JPH10257501A - Image reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reproducing device that adaptively selects a frame in a motion image signal decoded from motion image coding data to enable to reproduce a still image with high and almost constant image quality. SOLUTION: A moving image signal that is obtained by reading moving image coded data recorded on an optical disk 11 through an optical disk drive part 10 and by decoding the data through a decode part 20 is outputted from a moving image output part 22 and a frame with the highest image quality is selected among plural frames including a frame designated by a user and its adjacent frames from the moving image signal via a user interface 32 and the image signal of the frame is outputted via a still image output interface 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing apparatus which reproduces an image by decoding moving image encoded data, and more particularly to an image reproducing apparatus which can reproduce not only a moving image but also a still image selected from the moving images. It relates to a playback device.

[0002]

2. Description of the Related Art Video printers and video capture devices are known as devices that capture a moving image signal and secondary use of a specific frame image as a still image. 2. Description of the Related Art Conventional video printers and video capture devices input an analog TV image signal from a video device such as a VTR or a laser disk device, sample a specific frame selected by a user, and print or display a still image. The configuration is common.

However, it is hard to say that a TV image signal output from a VTR, a laser disk device, or the like has a sufficient resolution for secondary use as a still image.
Furthermore, since interlaced scanning is performed on the TV image signal, if the movement of the image is fast, printing or displaying the frame image will cause a noticeable image shift between the fields, When the display is performed, the vertical resolution decreases, and it is difficult to perform high-definition printing.

On the other hand, in recent years, an encoding system based on MPEG-2, which is an international standard for moving image encoding (hereinafter referred to as MPEG-
Digital video disc (DVD) and its playback device (DVD player) that store encoded data compressed using the two-encoding method have been put into practical use, and this enables high-definition images to be reproduced at the consumer device level. It is getting. As is well known, the MPEG-2 encoding method is a method for performing high-efficiency compression encoding of motion picture signals by motion-compensated prediction orthogonal transform encoding by digital processing. The encoded data is stored as digital data. Therefore, high-quality recording is expected compared to conventional analog video equipment.

[0005] However, the MPEG-2 encoding method is an irreversible encoding method in which an orthogonal transform coefficient is quantized to perform variable-length encoding. Therefore, uniform image quality is obtained for each frame depending on the characteristics of the image and the characteristics of the encoding device. Is generally difficult to obtain. Also, in order to improve the image quality of a reproduced moving image, encoding is generally performed at a higher SNR for a frame used as a reference image for motion compensation prediction than for a frame not used as a reference image. The method is performed, which also causes the image quality of each frame to be inconsistent.

Therefore, when a specific frame in a moving image to be decoded is selected from the moving image encoded data obtained by the MPEG-2 encoding method and a still image is printed or displayed, the selected frame is The image quality changes according to the image quality.

[0007]

As described above, when a conventional video printer device or video capture device captures an analog TV image signal and prints or displays a still image, the resolution is generally insufficient and the interface is not sufficient. High-definition printing and display were difficult due to the influence of race scanning.

Further, a moving picture signal decoded from moving picture coded data by a high efficiency moving picture coding method such as MPEG-2 has a higher resolution than an analog TV picture signal, but has a higher resolution for each frame. Since the image quality is different, there is a problem that when a specific frame is selected for printing or display, the image quality is different depending on the selected frame.

According to the present invention, a moving picture signal decoded from coded moving picture data is decoded in order to enable secondary use as a high-quality still picture signal in addition to normal moving picture reproduction. An image reproducing apparatus capable of adaptively selecting a frame in a moving image and outputting the selected image as a still image signal, and reproducing a high-quality still image having almost constant image quality. I do.

[0010]

According to the present invention, there is provided an image reproducing apparatus for decoding and outputting a moving image signal comprising a plurality of types of frames having different image qualities from encoded moving image data. Frame selecting means for selecting a frame of the highest image quality from a plurality of frames including a frame specified by a user and a frame in the vicinity of the frame specified by the user, and a frame selected by the frame selecting means in the moving image signal. A still image output means for outputting an image signal as a still image signal.

As described above, according to the present invention, one frame having the same image quality as the frame specified by the user and having the highest image quality is automatically selected, and the image signal of that frame is output as a still image signal. Is done. The still image signal output in this way has an average constant image quality, and does not significantly change depending on the type of frame specified by the user.

Further, a frame group selecting means for selecting a frame group including a frame designated by the user in the first stage and a frame in the vicinity of the output moving image signal, and a frame group selecting means of the moving image signal And a frame group output unit for outputting an image signal of the frame group selected by the above-described method, and the frame selection unit may select the frame specified in the second stage from the frame group. The frame group selecting means may select, for example, a plurality of frames of higher image quality from the designated frame and its neighboring frames as a frame group.

With this configuration, when a scene change or the like occurs near the frame specified by the user and a frame that is contrary to the user's intention is automatically selected, the frame specified by the user in the first step and the An image signal of a frame group including a frame in the vicinity is output and presented to the user, so that the next candidate can be selected, and the frame intended by the user can be efficiently selected.

In the frame selecting means, for example, from a plurality of frames including a frame designated by the user and a frame in the vicinity thereof, an intra-frame coded frame, a forward coded frame, a bidirectional predicted coded frame Frame is selected in the priority order.

In the motion compensated predictive orthogonal transform coding used in the MPEG-2 coding method, random access is generally enabled, and accumulation of errors in orthogonal transform and inverse orthogonal transform between a coding device and a decoding device is prevented. For the purpose, an I-picture, which is an intra-frame coded image, is inserted periodically, so that the image quality tends to decrease as the distance from the I-picture increases. In addition, since the I picture and the P picture for which the forward prediction coding is performed are used as reference images for the subsequent coded images, the quantization scale is smaller than the B picture which is a bidirectional prediction coded image that is not used as a reference image. In order to improve the relative image quality, a method of improving the coding efficiency of the entire moving image is used.

From these facts, it is considered that the picture quality is relatively good in the order of I picture, P picture and B picture in temporally adjacent frames. Therefore, by selecting and outputting a frame preferentially in accordance with this order, it is possible to select a frame with higher image quality.

The frame selecting means calculates an average quantization scale within a plurality of frames including, for example, a frame specified by a user and a frame in the vicinity thereof, and determines the plurality of frames having the minimum average quantization scale within the plurality of frames. Frame may be selected.

In general, a similar image has a strong correlation between the quantization scale and the image quality, and the smaller the quantization scale, the higher the image quality. In the MPEG-2 encoding method, a framework is employed in which the quantization width is variable for each macroblock in an image frame, and information on the quantization width of each macroblock is multiplexed with encoded data. Therefore, it is possible to select a high-quality frame by calculating an average value in the frame of this quantization scale in a frame near the frame specified by the user and selecting a frame having the minimum value. Become.

Further, the above-mentioned average quantization scale within a frame is weighted by a weighting function that decreases in accordance with a time interval from a frame designated by a user, and the average quantization scale within a frame after the weighting is performed. The frame with the smallest scale may be selected from the plurality of frames. By doing so, it is possible to select a frame with the best balance between temporal accuracy and image quality.

On the other hand, in the MPEG-2 encoding method, it is possible to perform encoding with different frame frequencies between the encoded frame and the display frame. When the moving image encoded data is encoded at different frame rates for the display frame and the encoded frame as described above, it is preferable that the frame selecting unit selects the frame in units of the encoded frame.

For example, when encoding a movie having a frame frequency of 24 Hz so that it can be displayed on a display having a field frequency of 60 Hz, the encoding is performed as a non-interlaced scan image of 24 Hz at the time of encoding, and the encoding is performed periodically during reproduction. In this case, data indicating that a display is performed at 60 Hz for a three-field period is multiplexed. Therefore, the configuration of the display frame of 30 Hz at the time of reproduction and the configuration of the encoded frame of 24 Hz at the time of encoding and decoding are different, and the display frame may be composed of temporally different fields.

In this case, disturbance may occur due to interlaced scanning during frame display. However, by outputting a frame selected in units of encoded frames as a still image signal, a still image is always output as a non-interlaced scanned image. Output can be performed, and a high-definition still image with high vertical resolution can be output.

The still image output means preferably has means for converting the output format of the still image signal. This conversion is realized by, for example, software. In this way, a normal analog image signal,
A signal such as a digital image signal or a printer output signal can be selected and changed.

The still image output means determines whether the frame selected by the frame selection means is a non-interlaced scanned image or an interlaced scanned image. If the frame is a non-interlaced scanned image, the image signal of the frame is converted to a still image signal , And in the case of an interlaced scanning image, only one of the even field and the odd field is output as a still image signal, or the image signal of both the even field and the odd field is output as a still image signal You may do so. In this way, a frame image is not disturbed when interlaced scanning is performed on an image with motion, and a still image output with a high vertical resolution is output for an interlaced image without motion or a non-interlaced image. can get.

Here, the determination as to whether the frame selected by the frame selection means is a non-interlaced scanning image or an interlaced scanning image is performed by detecting, for example, frame scanning information multiplexed on moving image encoded data. In this case, no special hardware is required.

Further, the correlation between adjacent even-numbered lines and the correlation between adjacent odd-numbered lines and the correlation between adjacent lines are calculated, and no special additional information is required based on the magnitude relationship between these correlations. Alternatively, it is possible to determine whether the image is a non-interlaced scan image or an interlaced scan image.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows a configuration of an image reproducing apparatus according to an embodiment of the present invention. The image reproducing apparatus is roughly divided into an optical disk drive unit 10 and a decoding unit 20.
And a decoding control unit 30 including a user interface for selecting a frame to be a still image.

The optical disk 11 set in the optical disk drive unit 10 is, for example, a digital video disk (DVD). Moving image coded data obtained by coding a moving image signal according to the MPEG-2 coding method has a pit sequence. Recorded as a mark string. This optical disk 1
The moving image encoded data recorded in 1 is read by the optical pickup 12 under the control of the control circuit 13. The read encoded video data is transmitted to the control circuit 13.
After being appropriately processed by, the error correction circuit 14 corrects any errors. The moving image encoded data that has passed through the error correction circuit 14 is output from the optical disk drive unit 10 and passed to the decoding unit 20.

In the decoding section 20, the decoding control section 30
Sends an encoded data output request to the optical disk drive unit 10 based on the instruction from the decoder control circuit 31 in the above, and decodes the moving image encoded data input from the optical disk drive unit 10 by the decoder circuit 21 in accordance with the request. Outputs an image signal. This moving image signal is output from the moving image output unit 22 to an image monitor. The still image output unit 23 outputs the image signal of the selected frame in the moving image signal as a still image output to, for example, a video printer or a video capture device.

The decoding control unit 30 controls the decoder control circuit 31 via the user interface 32 based on an instruction from the user to output a moving image or to specify a frame to be output as a still image in a moving image. It is configured such that an instruction such as a still image output of a frame selected based on a designated frame can be given. Hereinafter, the operation of the decode control unit 30 will be described in detail.

The MPEG-2 encoding system has a sequence, GOP (G
roup of Pictures), pictures, and macroblocks MB. The search for a moving image or a still image can be performed by sequentially searching the picture header PH. It is also possible to have a search table separately from the coded bit stream and realize a search for a moving image or a still image on the coded bit stream.

Further, in the MPEG-2 encoding method, the picture quality of a decoded image changes according to the characteristics of the image, the encoding method such as the prediction method and the quantization width (hereinafter referred to as quantization scale). General. FIG. 3 shows the SNR of the original image versus the decoded image for each frame on the horizontal axis and the frame on the vertical axis
This is an example. As shown in the figure, normally, although the images are similar between adjacent frames, the fluctuation of the SNR in the frame unit, that is, the fluctuation of the image quality is very large. Therefore, even if the images have substantially the same contents, the image quality greatly differs depending on the selected frame.

Therefore, in the present embodiment, a plurality of frames including a frame designated by the user via the user interface 32 and its neighboring frames are
The decoder control circuit 31 calculates an evaluation value (cost) reflecting the image quality for each frame, and outputs the frame with the minimum cost as a still image signal.
0 is controlled.

FIG. 4 shows an example of a frame selection method in the decoder control circuit 31 in this embodiment. In the figure, the axis of composition represents the frame, and the axis of ordinate represents the evaluation value. The decoder control circuit 31 calculates the above-described evaluation value 43 for a plurality of frames 42 including a frame 41 specified by the user via the user interface 32 and a frame in the vicinity thereof, and sets a frame 44 having the minimum value as a still image. Select and output a still image signal via the still image output unit 23.

FIG. 5 is a block diagram showing the configuration of the still image output unit 23. CPU 51, still image memory 52,
An instruction memory 53, a program interface 54, and a still image output interface 55 are connected by a bus 56.

The moving image encoded data relating to the frame selected by the decode control unit 30 is transmitted to the optical disk drive unit 1.
0, and the frame selected by the decoder circuit 21 in the decoding unit 20 is decoded as a still image signal. The decoded still image signal 57 is recorded in the still image memory 52 via the bus 57 under the control of the CPU 51.

The still image signal recorded in the still image memory 52 is converted into a predetermined output signal format (format) by the software recorded in the instruction memory 53 by the CPU 51 and output from the still image output interface 55. Here, when the instruction memory 53 is composed of a ROM, it is possible to easily change the output signal format according to the application by exchanging the ROM. When the instruction memory 53 is configured by a rewritable memory such as a RAM or a flash memory, it is possible to easily change the output signal format by downloading the format conversion software from the outside by the program interface 54. Become.

(Second Embodiment) Next, FIGS. 6 and 7
The second embodiment will be described with reference to FIG. In the present embodiment, the overall configuration of the image reproducing apparatus is the same as that of the first embodiment, and only the frame selection method in the decoder control circuit 31 is different from the first embodiment.

As shown in FIG. 3, in the MPEG-2 encoding method, a large variation in image quality is caused depending on the type of frame (picture type) even between adjacent frames depending on the encoding parameter. That is, in the MPEG-2 encoding method, relatively high-quality encoding is performed in the order of an I picture for performing intra-frame encoding, a P picture for performing forward prediction, and a B picture for performing bidirectional prediction. This means that the I picture is the basis for subsequent reference pictures, and the P picture is
Since it is used as a reference image like a picture,
This is a method generally used to increase the overall image quality of a moving image by changing the image quality for each picture type. Therefore, generally, in a plurality of adjacent frames having high similarity in content, the image quality is higher in the order of the I picture, the P picture, and the B picture.

Therefore, in this embodiment, the picture type (frame type) is used as the above-mentioned evaluation value shown on the vertical axis of FIG. 4, and the I picture closest to the frame 60 selected by the user as shown in FIG. Automatic selection of a high-quality frame is performed by automatically selecting 61 or by automatically selecting a P picture 71 closest to the frame 70 selected by the user as shown in FIG.

(Third Embodiment) Next, as a third embodiment of the present invention, another mode of frame selection will be described with reference to FIGS.

FIG. 8 is a block diagram showing a configuration of a portion related to frame selection in the present embodiment. In this embodiment, the configurations of a decoder circuit 81 and a decoder control circuit 83 are slightly different from those of the first embodiment, and an average quantization scale calculation circuit 82 is further added. The decoder circuit 81 outputs quantization scale information 84 indicating a quantization scale in macroblock units and a frame synchronization signal 85, and an average quantization scale calculation circuit 82 calculates an average quantization scale for each frame. The decoder control circuit 83 automatically selects a frame using the calculated average quantization scale as an evaluation value.

FIG. 9 is a diagram showing a specific example of the automatic frame selection. Reference numeral 91 denotes an example of the value of the average quantization scale of each frame calculated in a frame near the frame 95 specified by the user. ing. In this example, the value of the average quantization scale itself calculated as the evaluation value can be used, and in that case, the frame 95 is detected as the frame with the highest image quality.

When emphasis is placed on the resolution in the time direction, that is, when there is a request to select a high-quality frame with an image closer to the frame specified by the user, the calculated average quantization scale 91 is used. , A weighted average quantization scale 93 multiplied by a weight function 92 corresponding to a frame interval from the frame designated by the user is calculated, and the value of the calculated weighted average quantization scale 93 is used as an evaluation value. The lowest cost frame 9
4 is a selected frame.

(Fourth Embodiment) Next, FIGS.
A fourth embodiment of the present invention will be described with reference to FIG. In the embodiments described above, the image signal of the frame with the highest image quality is selected as a still image output from a plurality of frames including a frame specified by the user and frames in the vicinity thereof. On the other hand, in the present embodiment, the designation by the user is divided into two stages. First, a frame group including the frame designated by the user and its neighboring frames in the first stage is output as a still image output candidate frame. Finally, a frame specified by the user in the second stage is selected as a still image output from the candidate frames.

FIG. 10 is a flowchart showing the procedure for selecting a frame in the present embodiment. FIG. 11 shows an example of a GUI (graphical user interface) used when the user selects from candidate frames for still image output. I have.

First, a specific frame desired as a still image output in a moving image is designated by the user using a time code or a special reproduction function (jog and shuttle reproduction, pause, etc.) (step S101). Then, a still image signal of a candidate frame which is a frame group including the designated frame and its neighboring frames is decoded (step S102).

Next, the evaluation value of the image quality of the image of the candidate frame is calculated (step S103), and the image of the candidate frame 112 is reduced and displayed in a list (step S103).
104). At this time, the time 113 and the image quality (evaluation value) 114 of the image of each candidate frame 112 are also displayed. The candidate frames are displayed in the order of time or image quality set by the sort 115. FIG. 11 shows an example in which candidate frames are sorted and displayed in image quality order.
Further, it is also possible to switch one of the candidate frames to the full size display of a specific frame according to the user's specification.

Next, the user operates the next candidate 116 and the previous candidate 117 as appropriate to select a candidate frame (step S106), and finally decides a frame from which a still image is to be output. (Step S1
07), the still image signal of the determined frame is output after the output signal format is appropriately converted by the still image output unit 23 (step S108).

(Fifth Embodiment) Next, FIGS.
A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the still image output unit 23 in FIG. 1 determines whether the frame selected as the still image output is an interlaced scan image or a non-interlaced scan image. Either one of the odd fields is output as a still image signal, or the image signals of both the even and odd fields are output as a still image signal.

FIG. 12 is a block diagram showing a configuration of a main part according to this embodiment. In the present embodiment, the configurations of the decoder circuit 121 and the decoder control circuit 123 are slightly different from those of the first embodiment.
22 have been added. Display form determination / conversion circuit 122
Are included in the still image output unit 23 in FIG.

As shown in FIG. 13A, when a moving image including an object moving in the horizontal direction in time is viewed as a still image having a frame structure, each frame is an interlaced scan image ( The quality differs greatly between b) and the case of non-interlaced scanning image (c). That is, in a non-interlaced scanning image, a still image having a high vertical resolution and no disturbance is obtained, whereas in an interlaced scanning image, the time between fields is different.
The difference in time for each line has an adverse effect and does not result in a good still image.

On the other hand, when an image having no motion is viewed as a still image having a frame structure, both interlaced scanning and non-interlaced scanning are images with high vertical resolution and no disturbance. Therefore, when a still image is output, a non-interlaced scanning image always outputs a frame-structured image signal, and an interlaced scanning image has a field-structured image signal when there is motion, and a frame-structured image signal when there is no motion. It is considered that it is optimal to output the respective image signals.

Therefore, in the present embodiment, whether the display mode / judgment conversion circuit 122 should output and display the optimum display mode of a still image, that is, an image signal having a frame configuration as a still image signal (this is called frame display) ) Or to output and display an image signal having a field configuration (this is referred to as field display). Then, in the case of frame display, an image signal of a frame configuration is output, and in the case of field display, even or odd lines are output twice and output as still image signals, or An image signal having a frame configuration is reconstructed by adding a correction according to the amount of motion for each region, and is output as a still image signal.

That is, when the image selected as a still image by the decoder control circuit 123 is a non-interlaced scanning image, it is determined to be a frame display, and an image signal having a frame configuration is output as a still image signal.

On the other hand, when the image selected as a still image by the decoder control circuit 123 is an interlaced image, if there is motion in the image, it is determined to be a field display, and the image signal having the field configuration (even and odd fields) is displayed. An image signal of only one of the fields) is output as a still image signal. However, in the case of an image having no motion, it is determined that a frame is displayed, and an image signal having a frame configuration is output as a still image signal. By doing so, it is possible to output a still image with high vertical resolution and no disturbance due to interlaced scanning.

Here, for the determination of the field / frame display mode in the display mode / judgment conversion circuit 122, for example, scanning information of the original image included in the encoded data can be used. Specifically, when all frames are non-interlaced scanned images in the MPEG-2 encoding method, of the syntax elements shown in FIGS. 14 and 15, progressive-sequence in sequence-extension () is used.
The interlace scan image / non-interlace scan image can be determined by the quence flag. The determination of whether the image of each frame is an interlaced scanning image or a non-interlaced scanning image is made by picture-coding-extensio
This is possible with the progressive-frame flag in n ().

FIG. 16 shows another example of the configuration of the field display / frame display mode determination circuit in this embodiment.
In the figure, 130 indicates a frame image, 131 indicates pixels in an even field, and 132 indicates pixels in an odd field. The first adder 133 calculates the correlation between the lines in the same field, that is, the sum of the correlation between the lines in the even field and the correlation between the lines in the odd field. The second adder 134 calculates a correlation between lines in the same frame. The comparator 135 compares the intra-field correlation calculated by the first adder 133 with the intra-frame correlation calculated by the second adder 134. As a result of the comparison, when the intra-frame correlation exceeds the intra-field correlation, the display is automatically switched to the frame display, otherwise, the display is automatically switched to the field display, so that the optimal display mode can be automatically set.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIG. In the MPEG-2 encoding system, a frame rate conversion is generally performed using a method called 3: 2 pull-down so that a movie having a frame rate of 24 Hz can be displayed on a display having a field rate of 60 Hz. FIG. 17 is an explanatory diagram of this frame rate conversion.

In FIG. 17, reference numerals 140 to 144 denote continuous frames having a frame rate of 24 Hz. Encoding and decoding are performed in units of frames. On the other hand, at the time of display after decoding, the decoded frames are displayed by alternately changing the display time between the three-field period and the two-field period, thereby enabling display at a display with a field rate of 60 Hz. That is, in this case, the frame rate of the encoded frame is 24 Hz,
The frame rate of the display frame is different from 60 Hz.

In the three-field display and the two-field display, the decoded image of each frame is interlaced and divided into even lines and odd lines, and these are selected and output in accordance with the phase of the display field. .
In the case of the three-field period display, the same image signal is displayed in the first field and the third field. Therefore, in the display frame, a frame affected by the interlaced scanning and a frame not affected by the interlaced scanning are mixed.

For example, in FIG.
Since the display frame composed of the display frames 50 and 151 is composed of the same encoded frame 140, the image is not disturbed by the interlaced scanning. Two encoded frames 140 and 1
Since it is composed of 41, disturbance due to interlaced scanning occurs, and it is difficult to output a still image in a frame form when there is motion.

Therefore, in the present embodiment, the still image output is not composed of the display fields 150 to 162 but is selected and output from the coded frames 140 to 144. Still image output without the influence of interlaced scanning is enabled.

[0064]

As described above, according to the present invention, a moving picture signal composed of a plurality of types of frames having different image qualities is decoded from the coded moving picture data to reproduce the moving picture, and if necessary, the still picture is reproduced. In the image reproducing device that outputs the image, in the vicinity of the frame specified by the user in the moving image signal,
By selecting the frame with the highest image quality and outputting it as a still image signal, it becomes possible to reproduce a high-quality still image with almost the same scene and the same image quality as the frame specified by the user.

Further, a frame group including the frame designated in the first stage and its neighboring frames is selected and presented to the user, and the frame designated in the second stage is selected from the frame group to obtain a still image signal. By outputting a frame, even if there is a scene change in the vicinity of the frame specified by the user and a frame contrary to the user's intention is automatically selected, the frame intended by the user is eventually efficiently It can be selected and reproduced as a still image.

Further, it is determined whether the selected frame is a non-interlaced scanned image or an interlaced scanned image. If the selected frame is a non-interlaced scanned image, the image signal of the frame is output as a still image signal, and the interlaced scanned image is output. In the case of outputting only one of the even field and the odd field as a still image signal, or outputting both the even field and the odd field image signal as a still image signal,
Disturbance of a frame image generated when an interlaced scan is performed on a moving image is prevented, and a still image with a high vertical resolution can be reproduced in an interlaced image or a non-interlaced image without a moving image.

In the case where the encoded video data is encoded at different frame rates for the display frame and the encoded frame, it is necessary to select a frame for each encoded frame and output it as a still image signal. Thus, a still image can always be output as a non-interlaced scan image, and a high-definition still image with a high vertical resolution can be output.

Further, according to the present invention, the function of converting the output format by software processing when generating a still image signal is added, so that the software can be changed according to the format of the output device for printing or displaying the still image. It is possible to easily change the output signal format of a still image only by using the above.

[Brief description of the drawings]

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

FIG. 2 is a view for explaining the syntax structure of the MPEG-2 encoding method;

FIG. 3 is a diagram showing an example of image quality fluctuation in a frame unit in the MPEG-2 encoding method.

FIG. 4 is an exemplary view for explaining an outline of automatic frame selection according to the embodiment;

FIG. 5 is a block diagram showing the configuration of a still image output unit according to the embodiment;

FIG. 6 is a view for explaining a frame selection method according to a second embodiment of the present invention;

FIG. 7 is a diagram for explaining another frame selection method according to the second embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a main part according to a third embodiment of the present invention.

FIG. 9 is an exemplary view for explaining a frame selection method according to the embodiment;

FIG. 10 is a flowchart showing a frame selection procedure according to a fourth embodiment of the present invention.

FIG. 11 is an exemplary view showing an example of a GUI (graphical user interface) in the embodiment.

FIG. 12 is a block diagram showing a configuration of a main part according to a fifth embodiment of the present invention.

FIG. 13 is a diagram showing an example of disturbance of a frame image due to interlaced scanning.

FIG. 14 is a diagram showing a part of a sequence header in the MPEG-2 encoding method;

FIG. 15 is a diagram showing a part of a picture header in the MPEG-2 encoding method;

FIG. 16 is a block diagram showing a configuration of a main part according to a sixth embodiment of the present invention.

FIG. 17 is a diagram illustrating an example of frame rate conversion for explaining a seventh embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Optical disk drive part 11 ... Optical disk 12 ... Optical pickup 13 ... Optical disk drive control circuit 14 ... Error correction circuit 20 ... Decoding part 21 ... Decoder circuit 22 ... Moving image output part 23 ... Still image output part 30 ... Decode control part 31 ... Decoder control circuit 32 User interface 51 CPU 52 Still image memory 53 Instruction memory 54 Program interface 55 Still image output interface 56 Bus 81 Decoder circuit 82 Average quantization scale calculation circuit 83 Decoder control circuit 121 ... Decoder circuit 122 ... Display form determination / conversion circuit 123 ... Decoder control circuit 130 ... Frame image 131 ... Even field line pixel 132 ... Odd field line pixel 133 ... Field correlation calculation circuit 134 ... Frame correlation calculation circuit 135 ... Comparator

Claims (8)

[Claims] 1. A moving picture decoding means for decoding a moving picture signal composed of a plurality of types of frames having different image qualities from moving picture coded data, a moving picture output means for outputting the moving picture signal, and the moving picture signal A frame selecting means for selecting a frame with the highest image quality from a plurality of frames including a designated frame and a frame in the vicinity thereof; and a still image signal for converting the image signal of the frame selected by the frame selecting means from the moving image signals An image reproducing apparatus, comprising: a still image output unit that outputs a still image. 2. A moving picture decoding means for decoding a moving picture signal composed of a plurality of types of frames having different image qualities from moving picture encoded data, a moving picture output means for outputting the moving picture signal, and the moving picture signal. Frame group selecting means for selecting a frame group including the frame specified in the first stage and its neighboring frames; and a frame for outputting an image signal of the frame group selected by the frame group selecting means among the moving image signals Group output means, frame selection means for selecting a frame specified in the second stage from the frame group, and outputting, as a still image signal, an image signal of a frame selected by the frame selection means among the moving image signals An image reproducing apparatus comprising: a still image output unit. 3. The method according to claim 1, wherein said frame selecting means selects one of a plurality of frames including the designated frame and its neighboring frames, an intra-coded frame, a forward predicted coded frame, and a bidirectional predicted coded frame. 3. The image reproducing apparatus according to claim 1, wherein a frame is selected according to the priority of the frame. 4. The frame selecting means calculates an intra-frame average quantization scale of a plurality of frames including the designated frame and its neighboring frames, and determines a frame having the smallest average intra-frame quantization scale. 3. The method according to claim 1, wherein the selection is made from a plurality of frames.
An image reproducing device according to claim 1. 5. The frame selecting means calculates an intra-frame average quantization scale of a plurality of frames including the specified frame and its neighboring frames, and calculates the specified intra-frame average quantization scale with respect to the specified frame. Weighting with a weighting function that decreases in accordance with a time interval from the weighted frame, and selecting a frame having the smallest average quantization scale in the frame after the weighting from the plurality of frames. Item 3. The image reproducing device according to item 1 or 2. 6. The video coded data is coded at different frame rates for a display frame and a coded frame, and the frame selecting means selects a frame in units of the coded frame. The image reproducing device according to claim 1. 7. The image reproducing apparatus according to claim 1, wherein said still image output means has means for converting an output format of said still image signal. 8. The still image output means determines whether the frame selected by the frame selection means is a non-interlaced scanning image or an interlaced scanning image. If the frame is a non-interlaced scanning image, the image signal of the frame is determined. Is output as a still image signal, and in the case of an interlaced scanning image, only the image signal of one of the even field and the odd field is output as the still image signal, or the image signal of both the even field and the odd field 8. The image reproducing apparatus according to claim 1, wherein the image reproducing apparatus outputs the image as a still image signal.