JP2004032407A - Moving image recording and reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moving image recording and reproducing apparatus which enables a user to recognize that a recorded moving image cannot be correctly reproduced when recording an image having a large change in motion. <P>SOLUTION: The moving image recording and reproducing apparatus includes an amount-of-change-in-motion judging unit. When a lack of information increases when recording the image having a large amount of change in motion and it is decided that the recorded image cannot be correctly reproduced, an alarm for informing a user that the recorded moving image cannot be correctly reproduced is displayed on a display unit. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a moving image recording / reproducing apparatus, and more particularly to a moving image recording / reproducing apparatus which, when it is determined that an image recorded during recording of a moving image cannot be reproduced correctly, displays a warning to that effect.
[0002]
[Prior art]
2. Description of the Related Art Generally, with the international standardization of image coding methods, improvements in moving image coding technology have been activated. One of the international standardizations is an MPEG system (Moving Picture Expert Group).
[0003]
In the MPEG system, motion compensation is performed to reduce the redundancy in the time axis direction, an image difference is obtained, and then, in order to reduce the redundancy in the spatial axis direction, DCT (discrete cosine transform), which is a type of orthogonal transform, is performed. ) And variable length coding. As for the reduction of the redundancy in the time axis direction, a property that a continuous moving image has a high correlation between frames before and after or between fields is used.
[0004]
That is, a motion vector is detected for each block between an image to be coded (current image) and an image that is temporally before and after, and motion prediction is performed to predict the current image. Is calculated. Here, each picture constituting the moving picture is of three types: I picture (frame or intra-coded picture), P picture (forward predicted picture), and B picture (forward, backward, bidirectional predicted picture). And then encoded. On the other hand, with regard to the redundancy in the spatial axis direction, the prediction error signal of each image is quantized on DCT coefficients in block units, and then variable length coding is performed.
[0005]
Japanese Patent Application Laid-Open No. H11-298890 discloses a method in which a frame rate is changed in accordance with the magnitude of a change in motion so that an image having a large change in motion does not deteriorate in image quality. Have been.
[0006]
[Problems to be solved by the invention]
However, in the above-described method, when recording an image having a large change in motion, the motion vector for each block between the current image and the image that is temporally preceding and succeeding becomes too large, and encoding is performed at a low bit rate. When recording is performed, information is often lost, and when reproduced, the image becomes a blurred mosaic-like image as a whole, and the recorded image may not be correctly reproduced.
[0007]
In the technique described in Japanese Patent Application Laid-Open No. H11-298890, an image having a large amount of data per frame and having a large change in motion is controlled to increase the frame rate. There is a problem that the bit rate temporarily becomes too high, and reading and writing to a recording medium cannot be performed in real time.
[0008]
The present invention has been made in view of the above-described problems of the related art, and an object of the present invention is to prevent a recorded moving image from being correctly reproduced during recording of an image having a large change in motion. Is to provide a moving image recording / reproducing apparatus that allows a user to recognize the following.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a moving image recording / reproducing apparatus according to the present invention includes a motion change amount determination unit that determines a change amount of a motion. If it is determined that the recorded image cannot be reproduced correctly, a warning is displayed on the display unit informing that the recorded moving image cannot be reproduced correctly. In addition, a recording method selection unit is provided for selecting whether to perform recording at a reduced frame rate when it is determined that reproduction cannot be performed correctly.
[0010]
Further, an NG flag is recorded in a frame determined to be unable to be correctly reproduced.
[0011]
Further, a default setting storage unit for setting a default value (initial setting value) as a threshold value of the motion change amount used in the motion change amount determination unit, and a threshold value of the motion change amount used by the motion change amount determination unit are set by the user. And a switching means for switching whether to use the data of the default setting storage unit or the data of the change amount setting unit as the threshold value of the movement change amount.
[0012]
Furthermore, when the NG flag is detected during the reproduction of the moving image, a warning is displayed on the display unit informing that the moving image cannot be reproduced correctly, as in the recording.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing a configuration of a moving image recording and reproducing apparatus according to one embodiment of the present invention. As shown in FIG. 1, a moving image recording / reproducing apparatus according to the present embodiment includes an image input unit 101 including a CCD, an AGC circuit, etc., a signal processing unit 102 for generating Y, U, V signals, and a control for controlling the entire system. Unit 103, a DMA (Direct Memory Access) controller 104, a memory 105, an image compression / expansion unit 106, a recording / reading unit 107 for recording and reading compressed data on a medium (recording medium), a recording medium 108, a display unit interface 109, and a display (Display unit) 110, a movement change amount determination unit 111, a change amount setting unit 112, a default setting storage unit 113, a changeover switch 114, and a recording method selection unit 115.
[0015]
First, the operation before photographing will be described with reference to the flowchart of FIG. Using the changeover switch 114 in advance, it is determined whether the user sets the threshold value of the amount of change in the motion for giving a warning display indicating that the reproduction cannot be correctly performed during the reproduction or uses a default value (an initial setting value prepared in advance by the device itself). Select (step S11). When set by the user, a threshold value for the amount of change in movement is set via the change amount setting unit 112. When a default value (initial setting value) is used, the value in the default setting storage unit 113 is used as a threshold value of the amount of change in motion. Further, when it is determined via the recording method selection unit 115 that the image cannot be correctly reproduced at the time of reproduction, recording is performed at a reduced frame rate (hereinafter, referred to as an image quality priority mode), or a mosaic-like image is reproduced without decreasing the frame rate. Whether to record (hereinafter, referred to as frame rate priority mode) is selected (step S11). When the image quality priority mode is selected in step S11, if the change in the motion is large and the amount of change in the motion exceeds the threshold, a mode in which the frame rate is reduced and the image is recorded (image quality priority mode) is set. When the frame rate priority mode is selected in S11, a mode (frame rate priority mode) for recording without lowering the frame rate is selected even when the change in the motion is large and the amount of change in the motion exceeds the threshold. In both the image quality priority mode and the frame rate priority mode, when the change amount of the motion exceeds the threshold value, a warning indicating that the reproduction cannot be performed properly is displayed and an NG flag is recorded. You.
[0016]
Next, an actual photographing operation will be described. First, an optical signal of a photographed subject is input to an image input unit 101, photoelectrically converted to an analog video signal, subjected to processing such as AGC, and output to a signal processing unit 102. The video signal input to the signal processing unit 102 is A / D converted and converted into a digital signal, and is also subjected to processing such as gamma correction, filtering, and edge enhancement processing, and Y (luminance), U (red color difference) ), V (blue color difference) signal is generated. Then, the control unit 103 stores the Y, U, and V signals generated based on the program in the memory 105.
[0017]
Next, the stored digital video signal is read out to the image compression / decompression unit 106 via the DMA controller 104 and subjected to compression processing. The compressed data is temporarily stored in the memory 105, added with header information according to a predetermined format by the control unit 103, and then recorded on the recording medium 108 via the recording and reading unit 107.
[0018]
In the case of recording a moving image for a long time, compression is performed several times and recorded as one file when recording on a recording medium. Therefore, the header recording the photographing start time is attached only at the first compression when recording is started.
[0019]
Here, determination of the amount of change in motion will be described. Usually, a motion vector is obtained for each macroblock of a 16 × 16 image. An image of QVGA (Quarter Video Graphics Array; 320 × 240 pixels) is composed of 300 macroblocks. For example, when the threshold value of the amount of change in motion is set to 10 or 200 macroblocks in which the size of the motion vector (half pixel unit) is 10, 200 or more macroblocks in which the size of the motion vector is 10 or more Then, it is determined that the amount of change in the motion is large. That is, when the above condition is satisfied, a warning is displayed on the display 110, and at the same time, the NG flag is recorded in the corresponding frame.
[0020]
Next, the operation when the amount of change in the movement becomes large will be described with reference to the flowchart of FIG. The operation until the compression processing is performed is the same as the conventional one. The stored digital video signal is read out to the image compression / decompression unit 106 via the DMA controller 104 and subjected to a compression process. At this time, it is determined whether or not the currently processed image is an I picture (step S21). If it is an I picture, the process proceeds to step S30, and if it is not an I picture, the process proceeds to step S22.
[0021]
In step S22, the change amount A of the movement between the immediately preceding image and the currently processed image and the threshold value B of the change amount of the movement are sent to the movement change amount determination unit 111, and the process proceeds to step S23. In step S23, it is determined whether or not the change amount A of the movement exceeds the threshold value B. If A> B, the process proceeds to step S24. If not, the process proceeds to step S29. In step S24, a warning signal indicating that the movement change amount A has exceeded the threshold is sent from the movement change amount determination unit 111 to the control unit 103, and the process proceeds to step S25. In step S25, the control unit 103 that has recognized the warning signal performs a warning display on the display 110 via the display unit interface 109, such as "The motion is too intense and the recorded image cannot be correctly reproduced." move on. In step S26, it is determined whether the image quality priority mode is set or the frame rate priority mode is set. If the frame rate priority mode is set, the process proceeds to step S27, where the image quality priority mode is set. If is set, the process proceeds to step S28.
[0022]
In step S27, an NG flag is set in the user data portion of the currently processed image in the visual layer, and the flow advances to step S29. In step S29, the currently compressed image (P or B picture image) is temporarily stored in the memory 105, and then stored in the recording medium.
[0023]
In step S28, the processing of the next image is performed without recording the currently processed image (P or B picture).
[0024]
In step S30, which proceeds when the picture is an I picture, if a warning is being displayed, an NG flag is set, and the image of the currently compressed I picture is recorded on the recording medium 108. If it is not in the middle, the currently compressed I-picture image is recorded on the recording medium 108 as it is.
[0025]
As described above, in the present embodiment, when the image quality priority mode is set, the amount of information per frame is increased by recording only the I picture, and the frame rate is reduced. Record beautiful images. At this time, a warning is displayed, and an NG flag is set when the I picture is recorded. On the other hand, when the frame rate priority mode is set, a mosaic image is recorded at a constant frame rate by recording all compressed frame data. At this time, a warning is displayed and the NG flag is set when all the pictures are recorded. If A> B is not satisfied, the normal recording operation is continued.
[0026]
Next, the reproducing operation will be described. One moving image file recorded on the recording medium 108 is read by the recording / reading unit 107 and stored in the memory 105 via the DMA controller 104. Next, the header information is read from the memory 105 to the control unit 103, and the recorded shooting start time is read. The image data written in the memory 105 is sent from the memory 105 to the image compression / decompression unit 106 via the DMA controller 104, decompressed, and stored in the memory 105 again. Next, the decompressed data from the memory 105 is sent to the display 110 via the DMA controller 104 and the display interface 109 and displayed.
[0027]
Next, the operation at the time of reproduction when the NG flag is detected will be described with reference to the flowchart of FIG. The operation until the decompression processing is performed is the same as the conventional one. The image data written in the memory 105 is sent from the memory 105 to the image compression / decompression unit 106 via the DMA controller 104, decompressed, and stored in the memory 105 again (step S41). At this time, the control unit 103 monitors whether or not an NG flag is recorded in the user data portion of the picture layer of the currently processed image (step S42). A warning is displayed on the display 110 as in the case of recording (step S43). Also in this case, the image reproducing operation is constantly performed.
[0028]
In the above-described embodiment, the threshold value of the amount of change in motion for performing a warning display notifying that reproduction cannot be performed properly during reproduction is always set, and one of the image quality priority mode and the frame rate priority mode is set. Although the alternative is selected, no threshold is set for judging the amount of change in the motion, no warning is displayed even if an image with a lot of motion is recorded, and the NG flag is not recorded. A similar recording mode may be added to the image quality priority mode and the frame rate priority mode.
[0029]
【The invention's effect】
As described above, according to the present invention, when it is determined that a recorded image cannot be correctly reproduced, a warning display is displayed to inform the user that the recorded image cannot be correctly reproduced. It is possible to realize a moving image recording / reproducing apparatus that does not know that there is no video.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a moving image recording / reproducing apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a processing flow before photographing in the moving image recording / reproducing apparatus according to one embodiment of the present invention.
FIG. 3 is a flowchart showing a processing flow when the amount of change in motion is large in the moving picture recording and reproducing apparatus according to one embodiment of the present invention.
FIG. 4 is a flowchart showing a processing flow when an NG flag is detected during reproduction in the moving image recording / reproducing apparatus according to an embodiment of the present invention.
[Explanation of symbols]
101 image input unit 102 signal processing unit 103 control unit 104 DMA controller 105 memory 106 image compression / decompression unit 107 recording / reading unit 108 recording medium 109 display unit interface 110 display 111 motion change amount determination unit 112 change amount setting unit 113 default setting storage unit 114 Changeover switch 115 Recording method selection unit

Claims (3)

A motion change amount determination unit that determines the amount of change in motion is provided.During recording of an image with a large change in motion, the number of missing information increases, and when it is determined that the recorded image cannot be correctly reproduced, the recorded moving image is A moving image recording / reproducing apparatus, comprising: a warning that informs that reproduction cannot be correctly performed is displayed on a display unit; and a recording method selecting unit that selects whether to record at a reduced frame rate is provided. The moving image recording / reproducing apparatus according to claim 1,
A default setting storage unit for setting a default value as a threshold value of the motion change amount used in the motion change amount determination unit, and a change amount for the user to arbitrarily set the threshold value of the motion change amount used in the motion change amount determination unit A moving image recording / reproducing apparatus, comprising: a setting unit; and a switching unit that switches between using data of a default setting storage unit and using data of a change amount setting unit as a threshold value of a change amount of motion. The moving image recording / reproducing apparatus according to claim 1,
When an NG flag is recorded in a frame determined to be unable to be correctly reproduced, and when an NG flag is detected during reproduction of a moving image, a warning notifying that the moving image cannot be reproduced correctly is displayed on the display unit as in recording. A moving image recording / reproducing apparatus characterized by the above-mentioned.

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