JP2773594B2 - Playback method for playing back fast-forward and fast-rewind images from highly efficient encoded video information - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing method for reproducing a fast-forward or fast-return image from moving picture information coded with high efficiency, and more particularly to an image in which image data is compressed by applying an intra-frame prediction method. Frames and moving picture information which is highly efficient coded by a high efficiency compression coding method which has a signal configuration in which image data in which image data is compressed by applying inter-frame prediction are mixed. The present invention relates to a reproducing method for selectively reproducing only an image of an image frame in which image data is compressed by applying an intra-frame prediction method and reproducing a fast-forward or fast-reverse image.

[0002]

2. Description of the Related Art A video signal of a moving image is compressed and transmitted with high efficiency.
Research for recording and reproduction has been actively conducted, and various high-efficiency compression methods have been proposed in the past. One of the high-efficiency compression methods of the moving image signal is an intra-frame compression method. The signal configuration is such that the image frame in which the image data is compressed by applying the prediction method and the image frame in which the image data is compressed by applying the inter-frame prediction are mixed. Efficiency compression coding schemes have also been proposed. Attempts have been made, for example, to record high-efficiency compressed moving image data on small discs.However, international standards for compressing moving image signals by high-efficiency coding have been developed. Aiming to make, MPEG (Moving Picture)
es Expert Group) sequentially proposes various data formats related to high-efficiency compressed image data, and image data that has been efficiently compressed according to the data format proposed by MPEG (compressed image data that has been highly efficiently compressed by the MPEG method). Research and development of practical devices for transmitting, recording and reproducing signals) are also being conducted.

[0003] Also, in the moving picture information encoding method (MPEG method) for a recording medium for recording digital data such as a CD-ROM, image data compression is performed by applying the above-described intra-frame prediction method. As in the case of the high-efficiency compression method of a moving image signal having a signal configuration in which an image frame being performed and an image frame in which image data is compressed by applying inter-frame prediction are mixed. ,
An image in which image data of a moving image is highly efficiently compressed by employing a predictive coding method, and image data is compressed by applying an intra-frame predictive method as a predictive method. {I picture (Intra Pictures)画像 An image in which image data is compressed by applying an inter-frame prediction method in which inter-frame prediction is performed based on image data of a frame (hereinafter, also referred to as an I frame) and a past frame. ｛P picture (Predic
ted Pictures) frame (hereinafter, also referred to as a P frame), and an inter-frame prediction in which inter-frame prediction is performed based on both image data of a past frame and image data of a future frame. Image in which image data is compressed by applying a prediction method 法 B-picture (Bi-direction
al Prediction Pictures)｝ frames (hereinafter, also referred to as B-frames) in three types of image modes, in which digital data in a state where frames are arranged in a predetermined arrangement manner on a time axis,
A predetermined header is added to form encoded image data.

Since the above-mentioned MPEG system is also standardized by CCITT, in the following description, an image frame in which image data is compressed by applying an intra-frame prediction method and an inter-frame prediction are applied. The MPEG system will be described as an example of a high-efficiency compression system of a moving image signal having a signal configuration in which image frames in which image data is compressed are mixed. In the MPEG system, the relationship between the compression ratio of the image data in the I frame, the compression ratio of the image data in the P frame, and the compression ratio of the image data in the B frame is (compression ratio of the image data in the I frame). <(Compression rate of image data in P frame) <
(Compression rate of image data in B frame), and the reproduction is performed from the sequence header of the entry point, the past image information and the image information of the future frame. In order to reproduce the image information of the B frame for which the prediction has been performed, the image information of the future P frame used for the prediction of the image information of the B frame is recorded before the B frame. Need to be.

FIG. 2 is a view for explaining the arrangement of data relating to highly efficient compressed moving image information when moving image information highly compressed by the MPEG system is recorded on an optical disk conforming to the CD (Compact Disk) standard. FIG. 2B shows an arrangement of recording data in a sequential sector portion in which data relating to highly efficient compressed moving image information is recorded on an optical disk conforming to the CD (Compact Disk) standard. The state is shown. First, FIG. 2A shows a portion following the MPEG system header in each sector shown in FIG.
The contents of the data to be recorded sequentially are
(Group of Pictures). The GOP is preceded by a sequence header, followed by a GOP header,
Following the GOP header, a sequential image frame is arranged.

2 (c) to 2 (f) show the specific contents of the MPEG system header shown in FIG. 2 (b). The PTS and DTS shown in FIG. A time stamp, and one of the two types of time stamps PTS and DTS is a time stamp PTS (pr
esentation time stamp) is information indicating the time at which the image is actually displayed, and the other time stamp DT
S (decoding timestamps) is time information indicating times at which data is sent to the MPEG video decoder. By the way, there are many types of specific contents of the MPEG system header as shown in FIGS. 2C to 2F because of the presence or absence of the time stamp included in the MPEG system header. , And the type of the existing time stamp, so that the content of the image information recorded in the sector in which the MPEG system header exists and the recording mode can be indicated. It is.

[0007] The specific contents of the MPEG system header are those in which both types of time stamps PTS and DTS exist in the MPEG system header as shown in (c) and (d) of FIG. If the MPEG
In the sector where the system header is located, the encoded I
An MPEG system header having the content as shown in FIG. 2C means the beginning of a frame or a P-frame. In particular, the MPEG system header as shown in FIG. This indicates that a plurality of GOPs are placed in the first sector of each video sequence in a row. Also, as shown in FIG. 2E, a time stamp PT is included in the MPEG system header.
If only S exists, it means that the encoded B frame has started in the sector where the MPEG system header is placed, and furthermore, (f) of FIG.
When neither of the time stamps PTS and DTS is present in the MPEG system header as in the above, any one of the I frame, P frame and B frame is included in the sector where the MPEG system header is placed. This means that the boundary of the beginning of the image frame is not included.

The sequence header is composed of information on the horizontal size and the vertical size of the image, information on the aspect ratio, and other various information in addition to the sequence header code. The GOP header is a GOP (Group). of P
group start code, time code, information indicating whether or not the GOP is a closed GOP, and a broken link (if it is 1, the GOP header is attached). B-frame existing between an I-frame and a P-frame constituting a GOP that has a role of preventing the MPEG video decoder from performing a decoding operation), and other various information And so on. The GOP includes an I-frame image data, a P-frame image data, and a B-frame image data group. The I-frame image data is required immediately after the GOP header. Has been located. Also, in a bit stream in which I-frames, P-frames, and B-frames composed of moving picture information encoded at high efficiency by the MPEG method are mixed, the I-frames are arranged on the bit stream at substantially equal intervals on average. The encoding is performed in such a manner as to be performed.

[0009]

When an image reproducing apparatus reproduces a fast-forward or fast-reverse image from moving picture information which has been encoded with high efficiency by the MPEG system, the operator operates the image reproducing apparatus with respect to the operation unit. When an input for operating in the fast-forward / fast-reverse image playback mode is made, the central processing unit in the image playback device plays back the fast-forward / fast-reverse image from the moving picture information coded by the MPEG system with high efficiency. By sequentially controlling the operation of each component of the image reproducing apparatus in accordance with each step in FIG. 3 which exemplifies the procedure of the case, the I frame in which the sequence header and the GOP header are located immediately before is selected. And play,
A control operation is performed to obtain a fast-forward or fast-return image. That is, the operation of each component in the image reproducing apparatus according to the procedure as shown in FIG.
When a fast-forward or fast-rewind image is reproduced from moving picture information that has been highly efficient encoded by the G method, a seek operation is performed on the optical head in a disk drive device having an optical head in accordance with an instruction from the central processing unit. Performing an operation, and temporarily storing data read by the optical head in a buffer memory, reading the stored data from the buffer memory, and continuously supplying a bit stream to an MPEG video decoder, The MPEG video decoder looks at the entire bit stream supplied thereto, detects an I frame from the bit stream, decodes the image information of the I frame, and outputs the image information of the I frame. When the decoding operation for In processing apparatus, it gives a command to the disk drive device so as to seek the optical head to where you think that the next I-frame is present, operation as that is being that carried out.

[0010] Therefore, when a fast-forward or fast-rewind image is reproduced from the moving picture information which has been highly coded by the MPEG method as described above, the next reproduction is performed every time the image information of the successive I frames is reproduced. Each time, such as the time to skip to the position of the bit stream to be started, the time to start the reproduction of the bit stream from the skipped position, and to detect the I frame, and the time to reproduce the entire detected I frame. However, as described above, in a bit stream in which I-frames, P-frames, and B-frames composed of moving image information encoded at high efficiency by the MPEG method are mixed, as described above. The interval between successive I-frames in is not constant, and since there is a large variation in the interval, the bit to start the next reproduction Position the skip is performed as the position of the stream skips the advanced position with sufficient margin with respect to likely not exist I frame position,
In order to detect the I frame after starting the reproduction of the bit stream from the skipped position,
The time required for the detection of the I-frame as described above becomes longer, thereby reducing the number of reproduced images per unit time, so that the smoothness of the motion of the reproduced image becomes insufficient. This point includes an image frame in which image data is compressed by applying the intra-frame prediction method, including the above-described MPEG method, and an image frame in which image data is compressed by applying inter-frame prediction. Is a problem that also occurs in the high-efficiency compression method of a moving image signal having a signal configuration in which a fast-forward and fast-return image is reproduced from highly efficient encoded moving image information. There has been a need for an improvement to minimize the time required to detect an image frame in which image data is compressed by applying the intra prediction method.

[0011]

The present invention provides an image frame in which image data is compressed by applying an intra-frame prediction method, and an image frame in which image data is compressed by applying an inter-frame prediction. An image frame in which image data is compressed by applying an intra-frame prediction method from moving image information that has been highly coded by a high-efficiency compression coding method having a signal configuration in which a frame is mixed. When the fast forward and fast rewind images are played back by selecting and playing back only the images of the images, the average interval between the image frames in which the image data is compressed by applying the intra-frame prediction method is determined by the interval between the displayed images. An image frame in which image data has been compressed by applying the above-described intra-frame prediction method so as to have a predetermined interval that can be made constant is previously stored in a bit stream. Lay location, when playing fast forward image to be reproduced next to the image frame by applying the intra-frame prediction method of reproducing the image data compression is being performed,
A search for an image frame in which image data is compressed by applying the intra-frame prediction method is started from a position obtained by subtracting a constant value K from an integer multiple of the above-mentioned predetermined interval. At the time of reproduction, an image to be reproduced next to an image frame to which image data has been compressed by applying the reproduced intra-frame prediction method and to which image data has been compressed by applying the intra-frame prediction method A frame search is started from a position obtained by adding a constant value M to an integral multiple of the predetermined interval, and fast-forward and fast-rewind images are obtained from highly efficient encoded moving image information. It provides a reproducing method for reproducing.

[0012]

According to the present invention, there is provided an inter-frame prediction method in which inter-frame prediction is performed based on image data (I frame) in which image data is compressed by applying an intra-frame prediction method and image data of a past frame. Image frame (P frame) for which image data is compressed by applying
And an image in which image data is compressed by applying an inter-frame prediction method in which inter-frame prediction is performed based on both image data of a past frame and image data of a future frame. Frame (B-frame) is mixed with video information that is highly efficient encoded by the high-efficiency compression encoding scheme having a signal configuration
When fast-forwarding and fast-rewinding images are played back by selectively playing back only I-frame images, the average interval between I-frames arranged in the bit stream is set in advance so that the intervals between display images can be made constant. They are arranged in an arrangement so as to have a predetermined interval. Then, when playing the fast-forward image,
A search for an I frame to be reproduced next to the reproduced I frame is started from a position obtained by subtracting a fixed value K from an integer multiple of the above-described predetermined interval. A search for an I frame to be reproduced next to the I frame is started from a position obtained by adding a fixed value M to an integer multiple of the above-mentioned predetermined interval. As a result, it is possible to shorten the time from the start of the reproduction of the bit stream from the skipped position until the detection of the I frame, the number of reproduced images per unit time can be increased, and the reproduced image with good smooth motion can be obtained. Can be easily obtained.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a reproduction method for reproducing fast-forward and fast-return images from highly efficient encoded moving image information according to the present invention. FIG. 1 is a block diagram showing a schematic configuration of a playback apparatus to which a playback method for playing back fast-forward and fast-rewind images from highly efficient encoded moving picture information according to the present invention is applied, and FIG. FIG. 3 is a data layout diagram for explaining a reproduction method for reproducing a fast-forward / fast-reverse image from moving image information encoded with efficiency, and FIG. FIG. 4 is a flowchart showing an example of a procedure for reproducing, and FIG. 4 is a diagram showing an actual measurement example of intervals between I frames existing in a bit stream and the number of appearances of each of the intervals. In the playback apparatus shown in FIG. 1, reference numeral 1 denotes a playback signal source. From the playback signal source 1, an image frame in which image data is compressed by applying an intra-frame prediction method, and an image frame by applying inter-frame prediction. A highly efficient compressed bit stream of moving image information is reproduced by a high efficiency compression method of a moving image signal having a signal configuration in which image frames subjected to data compression are mixed. In the following description, it is assumed that the reproduction signal source 1 reproduces a bit stream of moving image information that has been highly efficiently compressed by the above-described MPEEG method. In the reproducing apparatus shown in FIG. 1, 2 is an interface, 3 is a buffer manager, 4 is a central processing unit, 5 is a buffer memory, 6 is an MPEG video decoder, 7 is an MPEG audio decoder, and 13 is a memory.

In the reproducing apparatus shown in FIG. 1, a reproduced signal source 1 applies at least an image frame (I frame) in which image data is compressed by applying an intra-frame prediction method and an inter-frame prediction. Time-series data including moving picture information and sound information, which are highly efficient coded by the MPEG system in which image frames (P frame, B frame) in which image data is compressed are mixed. A predetermined header is added to the data string (bit stream), which includes at least information on the type of each of the above-mentioned information as video information or audio information and time information (time stamp) for each information. Data read from an information recording medium, such as an optical disk, a magneto-optical disk, or another recording medium, on which a data string to be reproduced in the read state is recorded. A structure capable of transmitting a data train is used. In the following description, it is assumed that the reproduction signal source 1 is a high-efficiency compressed audio
It is said to be configured to be able to output reproduction data from an optical disk in accordance with the CD (Compact Disk) standard, in which moving image information highly efficiently compressed by a system is recorded.

The time-series bit stream including the moving picture information and the sound information data, which has been encoded by the MPEG method, in which the I frame, the P frame, and the B frame are mixed, is provided. A header portion in a data string to be reproduced in a state where a predetermined header is added as described below, which includes at least information of a type of each information and time information of each information. Is configured to include information indicating the type of each information, such as acoustic information, image information, and other information, time information for each information, and various information such as a sector number. Various data such as audio information data, image information data, and other data form a bit stream. In the reproduction signal source 1 described above, under the control of a control signal given from the central processing unit 4 via the transmission line 8 and the interface 2, for example, a data sequence reproduced from an optical disk, that is, at least data of acoustic information Data to be reproduced in a state where a header is added to a bit stream including data of image information and at least the information of the type of each of the information and the time information of each of the information. Column (playback data column)
To the transmission line 9.

Then, the reproduced data string transmitted to the transmission line 9 as described above is stored in the buffer memory 5 via the interface 2 and the buffer manager 3. The buffer manager 3 controls the reproduction line 1 and the transmission line 9 and the interface 2 under the control of a control signal supplied from the central processing unit 4 via the bus 10.
The reproduction data transmitted via the buffer memory 5 is sequentially written into the reproduction data, or the audio information data in the reproduction data train stored in the buffer memory 5 is read out, and is read via the bus 11. To supply the data to the MPEG audio decoder 7 or read the image information data in the reproduction data string stored in the buffer memory 5 and supply it to the MPEG video decoder 7 via the bus 12. It has functions that can be performed in real time.

When the playback device is operating in the normal playback mode, the central processing unit 4 operates according to the program stored in the memory 13 and
The information on the type of information included in the header portion of the playback data string stored in the buffer memory 5 via the buffer manager 3 and the time information for each information, that is, whether the data is audio information data or image information. The data is discriminated and the information such as the reproduction time of the audio information and the image information is looked at, and the buffer memory 5 is stored in the buffer memory 5 in response to a request from each MPEG decoder (6, 7) corresponding to each data. Data for each type of information in the stored reproduction data is transferred via the buffer manager 3. A request from each of the MPEG decoders (6, 7) is issued at a timing such that the reproduction state is continuous, and the data is transferred accordingly, whereby the reproduction signal on the time axis is continuously transmitted. Sex will be guaranteed by each MPEG decoder (6, 7). At the start of the reproduction, since the reproduction is discontinuous from the reproduction from the non-reproduction, the MPEG decoders (6, 7) are provided with means for starting the reproduction at a predetermined time at this time. As means for starting reproduction at the above-mentioned predetermined time, each of the MPEs via the bus 10 from the central processing unit 4 is used.
G decoders (6, 7) are configured to be instructed, and data including a time stamp is transmitted to bus 1
1 or an MPEG decoder (6,
7), and various means can be applied, such as allowing each MPEG decoder (6, 7) to start reproduction at a predetermined time based on the data including the time stamp.

As described above, when the audio information data is transferred from the buffer memory 5 to the MPEG audio decoder 7 via the buffer manager 3 and the bus 11 under the control of the buffer manager 3, the MPEG audio decoder 7 A reproduced sound information signal obtained by expanding the sound information data obtained by compressing the sound information signal supplied thereto is output from the buffer memory 5 under the control of the buffer manager 3 and the buffer manager 3 and the bus 12. The image information data is transferred to the MPEG video decoder 7 via the
The MPEG video decoder 7 outputs a reproduced image information signal obtained by decoding the image information data obtained by compressing the image information signal supplied thereto. Therefore, the MPEG audio decoder 7 outputs the reproduced audio information signal in a continuous state on the time axis, and the MPEG video decoder 7 outputs the image information signal continuously on the time axis. It is output in the state that it is.

As described above, on a bit stream in which I-frames, P-frames, and B-frames composed of moving picture information highly efficiently coded according to the MPEG system are mixed, the I-frames are substantially equal to each other on average. Although encoding is performed so as to be arranged at intervals, conventionally, when retrieving fast-forward and fast-return images from moving image information highly efficient encoded by the MPEG method by focusing on the above points, I in
The above point is not used to shorten the frame search time. Conventionally, when fast-forwarding and fast-rewinding images are reproduced from moving image information which has been highly efficient coded by the MPEG method, it is one after another. It takes a lot of time to search for an I-frame, and it is difficult to increase the number of reproduced images per unit time when reproducing fast-forward and fast-rewind images. In the playback method of playing back the fast-forward and fast-rewind images from the encoded moving image information,
I frame composed of highly efficient coded video information, P
In a bit stream in which frames and B frames coexist, encoding is performed so that I frames are arranged on the bit stream on average at substantially equal intervals. The average interval between each other is a predetermined interval so that the interval of the display image can be made constant, so that the above-mentioned I frame is effectively arranged in a bit stream,
When a fast-forward image is reproduced, a search for an I-frame to be reproduced next to the reproduced I-frame is started from a position obtained by subtracting a constant value K from an integer multiple of the above-mentioned predetermined interval. At the time of reproduction, the search for an I frame to be reproduced next to the reproduced I frame is started from a position obtained by adding a constant value M to an integer multiple of the above-mentioned predetermined interval. Like, MP
When fast-forwarding and fast-rewinding images are reproduced from a bit stream in which I-frames, P-frames, and B-frames composed of moving image information encoded with high efficiency by the EG method are reproduced, image information of successive I-frames is reproduced. The time required to skip to the position of the bit stream at which the next playback should be started, the time required to start the playback of the bit stream from the skipped position until the detection of an I frame, the detected I frame The time from the start of the reproduction of the bit stream from the skipped position to the detection of the I-frame can be greatly reduced within the time for reproducing the entire file.

FIG. 4 shows a reproduction method for reproducing a fast-forward or fast-rewind image from highly efficient encoded moving image information. The average interval between I frames is predetermined so that the display image interval can be made constant. In one example of the case where the above-mentioned I-frames are previously arranged in the bit stream so as to have the specified intervals, the interval value between the I-frames in the bit stream (the unit of the interval is 1 sector length = 2296)
The number of appearances (the number of appearances) of the byte).
In the case of the above example, the spacing between I-frames in the bit stream has a slight variation between spacing values corresponding to 36 sector lengths and spacing values corresponding to 43 sector lengths, The average interval corresponds to a 39.86 sector length. By the way, for example, in the MPEG standard, the storage capacity of the buffer memory in the MPEG decoder is specified as 40 kilobytes, so that the variation of the data amount due to the variation of the interval between I sectors in the bit stream is within ± 20 kilobytes. I just need. The variation in the data amount due to the variation in the interval between I sectors in the bit stream shown in FIG. 4 is within ± 9 kilobytes.

For example, as shown in FIG. 4, the interval between I frames in a bit stream is
When the minimum value of the interval is a value corresponding to the length of 36 sectors and the maximum value of the interval is a value corresponding to the length of 43 sectors, in order to select the next I frame, the currently reproduced I frame is selected. If a position that is 36 sectors away from the beginning of the frame is accessed, in the worst case the next I that is within 7 sectors between 36 and 43 sectors
A frame will appear. Therefore, the I-frames are arranged beforehand in the bit stream so that the average interval between I-frames is a predetermined interval that can make the interval between display images constant. If the average interval corresponds to the 39.86 sector length as in the example of FIG. 4 described above, for example,
At the time of fast forward playback, when a certain I frame is being played back, in order to select the next I frame, the average interval between the I frames described above is calculated from the position of the head of the currently played I frame. N times the corresponding sector length of 39.86 + 36 sector lengths (where N is a number indicating a larger numerical value as the fast-forward magnification increases, N = 0, 1, 2, 3)
..), The worst case would be that the next I-frame aimed within 7-sector length would appear, and the average spacing between I-frames would be The average interval between I-frames when the I-frames are arranged in a bit stream in advance so as to be a predetermined interval so that the intervals of the I-frames can be made constant is, for example, the example shown in FIG. Like 3
In order to select the next I frame when playing back one I frame at the time of fast reverse playback in the case of the length corresponding to the 9.86 sector length, the currently played back I frame is selected. From the head position, N times the sector length 39.86 corresponding to the average interval between I frames described above + 43 sector lengths (where N is a number indicating a larger value as the fast-rewind ratio increases, N = (0, 1, 2, 3...), The next I frame aimed within 7 sector lengths appears in the worst case.

That is, the average interval between I frames arranged beforehand in the bit stream is the same as that shown in FIG.
During fast forward playback in the case where the length corresponds to the 39.86 sector length as in the example of (3), f ｛39.86 × N−3.86｝ sector length from the position of the head of the I frame currently being played back. (FF) where f {n} is the largest natural number smaller than n.
Further, at the time of fast reverse playback, g {39.86 × N + 3.14} sector length... (FB) from the position of the head of the currently reproduced I frame, where g {n} is the smallest natural number larger than n. .
Then, N in the above-mentioned equations (FF) and (FB)
Are numbers indicating larger numerical values as the magnification of fast-forward and fast-return increases, and N = 1, 2, 3,... Therefore, if an access is made to a position separated by the interval shown by the above-mentioned formulas (FF) and (FB), the target I frame can be immediately searched. When the above-mentioned formulas (FF) and (FB) are generally written, the general formula at the time of fast-forward playback is as follows.
The general formula at the time of fast reverse playback is expressed by the following formula (FB1). f ｛N × (average interval value between I frames determined corresponding to a predetermined interval that can make the interval between display images constant) −K} (FF1) where f {n} is n It is the largest natural number that is smaller. g ｛N × (average interval value between I frames determined corresponding to a predetermined interval that can make the interval of display images constant) + M} (FB1) where g {n} is smaller than n Largest natural number. In the above formulas (FF1) and (FB1), N is a number indicating a larger value as the magnification of fast-forward and fast-return increases, N = 1, 2, 3,..., And K is K = ( (Average interval value between I frames determined corresponding to a predetermined interval so that the interval between display images can be made constant)
(Minimum value of the interval values between I frames), and M is M = (maximum value of the interval values between I frames)-(so that the intervals between display images can be made constant. (An average interval value between I frames determined corresponding to a predetermined interval).

[0023]

As is apparent from the above description, the reproducing method for reproducing fast-forward and fast-rewind images from highly efficient encoded moving image information according to the present invention employs an intra-frame prediction method. The image data is compressed by applying an inter-frame prediction method in which the inter-frame prediction is performed based on the image data (I frame) of which the image data is compressed and the image data of the past frame. Image data by applying an inter-frame prediction method in which inter-frame prediction is performed based on image data (P frame) of a current frame and image data of a past frame and image data of a future frame. Moving image that is highly efficient coded by a high efficiency compression encoding method having a signal configuration in which image frames (B frames) that have undergone compression are mixed. In the case where only the I-frame image is selectively reproduced from the image information to reproduce the fast-forward / rewind image,
In an arrangement mode, the average interval between I frames arranged in the bit stream is a predetermined interval so that the interval between display images can be made constant,
When a fast-forward image is reproduced, a search for an I-frame to be reproduced next to the reproduced I-frame is started from a position obtained by subtracting a constant value K from an integer multiple of the above-mentioned predetermined interval. At the time of reproduction, the search for an I frame to be reproduced next to the reproduced I frame is skipped by starting from a position obtained by adding a constant value M to an integer multiple of the predetermined interval. It is possible to shorten the time from the start of reproduction of a bit stream from the position to the detection of an I frame, increase the number of reproduced images per unit time, and easily obtain a reproduced image with good motion smoothness. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a playback apparatus to which a playback method for playing back fast-forward and fast-rewind images from highly efficient encoded moving image information according to the present invention is applied.

FIG. 2 is a data arrangement diagram for explaining a reproduction method for reproducing a fast-forward or fast-rewind image from highly efficient encoded moving image information according to the present invention.

FIG. 3 is a flowchart illustrating an example of a procedure for reproducing a fast-forward or fast-rewind image from moving image information that has been highly efficiently encoded by the MPEG method.

FIG. 4 is a diagram showing an actual measurement example of intervals between I frames existing in a bit stream and the number of appearances of each of the intervals.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reproduction signal source, 2 ... Interface, 3 ... Buffer manager, 4 ... Central processing unit, 5 ... Buffer memory, 6 ... MPEG video decoder, 7 ... MPEG audio decoder, 13 ... Memory,

Claims (1)

(57) [Claims] An image frame in which image data is compressed by applying an intra-frame prediction method and an image frame in which image data is compressed by applying an inter-frame prediction are mixed. Selectively reproduces only the image of the image frame in which the image data is compressed by applying the intra-frame prediction method from the moving image information which is highly efficient coded by the high efficiency compression coding method having the signal configuration. In reproducing fast-forward and fast-reverse images, the average interval between image frames in which image data is compressed by applying the intra-frame prediction method is set in advance so that the intervals between display images can be made constant. An image frame in which image data is compressed by applying the above-described intra-frame prediction method is arranged in a bit stream in advance so as to have a predetermined interval, and a fast-forward image At the time of reproduction, an image to be reproduced next to an image frame to which image data has been compressed by applying the reproduced intra-frame prediction method and to which image data has been compressed by applying the intra-frame prediction method A frame search is started from a position obtained by subtracting a constant value K from an integer multiple of the predetermined interval, and when a fast-rewind image is reproduced, the reproduced intra-frame prediction method is applied to compress the image data. The search for an image frame to be reproduced next to the image frame on which image data compression is performed by applying the intra-frame prediction method is performed by a constant value equal to an integral multiple of the predetermined interval. A reproduction method for reproducing fast-forward and fast-return images from highly efficient encoded moving image information, characterized in that the reproduction is started from the position where M is added.