JPH11155129A - Mpeg picture reproduction device and mpeg picture reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a picture at high speed without deteriorating the quality of the reproduced picture by decoding only I and P pictures, in high speed reproduction in a device in which a dynamic picture is compressed by the MPEG system, and picture coding data constituted of I, B, P pictures are decoded and the data are outputted for each frame. SOLUTION: In high speed reproduction, picture code data separated from a code input signal received by a PES decoder 2 are given to a B picture skip circuit 2. Since a B picture header detection circuit 11 activates a B picture skip signal, only while a B picture code is received, the B picture skip circuit 12 skips the B picture code and provides an output of only I, P picture codes. Then an M detection circuit 10 detects the interval of anchor frames of the image code data of the code input signal, and a display control section outputs image data of I, P pictures by a display method, depending on the anchor frame interval and high reproduction speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MPEG (Mot)
ion Picture Experts Grou
MPE that reproduces image data compressed by a moving image compression technique standardized by ISO called p) at high speed
The present invention relates to a G image reproducing apparatus and method.

[0002]

2. Description of the Related Art Image data compressed by a moving image compression technology standardized by ISO called MPEG is used to correlate an I picture compressed and coded in an image unit with an image located in the past in time. And a P picture compressed using the difference between the P picture and the I picture located in the past and the future in time.
It is composed of a picture or a B picture which is an image compressed by taking a correlation and a difference from a P picture.

The MPEG system includes MPEG1 (IS
O 11172), MPEG2 (ISO 13818)
But the basic method is the same.

In an MPEG image reproducing apparatus for decoding and reproducing image data compressed by MPEG, when reproducing P and B pictures, an I picture is first formed, and this is referred to. To form an image.

The relationship between the order of decoding the compressed image data and the order of displaying the decoded image data will be described with reference to FIG. In this figure, the order of arrangement is the order of decoding, and the numerals in the code indicate the order in which they are displayed.

First, the I picture I2 is decoded. Then, the P picture P5 is decoded based on the I picture I2 (). Next, B pictures B3 and B4 are decoded using the I picture I2 and the P picture P5 ().
The P picture P8 is decoded based on the picture P5 (). Then, the B pictures B6 and B7 are decoded based on the P pictures P5 and P8 (), and the P pictures P8,
B pictures B9 and B10 are decoded based on P11 (). Similarly, the P picture P14 and the B pictures B12 and B13 are also decoded. In this figure, the B pictures B0 and B1 are decoded based on the image data before the I picture I2, and will not be described in this figure.

When displayed, B0, B
1, I2, B3, B4, P5, B6, B7, P8, B
The display is performed in the order of 9, B10, P11, B12, and B13.

In the MPEG system, an I picture, P,
Means of motion compensation and orthogonal transformation of difference information are used to calculate the correlation between B pictures. As the orthogonal transform means, two-dimensional discrete predictive transform is performed in the MPEG system, and an enormous amount of calculation is required to obtain this. Therefore, when performing high-speed reproduction, the amount of calculation for obtaining all the image data becomes enormous, and as a result, the calculation cannot be performed at a normal decoder speed.
In order to solve this problem, Japanese Patent Application Laid-Open No. 63-310293 discloses an MPEG image reproducing apparatus which realizes high-speed reproduction by decoding and reproducing only I pictures which can be restored only with the compressed data. ing.

However, in the method of decoding and reproducing only an I picture, at most only about three images can be obtained per second, and only a very unnatural and discontinuous awkward image can be obtained as a moving image. There was a disadvantage that it could not be done.

[0010] MPEG for solving such a drawback
An image reproducing apparatus is described in JP-A-7-154743. This conventional MPEG image reproducing apparatus will be described with reference to FIG.

The conventional MPEG image reproducing apparatus includes a recording medium reading unit 102, a variable length decoding unit 114, a data switching unit 103, an inverse quantizer 104, an orthogonal transform information decoder 105, an image memory 106 , 110, 112, motion compensators 107, 111, adder 108, and controller 1
09, an image switching unit 113, and a header detection unit 115.

This conventional MPEG image reproducing apparatus uses MP
Although the image data compressed and decoded by the EG1 method is decoded and reproduced, the MPEG1 method and the MPEG2 method basically use the same element technology, and therefore have the same problems that occur during high-speed reproduction.

First, a recording medium reading unit 102 capable of fast-forward reproduction from a recording medium 101 on which MPEG data is recorded.
The compressed image data is read. Then, variable length decoding is performed by the variable length decoding unit 114,
It is necessary to determine whether to switch the decoding whether the data is a motion vector or orthogonal transformation information based on the decoding result. Then, the output data is sent to the data switching unit 103. At the same time, the header detection unit 115 detects a header that determines the type of image in the data.

In the case of normal reproduction, first, an I picture is restored. All the compressed data of this image undergoes inverse quantization via an inverse quantizer 104 which performs inverse transform of quantization, and is input to an orthogonal transform information decoding unit 105 and decoded. The I-picture data restored in this way is output as an image, and as data for restoring the next image,
The image is input to the image memory 106.

Next, using this I picture data,
The restoration of the P picture is performed. The input data is sorted by the data switching unit 103. The input data includes data relating to motion information between the areas and data relating to differences in that case.
Data relating to the motion information is sent to the motion compensation unit 107. Here, an optimal area is extracted from the previous image data using the motion information. Data relating to the difference is input to the inverse quantizer 104, and the output is sent to the orthogonal transform information decoding unit 105. Orthogonal transform information decoding unit 10
5, in the case of MPEG1, the inverse DCT operation is performed. As a result, the value of the difference between the areas is restored, and the adder 108 adds these two data to restore the image area data. This operation is performed for the entire area of the target image, and the entire image is restored. Here, the image restored by referring to the I picture is stored in the image memory 1.
10 is stored.

Then, a temporally succeeding P picture is
Decoding is performed sequentially using the stored I pictures. Next, at the time of decoding a B picture, the image is decoded using the two image data stored in the image memories 106 and 110 in the same manner as in the case of the P picture.
However, in this case, since data of two images is taken out, the distribution ratio of the pixel values is determined by the motion compensation unit 10.
7, 111 or by the adder 108.

In the MPEG system, decoding is performed in the order of I picture, B picture, and P picture.
The order of decoding is not necessarily the order of playback. For this reason,
The decoded image may be temporarily stored in the image memories 106 and 110 and output as an image after referring to the decoding of another image. Therefore, the image switching unit 113 switches these image data.

In the conventional MPEG image reproducing apparatus, when performing high-speed reproduction such as double speed, the control unit 10
According to the instruction of No. 9, the orthogonal transform in the orthogonal transform information decoding unit 105 is performed only on low-order data that is data that is easy to restore, or by suspending the orthogonal transform.

In the conventional MPEG image reproducing apparatus, in the case where high-speed reproduction such as double speed or the like is performed by suspending the orthogonal transformation in the orthogonal transformation information decoding unit 105, the image is shifted in time because orthogonal transformation is not performed. There was a problem that it would.

When the orthogonal transform information decoding unit 105 is controlled by the control unit 109 to perform orthogonal transform on only low-order data, there is a problem that a reproduced image is blurred.

[0021]

The conventional MPE described above.
The G image reproducing apparatus has a problem that an image reproduced when performing high-speed reproduction is shifted in time or is blurred.

An object of the present invention is to provide an MPEG image reproducing apparatus capable of performing high-speed reproduction without deteriorating the quality of a reproduced image.

[0023]

In order to achieve the above object, the present invention decodes image code data which is compressed by an MPEG moving image compression technique and is composed of an I picture, a B picture and a P picture. Then, in an MPEG image reproducing apparatus that outputs frame by frame as image output data, when performing high-speed reproduction, only the I picture and the P picture of the image code data are decoded.

According to the present invention, when performing high-speed reproduction, only I-pictures and P-pictures are decoded, and B-pictures are not decoded, so that the amount of calculation during high-speed reproduction is reduced.

Therefore, high-speed reproduction can be performed without affecting decoding of P-pictures and I-pictures, so that high-speed reproduction can be performed without deteriorating image quality.

According to an embodiment of the present invention, an I picture and a P picture or a P picture
An anchor frame interval, which is an interval between pictures, is detected, and a frame to be output as the image output data is selected based on the anchor frame interval and a high-speed playback speed.

The present invention detects an interval between anchor frames, which is an interval between an I picture and a P picture or between P pictures in image code data, and based on the interval between the anchor frames and the reproduction speed at the time of high-speed reproduction. A frame to be output as image output data is selected.

Therefore, high-speed reproduction corresponding to the input image code data can be performed at an arbitrary reproduction speed.

According to an embodiment of the present invention, when the interval between the anchor frames is two frames, the frame obtained by decoding only the I picture and the P picture is output as the image output data as it is, so that the double speed is obtained. Perform playback.

According to another embodiment of the present invention, when the interval between the anchor frames is three, a frame obtained by decoding only the I picture and the P picture is used once every two frames. By outputting the same frame as the image output data after repeating the same frame in
Perform double speed playback.

According to another embodiment of the present invention, when the interval between the anchor frames is three, a frame obtained by decoding only an I picture and a P picture is directly output as the image output data. As a result, triple speed reproduction is performed.

According to another embodiment of the present invention, when the interval between the anchor frames is four, the frame obtained by decoding only the I picture and the P picture is repeated twice each, and then the frame is decoded. Double-speed reproduction is performed by outputting as image output data.

According to another embodiment of the present invention, when the interval between the anchor frames is five, the frame obtained by decoding only the I picture and the P picture is repeated twice for the same frame. After repeating the same frame three times alternately and outputting the same as the image output data, double-speed reproduction is performed.

According to another embodiment of the present invention, when the interval between the anchor frames is five, the frame obtained by decoding only the I picture and the P picture is repeated twice for the same frame. After performing the image output data once every two frames, the data is output as the image output data to perform the triple speed reproduction.

Further, the MPEG image reproducing apparatus of the present invention
Memory, the input code input signal is separated into image code data and audio code data, and during normal playback, the image code data is transferred to the image code buffer area in the memory,
At the time of high-speed reproduction, the code of the B picture in the image code data is skipped and only the P picture and the I picture are transferred to the image code buffer area in the memory, and the I picture and the P picture or the P picture in the image code data are transferred. A PES decoder for detecting an interval between anchor frames, which is an interval between the frames, and outputting an M transmission signal for indicating the interval between the anchor frames; and reading the image code data from an image code buffer area in the memory, A variable-length code decoding unit that performs variable-length code decoding on the code data to obtain image data, an inverse quantization unit that inverse-quantizes the image data that has been subjected to variable-length code decoding by the variable-length code decoding unit, An inverse cosine transform is performed on the image data inversely quantized by the inverse quantization unit, and the obtained I The inverse cosine transform unit that outputs the B-picture and the P-picture, and performs motion compensation on the P-picture and B-picture image data output from the inverse-cosine transform unit, P picture area in the memory, B
A motion compensator for writing to a picture area; reading image data from an I picture area, a P picture area, and a B picture area in the memory during normal playback and outputting as image output data according to a predetermined display order; Image data is read from the I-picture area and the P-picture area in the memory, and a frame to be displayed is selected based on an interval between anchor frames indicated by the M transmission signal and a reproduction speed for performing high-speed reproduction, and then output as the image output data. And a display control unit.

According to the present invention, when performing high-speed reproduction, only the I and P pictures are decoded by the PES decoder so that the B picture is not decoded, and the interval between anchor frames and the M transmission signal are output. The control section selects a frame to be output as image output data based on the M transmission signal and the reproduction speed of the high-speed reproduction, thereby reducing the amount of calculation at the time of high-speed reproduction.

Therefore, high-speed reproduction can be performed without affecting decoding of P-pictures and I-pictures, so that high-speed reproduction can be performed without deteriorating image quality.

[0038]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an MPEG image reproducing apparatus according to one embodiment of the present invention, and FIG.
FIG. 3 is a block diagram of an ES decoder 2.

The MPEG image reproducing apparatus according to the present embodiment
ES (Packetized Elementary)
Stream) Decoder 2 and Variable Length Code Decoder 3
, An inverse quantization unit 4, an inverse cosine transform unit 5, a motion compensation unit 6, a display control unit 7, and a memory 9.

The PES decoder 2 first separates the input code input signal 1 into audio code data and image code data. Then, the PES decoder 2 transfers the separated image code data to the image code buffer area in the memory 9 at the time of normal reproduction, and transmits the B code of the image code data at the time of high-speed reproduction.
Skip only the sign of the picture,
Only the picture is transferred to the image code buffer area in the memory 9 and the I picture and the P
An interval between anchor frames (hereinafter referred to as M), which is an interval between pictures or P pictures, is detected and output as an M transmission signal 14 as a signal for indicating the interval between the anchor frames.

Here, the PES decoder 2 has an M detection circuit 10, a B picture header detection circuit 11, and a B picture skip circuit 12, as shown in FIG.

The M detection circuit 10 detects an I picture and a P picture or P picture from the audio code data of the code input signal 1.
An interval between anchor frames, which is an interval between pictures, is detected and output as an M transmission signal 14.

When the B picture header detection circuit 11 detects a B picture header in the audio code data of the code input signal 1, the B picture skip signal 15 is activated.

The B picture skip circuit 12 outputs the audio code data of the code input signal 1 as the PES decoder output signal 13 while the B picture skip signal 15 is inactive, and outputs the PES decoder output signal 13 while the B picture skip signal 15 is active. Does not output anything to the PES decoder output signal 13.

The variable-length code decoding section 3 reads image code data from the image code buffer area in the memory 9 and performs variable-length code decoding on the image code data to obtain image data.

The inverse quantization unit 4 inversely quantizes the image data that has been subjected to the variable length code decoding by the variable length code decoding unit 3.

The inverse cosine transform unit 5 performs an inverse cosine transform on the image data inversely quantized by the inverse quantization unit 4, stores the obtained I picture in an I picture area in the memory 9, The picture and the P picture are transmitted to the motion compensation unit 6.

The motion compensator 6 performs motion compensation on the received P-picture or B-picture image data, and writes them in the P-picture area and B-picture area in the memory 9, respectively.

The display controller 7 reads data from the I-picture area, P-picture area and B-picture area in the memory 9 during normal reproduction and outputs it as image output data 8 according to a predetermined display order. Data is read from the I-picture area and the P-picture area in 9, a frame to be displayed is selected based on the interval between anchor frames indicated by the M transmission signal 14 and the speed at which high-speed reproduction is performed, and output as image output data 8.

The variable length decoding unit 114 in the conventional MPEG image reproducing apparatus shown in FIG. 7 corresponds to the variable length code decoding unit 3 in this embodiment, and the inverse quantizer 104 is the inverse quantization unit 4 in this embodiment. And the orthogonal transform information decoding unit 1
Reference numeral 05 corresponds to the inverse cosine transform unit 5 in the present embodiment, and the motion compensation units 107 and 111, the image memories 106 and 1
11 and the adder 108 correspond to the motion compensating unit 6 in the present embodiment, and the image memory 112 and the image switching unit 1
Reference numeral 13 corresponds to the display control unit 7 in the present embodiment.

Next, the operation of this embodiment will be described with reference to FIG.

First, the case where normal reproduction is performed will be described.

The code input signal 1 input to the PES decoder 1 is separated into audio code data and image code data. The separated image code data is input to the B picture skip circuit 12, and the B picture skip circuit 12 outputs the B picture skip signal 1 during normal reproduction.
Since the operation of skipping the B picture is not performed even when 5 becomes active, the B picture is passed as it is, output as the PES decoder output signal 13, and stored in the image code buffer area in the memory 9. Thereafter, the variable length code decoding unit 3
, The inverse quantization is performed by the inverse quantization unit 4, and the inverse cosine transform is performed by the inverse cosine transform unit 5, so that I picture, P picture, and B
Converted to picture. The I picture is stored in the memory 9
The P picture and the B picture are sent to the motion compensator 6. Then, the motion compensator 6 performs motion compensation on the transmitted P picture and B picture. They are stored in a P picture area and a B picture area in the memory 9, respectively. Then, the display control unit 7
Since normal reproduction is performed, I pictures, P pictures, and B pictures are output as image output data 8 in accordance with a normal display order without referring to the M transmission signal 14.

Next, the case of performing high-speed reproduction will be described.

As in the normal reproduction, the code input signal 1 input to the PES decoder 2 is separated into audio code data and image code data. Then, the separated image code data is input to the B picture skip circuit 12. However, the B picture header detection circuit 11 outputs the B picture skip signal 15 only while the B picture code is being input.
To activate the B picture skip circuit 12
In B, the sign of the B picture is skipped and the I picture, P
Only the code of the picture is output as the PES decoder output signal 13. Further, the M detection circuit 10 detects an interval (= M) between anchor frames in the image code data of the input code input signal 1 and outputs the detected M as a M transmission signal 14.

The codes of the I and P pictures output as the PES decoder output signal 13 are processed in the same manner as in normal reproduction, and are stored in the I and P picture areas in the memory 9.

Since the display control section 7 is at the time of high-speed reproduction, the I-picture in the memory 9 is determined by the display method determined by the interval of the anchor frame indicated by the M transmission signal 14 and the reproduction speed of high-speed reproduction. The image data of the I picture and the image data of the P picture stored in the area and the P area are output as image output data 8.

NTSC (National Telev)
In the case where image data of an image system (i.e., an I / O System) is encoded in accordance with an MPEG2 compliant image compression unit, the interval between anchor frames is often three frames. Therefore, first, the code input signal 1
The case where M is 3 will be described.

Here, a case where double speed reproduction is performed with M = 3 frames will be described with reference to FIG.

FIG. 3A shows the image data described with reference to FIG.
When input to the S decoder 2, the code of the B picture is skipped, so that the PES decoder output signal 13 is
As shown in (b), the image data is composed of only I and P picture codes. Then, in the display control section 7, since the fact that M = 3 frames is transmitted by the M transmission signal 14, as shown in FIG. The same frame is reproduced twice at the same rate.

When reproducing at triple speed, the display control section 7 outputs the image data shown in FIG.

Next, the case where M in the image code data of the code input signal 1 is 2 frames will be described.

In this case, the B picture is skipped and P
Double-speed playback can be performed only by playing back pictures and I-pictures only.

Next, a case where M in the image code data of the code input signal 1 is 4 frames will be described with reference to FIG. In FIG. 4 and subsequent figures, the numbers indicating the display order in the codes of the P, I, and B pictures will be omitted.

In this case, as shown in FIG. 4, after skipping the B picture (FIG. 4 (b)), all frames are reproduced twice, so that double speed reproduction can be performed (FIG. 4B). FIG. 4 (c)).

Next, a case where M in the image code data of the code input signal 1 is 5 frames will be described with reference to FIG.

In this case, after skipping the B picture (FIG. 5B), double-speed playback can be performed by performing two repetitive playbacks and three repetitive playbacks for each frame. FIG. 5 ((c)). Also, after skipping the B picture, the same frame is repeated once every two frames, so that triple-speed playback can be performed.

Similarly, the display control unit 7
By changing the display method of I-pictures and P-pictures according to the value of M indicated by the transmission signal 14 and the high-speed reproduction speed, high-speed reproduction at various speeds can be performed in addition to double speed and triple speed.

As described above, the MPE of this embodiment
In the G image reproducing apparatus, even when performing high-speed reproduction such as double speed, it is not necessary to increase the decoding speed, so that the bus band with the memory 9 may be lower than that in normal reproduction. Also, the obtained image has the same image quality as the normally reproduced image.

[0071]

As described above, the present invention has the following effects. (1) High-speed reproduction such as double speed can be performed without deteriorating image quality. (2) Even when performing high-speed reproduction such as double-speed reproduction, it is not necessary to increase the decoding speed, and the bus band with the memory can be lower than that during normal reproduction.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a PES decoder 2 in FIG.

FIG. 3 is a diagram showing a decoding order (FIG. 3A), and a diagram when decoding is performed by skipping the code of a B picture (FIG. 3A).
FIG. 3 (b) is a diagram (FIG. 3 (c)) when the image is repeated once every two frames.

FIG. 4 is a diagram showing a decoding order (FIG. 4A), and a diagram when decoding is performed while skipping the code of a B picture (FIG. 4A).
FIG. 4B is a diagram (FIG. 4C) when all frames are repeated twice.

FIG. 5 is a diagram showing a decoding order (FIG. 5 (a)), and a diagram when decoding is performed while skipping the code of a B picture (FIG. 5).
(B)) is a diagram (FIG. 5 (c)) when two repeats and three repeats are repeated every other frame.

FIG. 6 is a diagram illustrating a decoding order of image data compressed by the MPEG method.

FIG. 7 is a block diagram showing a configuration of a conventional MPEG image reproducing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 code input signal 2 PES decoder 3 variable length code decoder 4 inverse quantization unit 5 inverse cosine transform unit 6 motion compensation unit 7 display control unit 8 image output signal 9 memory 10 M detection circuit 11 B picture header detection circuit 12 B picture Skip circuit 13 PES decoder output signal 14 M transmission signal 101 recording medium 102 recording medium reading unit 103 data switching unit 104 inverse quantizer 105 orthogonal transform information decoder 106 image memory 107 motion compensation unit 108 adder 109 control unit 110 image memory 111 Motion Compensation Unit 112 Image Memory 113 Image Switching Unit 114 Variable Length Decoding Unit 115 Header Detection Unit

Claims (18)

[Claims] 1. An MPEG image reproducing apparatus which decodes image code data composed of an I picture, a B picture, and a P picture, which is compressed by a moving image compression technique of the MPEG system, and outputs the decoded image data as image output data for each frame. An MPEG image reproducing apparatus, which decodes only I-pictures and P-pictures of the image code data when performing high-speed reproduction. 2. Detecting an interval of an anchor frame which is an interval between an I picture and a P picture or a P picture in the image code data, and as an image output data based on the interval of the anchor frame and a reproduction speed of high speed reproduction. 2. The M according to claim 1, wherein a frame to be output is selected.
PEG image playback device. 3. An MPEG image reproducing apparatus that decodes image code data composed of an I picture, a B picture, and a P picture, which is compressed by a moving picture compression technique of the MPEG system, and outputs the decoded image data as image output data for each frame. When performing high-speed playback, only I and P pictures of the image code data are decoded and the I and P pictures or P pictures in the image code data are decoded.
An MPEG image reproducing apparatus for detecting an interval between anchor frames, which is an interval between pictures, and selecting a frame to be output as the image output data based on the interval between the anchor frames and a reproduction speed of high-speed reproduction. 4. When the interval between the anchor frames is two frames, double-speed playback is performed by outputting a frame obtained by decoding only an I picture and a P picture as the image output data as it is. M
PEG image playback device. 5. When the interval between the anchor frames is three, a frame obtained by decoding only an I-picture and a P-picture is obtained by repeating the same frame once every two frames. 4. The MPE according to claim 3, wherein double-speed reproduction is performed by outputting the MPE.
G image reproducing device. 6. When the interval between the anchor frames is three, triple-speed reproduction is performed by outputting a frame obtained by decoding only an I picture and a P picture as the image output data as it is. M
PEG image playback device. 7. When the interval between the anchor frames is four, a frame obtained by decoding only an I-picture and a P-picture is repeated twice each, and then output as the image output data to perform double-speed reproduction. 4. The MPEG image reproducing apparatus according to claim 3, wherein 8. When the interval between the anchor frames is five, a frame obtained by decoding only an I picture and a P picture is alternately repeated twice for the same frame and repeated three times for the same frame. 4. The MPEG image reproducing apparatus according to claim 3, wherein double-speed reproduction is performed by outputting the data as the image output data later. 9. In the case where the interval between the anchor frames is 5, the frame obtained by decoding only the I picture and the P picture is obtained by repeating the same frame twice.
4. The MPEG image reproducing apparatus according to claim 3, wherein triple-speed reproduction is performed by outputting as said image output data after performing once per frame. 10. A memory, which separates an input code input signal into image code data and audio code data, transfers the image code data to an image code buffer area in the memory at the time of normal reproduction, and transfers the image code data at the time of high-speed reproduction. The code of the B picture in the code data is skipped and only the P picture and the I picture are transferred to the image code buffer area in the memory, and the I picture and the P picture or the P picture in the image code data are transferred.
A PES decoder for detecting an interval between anchor frames, which is an interval between pictures, and outputting an M transmission signal for indicating the interval between the anchor frames; and reading the image code data from an image code buffer area in the memory, A variable-length code decoding unit that performs variable-length code decoding on the image code data to make the image data, an inverse quantization unit that inverse-quantizes the image data that has been subjected to the variable-length code decoding by the variable-length code decoding unit, An inverse cosine transform for performing inverse cosine transform on the image data inversely quantized by the inverse quantization unit, storing the obtained I picture in an I picture area in the memory, and outputting a B picture and a P picture And a motion compensator for P-picture and B-picture image data output from the inverse cosine transform unit. A motion compensator for writing to a P-picture area and a B-picture area in a memory; and reading image data from an I-picture area, a P-picture area, and a B-picture area in the memory during normal playback.
It is output as image output data in accordance with the determined display order, and at the time of high-speed reproduction, the I picture area, P
A display control unit that reads image data from a picture area, selects a frame to be displayed based on the interval between anchor frames indicated by the M transmission signal, and a reproduction speed at which high-speed reproduction is performed, and outputs the selected frame as the image output data. MPEG image playback device. 11. An M detection circuit, wherein the PES decoder detects, from the image code data, an interval between an I picture and a P picture or an anchor frame that is an interval between P pictures, and outputs the M transmission signal as the M transmission signal. When code data is input and a B picture header is detected, a B picture skip signal is activated.
A picture header detection circuit that outputs the image code data to the memory while the B picture skip signal is inactive, and does not output the image code data to the memory while the B picture skip signal is active. 11. The MPEG image reproducing apparatus according to claim 10, further comprising: a B picture skip circuit. 12. An MPEG image reproducing method for decoding image code data composed of an I picture, a B picture, and a P picture, which is compressed by a moving image compression technique of the MPEG system, and outputs the decoded image data as image output data for each frame. When performing high-speed playback, only I and P pictures of the image code data are decoded and the I and P pictures or P pictures in the image code data are decoded.
An MPEG image reproducing method for detecting an interval between anchor frames, which is an interval between pictures, and selecting a frame to be output as the image output data based on the interval between the anchor frames and a high-speed reproduction speed. 13. When the interval between the anchor frames is two frames, double-speed playback is performed by directly outputting a frame obtained by decoding only an I picture and a P picture as the image output data. MPEG image reproduction method. 14. When the interval between the anchor frames is three, a frame obtained by decoding only an I picture and a P picture is used as the image output data after repeating the same frame once every two frames. 13. The M according to claim 12, wherein double-speed reproduction is performed by outputting as M.
PEG image playback method. 15. When the interval between the anchor frames is three, triple-speed playback is performed by outputting a frame obtained by decoding only an I picture and a P picture as the image output data as it is. MPEG image reproduction method. 16. When the interval between the anchor frames is four, a frame obtained by decoding only an I picture and a P picture is repeated twice each and then output as the image output data, thereby performing double-speed reproduction. 13. The method for reproducing an MPEG image according to claim 12, wherein 17. In a case where the interval between the anchor frames is five, a frame obtained by decoding only an I picture and a P picture is alternately repeated twice for the same frame and three times for the same frame. 13. The MPEG image reproducing method according to claim 12, wherein double-speed reproduction is performed by outputting the data as the image output data later. 18. When the interval between the anchor frames is 5 frames, a frame obtained by decoding only an I picture and a P picture is obtained by repeating the same frame twice for every two frames. 3. A triple speed reproduction is performed by outputting as image output data.
2. The MPEG image reproducing method according to 2.