on a recoding system signal, a docoded image switch 200 outputs the pre-deblock filtered decoded image to a recoder 300, while in case of not performing the deblock filtering at the time of recoding, the docoded image switch 200 outputs the post-deblock filtered decoded image to the recoder 300. The recoder 300 performs recoding after deblocking only when the pre-deblock filtered decoded image is input. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to re-encoding of digital moving images, and more particularly to a moving image re-encoding device, a moving image encoding method, and a moving image re-encoding program that suppress image quality degradation during re-encoding.

  In digital moving image encoding, an image is divided into blocks and encoded. Therefore, when the bit rate is lowered, discontinuity occurs at the block boundary and block noise occurs. Therefore, in coding represented by MPEG-4 / AVC, a deblocking filter that removes block noise in the motion compensation prediction loop (also called a deblocking filter. To improve the motion compensation prediction efficiency and subjective image quality.

  However, the deblocking filter that removes block noise has a problem that an edge component of an image is removed and a resolution of the image is lowered. Therefore, it is desirable to apply the deblocking filter only when block noise occurs in the encoding.

  On the other hand, as various high-compression encoding systems appear, video re-encoding that further compresses the amount of encoded video data using the same encoding system or converts it to another encoding system is attracting attention. Has been.

In general, moving image re-encoding is to decode encoded data once and re-encode it. In a conventional moving image re-encoding device, a decoded image is used as a re-encoding target image (see, for example, Patent Document 1).
JP 2002-344971 A

  However, in the above-described conventional moving image re-encoding device, there is no mention of re-encoding in the MPEG-4 / AVC encoding system equipped with a deblocking filter, and both in decoding and re-encoding. If the deblocking filter is applied twice, the image edge components and the like are removed before re-encoding, and the resolution of the image is reduced. Re-encoding reproduces the image edge components and the image resolution. As a result, there is a problem that the image quality deteriorates during re-encoding.

  Further, the processing amount of the deblocking filter is enormous, and there is a problem that it takes a very long processing time if the deblocking filter is performed twice.

  Accordingly, the present invention provides a moving image re-encoding device, a moving image encoding, which can prevent degradation of image quality and reduce processing time when re-encoding encoded data subjected to a deblocking filter. It is an object to provide a method and a moving image re-encoding program.

  In order to solve the above-described problem, in the present invention, in the case of a re-encoding method that applies a deblocking filter when re-encoding a decoded image obtained by decoding encoded data, decoding before the deblocking filter is applied. In the case of a re-encoding method in which an image is re-encoded and no de-blocking filter is applied, a decoded image subjected to the de-blocking filter is re-encoded.

  According to the present invention, when a decoded image obtained by decoding encoded data is re-encoded, in the case of a re-encoding method in which a deblocking filter is applied, the decoded image before the deblocking filter is re-encoded. On the other hand, in the case of a re-encoding method that does not perform the deblocking filter, the decoded image that has been subjected to the deblocking filter is re-encoded, so when decoding and re-encoding the encoded data, The number of times that the deblocking filter is applied can be reduced to one, so that deterioration of image quality can be prevented and the processing time can be shortened.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a first embodiment of a moving image re-encoding device according to the present invention.

  As shown in FIG. 1, the moving image re-encoding apparatus according to the first embodiment includes a decoding unit 100, a decoded image switching unit 200, and a re-encoding unit 300. Note that this configuration example is an example, and in addition, the decoded image switching unit 200 is provided in the decoding unit 100, the re-encoding unit 300, or the decoding unit 100. Of course, the decoded image switching unit 200 and the re-encoding unit 300 may be configured as a single unit.

  The decoding unit 100 includes an entropy decoding unit 101, an inverse quantization / inverse orthogonal transform unit 102, a deblock filter unit 103, an image memory 104, a motion compensation unit 105, and an adder 106. Yes.

  The re-encoding unit 300 includes a de-blocking filter-equipped re-encoding unit 310 that performs re-encoding by subjecting the re-encoding target image to a de-blocking filter by the MPEG-4 / AVC encoding method or the like, and MPEG-4 or MPEG And a non-deblocking filter-mounted re-encoding unit 320 that performs re-encoding without applying a deblocking filter such as −2.

  Next, the operation will be described with reference to a flowchart.

  FIG. 2 is a flowchart showing the operation of the moving picture re-encoding device according to the present invention.

  First, in the entropy decoding unit 101, when encoded data of a moving image encoded by applying a deblocking filter by the MPEG-4 / AVC encoding method is input, the entropy decoding unit 101 outputs the encoded data. And encoding parameters such as motion vector signals are entropy-decoded (step S10), and the entropy-decoded image signal is supplied to the inverse quantization / inverse orthogonal transform means 102, while the entropy-decoded motion vector signal is supplied. This is supplied to the motion compensation means 105.

  The inverse quantization / inverse orthogonal transform means 102 performs inverse quantization / inverse orthogonal transform on the input image signal and outputs the result to the adder 106 (step S20).

  The motion compensation unit 105 performs motion compensation using the reference image stored in the image memory 104 based on the motion vector signal input from the entropy decoding unit 101, obtains a motion compensated image, and outputs the motion compensated image to the adder 106.

  The adder 106 adds the motion compensated image from the motion compensation unit 105 if the image signal subjected to the inverse quantization / inverse orthogonal transform from the inverse quantization / inverse orthogonal transform unit 102 is predictively encoded. If the decoded image or the image signal that has been subjected to inverse quantization / inverse orthogonal transform has not been subjected to predictive coding, the decoded image is output as it is to the deblocking filter means 103 and without passing through the deblocking filter means 103. The decoded image is directly output to the decoded image switching unit 200.

  The deblocking filter means 103 applies a deblocking filter to the decoded image via the adder 106, and outputs the decoded image subjected to the deblocking filter to the image memory 104 and the decoded image switching unit 200 (step S30). ).

  In the image memory 104, the decoded image after the deblocking filter subjected to the deblocking filter by the deblocking filter unit 103 is stored as a reference image for motion compensation by the motion compensation unit 105 (step S40).

  Therefore, from the decoding unit 100 to the decoded image switching unit 200, the decoded image after the deblocking filter subjected to the deblocking filter and the decoded image before the deblocking filter not subjected to the deblocking filter are output.

  When the re-encoding unit 300 performs re-encoding, the decoded image switching unit 200 determines whether or not to apply a deblocking filter (step S50).

  Here, in the case of the first embodiment, the decoded image switching unit 200 determines whether or not to apply the deblocking filter at the time of re-encoding and is transmitted from the user's operation or other external device and is input from the outside. Judgment is made based on the encoding method signal.

  Then, when it is determined that the deblocking filter is to be applied at the time of reencoding based on the reencoding method signal input from the outside (step S50 “YES”), the decoded image switching unit 200 determines the decoded image before the deblocking filter. Is output to the re-encoding unit 300 (step S60), and when it is determined that the deblocking filter is not applied during the re-encoding (step S50 “NO”), the decoded image after the deblocking filter is re-encoded. The data is output to the conversion unit 300 (step S70).

  That is, the decoded image switching unit 200 of the first embodiment is configured to output the deblocked filter pre-decoded image to the deblocking filter-mounted recoding unit 310 based on the recoding method signal input from the outside. On the other hand, the output of the decoded image is switched so that the decoded image after the deblocking filter is output to the recoding unit 320 without the deblocking filter.

  In the re-encoding unit 300, when the decoded image before the deblocking filter that is not subjected to the deblocking filter is input from the decoded image switching unit 200, the re-encoding unit with the deblocking filter 310 performs the decoding before the deblocking filter. The image is re-encoded by a re-encoding method that applies a deblocking filter, and is output to the outside as re-encoded data (step S80). Here, the re-encoding method for applying the deblocking filter is, for example, an encoding method such as MPEG-4 / AVC.

  On the other hand, when the decoded image after the deblocking filter subjected to the deblocking filter is input from the decoded image switching unit 200, the non-deblocking filter re-encoding unit 320 outputs the decoded image after the deblocking filter. Then, re-encoding is performed by a re-encoding method without applying a deblocking filter, and the re-encoded data is output to the outside (step S80). Here, the re-encoding method without applying the deblocking filter is, for example, an encoding method such as MPEG-2 or MPEG-4 Main Profile.

  Therefore, according to the moving picture re-encoding device of the first embodiment, when decoding and re-encoding the encoded data subjected to the deblocking filter, the re-encoding applying the deblocking filter as the re-encoding method Regardless of whether the encoding method or non-encoding re-encoding method is adopted, the number of times that the deblocking filter is applied is set to one, so that image quality deterioration during re-encoding can be suppressed and the processing time is shortened. can do.

In particular, since the decoded image before the deblocking filter can be generated earlier than the decoded image after the deblocking filter, the timing of inputting the image to the re-encoding unit 300 can be advanced, and the deblocking filter means 103 in the decoding unit 100 It is also possible to simultaneously perform the process of applying the deblocking filter in FIG. 4 and the process of re-encoding the pre-deblock filter decoded image in the re-encoding unit 310 with the deblocking filter of the re-encoding unit 300.
Embodiment 2. FIG.
In Embodiment 1, as shown in FIG. 1, an example in which both a deblocking filter-mounted recoding unit 310 and a deblocking filter-unmounted recoding unit 320 are mounted in the recoding unit 300. However, in the second embodiment, the re-encoding unit 300 includes one of the de-block filter-mounted re-encoding unit 310 or the de-block filter non-de-installing re-encoding unit 320.

  FIG. 3 is a block diagram showing the configuration of the second embodiment of the moving image re-encoding device according to the present invention, in which only the de-block filter-equipped re-encoding unit 310 is mounted on the re-encoding unit 300. Is shown.

  In the case shown in FIG. 3, it is of course possible to input a re-encoding method signal to the decoded image switching unit 200 from the outside as in the first embodiment, but here, a de-blocking filter-equipped re-encoding unit A signal indicating the encoding method, that is, a re-encoding method for applying a deblocking filter, is input from 310 to the decoded image switching unit 200.

  As a result, in the decoded image switching unit 200 according to the second embodiment, even when there is no re-encoding method signal input from the outside, the decoding of the re-encoding unit 300 is performed when the re-encoding unit 300 is connected. Based on the re-encoding method signal input from the block filter-mounted re-encoding unit 310, the pre-deblock filter decoded image is output to the de-block filter-mounted re-encoding unit 310 of the re-encoding unit 300.

  FIG. 4 is a block diagram showing another configuration example of the moving image re-encoding device according to the second embodiment of the present invention. In the re-encoding unit 300, only the non-deblocking filter re-encoding unit 320 is mounted. An example configuration is shown.

  Also in the case shown in FIG. 4, as in the first embodiment, the re-encoding method signal may be input from the outside to the decoded image switching unit 200 by the user's input or the like. A signal indicating the encoding method, that is, the re-encoding method without applying the deblocking filter, is input from the non-filter-mounted re-encoding unit 320 to the decoded image switching unit 200.

  As a result, in the decoded image switching unit 200 according to the second embodiment, even when there is no re-encoding method signal input from the outside, the decoding of the re-encoding unit 300 is performed when the re-encoding unit 300 is connected. Based on the re-encoding method signal input from the non-block filter re-encoding unit 320, the decoded image after deblock filter is output to the re-encoding unit 320 without the de-block filter of the re-encoding unit 300. Become.

Therefore, according to the second embodiment, the same effects as those of the first embodiment can be obtained, and when the re-encoding unit 300 is connected, the re-encoding unit 300 re-encoding is performed. Since the pre-deblock filter decoded image or the deblock filter post-decoded image is output to the re-encoding unit 300 based on the re-encoding method signal input from the unit 310 or the non-deblock filter re-encoding unit 320. Even if there is no re-encoding method signal input from the outside, automatically depending on the re-encoding unit 310 with or without the deblocking filter connected as the re-encoding unit 300 The output of the decoded image from the decoded image switching unit 200 can be switched.
Embodiment 3 FIG.
In the first embodiment, as shown in FIG. 1, a re-encoding method signal is input only from the outside to the decoded image switching unit 200, and the pre-deblock filter decoding from the decoded image switching unit 200 to the re-encoding unit 300 is performed. Although it has been described that the output is switched between the image and the decoded image after the deblocking filter, the third embodiment is such that the re-encoding method signal is also input to the re-encoding unit 400. It is.

  FIG. 5 is a block diagram showing the configuration of the third embodiment of the video re-encoding device according to the present invention.

  The difference from the moving image re-encoding apparatus of Embodiment 1 shown in FIG. 1 is that the re-encoding method signal input to the decoded image switching unit 200 is also input to the re-encoding unit 300. And the re-encoding unit 300 switches between re-encoding with adaptive deblocking filter and re-encoding without deblocking filter based on the re-encoding method signal. is there.

  In this case, the re-encoding unit 300 according to the third embodiment is similar to the re-encoding unit 300 according to the first embodiment shown in FIG. It may be equipped with a re-encoding unit 320 and may be switched adaptively by turning on one or the like based on the re-encoding scheme signal, or re-encoding such as MPEG-4 Main Profile without a deblocking filter. A single deblock filter-equipped re-encoding unit that can be executed by switching between encoding and MPEG-4 / AVC re-encoding with deblock filter is installed. Of course, the re-encoding unit 310 may switch on / off of the deblocking filter for the decoded image signal based on the re-encoding method signal, and re-encode with both encoding methods.

  In this way, the re-encoding unit 300 according to the third embodiment inputs the re-encoding method signal that is also input to the decoded image switching unit 200, and re-encodes based on the re-encoding method signal. When the encoding scheme signal indicates that a deblocking filter is to be applied at the time of re-encoding, as in the case of the first embodiment, the decoding block pre-deblocking filter is subjected to a deblocking filter and re-encoded. On the other hand, if the re-encoding method signal indicates that the de-blocking filter is not applied at the time of re-encoding, the decoded image after the de-blocking filter is re-encoded without performing the de-blocking filter. It will become.

  Therefore, according to the moving image re-encoding device of the third embodiment, the same effect as in the first embodiment can be obtained, and the re-encoding method signal is also input to the re-encoding unit 400. Based on the re-encoding method signal, the re-encoding unit 400 can switch or select and apply the re-encoding method that performs the deblocking filter and the re-encoding method that does not.

  In the first to third embodiments, the hardware configuration is described as shown in FIGS. 1 and 3 to 5. However, the present invention is not limited to this, and the moving image is not limited thereto. A moving image encoding program for causing a computer to realize the function of the re-encoding device is read from a recording medium or downloaded via a communication network such as the Internet, and stored in a memory, an HDD or the like, and the CPU stores the program. Of course, it is possible to achieve the functions of the moving picture coding apparatus and the moving picture decoding apparatus.

It is a block diagram which shows the structure of Embodiment 1 of the moving image re-encoding apparatus of this invention. It is a flowchart which shows operation | movement of Embodiment 1 of the moving image re-encoding apparatus of this invention. It is a block diagram which shows the structure of Embodiment 2 of the moving image re-encoding apparatus which concerns on this invention, and is a figure which shows the structural example by which only a deblocking filter mounting re-encoding part is mounted in the re-encoding part. It is a block diagram which shows the other structural example of Embodiment 2 of the moving image re-encoding apparatus based on this invention, and shows the structural example by which only a deblocking filter non-mounting re-encoding part is mounted in the re-encoding part. FIG. It is a block diagram which shows the structure of Embodiment 3 of the moving image re-encoding apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Decoding part 101 Entropy decoding means 102 Dequantization / inverse orthogonal transformation means 103 Deblock filter means 104 Image memory 105 Motion compensation means 106 Adder 200 Decoded image switching part 300 Re-encoding part 310 Deblock filter mounted re-encoding 320 Re-encoding unit without deblock filter

Claims (5)

A video re-encoding device that decodes encoded data that has been subjected to deblocking filtering and re-encodes the encoded data using the same encoding method or another encoding method.
A decoding image having a deblocking filter means, and when the encoded data is decoded, a decoded image subjected to the deblocking filter by the deblocking filter, and a decoding before the deblocking filter is applied by the deblocking filter means A decoding unit for outputting an image;
A re-encoding unit that is connected to a subsequent stage of the decoding unit and re-encodes the decoded data output from the decoding unit using the same encoding method as the encoded data or another encoding method;
Provided between the decoding unit and the re-encoding unit, and when the re-encoding method is a re-encoding method in which a deblocking filter is applied, the deblocking filter means sends the deblocking filter to the deblocking filter unit. Is output to the re-encoding unit, while the re-encoding method is a re-encoding method that does not perform a de-blocking filter, the de-blocking filter means from the decoding unit A decoded image switching unit that outputs the decoded image subjected to the deblocking filter to the re-encoding unit;
A moving picture re-encoding device comprising: The moving image re-encoding device according to claim 1,
The re-encoding method in the re-encoding unit is:
Based on a re-encoding method signal input from the outside, the decoded image is output to the re-encoding unit before being subjected to the deblocking filter or after being subjected to the deblocking filter from the decoding unit.
A moving image re-encoding device characterized by the above. The moving image re-encoding device according to claim 1,
The decoded image switching unit
Based on the encoding method of the re-encoding unit input from the re-encoding unit, the decoded image from the decoding unit before being subjected to the deblocking filter or after being subjected to the deblocking filter is subjected to the re-encoding. Output to the encoding unit,
A moving image re-encoding device characterized by the above. A video re-encoding method that decodes encoded data that has been subjected to deblocking filter, and re-encodes the encoded data using the same encoding method or another encoding method.
When decoding the encoded data, generate a decoded image subjected to the deblocking filter and a decoded image before being subjected to the deblocking filter,
When re-encoding the decoded image, in the case of a re-encoding method in which a deblocking filter is applied, the decoded image before being subjected to the deblocking filter is re-encoded while the re-encoding without the deblocking filter is performed. In the case of an encoding method, re-encode the decoded image subjected to the deblocking filter,
A moving image re-encoding method characterized by the above. A moving picture re-encoding program for causing a computer to decode encoded data to which a deblocking filter has been applied and to re-encode the encoded data using the same encoding method or another encoding method. Because
On the computer,
When decoding the encoded data, generate a decoded image subjected to the deblocking filter and a decoded image before being subjected to the deblocking filter,
When re-encoding the decoded image, in the case of a re-encoding method in which a deblocking filter is applied, the decoded image before being subjected to the deblocking filter is re-encoded while the re-encoding without the deblocking filter is performed. In the case of an encoding method, re-encode the decoded image subjected to the deblocking filter,
A moving image re-encoding program characterized by causing the above to be executed.

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