JP2009105551A - Video data recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video data recording device capable of reducing a sense of visual incompatibility generated owing to switching of multi-angle video. <P>SOLUTION: A video data recording device is configured to horizontally reduce angle-A video and angle-B video, to synthesize them into one picture, and to record the picture, and further configured to gradually vary the number of horizontal pixels in prescribed picture units and to gradually vary a gain level for video data having a smaller number of horizontal pixels when starting recording the synthesized video data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video data recording apparatus for recording a plurality of video data on a recording medium.

  2. Description of the Related Art In recent years, mobile phones and the like have been introduced with two imaging units, an imaging unit for front shooting and an imaging unit for face-to-face shooting. By using such a mobile phone, an application for simultaneously recording two different video data can be considered. For example, it is expected that a portable video data recording device capable of easily recording a multi-angle video in real time will appear.

  In general, when recording multi-angle video, video data shot at a plurality of angles are individually recorded. For example, it is assumed that two front and rear video images are taken. When encoding such two-angle video and recording it in real time, two encoding units are required and the amount of information to be recorded is doubled compared to one angle.

As a stereoscopic video recording method, a method of recording a plurality of input video signals by compressing them in the horizontal direction has already been proposed (for example, see Patent Document 1). By applying such a method, the amount of data when recording a multi-angle video can be reduced.
JP 63-38386 A

  However, with the above-described conventional technology, it has been impossible to appropriately adjust the image quality and the like of a video recorded as a multi-angle video.

  In general, when playing back video content recorded as multi-angle video, normally one angle video is played back continuously unless the viewer switches the angle. In addition, when the multi-angle recording unit is intermittently present in the scene, the image quality changes suddenly at the time of switching between single-angle video recording and multi-angle video recording, which may give the viewer a sense of discomfort.

  Therefore, it is conceivable to always record with a fixed horizontal resolution in accordance with multi-angle video recording even when single-angle video is recorded. However, deterioration of image quality during single-angle video recording is inevitable.

  In consideration of such problems, the present invention provides a video data recording apparatus that can reduce the occurrence of visual discomfort by switching to multi-angle video with an easy configuration and without extremely increasing the amount of data. For the purpose.

  In order to achieve the above object, a video data recording apparatus according to the present invention is a video data recording apparatus that synthesizes a plurality of videos into one video data and records the first video data and the first video data that are input. Setting means for setting the number of horizontal pixels for each of the two video data, and the first video data and the second video data in the horizontal direction according to the number of horizontal pixels set by the setting means, respectively. Reduction means for reducing, recording means for recording on the recording medium video data obtained by combining the first video data and the second video data reduced in the horizontal direction by the reduction means, and the first video data or the Adjusting means for adjusting the gain level of the luminance information of the second video data, and when the recording means starts recording the synthesized video data, the setting means is a predetermined screen unit. In the gradually changing the number of horizontal pixels, the adjusting means it is characterized by gradually changing the gain level for the video data of more small number of horizontal pixels.

  According to the present invention, it is possible to record video data with an easy configuration and capable of reducing the occurrence of visual discomfort by switching to a multi-angle video without extremely increasing the amount of data.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a video data recording apparatus (for example, a digital video camera or a mobile terminal with a camera) according to an embodiment of the present invention. In the block diagram of FIG. 1, an operation unit 101 is an operation unit for the video data recording apparatus, and a CPU 102 (control unit) is a control unit (controller) for the video data recording apparatus. Based on a signal transmitted from the operation unit 101 in response to a user operation, the CPU 102 controls each unit constituting the video data recording apparatus. The operation unit 101 includes menu buttons for performing various settings in addition to operation keys for instructing recording, reproduction, and the like.

  An imaging system A103 as a first imaging means includes a lens optical system including an optical lens, a diaphragm, a focus control unit, and a lens driving unit, and a CCD image sensor or CMOS that converts optical information from the lens optical system into an electrical signal. It consists of an imaging unit such as a sensor. The imaging system B104 as the second imaging means has the same configuration as the imaging system A103. From the imaging system A103 and the imaging system B104, a plurality of video data (first video data and second video data) obtained by imaging the subject are output.

  In the video data recording apparatus of this embodiment, the imaging system A103 and the imaging system B104 are installed in the main body so as to capture different directions. For example, the imaging system A103 is arranged at a position for front photographing, and the imaging system B104 is arranged at a position for rear photographing for the purpose of face-to-face photography.

  The video signal processing unit 105 converts video data supplied from the imaging system A 103 and / or the imaging system B 104 into video data having a screen resolution defined by the recording format. Further, the video signal processing unit 105 can perform a scaling process in the horizontal direction on the video signal supplied from the imaging system A 103 or the imaging system B 104 during recording. Specifically, as shown in FIG. 2A, the horizontal resolution of a plurality of video signals supplied from the imaging system A103 and the imaging system B104 can be individually converted (reduced) and synthesized as a recorded image on one screen. Is possible. On the other hand, the image converted as shown in FIG. 2A is designated from the reproduced image supplied from the encoding / decoding processing unit 108 as shown in FIG. 2B by the video signal processing unit 105 during reproduction. A horizontal pixel is arbitrarily cut out, enlarged in the horizontal direction, and each is output as a playback image of one screen. Furthermore, the video signal processing unit 105 incorporates an OSD (on screen display) processing unit that can superimpose arbitrary character information or graphic information on video data. The OSD processing unit can multiplex characters and graphics with video data output to the digital-analog conversion (D / A) unit 106 and the display unit 107. The D / A unit 106 outputs a photographed video or a reproduced video to the outside.

  The encoding / decoding processing unit 108 compresses and encodes the video data input from the video signal processing unit 105 during recording, and supplies the encoded data to the recording / reproduction processing unit 109. On the other hand, at the time of reproduction, the encoded data input from the recording / reproduction processing unit 109 is decoded and supplied to the video signal processing unit 105 as a reproduction image. Here, it is assumed that the recorded image size is horizontal 720 pixels and vertical 480 lines, and the encoding method supported by the encoding / decoding processing unit 108 is MPEG-2 (Moving Picture Expert Group-2).

  The recording / playback processing unit 109 adds an error correction code to the encoded data input from the encoding / decoding processing unit 108 and records the recording data on the recording medium 110 together with the system information set by the CPU 102 Includes a processing unit. Further, the recording / reproduction processing unit 109 reads the recording data from the recording medium 110, performs error correction processing on the read reproduction data, and supplies the encoded data to the encoding / decoding processing unit 108. It is comprised including. The recording medium 110 is a hard disk, an optical disk, a semiconductor memory, or the like.

  Next, while the video data recording apparatus of FIG. 1 is recording video data input from the imaging system A103 for forward shooting, the video data input from the imaging system B104 for backward shooting (face-to-face shooting) is recorded as video. A procedure for combining and recording simultaneously on one screen by the signal processing unit 105 will be described. The same applies to the case where the image of the imaging system A103 is simultaneously recorded during recording by the imaging system B104. In the following, the video imaged by the imaging system A (or imaging system B) that started recording first is “angle A video”, and the video imaged by the imaging system B (or imaging system A) that starts recording later. Will be described as “Angle B video”.

  FIG. 3 is a diagram showing the transition of the number of horizontal pixels when recording of the angle B video is started during recording of the angle A video, that is, in the multi-angle video recording referred to in the present embodiment. In FIG. 3, when the recording of the angle B video is started, the horizontal pixel count of the angle B video starts from, for example, 32 pixels, and the horizontal pixel count is specified by the specified number of screens (frame unit). Will be increased. Eventually, it changes to 360 pixels, which is half the number of horizontal pixels of one screen of the recorded image. At the same time, the horizontal resolution of the angle A image starts from the number of pixels (720−32 = 688 pixels) obtained by subtracting the number of horizontal pixels of the angle B image from 720 pixels which is the number of horizontal pixels of the recorded image at the time of recording the single angle image. The number of horizontal pixels is reduced by the designated number of pixels in the designated frame unit. Then, the transition is made to 360 pixels, which is the number of horizontal pixels which is half of one screen. In this way, for each of the angle A video and the angle B video, video data obtained by converting the horizontal resolution with a ratio of the number of pixels that differ with time is combined and recorded on one screen.

  In addition, with respect to the angle B video, the luminance information is gained in units of designated frames from the start of recording, and the video is gradually shifted to the original luminance level. FIG. 3 shows an image in which the gain level starts from 1 or less (for example, gain = 0) and transitions to the gain level = 1, which is the luminance level of the original video, in the designated step. It is also possible to start and transition to gain level = 1.

  Next, FIG. 4 is a diagram showing the transition of the number of horizontal pixels when the recording of the angle B video is stopped during the recording of the angle A video and the angle B video, that is, when the multi-angle video recording is stopped. Here, the multi-angle video recording stop means that a single-angle video recording state has been reached. Since the number of horizontal pixels of the angle A video until the recording stop of the angle B video is 360 pixels, the horizontal resolution is increased by the designated number of pixels in the designated frame unit, and 720 which is the number of horizontal pixels of one screen of the recorded image. Transition to a pixel. At this time, an area of less than 720 pixels during the transition of the number of horizontal pixels shows an image in which black level pixels are inserted in FIG. 4, but arbitrary fixed data can also be inserted.

  Here, in an encoding method that performs DCT (Discrete Cosine Transfer) processing like MPEG-2, DCT processing is performed in units of blocks of 8 × 8 pixels, for example. Therefore, as described above, regarding the number of designated pixels when changing in units of designated frames, the number of pixels in the horizontal direction may be set to n times (e.g., 8, 16, 32 pixels) of 8 pixels, which is the unit of the DCT block. . That is, by preventing the boundary portion between the angle A image and the angle B image from entering the DCT block, it is possible to reduce the coding distortion at the boundary portion between the angle A image and the angle B image.

  FIG. 5 is a diagram showing timing for adjusting the number of horizontal pixels. In MPEG-2, inter-frame compression is performed. When a GOP (Group Of Pictures) is composed of 15 frames as shown in FIG. 5, the number of horizontal pixels and the gain adjustment of the luminance signal are adjusted in units of 15 frames in accordance with the encoding timing of the I picture as a reference image. Good to do. By doing so, it is possible to reduce image quality degradation due to encoding.

  The video data recording apparatus of this embodiment records multi-angle video in association with recording data when performing so-called multi-angle recording such as recording angle B video while recording angle A video. The multi-angle recording information shown is recorded simultaneously. FIG. 6 is a diagram showing an example of multi-angle recording information. As shown in FIG. 6, the multi-angle recording information includes a multi-angle flag (MAF) indicating a multi-angle recording state, information on the number of horizontal pixels (AH) of angle A video, and the number of horizontal pixels (BH) of angle B video. ) Information. If the MAF bit is “0”, single angle recording is indicated. If “1”, the angle A video and the angle B video are combined and recorded. Further, when the MAF bit is “2”, it indicates that single angle recording is performed, but the angle A video is recorded in a state of being reduced in the horizontal direction. That is, this indicates that the angle B video recording is stopped during the multi-angle video recording and the image is in a section where the horizontal pixel number of the angle A video transitions to the horizontal pixel number of the recorded video. By reading out the multi-angle information at the time of reproduction, multi-angle video reproduction that switches between angle A video and angle B video can be performed.

  Next, the control procedure of the multi-angle video recording process described above will be described with reference to the flowchart shown in FIG. FIG. 7 is a flowchart showing a multi-angle video recording method.

  When the recording of the angle A video is started and the recording of the angle B video is started during the recording of the angle A video (S701), the initial gain value of the luminance signal of the angle B video (S702) and the horizontal of the angle B video are recorded. An initial value of the number of pixels is set (S703). The video signal processing unit 105 converts the angle B video into the set number of horizontal pixels, and applies the gain set to the luminance signal. At the same time, the angle A video is converted to “recording horizontal pixel number 720 pixels−angle B video horizontal pixel number”, and the angle A video and the angle B video are combined into one screen image. The synthesized image is encoded by the encoding / decoding processing unit 108, and the encoded data is recorded on the recording medium 110 by the recording / reproducing processing unit 109. At this time, in the recording / reproduction processing unit 109, multi-angle flag (MAF = 1), horizontal pixel number (AH) information of angle A video, and horizontal pixel number (BH) information of angle B video as multi-angle recording information. Are recorded in association with the encoded data.

  When the recorded image is the I picture encoding timing (S704), when the luminance gain of the angle B video does not reach 1 (S705), the luminance gain value is set to be increased by a predetermined value (S705). S706). Furthermore, when the number of horizontal pixels of the angle B video has not reached 360 pixels which is half of the recorded horizontal pixel number (S707), the horizontal pixel number is set by adding a predetermined value (S708).

  As described above, the luminance level of the angle B video and the number of horizontal pixels of the angle A video and the angle B video are changed stepwise until they reach the specified values at the I picture encoding timing that is the reference image, and are combined into one screen. Recorded.

  Here, when the end of recording of the angle B video is instructed (S709), it is determined whether or not the recorded image is the I picture encoding timing (S710). When the recorded image is the I picture encoding timing, if the number of horizontal pixels of the angle A video is not equal to the number of horizontal pixels of the recorded video (S711), the horizontal pixel number of the angle A video is set by adding a predetermined value. (S712). Thereafter, until the number of horizontal pixels of the angle A video reaches 720 pixels, recording is performed while changing in stages at the I picture encoding timing. At this time, information on the number of horizontal pixels (AH) of the angle A video is recorded in association with the image simultaneously with the multi-angle flag (MAF = 2) as multi-angle recording information. The above processing is repeatedly executed until the end of recording of the angle A video is instructed (S713).

  By recording the multi-angle recording information together with the video data as described above, the multi-angle recording information is detected at the time of playback, and the viewer is notified that the video is a multi-angle video as shown in FIG. It is possible to prompt the switching of the video to be performed. FIG. 8 is an image diagram showing a multi-angle video playback method. When an angle A video is selected and played back from multi-angle recorded video data, an icon (indicator) for switching to angle B is displayed together with a playback image of the angle A video. Similarly, when the angle B video is selected and played back, an icon (indicator) for switching to the angle A is displayed together with the playback image of the angle B video. This is a configuration that enables video switching by selecting and instructing each icon by the operation unit 101 or the like.

  At this time, when the reproduction of the angle A video is instructed, the horizontal pixel number (AH) of the angle A video is cut out from the left side of one screen, and the horizontal pixel number is converted to 720 pixels and output. The playback image is generated. Similarly, when playback of an angle B video is instructed, the horizontal pixel count (BH) of the angle B video is cut out from the right side of one screen, the horizontal pixel count is converted to 720 pixels, and output. The playback image is generated.

  FIG. 9 is an image diagram showing a reproduced image at a multi-angle video recording start portion. As shown in FIG. 9, even when the angle A video recorded in the multi-angle video is reproduced, the horizontal pixel count of the angle A video is recorded so as to gradually decrease. It is possible to reduce the sense of incongruity of image quality changes when switching between angle video recordings. Similarly, in the playback image of the angle B video, since the luminance level is gradually changed from the black level to the original luminance level, the image quality changes for a frame with a low horizontal resolution near the start of recording of the angle B video. Discomfort is reduced.

  FIG. 10 is an image diagram showing a reproduced image of the multi-angle video recording stop portion. According to the present embodiment, as shown in FIG. 10, even when the multi-angle video recording is switched to the single-angle video recording, recording is performed by gradually increasing the number of horizontal pixels of the angle A video. Is reduced.

  As described above, the video data recording apparatus such as a digital video camera or a camera-equipped mobile terminal has been described as an example of the embodiment of the present invention. Applicable.

1 is a configuration block diagram of a video data recording apparatus according to an embodiment of the present invention. (A) is a diagram showing an example of reduction and synthesis of a captured video, and (b) is a diagram showing an example of enlargement of a reproduced video. It is a figure which shows the transition of the number of horizontal pixels at the time of multi-angle video recording. It is a figure which shows the transition of the number of horizontal pixels at the time of a multi-angle video recording stop. It is a figure which shows the timing which adjusts the number of horizontal pixels. It is a figure which shows the example of multi-angle recording information. It is a flowchart which shows the multi-angle video recording method. It is an image figure which shows the multi-angle video reproduction method. It is an image figure which shows the reproduction | regeneration image of the multi-angle video recording start part. It is an image figure which shows the reproduction | regeneration image of a multi-angle video recording stop part.

Explanation of symbols

101 Operation unit 102 CPU
103 Imaging system A
104 Imaging system B
105 Video Signal Processing Unit 106 D / A (Digital / Analog Conversion) Unit 107 Display Unit 108 Encoding / Decoding Processing Unit 109 Recording / Reproduction Processing Unit 110 Recording Medium

Claims (6)

A video data recording device for combining a plurality of videos and recording them as one video data,
Setting means for setting the number of horizontal pixels for each of the input first video data and second video data;
Reduction means for reducing the first video data and the second video data in the horizontal direction according to the number of horizontal pixels set by the setting means;
Recording means for recording on the recording medium video data obtained by combining the first video data and the second video data reduced in the horizontal direction by the reduction means;
Adjusting means for adjusting a gain level of luminance information of the first video data or the second video data;
When recording of the synthesized video data is started by the recording unit, the setting unit gradually changes the number of horizontal pixels in a predetermined screen unit, and the adjustment unit sets a gain level for video data having a smaller number of horizontal pixels. A video data recording apparatus characterized by being gradually changed.   The recording unit records the synthesized video data on a recording medium, and records information indicating the synthesized video data and information on the number of horizontal pixels set by the setting unit on the recording medium. The video data recording apparatus according to claim 1, wherein:   A first imaging unit that generates the first video data; and a second imaging unit that generates the second video data, wherein the first imaging unit and the second imaging unit are multi-layered. The video data recording apparatus according to claim 1 or 2, wherein an angle video is shot.   When the recording unit is recording the combined video data, if the recording of only one of the first video data and the second video data is stopped, the setting unit is recording in a predetermined frame unit. 4. The video data recording apparatus according to claim 1, wherein the number of horizontal pixels of the video data is gradually increased.   5. The video data recording according to claim 1, wherein the setting unit changes the number of horizontal pixels of the first video data and the second video data in units of DCT blocks. 6. apparatus.   The said setting means changes the number of horizontal pixels of said 1st video data and said 2nd video data according to the encoding timing of I picture, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Video data recording device.

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