JP2014110437A - Device, method and program for image reproduction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reproduction device capable of reproducing an image signal before frame rate conversion.SOLUTION: A recording unit 40 has a recorded coded stream in which a frame rate is converted by the interpolation of a motion-compensation-interpolated interpolation frame between real frames, and only a real frame is dynamic image coded as an I picture frame or a P picture (B picture) reference frame referred to by another P picture (B picture). From the coded stream reproduced by the recording unit, a real frame extraction unit 50 extracts only a frame generated based on the real frame to output a real frame extraction stream. A dynamic image decoding unit 70 decodes the real frame extraction stream to output decoded data.

Description

  The present invention performs a motion compensation type frame rate conversion on a first image signal having a first frame rate, and has a second frame rate having a frame rate higher than the first frame rate. The present invention relates to an image reproduction apparatus, an image reproduction method, and an image reproduction program for reproducing encoded data from a recording unit that records encoded data obtained by converting a second image signal into moving image encoding.

  In recent years, digital still cameras for capturing still images are generally equipped with a function for capturing moving images. Many digital still cameras equipped with a moving image shooting function are designed to repeatedly output an image signal captured by an image sensor having a low frame rate of about 15 to 30 fps (frame / second) and convert it to 60 fps.

  In addition, when an image signal is output in 60-field interlace (so-called 60i), there are many specifications that divide a frame of a 30 fps image signal into two fields by 2-2 pull-down. One of the reasons for this specification is that the maximum frame rate in an image sensor for a digital still camera is limited.

  The digital still camera records the captured image signal as 30 frame progressive (so-called 30p) or 60i format encoded data (encoded stream) when the frame rate at the time of imaging by the image sensor is 30 fps. Record on media.

Japanese Patent Laid-Open No. 9-299362

  When a subject with relatively fast motion is photographed at, for example, 30 fps, and a moving image obtained by repeatedly outputting a 30 fps image signal and converting it to 60 fps is viewed, a jerky motion called motion judder is visually recognized. One solution to reduce motion judder is to use motion compensated frame rate conversion. Specifically, the motion-compensated frame rate conversion apparatus detects a motion vector of a subject based on an image signal of 30 fps, and generates an interpolation frame obtained by predictive interpolation. The motion compensation frame rate conversion apparatus interpolates an interpolation frame between adjacent real frames of a 30 fps image signal and converts the frame rate to 60 fps.

  In the moving image converted to 60 fps by the motion compensation type frame rate conversion, the motion judder is reduced, and the movement is as smooth as if captured at 60 fps. If a coded stream obtained by moving-picture-coding an image signal converted to 60 fps by motion compensation frame rate conversion is recorded on a recording medium, a smooth reproduced image with little motion judder can be viewed.

  However, if the encoded data obtained by moving image encoding the image signal converted to 60 fps is recorded on a recording medium, the 30 fps image signal before the motion judder reduction cannot be reproduced. The interpolated frame generated by the motion-compensated frame rate conversion apparatus may have a degraded image as compared with the actual frame of the 30 fps image signal. Therefore, it is desired that the image signal before the frame rate conversion can be reproduced by the motion compensation type frame rate conversion.

  In order to meet such a demand, the present invention performs motion compensated frame rate conversion on the first image signal having the first frame rate, so that the second frame rate is higher than the first frame rate. An image that can be reproduced from an image signal before frame rate conversion from a recording unit that records the encoded data obtained by converting the second image signal into a second image signal having a frame rate of It is an object to provide a playback device, an image playback method, and an image playback program.

  In order to solve the above-described problems of the related art, the present invention generates an interpolated frame subjected to motion compensation interpolation from an actual frame constituting the first image signal having the first frame rate. By interpolating an interpolated frame, only the actual frame constituting the second image signal is converted into a second image signal having a second frame rate higher than the first frame rate. A recording unit (40) for recording a coded stream encoded as a moving picture as a frame of an I picture or a reference frame of a P picture or B picture referenced by another P picture or B picture; Extract actual frames by extracting only the frames generated based on the actual frames from the reproduced stream. Actual frame extraction unit for outputting a stream (50), said to provide an image reproducing apparatus characterized by comprising a video decoding unit for outputting the decoded data by decoding the actual frame extraction stream (70).

  In addition, in order to solve the above-described problems of the conventional technique, the present invention generates an interpolated frame subjected to motion compensation interpolation from an actual frame that constitutes the first image signal having the first frame rate. The interpolation frame is interpolated into a second image signal having a second frame rate that is higher than the first frame rate, and the actual image constituting the second image signal is converted into the second image signal. From a recording unit (40) in which a coded stream in which only a frame is an I picture frame or a moving picture coded as a reference frame of a P picture or B picture referenced by another P picture or B picture is recorded, The encoded stream is reproduced, and a frame generated based on the actual frame from the reproduced encoded stream is reproduced. It generates a real frame extraction stream by extracting said to provide an image reproducing method and generating a decoded data by decoding the actual frame extraction stream.

  Furthermore, in order to solve the above-described problems of the related art, the present invention generates an interpolated frame in which motion compensation interpolation is performed from an actual frame constituting a first image signal having a first frame rate in a computer. By interpolating the interpolated frame between actual frames, the second image signal is converted into a second image signal having a second frame rate higher than the first frame rate, thereby forming the second image signal. A recording unit (40) in which an encoded stream in which a moving image is encoded as an I picture frame or a reference frame of a P picture or B picture referred to by another P picture or B picture is recorded ) To reproduce the encoded stream and the actual frame from the reproduced encoded stream. Provided is an image reproduction program that realizes a function of generating only a frame generated according to the above and generating a real frame extraction stream and a function of decoding the real frame extraction stream and generating decoded data To do.

  According to the image reproduction device, the image reproduction method, and the image reproduction program of the present invention, the motion compensation type frame rate conversion is performed on the first image signal having the first frame rate, so that the first frame rate is higher than the first frame rate. The image signal before the frame rate conversion is converted from the recording unit that records the encoded data obtained by converting the second image signal into the second image signal having a high frame rate and the moving image encoding of the second image signal. Can be played.

It is a block diagram which shows an imaging recording device. It is a block diagram which shows the 1st specific structural example of the frame rate conversion part 20 in FIG. 6 is a timing chart for explaining the operation of the imaging and recording apparatus when the frame rate conversion unit 20 is the first specific configuration example. It is a block diagram which shows the 2nd specific structural example of the frame rate conversion part 20 in FIG. 12 is a timing chart for explaining the operation of the imaging / recording apparatus when the frame rate conversion unit 20 is in the second specific configuration example. It is a block diagram which shows the image reproduction apparatus of one Embodiment. 6 is a timing chart for explaining the operation of the image reproduction apparatus according to the embodiment.

  Hereinafter, an image reproduction apparatus, an image reproduction method, and an image reproduction program according to an embodiment will be described with reference to the accompanying drawings. First, the configuration and operation of an imaging recording apparatus that converts an image signal output from an image sensor into a moving image code by converting the frame rate and records it in a recording unit will be described.

<First Configuration Example of Imaging Recording Apparatus>
In FIG. 1, an image sensor 10 outputs an image signal S10 obtained by imaging a subject at a frame rate of 30 fps. The image signal S10 is input to a frame rate conversion unit 20 which is a motion compensated frame rate conversion device. The frame rate conversion unit 20 in the first configuration example is a so-called double speed conversion circuit.

  The frame rate conversion unit 20 detects a motion vector between frames in the image signal S10, and generates an interpolation frame obtained by predictive interpolation (motion compensation interpolation) based on the motion vector. The frame rate conversion unit 20 outputs an image signal S20 obtained by interpolating an interpolation frame between adjacent frames in the image signal S10 and converting the frame rate to 60 fps.

  The frame rate conversion unit 20 generates and outputs a flag signal Sfg indicating whether each frame in the image signal S20 is an actual frame that is a frame of the image signal S10 or an interpolation frame.

A first specific configuration example and operation of the frame rate conversion unit 20 will be described with reference to FIG. The frame rate conversion unit 20 in the first specific example configuration and frame rate conversion unit 20 _1. In FIG. 2, each pixel data constituting the image signal S 10 is sequentially input to the memory 201, the motion vector detection unit 202, the interpolation unit 203, and the memory 204. The memory 201 delays the input pixel data for one frame period. The one-frame delayed pixel data is input to the motion vector detection unit 202 and the interpolation unit 203.

  The motion vector detection unit 202 detects a motion vector MV between frames in a pixel unit or a block unit including a plurality of pixels by a known method. The interpolation unit 203 refers to the motion vector MV and interpolates between adjacent frames in the image signal S10 based on the pixel data of the image signal S10 and the one-frame delayed pixel data output from the memory 201. Is generated. Interpolated pixel data generated by the interpolation unit 203 is input to the memory 204.

  Based on the control by the timing control unit 25, the memory 204 alternately reads out the pixel data of the image signal S10 and the interpolation pixel data from the interpolation unit 203 every 1/60 seconds, and has a frame rate of 60 fps. An image signal S20 is output. The timing control unit 25 outputs a flag signal Sfg of “0” (low), for example, when the frame of the image signal S20 output from the memory 204 is a real frame, and “1” (high), for example, when the frame is an interpolated frame. Generate and output.

  The timing control unit 25 operates as a flag generation unit that generates a flag signal Sfg for identifying a timing for outputting an actual frame and a timing for outputting an interpolation frame.

Returning to FIG. 1, the image signal S20 and the flag signal Sfg output from the frame rate conversion unit 20 (20 ₁ ) are input to the moving image encoding unit 30. The moving image encoding unit 30 encodes the input image signal S20. At this time, the moving image encoder 30 refers to the flag signal Sfg to determine a method for encoding the image signal S20.

  The moving image encoding unit 30 receives the image signal S20 and the flag signal Sfg. The moving image encoding unit 30 encodes the image signal S20. The moving image encoding unit 30 selects any one of an I picture (Intra Coded Picture), a P picture (Predictive Coded Picture), and a B picture (Bidirectional Predictive Coded Picture) as the type of an image frame when the image signal S20 is encoded. The type is used.

  An I picture is a frame that uses only intraframe predictive coding. The P picture is a frame that can use not only intra-frame prediction encoding but also forward inter-frame prediction encoding that refers to a past frame. A B picture is a frame that can use not only intraframe predictive coding but also bidirectional interframe predictive coding that refers to past and future frames.

  The I picture is assigned as the first frame of a group of pictures called GOP (Group of Picture). The I picture is the basis of the reference frame in the GOP. Since the I picture does not refer to other frames, it is suitable for use in special reproduction such as search. When the P picture and the B picture are used, only the difference between the own frame and the reference frame is encoded, so that encoding with high compression efficiency can be performed.

With reference to FIG. 3 will be described how the frame rate conversion unit 20 ₁ and the first example of structure imaging and recording apparatus comprising a video encoding unit 30 encodes how determined by the image signal S20 to picture type . 3A shows frames f0, f2, f4,... Of the image signal S10 output from the image sensor 10. FIG. Here, the frame rate of the image signal S10 is 30 fps.

FIG. 3B shows frames f0, f1, f2, f3, f4,... Of the image signal S20 output from the frame rate conversion unit 20 (20 ₁ ). As can be seen by comparing (a) and (b) of FIG. 3, the frames f0, f2, f4, f6,... Are real frames, and the frames f1, f3, f5, f7,.

  For example, the frame f1 in FIG. 3B is obtained after the frame f2 in FIG. 3A is input. Accordingly, in practice, the image signal S20 shown in FIG. 3B is shifted in timing from the position of the frame f1 in FIG. 3B to the rear side of the frame f2 in FIG. become. In FIG. 3, for the sake of easy understanding, the delay time in the frame rate conversion unit 20 is ignored, and the timing of the frame of the image signal S10 and the frame of the image signal S20 is illustrated.

  As shown in FIG. 3 (c), the timing control unit 205 is high when the frame rate conversion unit 20 outputs real frames f0, f2, f4, f6,... As the frame of the image signal S20. When outputting the frames f1, f3, f5, f7,..., A low flag signal Sfg is output.

  As an example, the moving image encoding unit 30 encodes frames f0, f4,... As frames of I pictures I0, I4,. ,... Are encoded as frames of P pictures P1 to P3, P5 to P7,. Here, for simplification, the B picture is not used, but the encoded stream S30 may be generated so as to include the frame of the B picture.

  As can be seen from FIGS. 3C and 3D, the moving image encoding unit 30 assigns an I picture only to an actual frame in which the flag signal Sfg is low. In addition, the moving image encoding unit 30 encodes the reference frame referred to by the P picture or B picture as only the frame of the I picture, the P picture, and the B picture generated based on the actual frame in which the flag signal Sfg is low. To do. Furthermore, the moving image encoding unit 30 encodes only the P picture and B picture frames that are not the reference frames for the interpolated frames in which the flag signal Sfg is high.

  In the case of FIG. 3D, the frame f2 (P picture P2) is the reference frame of the frame f3 (P picture P3), and the frame f6 (P picture P6) is the reference frame of the frame f7 (P picture P7). ing. Frames f1 and f2 (P pictures P1 and P2) refer to frame f0 (I picture I0), and frames f5 and f6 refer to frame f4 (I picture I4).

  In an ordinary imaging / recording apparatus, it is common to assign picture types of I picture, P picture, and B picture on the basis of the characteristics of the image signal and so on, and assign I picture, P picture, and B picture in order in a certain sequence. Is. In the present embodiment, referring to the flag signal Sfg, the picture type is determined depending on whether the frame to be encoded is an actual frame or an interpolated frame, and whether or not to be a reference frame is determined. The encoded stream S30 is generated.

Since the interpolation frame is a frame generated by estimating the motion vector in the frame rate conversion unit 20 (20 ₁ ), it may include a conversion error. When the interpolation frame is used as a reference frame when generating the encoded stream S30, conversion errors accumulate in a plurality of frames, leading to image degradation. In the first configuration example, the moving image encoding unit 30 encodes the interpolated frame so as not to be used as a reference frame referenced from an I picture frame and other frames, and generates an encoded stream S30. Therefore, according to the imaging and recording apparatus of the first configuration example, it is possible to minimize image degradation due to the influence of the conversion error in the frame rate conversion unit 20.

  The encoded stream S30 output from the moving image encoding unit 30 is input to the recording unit 40 and recorded. The recording unit 40 includes a recording medium and a recording / reproducing drive unit that records the encoded stream S30 on the recording medium and reproduces the encoded stream S30 recorded on the recording medium. The recording medium may be an optical disk, a semiconductor memory, a hard disk drive, or the like, and is an arbitrary recording medium.

<Second Configuration Example of Imaging Recording Apparatus>
In the second configuration example, the image sensor 10 in FIG. 1 outputs an image signal S10 obtained by imaging a subject at a frame rate of 15 fps. The frame rate conversion unit 20 in the second configuration example is a so-called quadruple speed conversion circuit that converts 15 fps to 60 fps.

A specific configuration and operation of the frame rate conversion unit 20 in the second configuration example will be described with reference to FIG. The frame rate conversion unit 20 in the second configuration example and the frame rate conversion unit 20 _2. The same reference numerals are given to substantially same parts and the frame rate conversion unit 20 ₁ of the first configuration example shown in FIG. 2, the description thereof is omitted.

In FIG. 4, the motion vector detection unit 202 supplies motion vectors MV1, MV2, and MV3 to the interpolation units 2031, 2032, and 2033, respectively. To convert 15fps to 60fps, the frame rate converting unit 20 _2, it is necessary to interpolate the three frames of the interpolated frame between adjacent frames in the image signal S10. Therefore, three interpolation units 2031, 2032, and 2033 are required.

With reference to FIG. 5, a description will be given if the frame rate conversion unit 20 ₂ and the second configuration example imaging and recording apparatus comprising a video encoding unit 30 encodes how determined by the image signal S20 to picture type . 5A shows frames f0, f4, f8,... Of the image signal S10 output from the image sensor 10. FIG. Here, the frame rate of the image signal S10 is 15 fps.

  FIG. 5B shows frames f0, f1, f2, f3, f4,... Of the image signal S20 output from the frame rate conversion unit 20. As can be seen by comparing FIGS. 5A and 5B, the frames f0, f4, f8, f12,... Are real frames, and the frames f1 to f3, f5 to f7, f9 to f11, and f13 to f15. ,... Are interpolation frames. Here, the delay time in the frame rate conversion unit 20 is ignored, and the frame of the image signal S10 and the frame of the image signal S20 are shown to be matched.

  As shown in FIG. 5C, the timing control unit 205, which is a flag generation unit, outputs the actual frames f0, f4, f8, f12,... As the frame of the image signal S20. Then, the high flag signal Sfg is output at the timing of outputting the low, interpolated frames f1 to f3, f5 to f7, f9 to f11, f13 to f15,.

  As an example, the moving image encoding unit 30 encodes frames f0, f8,... As frames of I pictures I0, I8,... And frames f1 to f7, f9 to f15, as shown in FIG. ,... Are encoded as frames of P pictures P1 to P7, P9 to P15,. Again, the encoded stream S30 may be generated so as to include a B picture frame.

  Also in the second configuration example, the moving image encoding unit 30 assigns an I picture only to an actual frame whose flag signal Sfg is low. In addition, the moving image encoding unit 30 encodes the reference frame referred to by the P picture and the B picture as only the frame of the I picture, the P picture, and the B picture generated based on the actual frame in which the flag signal Sfg is low. To do. Furthermore, the moving image encoding unit 30 encodes only the P picture and B picture frames that are not the reference frames for the interpolated frames in which the flag signal Sfg is high.

  In the case of FIG. 5D, the frame f4 (P picture P4) is the reference frame of the frames f5 to f7 (P pictures P5 to P7), and the frame f12 (P picture P12) is the frames f13 to f15 (P picture P13). To P15). Frames f1 to f4 (P pictures P1 to P4) refer to frame f0 (I picture I0), and frames f9 to f12 (P pictures P9 to P12) refer to frame f8 (I picture I8).

  The encoded stream S30 output from the moving image encoding unit 30 is input to the recording unit 40 and recorded.

<Image Reproducing Apparatus of One Embodiment>
A specific configuration and operation of an image reproduction apparatus according to an embodiment for reproducing the encoded stream S30 recorded in the recording unit 40 by the imaging recording apparatus of the first or second configuration example will be described with reference to FIGS. 6 and 7. To do. FIG. 7 shows a timing chart in the case where the encoded stream S30 generated by the imaging recording apparatus of the first configuration example is recorded in the recording unit 40.

  As shown in FIG. 6, the image reproduction device of one embodiment includes a recording unit 40, an actual frame extraction unit 50, a mode selection unit 60, a moving image decoding unit 70, a frame rate conversion unit 80, and a mode selection unit 90. The image reproduction apparatus of one embodiment has two modes, a normal reproduction mode and an original image reproduction mode, as modes for reproducing the encoded stream S30 recorded in the recording unit 40.

  First, the operation in the normal playback mode will be described. In FIG. 6, the encoded stream S40 reproduced from the recording unit 40 is input to the real frame extraction unit 50 and the mode selection unit 60. In the normal reproduction mode, the mode selection unit 60 selects the encoded stream S40 reproduced from the recording unit 40 and supplies it to the moving image decoding unit 70.

  The video decoding unit 70 decodes the input encoded stream S40 and supplies the decoded data S70 to the frame rate conversion unit 80 and the mode selection unit 90. The mode selection unit 90 selects and outputs the decoded data S70 output from the video decoding unit 70.

  According to the normal reproduction mode, the normal operation of reproducing and decoding the encoded stream S30 recorded in the recording unit 40 is performed, so that there is less motion judder and smoothness, and there is little image deterioration due to the influence of the conversion error. High-quality playback images can be viewed.

  Next, the operation in the original image reproduction mode will be described. FIG. 7A shows an encoded stream S40 reproduced from the recording unit 40. The encoded stream S40 shown in (a) of FIG. 7 is the same as the encoded stream S30 shown in (d) of FIG. As described with reference to FIG. 3, I pictures I0, I4,... And P pictures P2, P6,.

  As shown in FIG. 7B, the actual frame extraction unit 50 extracts only the I picture I0, P picture P2, I picture I4, P picture P6,... Generated from the encoded stream S40 based on the actual frame. The actual frame extraction stream S50 is output by extraction. In the original image reproduction mode, the mode selection unit 60 selects the actual frame extraction stream S50 output from the actual frame extraction unit 50 and supplies the selected frame to the moving image decoding unit 70.

  The moving picture decoding unit 70 decodes the input real frame extraction stream S50. The moving picture decoding unit 70 supplies the decoded data S70 composed of the frames f0, f2, f4, f6,... To the frame rate conversion unit 80 and the mode selection unit 90, as shown in FIG. The frame rate of the decoded data S70 is 30 fps. The decoded data S70 in the original image reproduction mode is different from the decoded data S70 in the normal reproduction mode, but is denoted by the same reference symbol for convenience.

  The P pictures P2, P6,... Extracted by the real frame extraction unit 50 do not refer to the picture of the interpolation frame. Therefore, even if the P picture (or B picture) generated based on the interpolation frame is removed from the encoded stream S40, the moving picture decoding unit 70 can decode the actual frame extraction stream S50.

  The frame rate conversion unit 80 simply doubles the input decoded data S70 and converts it to 60 fps. The frame rate conversion unit 80 in FIG. 6 is a simple double speed conversion unit that simply performs double speed conversion on the decoded data S70, unlike the frame rate conversion unit 20 that generates an interpolation frame subjected to motion compensation interpolation in FIG. Specifically, as shown in FIG. 7D, the frame rate conversion unit 80 outputs the frame rate of 60 fps by repeatedly outputting the frames f0, f2, f4, f6,... Twice each. The double-speed decoded data S80 is generated.

  In the original image playback mode, the mode selection unit 90 selects and outputs the double-speed decoded data S80 output from the frame rate conversion unit 80.

  The double-speed decoded data S80 output from the mode selection unit 90 in the original picture reproduction mode is motion compensated by the frame rate conversion unit 20 interpolated between actual frames in the process of generating the encoded stream S30 recorded in the recording unit 40. There is no influence of the interpolation frame by interpolation.

  The double-speed decoded data S80 has an image quality equivalent to that of the image signal S10 output from the image sensor 10 although the frame rate is different. According to the present embodiment, it is possible to reproduce an image signal before frame rate conversion by motion compensation frame rate conversion. Strictly speaking, the double-speed decoded data S80 includes a loss due to encoding, but may be ignored.

  When the encoded stream S30 generated by the imaging recording apparatus of the second configuration example is recorded in the recording unit 40, the frame rate conversion unit 80 simply quadruples the input decoded data S70, What is necessary is just to convert so that it may become 60 fps.

  The frame rate conversion unit 80 may be omitted.

  In FIG. 1, the frame rate conversion unit 20 and the moving image encoding unit 30 may be configured by a microcomputer. In FIG. 6, the part for reproducing the encoded stream S40 from the recording unit 40, the real frame extracting unit 50, the mode selecting unit 60, the moving image decoding unit 70, the frame rate converting unit 80, and the mode selecting unit 90 are processed by a microcomputer. It may be configured. An image reproduction program that operates as in the present embodiment may be installed in a microcomputer, and functions equivalent to those of the image reproduction apparatus of the present embodiment may be realized by the microcomputer.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention.

40 recording unit 50 real frame extraction unit 60, 90 mode selection unit 70 moving image decoding unit 80 frame rate conversion unit

Claims (5)

An interpolation frame obtained by motion compensation interpolation is generated from an actual frame constituting the first image signal having the first frame rate. By interpolating the interpolation frame between the actual frames, the interpolation frame is calculated from the first frame rate. Is converted into a second image signal having a second frame rate with a higher frame rate, and only the actual frame constituting the second image signal is a frame of an I picture, or another P picture or B picture. A recording unit that records an encoded stream that has been encoded as a reference frame of a P picture or B picture that is referred to;
An actual frame extraction unit that extracts only a frame generated based on the actual frame from the encoded stream reproduced from the recording unit and outputs an actual frame extraction stream;
A video decoding unit that decodes the real frame extraction stream and outputs decoded data;
An image reproducing apparatus comprising:   2. The image reproducing apparatus according to claim 1, further comprising a frame rate conversion unit that repeatedly outputs each frame of the decoded data, converts the frame to the second frame rate, and outputs the second frame rate. A first selection unit that selects an encoded stream reproduced from the recording unit and an actual frame extraction stream output from the actual frame extraction unit;
A second selection unit that selects the decoded data output from the moving image decoding unit and the decoded data converted to the second frame rate output from the frame rate conversion unit;
The image reproducing apparatus according to claim 2, further comprising: An interpolation frame obtained by motion compensation interpolation is generated from an actual frame constituting the first image signal having the first frame rate. By interpolating the interpolation frame between the actual frames, the interpolation frame is calculated from the first frame rate. Is converted into a second image signal having a second frame rate with a higher frame rate, and only the actual frame constituting the second image signal is a frame of an I picture, or another P picture or B picture. Playing back the encoded stream from the recording unit in which the encoded stream encoded as a moving picture is recorded as a reference frame of the P picture or B picture to be referenced,
From the reproduced encoded stream, only a frame generated based on the actual frame is extracted to generate an actual frame extraction stream,
An image reproduction method, comprising: decoding the actual frame extraction stream to generate decoded data. On the computer,
An interpolation frame obtained by motion compensation interpolation is generated from an actual frame constituting the first image signal having the first frame rate. By interpolating the interpolation frame between the actual frames, the interpolation frame is calculated from the first frame rate. Is converted into a second image signal having a second frame rate with a higher frame rate, and only the actual frame constituting the second image signal is a frame of an I picture, or another P picture or B picture. A function of reproducing the encoded stream from a recording unit in which an encoded stream encoded as a moving picture is recorded as a reference frame of a P picture or B picture to be referred to;
A function of extracting only frames generated based on the actual frame from the reproduced encoded stream and generating an actual frame extraction stream;
A function of decoding the actual frame extraction stream to generate decoded data;
An image reproduction program characterized by realizing the above.

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