JPH08265749A - Picture reproducing device by mpeg system - Google Patents

Abstract

PURPOSE: To improve the quality of reproducing pictures by interpolating I picture decoded at every other interval when a high-speed reproduction is taken place by pictures to which gradually changing specified processings are performed. CONSTITUTION: A decoding part 11 decodes only the specified I pictures of encoded data and stores them in the first and second work memories 12 and 13 when the high-speed reproduction such as fast forward reproduction and rewinding reproduction, etc., is taken place. A picture processing part 16 performs a fade-in/fade-out process, a mosaic process, a shading process and a synthesis process, etc., to the I pictures I0 and I1 stored in the first and second work memories 12 and 13 and stores them in a third work memory 14. For instance, in the fade-in/fade-out process, the plural pictures for interpolation obtained by performing gradually changed weighting to the respective I pictures I0 and I1 are stored in the third work memory 14 and setting is performed so as to make the I picture I0 gradually disappear and to make the I picture I1 gradually appear instead when they are read out in order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing apparatus according to the MPEG system, and more particularly, to fast-forward reproducing or rewinding an image by intermittently decoding only I pictures existing in a bit stream of coded data according to the MPEG system. It is suitable for use in a reproducing device having a reproducing function.

[0002]

2. Description of the Related Art In recent years, MPEG (Moving Picture Image Coding) has been used as one of compression techniques for digital image signals.
A technique called Experts Group) has been developed. The compression technique of the image signal by this MPEG is ISO
/ IEC (International Organization for Standardization / International Electrotechnical Commission), and is used for storage media such as VideoCD.

For image reproduction by the above-mentioned storage medium, V
As in the case of TR playback, fast forward, rewind, midway playback, reverse playback, etc. are required. In order to realize such a requirement, MPEG1 employs a structure called GOP (Group of Pictures) for a sequence of image data. That is, in MPEG1, the coded image data is created based on the preceding and following image data, so that it is not information that is completed by only one image. For this reason, a video sequence is configured with a GOP, which is a collection of several pieces of image data, as a unit.

That is, as shown in FIG. 4, MPEG1
In the storage medium using, the GO in which a plurality of GOP data are prepared after the sequence start header
The video sequence is formed by sequentially storing the P header (data used for cueing for random access). A sequence end code is recorded at the end of this video sequence.

Three types of image types are defined for the image data in the GOP. That is, I picture,
There are three types, P picture and B picture. Of these image data, the I picture is image data generated by intraframe coding. Therefore, at the time of decoding, one image is reconstructed only by the data of one I picture itself.

The P picture is image data generated by the inter-frame forward predictive coding, and is data obtained by coding the difference from the immediately preceding I picture or P picture. A B picture is image data generated by bidirectional predictive coding, and encodes a difference from an I picture or P picture immediately preceding in time and a difference from an I picture or P picture immediately following in time. It is the converted data.

When performing fast-forward reproduction or rewind reproduction of an image from a bit stream based on a video sequence as shown in FIG. 4, normally only the I picture is reproduced and displayed. As can be seen from the above description, this reproduces (decodes) P pictures and B pictures.
In order to do so, it is necessary to use another picture, and the processing takes a lot of time. Therefore, if these pictures are reproduced, it is difficult to perform high-speed reproduction such as fast forward and rewind.

FIG. 5 is a diagram showing a state of image reproduction during fast-forward reproduction or rewind reproduction (hereinafter, these are collectively referred to as high-speed reproduction). FIG. 5A shows MP
A part of the bit stream of the encoded data by EG is shown, (b) shows the picture to be displayed, and (c) shows the time required for processing each picture.

Although the bit stream of the encoded data actually includes P pictures and B pictures between each I picture, these pictures are not reproduced during high speed reproduction. Therefore, FIG. 5 (a)
Shows only the I picture. Further, among the plurality of I pictures, only the I pictures that are reproduced at the high speed reproduction are shown surrounded by squares.

That is, although many I-pictures are present in the bit stream according to MPEG, not all of them are reproduced at high speed. In the example of FIG. 5, after reproducing the I1 picture, the next reproduction is I2.
Ia pictures, Ib pictures, Ic pictures, Id pictures, and Ie pictures between I1 pictures and I2 pictures are not reproduced.

As can be seen from FIG. 5C, this is because a seek time for reading an I picture from the storage medium is required to decode a certain I picture during high speed reproduction. Due to processing time,
This is because it is practically impossible to read and decode all I pictures.

[0012]

In the conventional image reproducing apparatus based on the MPEG system, during high-speed reproduction such as fast-forward reproduction and rewind reproduction, from displaying one I picture to displaying the next I picture, That is, in the example of FIG.
It took about 0.5 to 1 second from displaying one picture to displaying the next I2 picture. That is, 1
It took about 0.5 to 1 second until one I picture was read and the decoding was completed.

Then, as shown in FIG. 5B, I1
From the time a picture is decoded until the next I2 picture is decoded, the I1 picture continues to be displayed,
When the decoding of the I2 picture is completed, the I2 picture is displayed. As described above, conventionally, after the same I picture is displayed for a long time of 0.5 to 1 second, the display is suddenly switched to the next picture. For this reason, there is a problem that the viewer feels that the picture is changing and the image becomes very unsightly.

The present invention has been made to solve such a problem, and makes it easy to see the reproduced image when fast-forwarding or rewinding the image from the bit stream of the encoded data by the MPEG system. The purpose is to do.

[0015]

An image reproducing apparatus based on the MPEG system of the present invention is an image reproducing apparatus having a function of performing fast forward reproduction or rewind reproduction of an image from a bit stream of encoded data according to the MPEG system. An image for generating a plurality of images by performing a predetermined image processing on the I picture decoded by the decoding means and a decoding means for decoding the I pictures in the bit stream at the time of reproduction or rewinding reproduction. And processing means.

Further, another feature of the present invention is that
A plurality of work memories for sequentially storing the respective I pictures decoded by the decoding means are provided, and for each I picture stored in the plurality of work memories,
Image processing is performed by the image processing means.

Another feature of the present invention is that in the image processing performed by the image processing means, the I-pictures decoded in a discrete manner are faded in to bring them into a normal reproduced image state. The image processing is characterized by fading out after a lapse of a predetermined time from the normal reproduction image state.

Another feature of the present invention is that the image processing performed by the image processing means is image processing for performing mosaic on each I picture decoded in a discrete manner, and the mosaic is rough. Image processing that gradually changes from a state to a fine state to a normal reproduction image state, and finely applies a mosaic after a predetermined time has elapsed from the normal reproduction image state, and then gradually changes the mosaic roughly. It is characterized by being.

Another feature of the present invention is that the image processing performed by the image processing means is image processing for blurring each I picture that is decoded in a discrete manner. Gradually shift the degree of blurring from a large state to a small state to a normal reproduction image state, and after a predetermined time has elapsed after the normal reproduction image state, the degree of blurring is changed from a small state. The image processing is characterized by gradually shifting to a large state.

Another feature of the present invention is that the image processing performed by the image processing means is decoded and image processed temporally earlier in each of the I pictures that are decoded in a discrete manner. An image process for synthesizing an I picture and an I picture that has been temporally decoded and image-processed later, and is characterized in that it is an image process that gradually changes the ratio of synthesizing the two I pictures. There is.

Another feature of the present invention is that the image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time. Each is characterized by image processing in which the I picture is faded in to a normal reproduced image state, and faded out after a predetermined time has elapsed from the normal reproduced image state.

Another feature of the present invention is that the image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time. Is an image processing for applying mosaic to the I picture, and gradually changes the mosaic from a coarse state to a fine state to a normal reproduction image state, and a predetermined time elapses from the normal reproduction image state. After that, the mosaic processing is performed finely, and thereafter the image processing is performed to gradually and roughly change the mosaic.

Another feature of the present invention is that the image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time. Is an image process for blurring an I-picture, and gradually shifts the degree of blurring applied to the I-picture from a large state to a small state to bring it to a normal reproduced image state. The image processing is characterized by gradually changing the degree of blurring from a small state to a large state after a lapse of a predetermined time from the state.

[0024]

Since the present invention comprises the above technical means, a plurality of images which are missing between the I picture and the I picture which are intermittently displayed on the screen by the intermittent decoding are decoded in the discrete manner. Since each I picture can be subjected to predetermined image processing to generate an image that is similar to the above I picture and can be interpolated, even if the screen display is switched from the I picture that is decoded in abrupt manner to the I picture, It gives less natural feeling.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image reproducing apparatus based on the MPEG system of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the image reproducing apparatus according to the present embodiment. The image reproducing apparatus according to the present embodiment has a function of performing fast-forward reproduction or rewind reproduction of an image from a bit stream according to the MPEG system.

In FIG. 1, 11 is a decoding unit,
The image data (I picture, P picture, and B picture) in each GOP included in the bit stream of the input encoded data (see FIG. 4) is sequentially decoded. However, the decoding unit 11 sequentially decodes only a specific I picture during high speed reproduction such as fast forward reproduction and rewind reproduction. Reference numerals 12 to 14 denote first to third work memories, respectively, for storing each picture decoded by the decoding unit 11.

Reference numeral 15 is an output selection unit, which is the first to third units described above.
Of the pictures stored in the work memories 12 to 14 are selected and output. An image processing unit 16 executes image processing to be described later during high speed reproduction such as fast forward reproduction and rewind reproduction.

The operation of the image reproducing apparatus configured as described above will be described. First, during normal reproduction or reverse reproduction, the first work memory 12 and the second work memory 13 have I decoded by the decoding unit 11.
A picture or P picture is stored. In addition, the B picture decoded by the decoding unit 11 is stored in the third work memory 14. Then, each picture stored in each of the work memories 12 to 14 after being decoded is read by the decoding unit 11 and is used for decoding processing of a picture input thereafter.

That is, as described above, the P picture is data obtained by encoding the difference from the I picture or P picture immediately preceding in time. Therefore, when decoding this P picture, an I picture or P picture that is located immediately before in time and has already been decoded is required. Therefore, the I picture or P picture already stored in either the first or second work memory 12 or 13 is read by the decoding unit 11, and the P picture is decoded using this read picture. To be done.

The B picture is data obtained by encoding the difference from the I picture or P picture immediately preceding in time and the difference from the I picture or P picture immediately following in time. Therefore, when decoding this B picture,
An I or P picture that is located immediately before in time and has already been decoded, and an I picture or P picture that is located immediately after in time and has already been decoded
It is necessary to utilize pictures or P-pictures. Therefore, the first and second work memories 12,
The I picture or P picture already stored in each of 13 is read by the decoding unit 11, and the B picture is decoded using these read pictures.

Then, the decoding unit 11 is operated as described above.
The I-picture, P-picture, and B-picture that are decoded by and are stored in the work memories 12 to 14 are sequentially selected by the output selection unit 15 and output to a display device or the like not shown. As a result, reproduced images are displayed in the same order as the original image before encoding.

On the other hand, during high-speed reproduction, the decoding unit 11 decodes only a specific I picture, so
The decoded specific I-picture is stored in the work memory 12 and the second work memory 13. The I-pictures stored in the first and second work memories 12 and 13 are then given to the image processing unit 16,
Predetermined image processing is performed. The predetermined image processing is
For example, there are fade-in / fade-out processing, mosaic processing, blurring processing, combining processing, and the like.

The picture subjected to the image processing by the image processing unit 16 is stored in the third work memory 14. At this time, the output selection unit 15 selects the picture stored in the third work memory 14 and outputs it to a display device (not shown) or the like. As a result, the image that has undergone image processing is displayed.

Next, the operation during the above-mentioned high speed reproduction will be described in more detail with reference to FIG. here,
FIG. 2A is a diagram showing a bitstream of encoded data according to the MPEG system. It should be noted that this bit stream shows a part of the bit stream input to the decoding unit 11. Actually, I pictures also exist before and after the picture shown here, and at regular intervals. Only the existing pictures of I0, I1, I2, ... Are decoded by the decoding unit 11. Also, as in the case of FIG. 5, the P picture and the B picture that actually exist between each I picture are not shown.

FIG. 2B is a diagram showing a picture displayed during high-speed reproduction, and FIG. 2C is a diagram showing a time required for processing each I picture. The processing time of each I picture (the total time of the seek time and the decoding time) is about 0.5 to 1 second, as described in the conventional example.

As shown in FIG. 2A, first of all,
When the I1 picture in the bitstream is input, it is decoded by the decoding unit 11. Assuming that the I0 picture decoded earlier than that is already stored in the first work memory 12, this decoded I1 picture is stored in the second work memory 13.

The I0 picture and the I1 picture stored in the first work memory 12 and the second work memory 13, respectively, are sequentially sent to the image processing section 16 where they are subjected to predetermined image processing. When the predetermined image processing is, for example, fade-in / fade-out processing, the I0 picture and the I1 picture are sequentially weighted by predetermined values that change gradually.

Specifically, as shown in FIG. 3 (b), the I0 picture decoded by the decoding unit 11 is changed from a state in which a large weight is given first to a state in which the weight is gradually reduced to a normal value. In addition to the reproduction image state, the weighting is changed so that the weighting gradually increases after a predetermined time has elapsed from the normal reproduction image state.
Next, similar weighting is applied to the I1 picture.

As described above, after a plurality of images (see FIG. 3B) with different weights are generated from one I0 picture (see FIG. 3A) decoded by the decoding unit 11, the next decoding is performed. A plurality of images (see FIG. 3B) with different weights are generated from one I1 picture (see FIG. 3A) decoded by the unit 11.

The pictures weighted as described above are sequentially stored in the third work memory 14. At this time, the output selection unit 15 causes the third work memory 14
The pictures stored in are sequentially selected and output to a display device (not shown). As a result, when the I0 picture is switched to the I1 picture, an image in which the I0 picture gradually disappears and the I1 picture gradually appears is displayed.

Next, the same processing as above is performed for the I2 picture. That is, the I2 picture decoded by the decoding unit 11 is stored in the first work memory 12
Stored in. Then, the I2 picture stored in the first work memory 12 is given to the image processing unit 16,
The fade-in / fade-out processing as described above is performed.

The picture subjected to the fade-in / fade-out processing is stored in the third work memory 14 and then output to the display device (not shown) via the output selection section 15 for display. As a result, when the I1 picture is switched to the I2 picture, an image in which the I1 picture gradually disappears and the I2 picture gradually appears is displayed.

As described above, as shown in FIG. 2B, I0 picture → I1 picture → I2 picture → ...
The images are smoothly switched, and images that naturally transition are displayed.

As a mode of fade-in / fade-out, as shown in FIG. 3B, for example, the I0 picture may be completely faded out and then the I1 picture may be faded in. Three
As shown in (c), the I1 picture may be faded in while the I0 picture is faded out.

That is, the fade-out image of the I0 picture and the fade-in image of the I1 picture may be superimposed and output. In this way, the displayed image does not completely disappear when the picture is switched, so that the image can be switched more smoothly.

When the predetermined image processing performed by the image processing unit 16 is mosaic processing, for example, during the transition period from the I0 picture to the I1 picture, the I0 picture is gradually roughened to a certain degree of roughness. When it becomes, switch to the I1 picture with a coarse mosaic. After that, the mosaic applied to the I1 picture is gradually made finer, so that the image can be smoothly switched from the I0 picture to the I1 picture.

In the mosaic processing as described above, for example, the lower bit of the read address when reading the I picture from the first work memory 12 and the second work memory 13 is fixed to "0" or "1". Can be done by In this case, the roughness of the mosaic can be determined by fixing the lower bits. Therefore, the roughness of the mosaic can be gradually changed by changing the number of fixed bits with time.

When the image processing unit 16 performs the blurring process, for example, during the transition period from the I0 picture to the I1 picture, the blurring of the I0 picture is gradually increased, and when the blurring is increased to some extent, First, switch to the I1 picture that has been greatly blurred. After that, the blur of the I1 picture is gradually reduced.

When the image processing unit 16 performs the combining process, the combining ratio of the I0 picture and the I1 picture is changed so that the ratio of the I1 picture increases with time. It should be noted that the I0 picture and the I1 picture that have been subjected to the mosaic processing or blurring processing as described above may be combined, and the combination ratio thereof may be changed with time. By doing so, the image can be smoothly switched from the I0 picture to the I1 picture.

In performing the fade-in / fade-out process, the mosaic process, the blurring process, or the combining process as described above, a long seek time as shown in FIG. 2C is not necessary. Moreover, these processes are
This can be performed during the seek time of each I picture because it can be performed more easily than the picture decoding process and the processing time is short.

As described above, according to this embodiment,
When an image is switched from one I-picture to the next I-picture, many images that are missing between I-pictures that are randomly decoded can be interpolated with images generated by image processing. it can. As a result, the image can be displayed as if it was smoothly switched, so that it is possible to perform screen display that is very easy for the viewer to see.

Further, in the present embodiment, between a certain I picture and the next I picture, a plurality of images similar to these I pictures are generated and interpolated by image processing.
Images can be smoothly switched even if the intervals of I-pictures to be decoded are made wider than the interval of 6 skips shown in FIG. Therefore, it is possible to perform fast-forward reproduction or rewind reproduction at higher speed without obscuring the display screen.

In the above embodiment, the image processing unit 16
Although four examples are given as the predetermined image processing performed by the present invention, the present invention is not limited to this. That is, any image processing can be used as long as it can generate an image that interpolates between a certain I picture and the next I picture.

[0054]

As described above, according to the present invention, a plurality of images which are missing between I-pictures which are intermittently displayed on the screen due to the intermittent decoding are decoded as described above. Since it is possible to interpolate with an image generated by performing a predetermined image processing on each I picture, even if the I picture displayed on the screen is switched to the next I picture, an unnatural feeling is less likely to occur. Therefore, it is possible to make the image displayed during fast-forward reproduction or rewind reproduction easier to see.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an MPEG image reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state of image reproduction during fast-forward reproduction or rewind reproduction according to the present embodiment, and FIG.
It is a figure which shows a part of bit stream by PEG, (b) shows the picture displayed, (c) is a figure which shows the processing time of each picture.

FIG. 3 is a conceptual diagram showing a state of image processing.

FIG. 4 is a diagram showing a video sequence of encoded data according to MPEG.

FIG. 5 is a diagram showing a state of image reproduction during conventional fast-forward reproduction or rewind reproduction, in which (a) shows a part of an MPEG bitstream, (b) shows a picture to be displayed, (C) is a figure which shows the processing time of each picture.

[Explanation of symbols]

 11 decoding unit 12, 13, 14 work memory 15 output selecting unit 16 image processing unit

Claims (9)

[Claims] 1. An image reproducing apparatus having a function of performing fast forward reproduction or rewind reproduction of an image from a bit stream of encoded data according to the MPEG system, wherein when performing the fast forward reproduction or rewind reproduction, An image according to the MPEG system, which is provided with a decoding means for decoding I-pictures at random, and an image processing means for subjecting the I-pictures decoded by the decoding means to predetermined image processing to generate a plurality of images. Playback device. 2. The image reproducing apparatus based on the MPEG system according to claim 1, wherein a plurality of work memories for sequentially storing each I picture decoded by said decoding means are provided and stored in said plurality of work memories. An image reproducing apparatus according to the MPEG system, characterized in that each I picture is subjected to image processing by the image processing means. 3. The image processing performed by the image processing means fades in each of the I-pictures decoded in a discrete manner to a normal reproduced image state, and a predetermined time after the normal reproduced image state. The image reproducing apparatus according to the MPEG system according to claim 1 or 2, wherein the image processing is to fade out after a lapse of time. 4. The image processing performed by the image processing means is image processing for applying mosaic to each of the I-pictures that are decoded in a discrete manner, and is usually performed by gradually changing the mosaic from a coarse state to a fine state. 2. The image processing in which the mosaic is finely applied after a lapse of a predetermined time from the normal playback image state in addition to the normal playback image state, and then the mosaic is gradually and roughly changed. 2. An image reproducing device according to the MPEG method described in 2. 5. The image processing performed by the image processing means is image processing for blurring each I picture that is decoded in a discrete manner, wherein the degree of blurring applied to each I picture is large to small. Image processing for gradually changing the blurring degree from a small state to a large state after a lapse of a predetermined time from the normal reproduction image state. Claim 1 or 2 characterized in that
An image reproducing device according to the MPEG method described in 1. 6. The image processing performed by the image processing means is such that, in each I picture that is decoded in a discrete manner, an I picture that is decoded first in time and image processed and an image that is decoded in time later. 3. The MPEG system according to claim 1, wherein the MPEG method is image processing for combining the processed I picture and gradually changing a ratio for combining the two I pictures. Image playback device by. 7. The image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time are each made by normally fading in the I picture. 7. The image reproducing apparatus according to the MPEG system according to claim 6, wherein the image reproducing apparatus uses the MPEG system according to claim 6, wherein the image processing is performed in the reproduction image state and the fade-out is performed after a predetermined time has elapsed after the normal reproduction image state. 8. The image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time are each image processing for mosaicing the I picture. That is, the mosaic is gradually changed from a coarse state to a fine state to a normal reproduction image state, and after a predetermined time has elapsed from the normal reproduction image state, the mosaic is finely applied, and then the mosaic 7. The image reproducing apparatus according to the MPEG method according to claim 6, wherein the image processing is an image processing for gradually changing the image. 9. The image processing performed on the I picture decoded earlier in time and the image processing performed on the I picture decoded later in time are each image processing for blurring the I picture. In addition, the degree of blurring applied to the I picture is gradually changed from a large state to a small state to be a normal reproduced image state, and after a predetermined time has elapsed after the normal reproduced image state, 7. The image reproducing apparatus according to the MPEG system according to claim 6, wherein the image processing is an image process for gradually shifting the degree of blurring from a small state to a large state.