JP2763057B2 - Video coding and playback method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding and reproducing method for accumulating a moving image so that the moving image can be reproduced in both forward and reverse directions.

(Prior art)

Conventionally, in the high efficiency coding method used in the field of communication, in particular, a video (TV) telephone, a video (TV) conference, etc., it was not necessary to perform decoding in the reverse direction.

[Problems to be solved by the invention]

 Therefore, reverse reproduction was impossible.

In addition, in order to reproduce the moving image for storage media in both forward and backward directions, the data amount is doubled by independently encoding and storing the moving image, and the data can be stored in one storage medium. There was a problem that the data amount was reduced by half.

The present invention has been made to solve the above problems.

An object of the present invention is to provide a technique capable of realizing a moving image encoding / decoding that can be reproduced in both forward and backward directions in a moving image encoding and reproducing method.

The above and other objects and novel features of the present invention are as follows.
It will become apparent from the description of the present specification and the accompanying drawings.

[Means for solving the problem]

In order to achieve the above object, in the present invention, a frame interval of a frame image to be encoded within a frame in a series of frame images controlled by a moving image sequence is predetermined, and a frame having the determined frame interval is set. An image is encoded in a frame, and the frame images other than the frame image encoded in the frame are the frame images closest to the encoded frame image among the frame images encoded in the frame. And encoding using the inter-frame correlation with the decoded image of the frame image encoded in step (1) as a reference image.

Further, if the current playback target frame image is a frame image encoded in the frame and the decoded image of the frame image is not stored in the frame buffer, the frame image is decoded and displayed, and the frame image is simultaneously displayed. If a decoded image of the frame image is stored in the frame buffer, this is displayed, and the current playback target frame image is a frame image coded between frames, and If the decoded image of the reference frame image used as the reference image is not stored in the frame buffer, the encoded data of the reference frame image is read and decoded, stored in the frame buffer, and stored in the frame buffer. The current playback target frame image is decoded using the decoded image of the reference frame image Characterized in that it raw.

[Action]

According to the means, for example, in the storage of a moving image in a storage medium, a frame image is encoded in a frame at a frame interval appropriate for the target moving image, and a frame image other than the frame image encoded in the frame is encoded. The frame image is encoded between frames using a decoded image of the frame image encoded in the frame as a reference image, and at the time of reproduction, the frame image encoded in the frame is decoded and displayed at the same time. The frame image stored in the frame buffer and encoded between the frames is decoded and displayed using the decoded image of the frame image encoded in the frame stored in the frame buffer as a reference image.

As a result, reproduction can be performed using common encoded data in the forward and reverse directions, and encoding can be performed with high efficiency.

(Example of the invention)

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment in which the present invention is applied to a moving image encoding method for storage media.

As shown in FIG. 1, the moving picture coding method of the present embodiment captures a target moving picture by an input circuit 12 and encodes a frame interval of a frame picture to be encoded in a frame by a frame interval determining circuit 13. The target moving image is obtained in advance. Again, the target image is taken into the frame buffer 15 via the input circuit 14 for each frame image. The frame interval determination circuit 13 determines whether the image of the current frame is to be encoded between frames or to be encoded within a frame.

According to this determination, when encoding is performed within a frame,
The changeover switch 17 is connected to the side a, and encoding is performed in the frame by the intraframe encoder 18. The encoded data is input to a storage processing circuit 29 through a changeover switch 28, and is added with header information indicating that the data has been encoded in the frame by the storage processing circuit 29, and is stored.
The signal is input to the decoder 19, decoded by the decoder 19, and stored in the frame buffer 20. At this time, the changeover switch 28 is closed.

If it is determined that the image of the current frame is encoded between frames, the changeover switch 17 is connected to the b side. The buffer check circuit 22 checks whether or not a decoded image of a reference frame image used for inter-frame coding (hereinafter, simply referred to as a reference decoded image) is already stored in the frame buffer 20.

If the reference decoded image has already been stored in the frame buffer 20, the changeover switch 21 is connected to the a side, and the difference between the reference decoded image and the current encoding target frame image is obtained by the difference circuit 26. Is the interframe encoder 27
. The encoded data is accumulated with header information indicating that it has been encoded between frames by the accumulation processing circuit 29 and the frame of the reference decoded image used for encoding.

If the reference decoded image has not been stored in the frame buffer 20, the changeover switch 21 is connected to the b side, and
The encoding target frame image is delayed by the delay unit 25 until the reference decoded image is stored in the frame buffer 20.

During this time, the reference frame image is searched by the reference image search circuit 23, the reference frame image is read through the input circuit 24, and the frame buffer is passed through the intra-frame encoder 18 and the decoder 19 as described above. In 20, it is stored as a reference decoded image. At this time, the changeover switch 28 is open, and the encoded data of the reference frame image is not stored at this time.

The difference between the reference decoded image and the current encoding target frame image delayed by the delay unit 25 is obtained, and the difference is encoded and stored as described above.

A frame image to be encoded in a frame in a series of frame images controlled by the moving image sequence is determined to be an appropriate frame image for the target moving image. For example, the target moving image is divided into groups each including a series of frame images having little motion in the group, and a frame image to be encoded in the frame is a frame image which is the center of the group. is there.

As a result, encoding between frames in the present method can be performed with a frame image as close as possible. Here, the grouping is performed by a predetermined evaluation function defined by the magnitude of the difference between frames and the like.

FIG. 2 is a conceptual diagram for explaining a moving image reproducing method according to the present invention. In the figure, the hatched frame images indicate frame images encoded within the frame, and other than the frame images indicate frame images encoded between frames. The lower part shows the frame buffer 10.
Now, assume that the reproduction is performed in the direction of the arrow. However, it does not matter whether this is the forward direction.

It is assumed that the display of the frame image 2 which is the current image is completed and the reproduction of the frame image 3 is started. In this case, the frame image 2 is a frame image encoded between frames using the frame image 1 as a reference decoded image, but the frame image 3 is encoded between frames using the frame image 5 as a reference decoded image. , The frame buffer 10 needs to be rewritten.

Therefore, before decoding the frame image 3, a reference image (frame image 5) used for encoding is searched between frames, and encoded data of the reference image is read and decoded.
Store in the frame buffer 10. Thereafter, the frame image 3 is decoded and displayed using the reference decoded image (the decoded image of the frame image 5) in the frame buffer 10.

The frame image 4 is immediately decoded and displayed using the reference decoded image already stored in the frame buffer 10. Since the frame image 5 has already been decoded and stored in the frame buffer 10, the decoded image is displayed. The frame images 6, 7, and 8 are decoded and displayed in the same manner as the frame image 4. Since the frame image 9 is encoded between frames using the frame image 11 as a reference image, the same reproduction as that of the frame image 3 is performed, and the reproduction continues in the same manner.

FIG. 3 is a block diagram showing a schematic configuration of an embodiment in which the present invention is applied to a moving image reproducing method for a storage medium.

As shown in FIG. 3, the moving image reproducing method of this embodiment
The header information is read from the encoded data 30 by the header reading circuit 31, and whether the image of the current reproduction target frame is coded in the frame or whether it is coded between the frames is determined by the intra / frame determination circuit 32. You. When encoded within a frame, the changeover switch 33 is connected to the a side.

If a decoded image of the frame image has already been stored in the frame buffer 42, it is displayed on the display device 45. When the decoded image of the frame image is not stored in the frame buffer 42 yet, the encoded data of the current reproduction target frame image is read through the encoded data reading circuit 36, decoded by the decoder 37, and displayed. The image is displayed on the device 45 and the decoded image is stored in the frame buffer 42.

When the current playback target frame image is encoded between frames, the changeover switch 33 is connected to the b side and reads the encoded data via the encoded data reading circuit 38.
The data is decoded by the decoder 39. Here, the decoded image is a difference decoded image from the reference image, and is not a complete decoded image.

Next, the buffer check circuit 34 checks whether or not the reference decoded image is already stored in the frame buffer 42. If not, the changeover switch 40 is connected to the a side, and the differential decoding is performed by the delay unit 43. Delay the image, while
During this time, the encoded data of the reference frame image is searched by the reference image search circuit 41, the encoded data of the reference frame image is read by the encoded data reading circuit 36, decoded by the decoder 37, and stored in the frame buffer 42. The sum of the reference decoded image and the difference decoded image is obtained by the adder 44, and a completely restored image is displayed on the display device 45.

As can be understood from the above description, in storing a moving image in a storage medium, a frame image is encoded in a frame at a frame interval appropriate for a target moving image, and a frame image other than the frame image encoded in the frame is encoded. A frame image is encoded between frames using a decoded image of the frame image encoded in the frame as a reference decoded image,
At the time of reproduction, the frame image encoded in the frame is decoded and displayed, and at the same time, the frame buffer 42 is displayed.
The frame image encoded between the frames is decoded using the reference decoded image stored in the frame buffer 42 and displayed, thereby using common encoded data in the forward and reverse directions. It will be playable,
Encoding and decoding can be performed with high efficiency.

As mentioned above, although the present invention was explained concretely based on an example, the present invention is not limited to the above-mentioned example.
It goes without saying that various changes can be made without departing from the scope of the invention.

For example, a discrete cosine transform (DCT), DPCM, GBTC, or the like can be applied to the intraframe coding method according to the present invention. In the interframe coding method, it is effective to perform coding using a motion compensation difference. is there.

〔The invention's effect〕

As described above, according to the present invention, in the method of encoding and reproducing a moving image, it is possible to reproduce the same encoded data regardless of the forward direction and the reverse direction. It can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment in which the present invention is applied to a moving image encoding method for a storage medium, FIG. 2 is a conceptual diagram for explaining a moving image reproducing method according to the present invention, FIG. 3 is a block diagram showing a schematic configuration of an embodiment in which the present invention is applied to a moving image reproducing method for a storage medium. In the figure, 12, 14, 24 ... an input circuit, 13 ... a frame interval determination circuit, 15, 20, 42 ... a frame buffer, 16, 32 ... an intra-frame / inter-frame determination circuit, 17, 21, 28, 33 , 35, 40 ... changeover switch, 18 ... intraframe encoder, 19, 37, 39 ... decoder, 22, 34 ... buffer inspection circuit, 23 ... reference image search circuit, 25, 43 ... ... Delayer, 26 ... Difference circuit, 27 ... Interframe encoder, 29 ... Storage processing circuit, 30 ... Encoded data, 31 ... Header reading circuit, 36,38 ... Code data reading circuit 41: Reference image search circuit, 44: Adder, 45: Display device.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-274274 (JP, A) JP-A-62-213494 (JP, A) JP-A-2-234586 (JP, A)

Claims (2)

(57) [Claims] 1. A frame interval of a frame image to be encoded in a frame in a series of frame images controlled by a moving image sequence is determined in advance, and a frame image having the determined frame interval is encoded in the frame. A frame image other than the frame image encoded in the frame is a frame image encoded in the frame closest to the encoded frame image among the frame images encoded in the frame. A moving picture coding method characterized by coding using a decoded picture as a reference picture and using inter-frame correlation. 2. If the current frame image to be reproduced is a frame image encoded in a frame and a decoded image of the frame image is not stored in the frame buffer, the frame image is decoded and displayed. At the same time, the image is stored in a frame buffer, and if a decoded image of the frame image is stored in the frame buffer, this is displayed, and the current playback target frame image is a frame image encoded between frames, If the decoded image of the reference frame image used as the reference image at the time of encoding is not stored in the frame buffer, the encoded data of the reference frame image is read and decoded, and stored in the frame buffer. Decodes the current playback target frame image using the decoded reference frame image stored in the A moving picture reproducing method characterized in that the moving picture is reproduced after being converted.