JP3152268B2 - Image information recording method and image information reproducing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications] The present invention enhances digital image information.
Efficient encoding for transmission or recording of image information processing methods
For digital tape recorders (D-VTRs)
Image information processing method suitable for reproduction when editing is performed in
About the law.

[0002]

2. Description of the Related Art As an encoding method for compressing moving image information in a storage medium such as a video tape recorder or a video disk, MPEG, M
There is PEG-2 (Watanabe, "MPEG2 Interframe Prediction Method", Technical Report of the Institute of Television Engineers of Japan, ITEJ Technical R
eport Vol.16, No.61, pp.32-42ICS'92-73, Oct.199
2, or Katayama, "MPEG2 Quantization and Coding Control", pp. 43-48, ICS'92-74, Oct. 1992).

[0003] The MPEG standard basically performs high-efficiency coding of a moving image by a combination of motion compensation inter-frame prediction and DCT. In this MPEG, frames (images) are divided into three types. This is the so-called picture type, which is an I picture to be coded in a frame, a P picture using inter-frame prediction referring to a preceding I picture or a P picture frame, an I or P picture frame in both forward and backward directions, and a This is a B picture using insertion.

[0004] Of these, the compressed information of a P picture contains, for each macroblock, either a code indicating an inter block with motion compensation prediction or a code indicating an intra block without motion compensation prediction. . Further, for the inter block, information of a motion vector for the referenced frame is also included.

[0005] The compressed information of a B picture includes, for each macroblock, a code indicating the intra block, a code indicating an inter block for performing prediction from the front, a code indicating an inter block for performing prediction from the back, And any of the codes indicating the inter-blocks for which prediction is performed from the backward interpolation. Further, for a block for which prediction is performed from the front, motion vector information for a preceding frame, for a block for which prediction is to be performed from the back, motion vector information for a subsequent frame, and for a block for which prediction is performed from the front and the rear, interpolation is performed. And motion vector information for the subsequent frame.

[0006]

[Problems to be solved by the invention] By the way, D-VTR
Allows editing in as few frames as possible
It is desirable to use the MPEG method as it is
And one frame unless all frames are I-pictures
Cannot edit and play in system units. This is
For a picture, the encoding is in its own frame.
Since decoding is performed, decoding and reproduction can be performed in units of one frame.
However, P pictures and B pictures are compressed
Forward or backward frame referred to in is not decoded and reproduced
This is because decoding and reproduction cannot be performed as satisfactorily as possible.

[0007] However, editing and reproduction are performed for each frame.
Assuming that all frames are I pictures,
Since only information compression by compression is performed, code amount compression
Is very disadvantageous in terms of The present invention addresses these points.
It is a one-frame unit while compressing image information.
Information that can be edited and played back with good image quality
Its purpose is to provide a processing method.
You.

[0008]

In order to achieve the above object, a first aspect of the present invention is to provide a digital camera using motion compensation predictive coding.
Image information recording that encodes image information and records it on a recording medium
In the recording method, either the forward or backward
One-way prediction block with motion compensated prediction from encoded image
For the motion compensation prediction code based on this motion compensation prediction
Image and the motion compensation of the unidirectional prediction block
The forward or backward intra-coded image used for predictive coding
A motion vector for a first image that is an image;
Not used for motion-compensated prediction coding for directional prediction blocks
In the second image that is the front or rear intra-coded image,
And recording a corresponding motion vector . In a second aspect of the present invention, in the image information recording method,
The second obtained by performing motion compensation with a motion vector for the image.
Between the block on the image and the unidirectional prediction block
Is smaller than a predetermined value set in advance.
If it is not possible to search for a suitable motion vector, the second image
Identifier not to record motion vector for image
No. is recorded .

A third invention is directed to the image information recording method.
The digital image information recorded on the recording medium
When performing the editing process, start editing on the recording medium.
Indicates that the point or edit end point is the start point or end point.
In this case, an identification code is recorded . According to a fourth aspect of the present invention, there is provided the recording medium according to the image information recording method.
Play back and decode the digital image information recorded above
In the image information reproducing method, the first image may be stored in the recording medium.
If not present on the body, the second image and the second image
The one-way prediction using the motion vector for the current image.
The image of the measurement block is decoded .

[0010]

According to the present invention, among the blocks of a motion-compensated prediction coded image, a unidirectional prediction block which has been subjected to motion-compensated prediction from either a forward or backward intra-coded image is used.
The motion vector for the bidirectional intra-coded image
Is recorded. Therefore, even if one of the forward and backward intra-coded images is replaced by editing or the like, decoding can be performed using the motion vector of another intra-coded image.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image information processing method according to the present invention will be described below in detail with reference to the accompanying drawings. <First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, FIG.
As shown in (1), I pictures and B pictures are alternately arranged for each frame. Of these, I-pictures are subjected to intra-frame encoding. Then, for the B picture, bidirectional motion compensation inter-frame encoding using the preceding and following I pictures is performed as indicated by the arrow. These encoding processes are basically in accordance with the conventional standard.

More specifically, of each macroblock of a B picture, an intra block in which motion compensation is not performed and in-plane compression is performed, and a block in which motion compensation prediction coding is performed from forward and backward interpolation (hereinafter referred to as “inner block”). Insertion Prediction Block "
) Is encoded in the same manner as in the prior art.

On the other hand, for a block for which motion-compensated prediction coding from the front is performed (hereinafter, referred to as a "forward prediction block"), a motion vector for a backward frame is obtained along with a motion vector for a forward frame. In addition, for a block that performs motion compensation prediction coding from the rear (hereinafter, referred to as a “rear prediction block”), a motion vector for a front frame is obtained along with a motion vector for a rear frame.

FIG. 2 shows these states.
In the figure, I ₁ frame in front of the I-picture, I ₂ is the frame of the rear of the I picture. In the B picture, an intra block BA is subjected to encoding processing by itself as shown in FIG. For the interpolated prediction block BB, motion vectors MV _B1 and MV _B2 from previous and subsequent frames are obtained, respectively, as shown in FIG. In this embodiment, the forward prediction block B
As for C, motion vectors MV _C1 and MV _C2 from previous and subsequent frames are obtained, respectively, as shown in FIG. Also, for the backward prediction block BD, similarly, as shown in FIG. _3D , the motion vectors MV _D1 and MV _D2 from the previous and next frames are obtained, respectively.

As described above, according to this embodiment, for a block on which motion-compensated inter-frame prediction coding is performed,
In all cases, motion vectors for both the forward and backward frames are obtained. The compressed image information thus encoded is recorded on a medium such as a video tape.

Next, it is assumed that assembly editing for recording further information on the recording medium is performed. First, it is assumed that a new edit record has been made using the position PA in FIG. 2 as an edit start point. FIG. 3 shows a state of the recording.
Frame I ₂ in FIG. 2 is rewritten in the frame I _X.
At this time, the first frame I _X that initiated the editing is recorded in code S _X is added into a media that indicates the start of the editing point.

When the medium edited and recorded as described above is reproduced, the B picture immediately before the editing start point PA is decoded as follows. As for the intra block BA shown in FIG.
Since the decoding can be performed only with the information of the B picture, the decoding process is performed in the same manner as in the related art.

The interpolation prediction block BB shown in FIG.
For utilizes only the information of the motion vector MV _B1 and the frame I ₁ to the frame I ₁ which is ahead of the I-picture, a block image of the relevant part of the frame I ₁ to apply it.

The forward prediction block BC shown in FIG.
For, it is possible to decode by using the information of the information and B-picture frames I ₁ is a front of the I-picture, performs similarly to the conventional decoding.

The backward prediction block BD shown in FIG.
For, since the rear of the I-picture is replaced from I ₂ to I _X by the editing, it is impossible to perform the decoding if conventional. However, according to this embodiment, the motion vector MV _D1 for front frame I ₁ as shown in FIG.
Since also recorded, by so using only frame I ₁ information and the motion vector MV _D1 is forward of the I-picture, apply it to the image of the block in that part of the frame I _1, decoding Becomes possible.

Next, it is assumed that a new insert edit recording is performed with the position PB in FIG. 2 as an edit end point. In FIG.
The state of the recording is shown, and the frame I _{1 in} FIG.
It is rewritten to the frame I _Y. In this case, the last frame I _Y ended the editing, is recorded in code S _Y is added into a media indicating the end of the editing point.

When a medium edited and recorded as described above is reproduced, a B picture immediately after the editing end point PB is decoded as follows. Regarding the intra block BA shown in FIG.
Since the decoding can be performed only with the information of the B picture, the decoding process is performed in the same manner as in the related art.

The interpolation prediction block BB shown in FIG.
For, using only information of the motion vector MV _B2 and the frame I ₂ relative to the frame I ₂ is a rear of the I-picture, the block image of the relevant part of the frame I ₂ to apply it.

The forward prediction block BC shown in FIG.
For, since the front of the I-picture is replaced from I ₁ to I _Y by the editing, it is impossible to perform the decoding if conventional. However, according to this embodiment, the motion vector MV _C2 for the rear of the frame I ₂ as shown in FIG.
Since also recorded, using only the frame I ₂ information and the motion vector MV _C2 is behind the I picture by the block image of the relevant part of the frame I ₂ to apply it, the decoding Do.

The backward prediction block BD shown in FIG.
For, it is possible to decode by using the information of the rear frame I ₂ Information and B picture is an I-picture, performs similarly to the conventional decoding.

As described above, according to this embodiment, even if the rear frame I ₂ is replaced with _IX by editing and recording,
Also on behalf of the I _Y front frame I ₁ is the edit recording can be performed successfully decoded for the B-picture. In other words, it is possible to edit one frame at a time while maintaining a relatively high image quality while using a B picture having a large code amount compression effect. Also, since the codes indicating the start and end points of the editing are added, it is possible to quickly find the position on the medium where the compression encoding process is performed.

In addition, even when the information of the I picture in front of or behind the B picture is partially lost, the above-described processing is performed using the information of the I picture in which no loss occurs, so that the B picture can be obtained. Decryption can be performed.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. In the processing shown in FIG. 4, decoding is performed using the rear frame I _2. However, for example, when a scene change is performed at the point PA (see FIG. 2), the prediction from the rear frame I ₂ is performed. Is meaningless.

[0029] Therefore, in this embodiment, among the macroblock of the B picture, an interpolation prediction block BB, the forward prediction block BC, for backward prediction block BD, when obtaining the motion vector MV ₂ against the rear of the frame I _2, The evaluation value (for example, the sum of absolute values of the motion compensation prediction error in the macroblock) is compared with a predetermined threshold. Then, if unable to search the motion vector of this threshold is smaller than the evaluation value, as shown in FIG. 5, adds the code S _Z indicating that not send motion vector MV ₂ is for the rear of the frame I ₂ To do. By doing this,
The changed image of the subsequent frame is not taken into the decoding of the B picture, so that the image quality can be improved.

[0030] Incidentally, may not be performed any prediction using frames I ₁ of the rear of the scene change.
In this case, it is sufficient transmit symbols S _Z indicating that not send motion vector MV ₂ is for the rear of the frame I ₂ unconditionally.

Further, the In any case, in one frame of B picture, when the macroblock code S _Z indicating that not send motion vector MV ₂ is for the rear of the frame I ₂ is attached there are many It can be considered that a good reproduced image cannot be obtained even if decoding is performed as shown in FIG. 4 when the insert editing end point is PB. Accordingly, the at the time of reproduction of the case, holding the I ₁ is an I picture immediately before the B-picture to be output. The same applies to a case where a scene change is performed at a point PB opposite to the point PA.

<Other Embodiments> The present invention is not limited to the above-described embodiments, but includes, for example, the following. (1) In the above embodiment, encoding is performed in units of frames,
Although decoding has been performed, the conventionally used techniques such as switching between inter-frame motion compensation and inter-field motion compensation, and switching between field-based DCT and frame-based DCT are also applicable to the present invention. is there.

(2) Further, it is not always necessary to use DCT for coding I pictures and B pictures, and coding may be performed by another coding method, for example, subband coding. (3) In the above embodiment, an example in which I pictures and B pictures are alternately arranged has been described. However, in a general case where one or more B pictures or P pictures exist between I pictures and I pictures. In addition, the present invention is applicable.

[0034]

As described above, the image according to the present invention is
According to the information recording method and the image information reproducing method , the following effects can be obtained. (1) Either forward or backward intra-coded image
For the unidirectional prediction block that has been motion compensated prediction from
Before used for motion compensated predictive coding of unidirectional prediction blocks
To the first image, which is the forward or backward intra-coded image
Motion vector and motion-compensated prediction code for unidirectional prediction block
In the forward or backward intra-coded image not used for encoding
Both the motion vector and the motion vector for a certain second image
Motion compensation of unidirectional prediction block to record the vector
The first image used for predictive encoding is edited or missing
Also, it is possible to carry out editing of a single frame unit, the play with good image quality.

(2) The motion vector for the second image
A block on the second image obtained by motion compensation;
Where the prediction error between the one-way prediction block and the
Cannot search for a motion vector that is smaller than the specified value
The motion vector for the second image,
To record an identification code indicating that
Even in the case of an image such as
The image quality can be improved without decoding based on the inappropriate image .

[Brief description of the drawings]

FIG. 1 is a diagram showing an image information recording method and an image information reproducing method according to the present invention.
FIG. 4 is an explanatory diagram showing a frame arrangement in a first embodiment of a raw method .

FIG. 2 is an explanatory diagram showing a state of first recorded information in the first embodiment.

FIG. 3 is an explanatory diagram showing a state of recording information at the time of editing recording in the first embodiment.

FIG. 4 is an explanatory diagram showing a state of recording information at the time of editing and recording in the first embodiment.

FIG. 5 is an explanatory diagram showing a state of first recorded information in a second embodiment of the present invention.

[Explanation of symbols]

B, I: picture, BA: intra block, BB: interpolation prediction block, BC: forward prediction block, BD: backward prediction block, I ₁ : front I picture, I ₂ : rear I
Picture, I _X ... Edited rear I picture, I _Y ... Edited front I picture, MV _B1 , MV _C1 , MV _D1 .
Motion vector, MV _B2 , M obtained from the previous frame
V _C2 , MV _D2 ... Motion vector obtained from the subsequent frame,
PA: edit start point, PB: edit end point, S _X : code indicating edit start, S _Y ... code indicating edit end, S _Z ... code indicating that there is no motion vector.

──────────────────────────────────────────────────続 き Continuing the front page (56) References edited by Hiroshi Yasuda, “International Standards for Multimedia Coding”, Maruzen, published June 30, 1991, third print published February 10, 1992, p. . 128-140 (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N ^7/ 24-7/68 H04N 5/91-5/956

Claims (4)

(57) [Claims] 1. A digital image obtained by motion-compensated predictive coding.
A method of recording image information that encodes information and records it on a recording medium
Motion from either the forward or backward intra-coded image
For one-way prediction blocks for which compensated prediction has been performed,
Image that has been motion-compensated and predicted based on compensated prediction
Used for motion-compensated prediction coding of the one-way prediction block.
The first or second intra-plane coded image used
A motion vector for an image and the unidirectional prediction block
The forward or rear not used for motion compensated prediction coding
Motion vector for the second image, which is the
And recording the image information. 2. An image information recording method according to claim 1, wherein
And performing motion compensation with a motion vector for the second image.
The block on the second image and the one-way prediction block
Prediction error is smaller than a preset value.
If you cannot search for a motion vector that
Not record the motion vector for the second image.
Image information recording characterized by recording an identification code shown
Method. 3. The image information recording method according to claim 1, wherein:
In the above, for digital image information recorded on the recording medium
When performing the editing process, the editing start point on the recording medium or
Identification indicating that the editing end point is the start point or end point
Image information recording characterized by recording a code
Recording method. 4. The image information recording method according to claim 1, wherein
Reproduction of digital image information recorded on the recording medium
In the image information reproducing method for decoding, when the first image does not exist on the recording medium,
The second image and a motion vector for the second image
Decoding the image of the unidirectional prediction block using
And an image information reproducing method.