JP2001145111A - Device and method for decoding dynamic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a reverse reproducing process, without image breaks nor repetitive display of the same image. SOLUTION: This dynamic decoding device equipped with a buffer memory 102, a decoding means 103 which decodes encoded data, a reproduced image memory 104 which stores decoded image data, an image memory area managing means 106 which manages the contents of the decoded image data stored in the reproduced image memory, and a display area switching means 105 which selects decoded image data to be displayed out as reproduced image data among the decoded image data stored in the reproduced image memory and controls the output switching of the reproduced image data is equipped with a start code detecting means 111, which detects encoding type and display order information and a buffer memory managing means 112, which manages the data storage information in the buffer memory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital moving image decoding apparatus and method for decoding image data encoded using a predictive encoding method for digital storage media or broadcasting and communication, and in particular, to a digital moving image decoding apparatus and method. The present invention relates to a moving image decoding apparatus and method for speeding up a playback mode switching time by switching a playback mode from forward normal playback to reverse playback, and controlling a normal-speed reverse playback.

[0002]

2. Description of the Related Art Digital storage media or broadcasting,
The demand for general-purpose encoding methods for moving images and associated audio for various applications including communication and communication has been increasing, and the International Electrotechnical Commission (IEC) Mo of the International Organization for Standardization (ISO)
In the ving Picture Experts Grope (hereinafter referred to as MPEG), international standardization of moving picture coding methods has been promoted,
SO / IEC13818-2 (MPEG2 video) and the like are standardized.

[0003] As an example of the prior art, a moving picture decoding apparatus for decoding data encoded by the MPEG encoding method will be described below.

In the MPEG encoding method, one frame of image is an I picture (intra-frame predictively encoded image:
Intra-coded picture), P picture (Predictive-coded picture), or B picture (Bidirectionally-coded pict)
ure), and high-efficiency image data compression is realized by performing coding by combining them.

[0005] The encoded data of the MPEG system is shown in FIG.
And the picture group GOP (Gr.
The “up of picture” includes one or more I pictures, zero or more P pictures, and zero or more B pictures.

FIG. 9 shows one I picture (I _2E ), four P pictures (P _5E , P _8E , P _11E , P _14E ), and ten B pictures (B _0E , B _1E , B _3E , _B4E , _B6E , _B7E , B
_9E , _B10E , _B12E , and _B13E ) to form one GOP.

[0007] The configuration of encoded data encoded by an encoding method using bidirectional predictive encoding such as the MPEG method is as follows.
The order of arrangement of the image data in the encoded data and the order of display when reproducing the image are different from each other. When decoding a B picture that has been bidirectionally coded, the P picture that is positioned earlier in display time is displayed. Not only (or I-pictures that have been intra-frame predictive coded) but also P-pictures (or I-pictures) that are located later in display time are stored in the playback image memory as decoded image data that has already been decoded. Have been.

Next, referring to FIGS. 10 and 11,
The operation at the time of normal reproduction according to the conventional configuration will be described. FIG. 10 is a block diagram of a video decoding device having a conventional configuration. FIG. 11 shows transition states of the picture types stored in the first, second, and third image memory areas in the playback image memory during normal playback in the conventional configuration and the picture types displayed and output. I, P, and B in FIG. 11 indicate picture types, and the suffix numbers indicate the display order in a GOP including the image. Also, the subscript [']
And [″] indicate different GOPs, and the subscripts [E] and [D] indicate coded data and decoded image data, respectively.

(1) First, stream input means 1001
To the buffer memory 1002. The decoding means 1003 decodes the coded data I _2E (FIG. 9) at the head of the GOP input from the buffer memory 1002. Since the I picture is data that has been subjected to intra-frame prediction coding, decoding processing is performed using only the coded data I _2E , and decoded image data I _2D is stored in the first image memory area 1008.

(2) Next, the decoded image data I _2D decoded as described above and the encoded data B _0E to be inputted next
(FIG. 9), the decoding process is performed, and the decoded image data B
_0D is stored in the third image memory area 1010. In addition,
When the coded data B _0E is decoded using the GOP _immediately preceding the current GOP being decoded, the decoded image data of the last I or P picture in the _immediately preceding GOP is used. Then, decoding processing is performed from the decoded image data I _2D in the current GOP and the coded data B _0E .

The decoded image data B _0D is displayed and output by the display area switching means 905 at the next display timing.

(3) Decoding the next encoded data B _1E
In the same concept as the decoding of the encoded data B _{0E in} the above (2), the decoded image data I _2D is processed using the decoded image data I _2D , the decoded image data B _1D is accumulated in the third image memory area 1010, and the display output is performed. Is done.

(4) Next, the decoded image data I _2D decoded in the above (1) and the coded data P _5E to be inputted next.
(FIG. 9), the decoding process is performed, and the decoded image data P
_5D is stored in the second image memory area 1009. The decoded image data P _5D is not immediately displayed and output, and the display output of the decoded image data I _2D is performed at the next display timing after the display of the decoded image data B _1D .

(5) Thereafter, processing is performed with the same concept.
Result As shown in FIG. 11, the decoding order of the encoded data is I
_2D→ B_0D→ B_1D→ P_5D→ B_3D→ B_4D→ P_8D→ B_6D→ B_7D
→ P _11D→ B_9D→ B_10D→ P_14D→ B_12D→ B_13D→ 'I
_2D→ 'B_0D→ ... and the display order is B_0D→ B_1D→
I_2D→ B_3D→ B_4D→ P_5D→ B_6D→ B_7D→ P_8D→ B_9D→ B
_{Ten D}→ P_11D→ B_12D→ B_13D→ P_14D→ 'B_0D→ 'B_1D→…
become that way.

As described above, in the encoding of the MPEG system, the encoding is performed using the inter-frame correlation, and at the time of decoding, the image data located before and after in the display order is decoded first. , A new image is decoded using the decoded image data.

Next, with reference to FIG. 10 and FIG. 12, the operation in the case where the above-mentioned MPEG encoded data is reproduced in the backward direction will be described.

FIG. 12 shows a first image memory area 1008 and a second image memory area 108 in the reproduced image memory 1004 when the moving image decoding apparatus having the conventional configuration performs reverse reproduction.
09 and the transition state of the picture type of the decoded image data stored in the third image memory area 1010 and the picture type of the display output.

Here, the decoding processing time of each image by the decoding means 1003 is set to about half the time for displaying one screen on a television monitor or the like. That is, the decoding process for one frame is performed during the display time of one field, so that while the display area switching unit 1005 is displaying one screen (one frame), the decoding unit 1003
Can decode encoded data for two screens.

I, P, and B in FIG. 12 indicate picture types, and subscript numbers indicate the display order in a GOP including the image. The subscripts ['] and ["] indicate different GOPs. Furthermore, the subscript "T"
Indicates that the first field image of the image is being displayed, and the suffix “B” indicates that the second field image is being displayed.

As shown in FIG. 12, in the display as the display image data decoded image data '' B _3D in the forward play mode, when the reproduction mode is switched to the reverse reproduction, then an image to be displayed That is, since the decoded image data “I _2D displayed immediately before the decoded image data“ B _3D ”is stored in the first image memory area 1008, the next display is performed by the display area switching unit 1005. The display output of the decoded image data " _I2D " is performed at the timing.

[0021]

However, in the above-described conventional technique, the decoded image data "decoded image data to be displayed next to the display of _I2D " in the reverse reproduction order.
B _1D stores the reproduced image memory 1004 as shown in FIG.
It is not stored in any of the image memory areas.

Therefore, the encoded data "B _1E " must be newly decoded. However, as shown in FIG. 11, the encoded data "B _1E " must be newly decoded as one of the reference images as shown in FIG. The decoded image data ' _P14D , which is the last P picture in the GOP, is required. In order to obtain the decoded image data ' _P14D , the coded data from the first I picture in the immediately preceding GOP is transferred to the decoding means 1003, and the decoded data up to the coded data' _P14E is decoded. In other words, 'I _2E →' P
_5E- > _P8E- > _P11E- > _P14E must be decoded.

Thereafter, the coded data "B _1E" is transferred to the decoding means 1003, and the first image memory area 100
'Decoded image data is transferred from the I _2D and the second image memory area 1009' P decoded image data 'to be transferred from the 8
The decoding process of the encoded data "_B1E" must be performed using _14D as a reference image.

[0024] As a result, decoded image data '' from I _2D ''
_Before the display can transition to B _1D , a blank period of at least two frames occurs as shown in FIG. 12, and in the conventional video decoding device, the display transition from forward reproduction to reverse reproduction is performed. There was a problem that it took a long time.

After displaying the decoded image data “B _1D” , the encoded data “B _0E” is transferred to the decoding means 1003, and “I _2D transferred from the first image memory area 1008.
And the decoded image data 'P _14D transferred from the second image memory area 1009 is used as a reference image to perform decoding processing.
After displaying the decoded image data “B _0D ”, since the decoded image data “P _14D is stored in the second image memory area 1009, the decoded image data“ P _14D is directly displayed, and then the decoding is performed. The _converted image data ' _B13D is displayed.

However, in order to decode the decoded image data 'B _13D from the encoded data' B _13E , the decoded image data 'P _14D as well as the decoded image data'
_P11D is required. In order to obtain the decoded image data ' _P11D , the coded data from the first I picture in the GOP is transferred to the decoding means 1003, and the decoding up to the coded data' _P11E , that is, ' I _2E → 'P _5E →' P _8E
→ The four images of ' _P11E must be decoded.

Thereafter, the coded data "B _13E" is transferred to the decoding means 1003, and the second image memory area 10
As the decoded image data is transferred from 09 'P _14D and is transferred from the third image memory area 1010' reference image P _11D, it must be performed a decoding process of coded data '' B _1E.

As a result, the decoded image data 'P _14D to'
By the time the display transitions to _B13D , as shown in FIG.
There is a problem that a blank period of at least one frame occurs, a display blank period occurs during reverse playback, and reverse playback at the same speed cannot be performed, and a viewer looking at the screen feels strange.

Accordingly, the present invention has been made to solve the above-mentioned problems, and is intended to solve the problem of forward normal reproduction in a moving picture coded data decoding technique utilizing inter-frame correlation such as the MPEG system. To provide a moving picture decoding apparatus and method that can shorten the playback mode change from the playback mode to the reverse playback and the output image transition time associated therewith, and realize the same-speed reverse playback with an easy and minimum necessary configuration. Aim.

[0030]

In order to achieve the above object, a first moving picture decoding apparatus according to the present invention comprises: a buffer memory for storing encoded data according to a predetermined unit sequence; Decoding means for decoding the encoded data from the memory, a reproduced image memory for storing a plurality of screens of image data decoded by the decoding means for each image memory area, and decoding stored in the image memory area. Image memory area management means for managing the content of coded image data,
A display area switching means for selecting decoded image data to be displayed and output as reproduced image data from among the decoded image data stored in the reproduced image memory and controlling output image switching of the reproduced image data; A decoding device, wherein, from the encoded data, a start code detecting unit that detects a specific code pattern including encoding type information and display order information for the image of the predetermined unit and outputs the same as a code detection signal; Receiving a code detection signal from a start code detection unit and a storage address signal from the buffer memory, obtaining management information for managing a location where the encoded data is stored in the buffer memory,
A buffer memory management unit that controls the buffer memory according to the management information, transfers the encoded data to the decoding unit in the predetermined unit, and deletes the encoded data in the buffer memory. It is characterized by the following.

According to the first moving picture decoding apparatus, the buffer memory management means stores the storage address information indicating in which area in the buffer memory the leading data of each GOP is stored, and stores the information in the buffer memory. Each of the stored encoded image data is any one of the intra prediction encoded image data (I picture), the forward predicted encoded image data (P picture), and the bidirectional predicted encoded image data (B picture). , And the display order information of each picture in the GOP is managed, so that when the normal forward reproduction is switched to the reverse reproduction, it should be displayed next in the reproduced image memory. When it is known through the image memory area management means that the decoded image data is not stored, the buffer memory is immediately controlled and the necessary encoded data is stored. It can be transferred to the decoding means.

In order to achieve the above object, the second aspect of the present invention
A moving image decoding apparatus comprising: a buffer memory for accumulating encoded data according to a predetermined unit sequence; a decoding unit for decoding encoded data from the buffer memory; A playback image memory for storing image data for a plurality of screens in each image memory area, and decoding image data to be displayed and output as playback image data from among the decoding image data stored in the playback image memory, and playback. A moving image decoding apparatus comprising: a display area switching unit that controls output image data switching, wherein during normal normal reproduction in a forward direction, an intra-frame prediction code of encoded data continuous in the predetermined unit sequence is used. The encoded image data and the decoded image data of the forward prediction encoded image data are always stored in three or more of the image memory areas in decoding order. At the time of reverse reproduction, in one of the image memory areas in which the intra-frame prediction encoded image data and the decoded image data of the forward prediction encoded image data are stored, according to a display order. hand,
An image memory area management means for controlling data storage contents in each of the image memory areas so as to store decoded image data of the bidirectional predictive encoded image data is provided.

According to the second moving picture decoding apparatus, during normal forward reproduction, bidirectional predictive coded picture data (B
Since the intra-frame prediction coded image data (I-picture) and the forward prediction coded image data (P-picture) required as reference image data for decoding a picture) are stored in three or more image memory areas. When the mode is switched to the reverse playback mode, the decoded image data displayed up to three times before the currently displayed image is a B picture, and the B picture and the reference pictures I and P pictures are Even when the picture is not in the playback picture memory, I and P pictures can be decoded in advance, B pictures can be decoded using the pictures as reference pictures, and the pictures can be stored in an optimal picture memory area in accordance with the display order.

To achieve the above object, the third aspect of the present invention
A moving image decoding apparatus comprising: a buffer memory for accumulating encoded data according to a predetermined unit sequence; a decoding unit for decoding encoded data from the buffer memory; A playback image memory for storing image data for a plurality of screens for each image memory area; and selecting and playing back decoded image data to be displayed and output as playback image data from among the decoded image data stored in the playback image memory. A moving image decoding apparatus comprising: a display area switching unit configured to control switching of output of image data, wherein the identification information includes encoding type information and display order information on an image of each predetermined unit from the encoded data. A start code detecting means for detecting a code pattern and outputting the detected code pattern as a code detection signal; Receiving a storage address signal from a buffer memory, obtaining management information for managing a place where the encoded data is stored in the buffer memory, controlling the buffer memory according to the management information, Buffer memory management means for transferring to the decoding means in the predetermined unit and deleting the coded data in the buffer memory; Among the data, the decoded image data of the intra-frame predictive coded image data and the forward predictive coded image data are always stored in three or more of the image memory areas in the decoding order. At the time of reproduction, before the intra-frame prediction coded image data and the decoded image data of the forward prediction coded image data are accumulated. To any of the image memory area, in accordance with the display order, to accumulate the decoded image data of the bidirectional predictive coded image data,
An image memory area management means for controlling data storage contents in each of the image memory areas is provided.

According to the third moving picture decoding apparatus, the effects of the first and second moving picture decoding apparatuses can be simultaneously obtained, and the buffer memory management means can transfer the data from the buffer memory to the decoding means. The transfer efficiency of the encoded data can be improved, and the decoded image data can be stored in the optimal image memory area in the display order by the image memory management means.

The first, second, and third moving picture decoding apparatuses further include an address at which the leading data of each coded picture group among the coded data stored in the buffer memory is stored. Data for transferring encoded data from the head data of the coded image group to the decoding means in response to a head data transfer request signal from the image memory area management means. It is preferable to provide a head transfer means.

According to this configuration, even when the coded data necessary for decoding is not in the buffer memory, the coded image group including the I and P pictures necessary for decoding the next B picture to be displayed is buffered. It can be immediately transferred to the decoding means via the memory.

To achieve the above object, the first aspect of the present invention
Is a method of decoding encoded data according to a sequence of a predetermined unit, storing decoded decoded image data in a reproduced image memory, and decoding the decoded image data stored in the reproduced image memory. A moving image decoding method for displaying and outputting reproduced image data, comprising detecting an instruction to switch display of reproduced image data from normal forward reproduction to reverse method reproduction, and decoding decoded image data currently displayed as reproduced image data. In contrast, the immediately preceding decoded image data in the forward reproduction order is stored in the reproduced image memory,
It is determined that the immediately preceding decoded image data and the reference image data necessary for the decoding are not stored in the reproduced image memory, or the decoded image data currently displayed is reproduced in the forward direction. The decoded image data one immediately before and two before are stored in the reproduced image memory, and the decoded image data three immediately before and the reference image data necessary for the decoding in the forward reproduction order are stored in the reproduced image memory. When it is determined that the reference image data is not stored in the image memory, decoding is performed from the first intra-frame prediction coded image data in the coded image group including the reference image data in the sequence of the predetermined unit. I do.

According to the first moving picture decoding method, when the mode is switched to the backward reproduction mode, the decoded picture data displayed up to three times before the currently displayed picture is a B picture. If the B picture and the reference pictures I and P pictures are not in the playback picture memory, decoding is performed in advance from the first I picture for the coded picture group including the I and P pictures. No matter where the B picture to be displayed is located in the sequence, it can be decoded and displayed without delay.

[0040] In the first moving picture decoding method, the first intra-frame predictive encoded image data is sequentially transmitted from the first intra-frame predictive encoded data until the reference image data is decoded and stored in the reproduced image memory. It is preferable to decode only the forward prediction coded image data.

In the first moving picture decoding method, after the reference picture data is decoded and stored in the playback picture memory, the reference picture data is stored in the playback picture memory using the reference picture data. It is preferable to decode the encoded data corresponding to the two or three preceding decoded image data.

According to the configuration and method of the present invention, when the playback mode is switched from the normal forward playback to the reverse playback, at least two frames of the blank period are displayed while the display screen of the reverse playback is transitioning. Does not occur and it does not take a long time for the display to transition from the forward reproduction to the reverse reproduction, and the display can be switched to the reverse reproduction display immediately.

Further, a high-quality and smooth reverse reproduction at the same speed can be realized without generating a blank period of at least one frame during the reverse reproduction.

[0044]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 is a block diagram of a video decoding device according to the embodiment. In FIG. 1, reference numeral 101 denotes a stream input unit (data head transfer unit) for transferring encoded data according to a sequence of a predetermined unit to a buffer memory 102 described later via a start code detection unit 111 described later.

The start code detecting means 111 selects a specific code pattern, for example, a GOPH (Grope of Picture Header) or PH (Pic
header information, such as the image header, is analyzed, and the header information is analyzed, and picture type information (encoding type information) indicating whether each encoded image data is an I, P, or B picture and a GOP. A specific code pattern including the display order information of each picture is notified as a code detection signal to a buffer memory management unit 112 described later.

The buffer memory 102 is a buffer memory for storing coded data according to a sequence of predetermined units before input, and has a relatively large capacity of, for example, about 400 Kb. According to a data transfer request signal from the memory management means 112,
The stored encoded data is output. Further, the buffer memory 102 uses, as a storage address signal, address information for accumulating encoded data input from the start code detection means 111 as a buffer memory management means
Notify 2. Further, the buffer memory 102 deletes data in the designated internal area according to an unnecessary data deletion signal from the buffer memory management unit 112 described later.

The buffer memory management means 112 (data head management means) receives the code detection signal from the start code detection means 111 and the storage address signal from the buffer memory 102, and in any area in the buffer memory 102, The storage address information indicating whether data is stored, the picture type information indicating whether each of the encoded image data stored in the buffer memory 102 is an I, P, or B picture, and the The display order information of each picture is managed. Further, based on the management information, the buffer memory management unit 112 outputs an instruction to delete the data determined to be unnecessary to the buffer memory 102 as a data deletion request signal. further,
The buffer memory management unit 112 outputs a data transfer request signal to the buffer memory 102 in accordance with an image data request signal from the image memory area management unit 106, which will be described later. The data is transferred to the decoding means 103.

The decoding means 103 decodes the coded data from the buffer memory 102, and decodes the decoded image data based on an image memory area signal from an image memory area management means 106 which will be described later. A first image memory area 108 in the reproduced image memory 104,
Image memory area 109 or third image memory area 110
Transfer to Here, the data decoded by the decoding means 103 is transferred from the first image memory area 108 to the third image memory area 1 in the reproduced image memory 104 in units of one display image.
Will be stored in one of the ten. When decoding a P picture or a B picture, if necessary, the decoding processing is performed using the decoded image data of the I picture or the P picture in the reproduced image memory 104 as reference image data.

The display area switching means 105 receives, as a display data area signal, information on each image memory area to be displayed next from an image memory area management means 106, which will be described later.
Based on the display data area signal, the first image memory area 1
08, and switches the respective reproduced image data from the second image memory area 109 and the third image memory area 110, and outputs them as display image data in accordance with a synchronization signal of a display device (for example, a television monitor).

The image memory area management means 106 stores an I picture, a P picture, and a B picture in any one of the first image memory area 108, the second image memory area 109, and the third image memory area 110. Of which type of image data is stored, the order of images in the GOP to be displayed, and the location of the currently displayed area. It is determined in which area the decoded image data is to be stored, and which image memory area can be displayed next.

At the time of normal reproduction in the forward direction, a moving image is reproduced by the above-described configuration.

Next, the reverse reproduction operation will be described with reference to FIGS. 1, 4 and 5.

FIG. 4 shows a first image memory area 108, a second image memory area 109, and a second image memory area 109 in the reproduced image memory 104 when the moving image decoding apparatus according to the first embodiment of the present invention performs reverse reproduction. And the transition state of the picture type of the decoded image data stored in the third image memory area 110 and the picture type of the display output.

FIG. 5 is a flowchart showing playback mode switching control for performing reverse playback in the moving picture decoding apparatus according to the first embodiment of the present invention.

First, when a reproduction mode switch from forward normal reproduction to reverse reproduction is input from a remote controller or the like to the reproduction mode switching means 107, the reproduction mode switching means 1
07 outputs a reproduction mode switching signal to the decoding means 103 and the image memory area management means 106 (S50).
1).

Next, the decoding means 103 immediately stops the current decoding processing upon input of the reproduction mode switching signal, and enters a state of waiting for input of encoded data for reverse reproduction (S502).

The image memory area management means 106 immediately determines the next image to be displayed in the reverse reproduction order from the currently displayed image information upon input of the reproduction mode switching signal (S).
503). If the image data to be displayed next is in the reproduced image memory 104 (Yes), the display data area signal is output to the display area management means 105 at the next display timing, and the image is output for display (S510).

If the result of determination in S503 is that there is no image data to be displayed next in the reproduced image memory 104, the image memory area management means 106 determines whether the image to be displayed next is a B picture. (S504).

Here, as an example, the decoded image data 'B
The reverse playback operation when switching to the reverse playback mode occurs while displaying _13D as display image data will be described.

(1) Since the decoded image data displayed _immediately before the decoded image data 'B _13D is' B _12D , S50
4, it is determined that the image is a B picture (Yes), and then the reference image necessary for decoding the decoded image data 'B _12D in the reproduced image memory 104, that is, the decoded image data' P _11D and the decoded image It is determined whether there is data ' _P14D (S505).

As shown in FIG. 4, the decoded image data 'P
_{Since 11D} is stored in the first image memory area 108 and the decoded image data ' _P14D is stored in the second image memory area 109 (Yes), the buffer memory management unit 112
The image data request signal received from the image memory area management unit 106 and the buffer memory 102 managed by itself
Based on the storage address information of the
Outputs a data transfer request signal to the buffer memory 102
To immediately decode the encoded data 'B _12E
03, and the decoding means 103 outputs the decoded image data 'P transferred from the first image memory area 108.
_11D and the decoded image data 'P _14D transferred from the second image memory area 109 as a reference image, and the encoded data' B
_{A 12E} decoding process is performed (S508).

The decoded image data 'B _12D is
The image data is stored in the third image memory area 110 of the reproduction image memory 104 (S509), and is output as display image data from the third image memory area 110 via the display area switching means 105 at the next display timing (S510).

Next, the reproduction mode switching means 107 determines whether or not the reverse reproduction mode is continued (S51).
1). If the result of the determination is that the continuation is to be continued (Yes), S503
Then, it is determined whether the decoded image data to be displayed next is in the reproduced image memory 104 or not.

(2) Since the decoded image data displayed _immediately before the decoded image data 'B _12D is' P _11D and is stored in the first image memory area 108 (Yes), S5
The process proceeds to step S10, where the image is output as display image data from the first image memory area 108 via the display area switching means 105 at the next display timing.

Next, the reproduction mode switching means 107 determines whether or not the reverse reproduction mode is continued (S51).
1). If the result of the determination is that the continuation is to be continued (Yes), S503
Then, it is determined whether the decoded image data to be displayed next is in the reproduced image memory 104 or not.

(3) The decoded image data displayed _immediately before the decoded image data 'P _11D is' B _10D, which is not stored in the reproduced image memory 104 (No). The means 106 determines whether the image to be displayed next is a B picture (S504). Since the decoded image data to be displayed next is “B _10D” , it is determined in S504 that the decoded image data is a B picture (Yes), and then the decoded image data “B _10D” is decoded in the reproduction image memory 104. It is determined whether there is a necessary reference image, that is, the decoded image data 'P _11D and the decoded image data' P _8D (S505).

As shown in FIG. 4, the decoded image data 'P
_11D is stored in the first image memory area 108,
Since the decoded image data 'P _8D is not stored in the reproduction image memory 104 (No), the buffer memory management unit 1
12 is stored in the buffer memory 102 based on the storage address information of the buffer memory 102 managed by itself.
Encoded data 'encoded data required for decoding up to _P8E '
The data transfer request signals of I _2E , 'P _5E ,' P _8E are continuously output (S506), and the buffer memory 102 is controlled.
Output to the decoding means 103.

The decoding means 103 first decodes the coded data 'I _2E received from the buffer memory 102 to obtain decoded image data' I _2D 'in the second image memory area 10.
9 is stored. Next, using the decoded image data 'I _{2 D} transferred from the second image memory area 109, the encoded data' P _5E received from the buffer memory 102 is decoded to generate the decoded image data 'P _5D 3 image memory area 1
10 is stored. Finally, a third 'with P _5D, the encoded data received from the buffer memory 102' decoded image data transferred from the image memory area 110 and the second as the decoded image data 'P _8D decodes the P _8E It is stored in the image memory area 109 (S507).

Next, the buffer memory management means 112
The image data request signal received from the image memory area management unit 106 and the buffer memory 102 managed by itself
Based on the storage address information of the
Outputs a data transfer request signal to the buffer memory 102
And immediately decodes the encoded data ' _B10E into decoding means 1
03, and the decoding means 103 outputs the decoded image data 'P transferred from the first image memory area 108.
_11D and the decoded image data 'P _8D transferred from the second image memory area 109 as a reference image, and the encoded data' B
_{A 10E} decoding process is performed (S508).

The decoded image data 'B _10D is
The image data is stored in the third image memory area 110 of the reproduction image memory 104 (S509), and is output as display image data from the third image memory area 110 via the display area switching means 105 at the next display timing (S510).

As described above, the above S503 to S511
Is repeated to perform reverse reproduction. However, S511
If the result of the determination in (1) is not continuation, the reverse playback mode ends.

The moving picture decoding apparatus according to the present embodiment
According to the processing in the above, conventionally, the encoded data at the head of the GOP is
Ta'I_2EFrom 'B_12EUntil 'I_2E→ 'B_0E→ 'B_1E
→ 'P_{Five E}→ 'B_3E→ 'B_4E→ 'P_8E→ 'B_6E→ 'B_7E→ 'P_11E
→ 'B_9E→ 'B_10E→ 'P_14E→ 'B _12EUp to 14 images
Where the encoded data was transferred to the decoding means 103
From the buffer memory 102 for one image.
Data 'B_12ECan be handled by transferring.

In the decoding process, if the encoded data requested by the image data request signal from the image memory area management means 106 is not in the buffer memory 102, the buffer memory management means 112 That there is no requested data. In this case, the necessary GO
A request for P data is output to the stream input means 101 as a GOP data request signal, and a stream is input in GOP units.

(Second Embodiment) Next, a moving picture decoding apparatus and method according to a second embodiment of the present invention will be described with reference to FIGS.

FIG. 2 is a block diagram showing a moving picture decoding apparatus according to a second embodiment of the present invention.

FIG. 6 shows picture types stored in the first, second and third image memory areas and the fourth image memory area in the reproduced image memory during normal reproduction according to the second embodiment of the present invention. , The transition state of the picture type to be displayed and output.

In FIG. 2, reference numeral 201 denotes a buffer memory 202 which stores encoded data in accordance with a sequence of a predetermined unit.
Stream input means for transferring the data.

The buffer memory 202 has a relatively large capacity of, for example, about 400 Kb in order to store the input encoded data in accordance with the sequence of each predetermined unit before decoding. In accordance with the data transfer request from 203, the stored encoded data is output.

The decoding means 203 decodes the encoded data from the buffer memory 202, and determines the decoded image data by the image memory area signal from the image memory area management means 206 which will be described later. The first image memory area 208, the second image memory area 209, the third image memory area 210,
Alternatively, the data is transferred to the fourth image memory area 211.

The reproduced image memory 204 has, for example, 2 Mb.
It has a capacity of about (500 Kb × 4), and can store four frames of decoded image data as reproduced image data. The decoded image data decoded by the decoding means 203 is stored in the reproduced image memory 20 in units of one display image.
4 is stored in one of the first image memory area 208 to the fourth image memory area 211.

The display area switching means 205 receives information on each image memory area to be displayed next from the image memory area management means 206 described later as a display data area signal,
Based on the display data area signal, the first image memory area 2
08, the second image memory area 209, the third image memory area 210, and the reproduction image data from the fourth image memory area 211 are switched, and the display image data is synchronized with a synchronization signal of a display device (for example, a television monitor). Output as

The image memory area management means 206 includes a first image memory area 208, a second image memory area 209, and a third image memory area 209.
Image memory area 210 and fourth image memory area 211
Of which type of image data among the I picture, P picture, and B picture is stored in which image memory area, the image to be displayed in the order in the GOP, and the current display The area in the middle is managed, and in which area the image data decoded by the decoding means 203 is stored, and which image memory area can be displayed next is determined. I have.

At the time of normal reproduction in the forward direction, a moving image is reproduced according to the above-described configuration, and as shown in FIG. 6, an I picture and a P picture necessary as reference picture data for decoding a B picture are The B picture is stored in the first, second, and third image memory areas, and the B picture is stored in the fourth image memory area.

Next, the reverse reproduction operation will be described with reference to FIGS. 2, 7, and 8.

FIG. 7 shows a first image memory area 208, a second image memory area 209, and a second image memory area 209 in the reproduced image memory 204 when the moving image decoding apparatus according to the second embodiment of the present invention performs reverse reproduction. Third image memory area 210 and fourth image memory area 210
The transition state of the picture type of the decoded image data stored in the image memory area 211 and the picture type of the display output is shown.

FIG. 8 is a flowchart showing playback mode switching control for performing reverse playback in the moving picture decoding apparatus according to the second embodiment of the present invention. First, when a reproduction mode switch from forward normal reproduction to reverse reproduction is input to the reproduction mode switching unit 207 from, for example, a remote controller, the reproduction mode switching unit 207 sets the decoding unit 203 and the image memory area management. A reproduction mode switching signal is output to the means 206 (S801).

Here, the image memory area management means 206
Controls, as shown in FIG. 6, at the time of forward reproduction, the decoded image data of I picture or P picture for three screens is always stored in the reproduced image memory 204.

Next, the decoding means 203 immediately stops the current decoding processing upon input of the reproduction mode switching signal, and enters a state of waiting for encoded data input for reverse reproduction (S802).

The image memory area management means 206 immediately determines whether or not there is an image to be displayed next in the reverse reproduction order in the reproduction image memory 204 from the image information currently being displayed in response to the input of the reproduction mode switching signal. (S803). If there is image data to be displayed next in the reproduced image memory 204 (Yes), a display data area signal is output to the display area management means 205 at the next display timing, and the image is output for display (S806).

As a result of the determination in S803, if there is no image data to be displayed next in the reproduced image memory 204, the image memory area management means 206 determines a code necessary for decoding the next image to be displayed. G
Output to the stream input means 201 as an OP data request signal. For example, as described in the first embodiment of FIG. 4, when switching to the reverse playback mode occurs while the decoded image data 'B _13D is being displayed, the decoded image data' B _{Since 12D} is not in the reproduced image memory 204, the encoded data 'B
_A GOP data request signal is output to transfer GOP data including _12E .

If the image data to be displayed next is not in the reproduced image memory 204, the image memory area management means 206 determines whether or not the image to be displayed is a B picture (S809).

Here, the case where the switching to the backward reproduction mode has occurred while the decoded image data 'B _13D is being displayed has been described in the first embodiment, so that another example is shown in FIG. Next, a description will be given of a reverse reproduction operation when switching to the reverse reproduction mode occurs while the decoded image data '' _B3D is being displayed in the forward reproduction mode.

(1) When switching to the backward reproduction, the image to be displayed next, that is, the decoded image data “I _2D displayed immediately before the decoded image data“ B _3D ”is the second image. Since the image data is stored in the memory area 209 ("Yes" in S803), the image memory area management unit 20 outputs the display image data as display image data at the next display timing.
6 outputs a display data area signal to the display area switching means 205 (S804).

Here, the decoded image to be displayed after the currently displayed decoded image data “B _3D ” in the display order in the forward direction from the first image memory area 208 to the fourth image memory area 211. Although the data "_P5D" has been stored, since this data is no longer required to be displayed, the image memory area management means 206 _returns to the third image memory area 210 storing the encoded image data "P5D. Invalidate the data.

(2) Next, after the display of the decoded image data “I _2D ”, that is, the decoded image data “B _3D
Since the decoded image data “B _1D ” displayed two times before is not stored in any area in the reproduced image memory 204 (“No” in S805), the newly encoded data “B _1D” is newly displayed.
_1E must be decrypted (judgment “Ye
s "). The reference image data “I _2D and“ P _14D necessary for decoding the encoded data “B _1E” are stored in the second image memory area 2, respectively.
09 and because it is accumulated in the first image memory area 208 (determined by S810 "Yes"), from the image memory area management unit 206 transfers the request of the GOP data including coded data '' B _1E as GOP data request signal Output to the stream input means 201.

The decoding means 203 outputs the encoded data “B _1E
There skipped data until the input, performs decoding of the coded data '' B _1E only with reference image data '' I _2D and 'P _14D transferred from the playback image memory 204 (S81
3) The decoded image data '' B _1D is stored in the third image memory area 210 whose data has been invalidated by the image memory area management means 206 (S816), and displayed and output as display image data at the next display timing. Then, the image memory area management means 206 outputs a display data area signal to the display area switching means 205 (S817).

(3) The decoded image data “B _0D to be displayed next to the decoded image data“ B _{1D ”} , that is, the decoded image data“ B _0D displayed three times before the decoded image data “B _3D” is also Are not stored in any area in the playback image memory 204 ("No" in S803, "N" in S809).
o "). Since the reference image data “I _2D and“ P _14D necessary for decoding the encoded data “B _0D” are stored in the second image memory area 209 and the first image memory area 208, respectively (see S810). judgment "Yes"), and outputs from the image memory area management unit 206 a request for transferring GOP data including coded data '' B _0E the stream input unit 201 as GGOP data request signal.

Here, the image memory area management means 206
Indicates that the display output is the decoded image data '' I _2DTransitions to
Decoded image stored in fourth image memory area 211
Data "B"_3DIs determined to be unnecessary, and the decryption means 20
3 by outputting an image memory area signal.
To store the decoded image data in the fourth image data area 211
Allow product.

The decoding means 203 outputs the encoded data “B _1E
After the decoding process, 'skip data until B _0E is input, reference image data is transferred from the playback image memory 204' encoded data '' and I _2D 'with P _14D coded data''B _0E only is decoded (S813), and the decoded image data''B _0D is stored in the fourth image memory area 211 designated by the image memory area management means 206 (S813).
16) The image memory area management means 206 outputs a display data area signal to the display area switching means 205 so as to display and output as display image data at the next display timing (S817).

(4) Since the decoded image data 'P _14D to be displayed next to the decoded image data' B _0D is currently stored in the first image memory area 208 (determined in S803 by "Y
es "), the first until the decoded image data ' _P14D is displayed.
The image memory area 208 is managed by the image memory area management means 206 so as to hold the data.

(5) The decoded image data 'B _13D to be displayed next to the decoded image data' P _14D is stored in the reproduced image memory 20.
4 (“No” in S803, “Yes” in S809), and the decoded image data 'P _11D required as a reference image is not in the reproduced image memory 204 (S10).
(No at 810), the image memory area management unit 20
6 outputs a GOP data transfer request including the encoded data 'P _11E and' B _13E to the stream input means 201 as a GOP data request signal (S811).

The image memory area management means 206
Every time the display output changes, the contents of each image memory area in the reproduced image memory 204 are checked, and the unnecessary area is notified to the decoding means 203.

(6) After decoding the encoded data “B _0E” , the decoding means 203 decodes the encoded image data “B _13E as decoded image data” as a reference image necessary for decoding the data B _13E.
To prepare _P11D , the image memory area management means 20
6, using the available image memory area notified from
The decoding process of only the I picture and the P picture is performed in the order of the encoded data 'I _2E →' P _5E → 'P _8E →' P _11D (S81).
2). Thereafter, decoding processing of the encoded data 'B _13E is performed using the decoded image data' P _11D and 'P _14D transferred from the reproduced image memory 204 as reference images (S813).

In the same manner as above, if the processing is performed according to the flowchart showing the reproduction mode switching control in FIG.
Reverse playback at the same speed as shown in FIG. 7 can be realized.

(Third Embodiment) Next, a moving image reproducing apparatus and a method thereof according to a third embodiment of the present invention will be described with reference to FIG.

FIG. 3 is a block diagram of a moving picture reproducing apparatus according to a third embodiment of the present invention, which has the same start code detecting means 312 as that of the first embodiment.
And buffer memory management means 313, and the second
A first image memory area 308 similar to that of the embodiment,
Second image memory area 309, third image memory area 31
0 and a reproduced image memory 304 having a fourth image memory area 311, and an image memory area management unit 306.

Thus, the respective effects described in the first and second embodiments can be simultaneously realized.

[0109]

As described above, according to the moving picture decoding apparatus and method according to the present invention, when the reproduction mode is switched from forward normal reproduction to reverse reproduction, the conventional moving picture decoding apparatus has problems. As described above, a blank period of at least two frames occurs during the transition of the display screen for reverse playback, and it takes a long time for the display to transition from forward playback to reverse playback. This has the effect of immediately switching to the reverse playback display.

Also, the image may be interrupted during reverse playback,
To avoid this, it is possible to solve the conventional problem of giving a stranger to the person watching the display screen without repeatedly displaying the same image, and realize high-quality and smooth 1x speed reverse playback. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video decoding device according to a first embodiment of the present invention;

FIG. 2 is a block diagram of a video decoding device according to a second embodiment of the present invention;

FIG. 3 is a block diagram of a video decoding device according to a third embodiment of the present invention;

FIG. 4 is a reverse playback transition diagram showing the content and display output of a playback image memory according to the first embodiment of the present invention.

FIG. 5 is a flowchart of a playback mode switching control showing a reverse playback operation according to the first embodiment of the present invention.

FIG. 6 is a forward reproduction transition diagram showing a reproduction image memory content and a display output according to a second embodiment of the present invention.

FIG. 7 is a reverse playback transition diagram showing the content and display output of a playback image memory according to the second embodiment of the present invention.

FIG. 8 is a flowchart of playback mode switching control showing a reverse playback operation according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram of encoded data in the MPEG system.

FIG. 10 is a block diagram of a conventional video decoding device.

FIG. 11 is a forward reproduction transition diagram showing a reproduction image memory content and a display output in a conventional configuration.

FIG. 12 is a reverse playback transition diagram showing the playback image memory contents and display output in the conventional configuration.

[Explanation of symbols]

101, 201, 301 Stream input means (data head transfer means) 102, 202, 302 Buffer memory 103, 203, 303 Decoding means 104, 204, 304 Reproduction image memory 105, 205, 305 Display area switching means 106, 206, 306 Image memory area management means 107, 207, 307 Playback mode switching means 108, 208, 308 First image memory area 109, 209, 309 Second image memory area 110, 210, 310 Third image memory area 111, 312 Start code Detection means 112, 313 Buffer memory management means (data head management means) 211, 311 Fourth image memory area

Continued on front page F term (reference) 5C052 GA03 GB06 GB07 GC05 GE04 GF04 5C053 FA27 GA11 GB08 GB11 GB29 GB38 HA25 JA01 KA04 LA06 5C059 MA00 MA05 MA12 PP05 PP06 PP07 SS01 SS06 SS11 SS30 UA05 UA35 UA36 UA37 UA38

Claims (7)

[Claims] 1. A buffer memory for storing encoded data according to a sequence of a predetermined unit, decoding means for decoding encoded data from the buffer memory, and decoding image data by the decoding means. A reproduced image memory for storing a plurality of screens for each image memory area; an image memory area managing means for managing the contents of the decoded image data stored in the image memory area; and a decoding stored in the reproduced image memory. The decoded image data to be displayed and output as the reproduced image data among the decoded image data, and a display area switching means for controlling output switching of the reproduced image data. Detecting a specific code pattern including coding type information and display order information for the image of each predetermined unit, and outputting the code pattern as a code detection signal. Receiving a code detection signal from the start code detection unit and a storage address signal from the buffer memory, and obtaining management information for managing a location where the encoded data is stored in the buffer memory. Buffer memory control means for controlling the buffer memory according to the management information, transferring the encoded data to the decoding means in the predetermined unit, and deleting the encoded data in the buffer memory. A moving picture decoding apparatus, comprising: 2. A buffer memory for storing encoded data according to a sequence of a predetermined unit, decoding means for decoding encoded data from the buffer memory, and decoding image data by the decoding means. A playback image memory for storing a plurality of screens for each image memory area; and decoding image data to be displayed and output as playback image data from among the decoding image data stored in the playback image memory. In a moving picture decoding apparatus provided with a display area switching means for controlling output switching, during forward normal reproduction, the intra-frame prediction encoded image data and the The decoded image data of the directional prediction encoded image data is always stored in three or more of the image memory areas in the decoding order, and At the time of reverse reproduction, one of the image memory areas in which the intra-frame prediction coded image data and the decoded image data of the forward prediction coded image data are stored, according to the display order, A moving image decoding apparatus, comprising: an image memory area management unit that controls data storage contents in each of the image memory areas so as to accumulate decoded image data of directional prediction encoded image data. 3. A buffer memory for storing encoded data according to a sequence of a predetermined unit, decoding means for decoding encoded data from the buffer memory, and decoding image data by the decoding means. A playback image memory for storing a plurality of screens for each image memory area, and selecting the decoded image data to be displayed and output as the playback image data among the decoded image data stored in the playback image memory;
A moving image decoding apparatus comprising: a display area switching unit that controls output switching of reproduced image data. A specific code including encoding type information and display order information for an image of each predetermined unit from the encoded data. A start code detecting means for detecting a pattern and outputting it as a code detection signal; a place for receiving a code detection signal from the start code detection means and a storage address signal from the buffer memory, and storing the encoded data in the buffer memory Controlling the buffer memory according to the management information, causing the encoded data to be transferred to the decoding unit in the predetermined unit, and controlling the encoding in the buffer memory. A buffer memory management means for deleting data; and The encoded image data of the intra-frame predictive encoded image data and the forward predictive encoded image data of the encoded data that are consecutive in the same sequence are always stored in three or more of the image memory areas in the decoding order. In such a manner that the image data is stored in one of the image memory areas in which the intra prediction encoded image data and the decoded image data of the forward prediction encoded image data are accumulated during the backward reproduction. A moving image storing means for controlling data storage contents in each of the image memory areas so as to store decoded image data of the bidirectional predictive encoded image data in accordance with the order. Image decoding device. 4. The moving picture decoding apparatus further comprises a data head managing means for managing an address at which head data of each coded image group among coded data stored in the buffer memory is stored. A data head transfer unit for transferring encoded data from the head data of the encoded image group to the decoding unit in response to a head data transfer request signal from the image memory area management unit. The moving picture decoding apparatus according to any one of claims 1 to 3, wherein 5. Decoding encoded data according to a predetermined unit sequence, storing the decoded image data in a reproduced image memory, and decoding the decoded image data stored in the reproduced image memory into reproduced image data. In the moving picture decoding method of displaying and outputting as the reproduced picture data, an instruction to switch the display of the reproduced picture data from the normal forward reproduction to the reverse reproduction is detected, and the decoded picture data currently displayed as the reproduced picture data is sequentially processed. The previous decoded image data in the forward reproduction order is stored in the reproduced image memory, and the second previous decoded image data in the forward reproduction order and the reference image data necessary for decoding the decoded image data are stored in the reproduced image memory. It is determined that the decoded image data is not stored in the playback image memory, or the immediately preceding and next decoded image data in the forward playback order with respect to the currently displayed decoded image data are stored in the playback image memory. If it is determined that the decoded image data three times earlier in the forward reproduction order and the reference image data necessary for the decoding are not stored in the reproduced image memory, Wherein the decoding is performed from the first intra-frame prediction coded image data in the coded image group including the reference image data. 6. Until the reference image data is decoded and stored in the reproduction image memory, only the intra-frame prediction coded image data and the forward prediction coded image data are sequentially arranged from the first intra-frame prediction coded data. The moving picture decoding method according to claim 4, wherein the moving picture is decoded. 7. After the reference image data is decoded and stored in the reproduced image memory, the second or third previous decoding not stored in the reproduced image memory is performed using the reference image data. 6. The moving picture decoding method according to claim 4, wherein the decoding of the coded data corresponding to the coded image data is performed.