JP6976219B2 - Video recording / playback device and video recording / playback method - Google Patents

Description

The present invention relates to a video recording / playback device for recording and playing back a digital broadcast program and a video recording / playback method.

In recent years, high-resolution 4K broadcasting or 8K broadcasting encoded by HEVC (High Efficiency Video Coding) with high compression efficiency is scheduled to be put into practical use as compared with 2K broadcasting, which is the current high-definition broadcasting. When recording such a high-resolution broadcast program, both the high-resolution recording stream and the low-resolution recording stream are recorded, and by using the low-resolution recording stream during special playback, the number of images to be displayed per unit time is displayed. A recording / reproducing device for smooth reproduction is disclosed (see, for example, Patent Document 1). Here, special playback refers to playback different from normal playback, such as fast forward, fast rewind, and slow playback. Normal playback is also called 1x speed playback.

Japanese Unexamined Patent Publication No. 2003-125353

In the recording / playback device disclosed in Patent Document 1, since the resolution is low during low-speed special playback, the displayed subtitles are difficult to read, or the fineness of the displayed image is impaired, making it difficult to recognize the video scene. There are problems such as. Further, since the recording / playback device disclosed in Patent Document 1 employs a unique data method for managing a plurality of recording streams for one broadcast program, Blu-ray Disc (registered trademark, the same applies hereinafter). ) When recording to a general-purpose disc format such as a standard, there is a problem that the recorded broadcast program cannot be specially played back.

As described above, conventionally, there is room for improvement in easily searching for a desired video scene during special playback, and special playback of a broadcast program recorded in a general-purpose disc format has not been possible.

The present invention has been made to solve such a problem, and it is possible to easily search for a desired video scene at the time of special reproduction, and specially reproduce a broadcast program recorded in a general-purpose disc format. It is an object of the present invention to provide a video recording / playback device and a video recording / playback method capable of the above.

In order to solve the above problems, the video recording / playback device according to the present invention is a video recording / playback device capable of recording / reproducing a high-resolution digital broadcast program having a resolution equal to or higher than a predetermined resolution, and is a code of the digital broadcast program. Control is performed to generate at least one representative image encoded by the still image compression method for each compression unit, and the generated representative image is recorded in a user-specific area in which the metadata information in the encoding compression unit can be recorded. A representative image generation control unit that controls and a special reproduction position control unit that selects a representative image corresponding to the special reproduction at the time of special reproduction different from the normal reproduction speed and controls to display the selected representative image. Be prepared.

Further, the video recording / playback method according to the present invention is a video recording / playback method capable of recording / reproducing a high-resolution digital broadcast program having a resolution equal to or higher than a predetermined resolution, and (a) for each coded compression unit of the digital broadcast program. A step of controlling the generation of at least one representative image encoded by the still image compression method and recording the generated representative image in a user-specific area in which the metadata information in the coded compression unit can be recorded. And (b) a step of selecting a representative image corresponding to the special reproduction at the time of special reproduction different from the normal reproduction speed and controlling the display of the selected representative image.

According to the present invention, the video recording / playback device is a video recording / playback device capable of recording / reproducing a high-resolution digital broadcast program having a resolution equal to or higher than a predetermined resolution, and is a still image for each coded compression unit of the digital broadcast program. Representative image generation control that controls the generation of at least one representative image encoded by the compression method and records the generated representative image in a user-specific area in which the metadata information in the coded compression unit can be recorded. Since it is provided with a unit and a special reproduction position control unit that selects a representative image corresponding to the special reproduction at the time of special reproduction different from the normal reproduction speed and controls to display the selected representative image, it is desired at the time of special reproduction. It is possible to easily search for the video scene of the above, and it is possible to specially play back the broadcast program recorded in the general-purpose disc format.

Further, the video recording / playback method is a video recording / playback method capable of recording / reproducing a high-resolution digital broadcast program having a resolution equal to or higher than a predetermined resolution, and (a) a still image for each coded compression unit of the digital broadcast program. A step of controlling to generate at least one representative image encoded by a compression method, and controlling to record the generated representative image in a user-specific area in which the metadata information in the coded compression unit can be recorded, and ( b) Since it is provided with a step of selecting a representative image corresponding to the special reproduction at the time of special reproduction different from the normal reproduction speed and controlling the display of the selected representative image, it is easy to obtain a desired video scene at the time of special reproduction. It is possible to search for and specially play back the broadcast program recorded in the general-purpose disc format.

It is a block diagram which shows an example of the structure of the video recording / playback apparatus according to the embodiment of this invention. It is a figure for demonstrating the resolution of the broadcast program by embodiment of this invention. It is a figure which shows an example of the logical file structure of the optical disk by embodiment of this invention. It is a figure for demonstrating the internal data structure of the stream information file by embodiment of this invention. It is a figure for demonstrating the internal data structure of the reproduction control information file by embodiment of this invention. It is a figure for demonstrating the data structure of the video stream by embodiment of this invention. It is a figure for demonstrating the internal data structure of SEI by embodiment of this invention. It is a figure for demonstrating the internal data structure of the special reproduction speed table by embodiment of this invention. It is a figure for demonstrating the internal data structure of the display function table by embodiment of this invention. It is a flowchart which shows an example of the operation of the video recording / playback apparatus by embodiment of this invention. It is a flowchart which shows an example of the operation of the video recording / playback apparatus by embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment>
<Structure>
The video recording / playback device according to the present embodiment analyzes a broadcast stream of a digital broadcast program and records one or more representative images in a coded compression unit in a user-specific region in the broadcast stream. At the time of special reproduction, it is easy to find a desired video scene by selecting a representative image that has both smoothness and high definition according to the special reproduction speed. Further, the performance of the display device is obtained by selecting a representative image having the optimum resolution within the performance range of the display device based on the displayable format which is the attribute information acquired from the display device connected to the video recording / playback device. The processing load of the video recording / playback device is reduced without wastefully executing the above video display. Hereinafter, it will be described in detail.

FIG. 1 is a block diagram showing an example of the configuration of the video recording / playback device 100 according to the present embodiment.

As shown in FIG. 1, the video recording / playback device 100 includes a system control unit 101, a recording / playback drive unit 102, a tuner unit 104, a stream control unit 110, a video / audio decoder unit 111, and a still image encoder unit 112. And a digital interface unit 113 and a memory unit 120. The system control unit 101 has a representative image generation control unit 151, a special reproduction position control unit 152, and a display device information acquisition unit 153, and is connected to the operation unit 130. The digital interface unit 113 has a display device communication unit 115 and is connected to the display device 114.

The system control unit 101 controls the entire video recording / playback device 100. The recording / reproducing drive unit 102 reads out the information recorded on the optical disc 103.

The optical disk 103 records stream information in which a coded video described later is multiplexed and reproduction control information of the stream information. The reproduction control information is reproduced in the access unit of the video attribute information related to the encoded video stream, the audio attribute information related to the encoded audio stream, and the stream information separated from the stream information recorded on the optical disk 103. It contains information indicating the correspondence between the start time information and the playback start position information. Here, the access unit of stream information means a coded compression unit, and usually means a GOP (Group of Picture) unit.

In the present embodiment, the recording / playback drive unit 102 will be described as an optical disk drive reading device, but the recording / playback drive unit 102 may be a hard disk drive device or an SD (registered trademark, the same applies hereinafter) media drive device. In this case, stream information and playback control information are stored in the hard disk drive or SD media, and the recording / playback drive unit 102 reads these information.

Here, the recording process by the video recording / playback device 100 will be described.

The broadcast wave received by the video recording / playback device 100 is decoded by the tuner unit 104 into, for example, an MPEG-2 transport stream (hereinafter referred to as MPEG-2 TS). The MPEG-2 TS decoded by the tuner unit 104 is temporarily stored in a memory area (not shown) in the stream control unit 110 in a coded compression unit.

After that, the stream control unit 110 extracts an I-picture that can be independently decoded in a coded compression unit from the memory area of the stream control unit 110 according to an instruction from the representative image generation control unit 151 described later. The video / audio decoder unit 111 decodes the I picture extracted by the stream control unit 110 by HEVC. The still image encoder unit 112 encodes and compresses the I picture decoded by the video / audio decoder unit 111 with JPEG. The I-picture encoded and compressed by the still image encoder unit 112 corresponds to a representative image. The code-compressed I picture, that is, the representative image by the still image encoder unit 112 is sent to the stream control unit 110.

The representative image generation control unit 151 sends the resolution and codec information of the representative image to the stream control unit 110 as control information. The resolution of the representative image indicates the number of pixels in the width and height of the representative image. Further, the representative image generation control unit 151 also sends information on the drawing area of the subtitle information in the I picture decoded by the video / audio decoder unit 111, the font size of the subtitle, and the expected decoding time of the I picture to the stream control unit 110.

The stream control unit 110 records a representative image in SEI (Supplemental Enhancement Information), which is a user-specific area in the video / audio stream stored in the memory area of the stream control unit 110. The still image encoder unit 112 may be decoded into one representative image, or may be decoded into a plurality of representative images having different resolutions. For example, when the video recording / playback device 100 records an 8K broadcast, the still image encoder unit 112 decodes the image into three types of representative images, such as a representative image having an 8K resolution, a representative image having a 4K resolution, and a representative image having a 2K resolution. May be good.

After that, the recording / reproducing drive unit 102 records the video / audio stream on the optical disc 103 for each coded compression unit according to the instruction of the stream control unit 110. Further, the recording / reproducing drive unit 102 records the reproduction control information on the optical disc 103 at the end of recording according to the instruction of the system control unit 101.

In the present embodiment, the video / audio stream will be described as being multiplexed by MPEG-2 TS, but the present invention is not limited to this. For example, the video / audio stream may be multiplexed by MMT (MPEG Media Transport).

Next, the normal reproduction process by the video recording / reproducing device 100 will be described.

As described above, normal reproduction refers to reproduction that is not special reproduction, and is also referred to as 1x speed reproduction.

When reproducing the stream information encoded and compressed by MPEG-2 TS or the like and recorded on the optical disk 103, the system control unit 101 reads in advance the reproduction control information related to the stream information to be reproduced and stores it in the memory unit 120. do. As a result, the system control unit 101 can immediately read the reproduction control information from the memory unit 120. The system control unit 101 reads the reproduction control information from the memory unit 120 and instructs peripheral devices to prepare for reproduction.

After that, the recording / reproducing drive unit 102 reads the stream information recorded on the optical disc 103 and sends it to the stream control unit 110. The stream control unit 110 sends the received stream information to the video / audio decoder unit 111. The video / audio decoder unit 111 sequentially captures the stream information, and then separates and extracts the coded and compressed video stream and audio stream. Then, the video / audio decoder unit 111 decodes the video stream encoded by MPEG-2 or the like into a video signal, and decodes the audio stream encoded by AC-3 or the like into an audio signal. Decrypt.

The decoded video signal and audio signal are sent to the digital interface unit 113. The digital interface unit 113 converts the video signal and the audio signal into a signal conforming to HDMI (High Definition Multimedia Interface (registered trademark, the same applies hereinafter)), and sends the converted video signal and the audio signal to the display device 114. The display device 114 displays a video based on the transmitted video signal, and outputs audio based on the transmitted audio signal.

Returning to the description of FIG. 1, the display device information acquisition unit 153 acquires a displayable format including information on the performance of the display device 114 from the display device 114 via the display device communication unit 115. The displayable format includes the TV size of the display device 114, the display resolution, whether or not HDR (High Dynamic Range) is supported, the maximum output brightness level, the recommended maximum brightness level, the manufacturer name, the year of manufacture, and whether or not interlacing is supported. The TV size is the display image size of the display device 114, and corresponds to the size of the display screen of the display device 114. It is assumed that the display device 114 records the displayable format as EDID (Extended Display Identification Data) in the non-volatile memory.

In this embodiment, a case where the displayable format of the display device 114 is acquired by using HDMI will be described, but the present invention is not limited to this. For example, the displayable format of the display device 114 may be acquired by using iLink (registered trademark, the same applies hereinafter) or infrared communication.

In FIG. 1, the digital interface unit 113 has a display device communication unit 115, but is not limited thereto. The display device communication unit 115 may be provided separately from the digital interface unit 113.

The decoder block 116 is a general term for a recording / playback function of a video / audio stream. The decoder block 116 records or reproduces stream information according to an instruction from the system control unit 101.

The operation unit 130 receives a user's request for the video recording / playback device 100. Generally, the operation unit 130 is an operation panel or a remote controller arranged on the front panel of the video recording / playback device 100. The system control unit 101 interprets the content requested by the user using the operation unit 130, and controls the decoder block 116 based on the interpretation to reproduce arbitrary stream information. Further, the system control unit 101 receives instructions from the operation unit 130 such as video reproduction start, reproduction stop, pause, fast forward, fast rewind, slow reproduction, or skip.

As described above, special reproduction refers to reproduction different from normal reproduction such as fast forward, fast rewind, and slow reproduction. The special reproduction is performed at a speed faster or slower than the 1x speed, assuming that the normal reproduction speed is 1x speed. In the special reproduction, the I picture existing for each coded compression unit in the video / audio stream is used. The I picture existing at the skipped time position is decoded based on the special playback speed, and the video frame which is the decoded I picture is displayed. After that, the special reproduction is performed by sequentially decoding the I-picture by skipping the predetermined time position in the same manner. If the video recording / playback device 100 is capable of decoding two I pictures per second and the special playback speed is 10 times faster, the above-mentioned predetermined time is in units of 5 seconds. Become.

The representative image generation control unit 151 controls to record a representative image in a user-specific area of the video stream in a coded compression unit. The special reproduction position control unit 152 selects a representative image recorded in the user's own area of the video stream recorded at the time of special reproduction. By reproducing a still image such as JPEG having a low decoding difficulty selected by the special reproduction position control unit 152, an image per unit time is output without decoding the HEVC I picture having a high resolution and a high decoding difficulty. Smooth special playback can be performed by increasing the number of sheets.

The representative image generation control unit 151, the special reproduction position control unit 152, and the display device information acquisition unit 153 show an example in which the system control unit 101 is composed of firmware or the like, but the present invention is not limited thereto. The representative image generation control unit 151, the special reproduction position control unit 152, and the display device information acquisition unit 153 may be provided outside the system control unit 101, or may be hardware having these functions. Further, although the representative image generation control unit 151, the special reproduction position control unit 152, and the display device information acquisition unit 153 are shown as separate functional blocks, these functions may be integrated and further subdivided. It may be a functional block.

<Resolution of broadcast programs>
FIG. 2 is a diagram for explaining the resolution of a broadcast program.

The current broadcast is called 2K broadcast 201 and has a resolution of 1920 pixels wide by 1080 pixels high. In recent years, broadcast programs of ultra-high-definition video have begun to be broadcast, and standardization of 4K broadcasting 202 and 8K broadcasting 203 is being promoted.

The 4K broadcast 202 has a resolution of 3840 pixels wide × 2160 pixels wide, which is four times the resolution of the 2K broadcast 201. The 8K broadcast 203 has a resolution of 7680 pixels (horizontal) x 4320 pixels (vertical), which is four times that of the 4K broadcast 202.

Further, HEVC, which has a coding compression efficiency about four times that of the coding compression method adopted in the current 2K broadcasting 201, is adopted for the 4K broadcasting 202 and the 8K broadcasting 203. Since HEVC has high coding and compression efficiency, the load on the CPU (Central Processing Unit) required for the decoding process is also high. As described above, since the amount of information in the 8K broadcast 203 is larger than that in the current 2K broadcast 201, there is a problem that the load of decoding by the video recording / playback device 100 becomes large.

<Logical file structure of optical disc>
FIG. 3 is a diagram showing an example of the logical file structure of the optical disk 103.

The root directory 300 is a directory structure at the highest level of the file structure that constitutes a logical hierarchical structure. The disk directory 301 is a directory structure arranged in a lower hierarchy of the root directory 300. The disk directory 301 is composed of a playback control information file 310 and a stream management directory 302. The reproduction control information file 310 records the reproduction control information for managing the disc contents recorded on the optical disc 103 in a file format. The stream management directory 302 is a folder in which the stream information files 320 are collectively recorded.

It is assumed that the stream information file 320 is recorded with a 5-digit file name. The file name of the stream information file 320 may be a 5-digit number and does not have to be a serial number. FIG. 3 shows an example in which the stream information file 320 is arranged in a separate directory, but the present invention is not limited to this. For example, the stream information file 320 may be placed directly in the root directory 300 or may be placed in another directory. Further, although FIG. 3 shows an example in which the stream information file 320 is recorded in an individual file for each management unit, the stream information file 320 may be collectively recorded in one file.

<Internal data structure of stream information file>
FIG. 4 is a diagram for explaining the internal data structure of the stream information file 320.

The stream information file 320 is composed of a collection of fixed-length data units called packets 400. The video data, audio data, and stream management data are divided into 400 packets and then multiplexed to form the stream information file 320. There is header information 401 at the head of each packet 400, and the data in the packet 400 is identified by using the ID (Identification) 402 described in the header information 401. The stream control unit 110 identifies the ID 402 and separates the data in the packet 400 into video data, audio data, stream management data, and the like.

<Internal data structure of playback control information file>
FIG. 5 is a diagram for explaining the internal data structure of the reproduction control information file 310, and shows the syntax of the reproduction control information file 310.

The program title recorded on the optical disk 103 is called a playlist. In the reproduction control information file 310, "num_of_playlist 503" indicating the total number of playlists is recorded, and the following loop statements for and below are repeated by the number of "num_of_playlist 503". The playlist is composed of a plurality of play items described later. One play item is composed of a plurality of video frames, and one video frame is composed of a plurality of pixels.

As mentioned above, a playlist is composed of a plurality of play items. In the reproduction control information file 310, "num_of_playitem 508" indicating the total number of play items is recorded, and the following loop statements for and below are repeated by the number of "num_of_playitem 508". One reproduction section information is recorded in the play item, and it is composed of a stream file name 509 to be reproduced, a reproduction start time 510, and a reproduction end time 511. The video recording / playback device 100 can determine which section of the stream information file 320 should be played back based on the playback section information.

Further, in the reproduction control information file 310, "num_of_stream 512" indicating the total number of stream information files 320 recorded on the optical disk 103 is recorded, and the following loop statements for and below are repeated by the number of "num_of_stream 512". Will be. The stream information file name 513 is 5-digit numerical information indicating the name of the stream information file 320. The attribute information management table 514 records attribute information such as video information and audio information used in the stream information file 320. Further, the attribute information management table 514 records the video information constituting the video stream, the ID 402 that identifies the packet for each audio information constituting the audio stream, and the like. The stream control unit 110 uses the ID 402 to separate video data, audio data, stream management data, and the like.

The access point management table 515 is list information recording a position for reading a video / audio stream and a playback start time for each access point, and random access playback such as time search or special playback can be performed using the list information. .. For example, when the video data is encoded by the MPEG-2 video stream, the head of the GOP corresponds to the access point, and the information on the reproduction start time and the reproduction start address is described for each GOP. The playback start address is the position starting from the beginning of the stream file. The video recording / playback device 100 determines the playback start address of the stream information file 320 from the playback start time and performs random access playback.

<Data structure of video stream of broadcast program>
FIG. 6 is a diagram for explaining the data structure of the video stream 600 of the broadcast program, and shows the data structure of the coded and compressed video stream 600 generated by demultiplexing by the stream control unit 110. There is.

The video stream 600 is compressed in units of GOP601, which is a coded compression unit. The GOP601 includes an I-picture 610 data-compressed in a frame, a P-picture 611 data-compressed by adding motion compensation by the I-picture 610 in the forward direction in time, and an I-picture 610 or P in the front-back direction in time. It is composed of a B picture 612 data-compressed with motion compensation by the picture 611, and is code-compressed every 0.5 second playback time, for example.

The I picture 610 is located at the head of the GOP 601 and can be independently decoded because it has no reference relationship, and is decoded first in the GOP 601. Further, the I picture 610 is composed of display time information 620, video attribute information 630, and coded video data 640.

A PTS (Presentation Time Stamp) is attached to the display time information 620, and the presentation time information to the display device 114 is recorded. The display time information 620 may be any time information in which video and audio can be synchronized, and may be time information defined by NTP (Network Time Protocol) instead of PTS.

The video attribute information 630 is composed of an AUD (Access Unit Delimiter) 631, an SPS (System Parameter Set) 632, a PPS (Picture Parameter Set) 633, and a SEI 634.

The AUD631 shows the identifier information indicating the head of the video access unit, and records the information indicating the type of the slice 641 included in the access unit. The SPS632 records information such as the profile, level, resolution, frame rate, and bit rate upper limit related to the coding of the entire GOP601. The PPS 633 contains information related to the coding of the entire picture, and records information such as the entropy coding mode or the quantization parameter for each picture.

The SEI634 is a user-specific area of the GOP601, and the video recording / playback device 100 can record arbitrary metadata information. In the present embodiment, the representative image control information for special reproduction of GOP601, which will be described later, and one or more representative images are recorded in SEI634 as metadata information.

The coded video data 640 is composed of one or more slices 641. When the coded video data 640 is decoded, it becomes image information.

The P picture 611 and the B picture 612 do not include the SPS 632 and the SEI 634, and the other configurations are the same as those of the I picture 610.

<Internal data structure of SEI>
FIG. 7 is a diagram for explaining the internal data structure of SEI634.

The SEI634 is composed of the representative image control information 700 and one or more representative images 701. In the present embodiment, it is assumed that there are three representative images 701, a representative image 701a, a representative image 701b, and a representative image 701c. In the following, the representative image 701a, the representative image 701b, and the representative image 701c are collectively referred to as a representative image 701.

The representative image 701a has a resolution of 8K, the representative image 701b has a resolution of 4K, and the representative image 701c has a resolution of 2K. If the resolution of the representative image 701 is high, the resolution is high, but since the decoding process takes time, the number of images to be output per unit time is reduced and the representative image 701 cannot be reproduced smoothly. On the other hand, if the road degree of the representative image 701 is low, the visibility of the video scene is deteriorated at low resolution, but since the decoding process can be performed at high speed, the number of images output per unit time increases and the image can be reproduced smoothly. can.

The representative image control information 700 is composed of Data_type721, Marker_ID722, number_of_Picture723, and picture management information 724 for each representative image 701.

Data_type721 indicates the data type recorded in SEI634. In the present embodiment, the Data_type721 is recorded with an identifier indicating that the metadata is for smooth reproduction during special reproduction. The maker identifier of the video recording / playback device 100 that has written the metadata to the SEI634 is recorded in the Maker_ID722. number_of_Picture 723 indicates the total number of picture management information 724. Since three representative images 701 are recorded in the present embodiment, "3" is recorded in num_of_Picture 723.

The picture management information 724 is composed of offset_byte731, pic_size 732, pic_width733, pic_height734, pic_codec735, subtitle_rate736, subtitole_frontsize737, and time_of_pro.

offset_byte731 indicates the start address position of the representative image 701. In offset_byte731, an offset byte indicating a relative address calculated from the first byte of SEI634 is recorded. The number of bytes indicating the size of the representative image 701 is recorded in the pick_size 732.

The pic_width 733 and the pic_height 734 are information indicating the resolution of the representative image 701. The number of pixels in the width of the representative image 701 is recorded in the pic_width 733, and the number of pixels in the height of the representative image 701 is recorded in the pic_height 734. pic_codec 735 shows a still image compression method of the representative image 701. An identifier indicating a codec type such as JPEG, JPEG2000, or a bitmap is recorded in pic_codec735.

The subtitle_rate 736 indicates the area occupied by the subtitles in the representative image 701, that is, the ratio occupied by the subtitles in the representative image 701. For example, if "20" is recorded in the subtitle_rate736, this indicates that 20% of the representative image 701 is subtitles.

In the subtitle_frontsize 737, the font size of the most used subtitle among the subtitles displayed in the representative image 701 is recorded. By referring to the font size of the recorded subtitles of subtitle_frontsize737, it is possible to identify how large the subtitles are with respect to the display screen. In the present embodiment, it is assumed that the font size most used is recorded in the subtitle_frontsize 737, but the present invention is not limited to this. In the subtitle_frontsize 737, for example, the font size of the smallest subtitle among the subtitles displayed in the representative image 701 may be recorded.

time_of_proc738 indicates a guideline time required for the decoding process of the representative image 701. When the high resolution and high efficiency coding compression method of the representative image 701 is adopted, a high value parameter is recorded in time_of_proc738.

<Internal data structure of special playback speed table>
FIG. 8 is a diagram for explaining the internal data structure of the special reproduction speed table 800. The special reproduction speed table 800 is used when selecting a representative image 701 at the time of special reproduction based on the special reproduction speed and the subtitle ratio. The special reproduction speed table 800 is composed of a special reproduction speed entry 801 and a subtitle ratio division 802. In the present embodiment, the threshold value of the special reproduction speed entry 801 is 4 stages, and the threshold value of the subtitle ratio category 802 is 20%. The special reproduction speed table 800 is stored in, for example, the memory unit 120.

The special playback speed entry 801 is "S_tp <× 1.0 times speed (slow reproduction)" and "× 1.0 <S_tp ≦ × 5.0 (fast forward / fast rewind: low speed)", where S_tp is the special reproduction speed. , "X5.0 <S_tp≤x15.0 (fast forward / fast rewind: medium speed)" and "x15.0 <S_tp (fast forward / fast rewind: high speed)".

The special playback speed entry 801 holds a setting value such that a high-definition and high-resolution representative image 701 is presented so that the slower the special playback speed, the easier it is to find the desired video scene in the recorded program. ing. On the other hand, the special reproduction speed entry 801 holds a set value such that a low-resolution representative image 701 that can shorten the time until the image is output is presented as the special reproduction speed is faster.

In high-speed special playback, even if the visibility of screen details deteriorates, it is easier to find a rough video scene if the number of images output per unit time is large. In particular, when specially playing back a code-compressed video, the number of images output per unit time is small, so it is easier to find an arbitrary video scene if the interval for skipping the video output during special playback is small. On the other hand, in low-speed special playback, it is possible to pinpoint the desired video scene while checking the detailed information on the screen.

The subtitle ratio category 802 uses 20% of the screen area as a determination threshold value to distinguish whether or not the drawing area of the subtitle is larger than 20% of the screen area. Subtitles are useful information when searching for a desired video scene. Therefore, the special reproduction speed table 800 is configured to select a higher resolution representative image 701 when the special reproduction speed is slow.

In the present embodiment, the representative image 701 at the time of special reproduction is selected based on the special reproduction speed and the subtitle ratio, but the present invention is not limited to this. For example, the representative image 701 at the time of special reproduction may be selected based only on the special reproduction speed or only the subtitle ratio.

In the present embodiment, the case where the special reproduction speed entry 801 has four stages has been described, but it may be more than four stages or less than four stages.

In the present embodiment, the determination threshold value of the subtitle ratio category 802 is set to 20%, but the determination threshold value may be changed. Further, the determination threshold value of the subtitle ratio category 802 is not limited to the ratio of the drawing area of the subtitle to the screen area, and may be, for example, the font size of the subtitle displayed on the screen. In this case, when the font size of the subtitle is smaller than the predetermined font size, the high-resolution representative image 701 may be selected.

<Internal data structure of display function table>
FIG. 9 is a diagram for explaining the internal data structure of the display function table 900. The display function table 900 is used when selecting a representative image 701 at the time of special reproduction based on the TV size and the display resolution. That is, it is prevented from selecting the representative image 701 having an unnecessarily high resolution according to the performance of the display device 114, and consideration is given so as not to unnecessarily increase the processing load of the video recording / playback device 100. The display function table 900 is composed of a TV size entry 901 and a resolution division 902. In this embodiment, the TV size entry 901 has three stages and the resolution division 902 has three stages. The display function table 900 is stored in, for example, the memory unit 120.

The TV size entry 901 is divided into three categories: "30 inches or less (small size)", "30 inches to 50 inches (medium size)", and "50 inches or more (large size)". The resolution category 902 is divided into three categories: "2K low resolution", "4K medium resolution", and "8K high resolution".

The display function table 900 is configured to output more low-resolution representative images 701 as the TV size is smaller or the display resolution of the display device 114 is lower. On the other hand, when the TV size is large or the display resolution of the display device 114 is high, a low-resolution representative image 701 is displayed to prevent it from being difficult to find a desired video scene.

In the present embodiment, the representative image 701 at the time of special reproduction is selected based on the TV size and the display resolution, but the present invention is not limited to this. For example, the representative image 701 at the time of special reproduction may be selected based only on the TV size or only the display resolution.

In the present embodiment, the case where each of the TV size entry 901 and the resolution division 902 has three stages has been described, but it may be more than three stages or less than three stages.

<Example 1>
FIG. 10 is a flowchart showing an example of the operation of the video recording / reproducing device 100, and shows the operation at the time of special reproduction. Hereinafter, a case where a representative image is selected using the special reproduction speed table 800 shown in FIG. 8 will be described.

In step S101, the system control unit 101 determines whether or not the reproduction of the recorded program is a special reproduction. In the case of normal reproduction instead of special reproduction, the process shown in FIG. 10 is terminated. On the other hand, in the case of special reproduction, the process proceeds to step S102.

In step S102, the system control unit 101 determines whether or not the special reproduction is completed. When the special reproduction is completed, the process shown in FIG. 10 is terminated. On the other hand, if the special reproduction is not completed, the process proceeds to step S103.

In step S103, the special reproduction position control unit 152 acquires the special reproduction speed S_tp from the operation unit 130.

In step S104, the special reproduction position control unit 152 identifies the next GOP601 to be reproduced with reference to the access point management table 515 of the reproduction control information file 310, and seeks to the head position of the specified GOP601.

In step S105, the special reproduction position control unit 152 reads the SEI634 from the video attribute information 630 recorded at the beginning of the GOP601. Then, the special reproduction position control unit 152 reads out the representative image 701 from the representative image control information 700 of the SEI634. In the present embodiment, the 8K representative image 701a, the 4K representative image 701b, and the 2K representative image 701c are read out.

In step S106, the special reproduction position control unit 152 determines whether or not the special reproduction speed S_tp is slower than 1.0 times speed. If the special reproduction speed S_tp is slower than 1.0 times speed, the process proceeds to step S107. On the other hand, if the special reproduction speed S_tp is not slower than 1.0 times the speed, the process proceeds to step S108.

In step S108, the special reproduction position control unit 152 determines whether or not the special reproduction speed S_tp is "× 1.0 <S_tp ≦ × 5.0", that is, whether or not the speed is fast forward or rewind. do. If the speed is fast forward or fast rewind, the process proceeds to step S109. On the other hand, if it is not a low-speed fast forward or fast rewind, the process proceeds to step S111.

In step S109, the special reproduction position control unit 152 determines whether or not the subtitle ratio exceeds 20%. If the subtitle ratio exceeds 20%, the process proceeds to step S107. On the other hand, if the subtitle ratio does not exceed 20%, the process proceeds to step S110.

When it is determined in step S106 that the special reproduction speed S_tp is slower than 1.0 times speed, and when it is determined in step S109 that the subtitle ratio exceeds 20%, in step S107, the special reproduction position control unit 152 sets the special reproduction position control unit 152. A high resolution 8K representative image 701a is selected, and the decoder block 116 is controlled so that the representative image 701a is displayed on the display device 114. As a result, the display device 114 displays the representative image 701a at the time of special reproduction.

In step S111, the special reproduction position control unit 152 determines whether or not the special reproduction speed S_tp is "× 5.0 <S_tp ≦ × 15.0", that is, whether or not the medium speed is fast forward or fast rewind. to decide. In the case of medium speed fast forward or fast rewind, the process proceeds to step S112. On the other hand, if it is not a medium speed fast forward or fast rewind, the process proceeds to step S113.

In step S112, the special reproduction position control unit 152 determines whether or not the subtitle ratio exceeds 20%. If the subtitle ratio exceeds 20%, the process proceeds to step S110. On the other hand, if the subtitle ratio does not exceed 20%, the process proceeds to step S113.

If it is determined in step S109 that the subtitle ratio does not exceed 20%, or if it is determined in step S112 that the subtitle ratio exceeds 20%, in step S110, the special reproduction position control unit 152 has a medium resolution. A 4K representative image 701b is selected, and the decoder block 116 is controlled so that the representative image 701b is displayed on the display device 114. As a result, the display device 114 displays the representative image 701b at the time of special reproduction.

If it is determined in step S111 that the fast forward or reverse speed is not medium speed, or if it is determined in step S112 that the subtitle ratio does not exceed 20%, in step S113, the special reproduction position control unit 152 has a low resolution. A 2K representative image 701c is selected, and the decoder block 116 is controlled so that the representative image 701c is displayed on the display device 114. As a result, the display device 114 displays the representative image 701c at the time of special reproduction.

In step S114, the special reproduction position control unit 152 reads the next GOP601 and returns to step S102.

From the above, the video recording / playback device 100 selects and displays a representative image 701 that has both smoothness and high definition according to the special playback speed at the time of special playback of a high-resolution broadcast program. Therefore, it is possible to easily find a desired video scene. Further, since the representative image 701 is recorded in the SEI634, which is a user-specific area constituting the I-picture 610 of the video stream 600, it can be recorded in a data format highly compatible with a general-purpose disk format.

<Example 2>
FIG. 11 is a flowchart showing an example of the operation of the video recording / reproducing device 100, and shows the operation at the time of special reproduction. Hereinafter, a case where a representative image is selected using the display function table 900 shown in FIG. 9 will be described.

In step S201, the system control unit 101 determines whether or not the reproduction of the recorded program is a special reproduction. In the case of normal reproduction instead of special reproduction, the process shown in FIG. 11 is terminated. On the other hand, in the case of special reproduction, the process proceeds to step S202.

In step S202, the system control unit 101 determines whether or not the special reproduction is completed. When the special reproduction is completed, the process shown in FIG. 11 is terminated. On the other hand, if the special reproduction is not completed, the process proceeds to step S203.

In step S203, the special reproduction position control unit 152 identifies the next GOP601 to be reproduced with reference to the access point management table 515 of the reproduction control information file 310, and seeks to the head position of the specified GOP601.

In step S204, the special reproduction position control unit 152 reads the SEI634 from the video attribute information 630 recorded at the beginning of the GOP601. Then, the special reproduction position control unit 152 reads out the representative image 701 from the representative image control information 700 of the SEI634. In the present embodiment, the 8K representative image 701a, the 4K representative image 701b, and the 2K representative image 701c are read out.

In step S205, the special reproduction position control unit 152 determines whether or not the display resolution of the display device 114 is a resolution of 8K based on the display device information acquired by the display device information acquisition unit 153. If the display resolution of the display device 114 is a resolution of 8K, the process proceeds to step S206. On the other hand, if the display resolution of the display device 114 is not the resolution of 8K, the process proceeds to step S208.

In step S206, the special reproduction position control unit 152 determines whether or not the TV size of the display device 114 is 30 inches or more based on the display device information acquired by the display device information acquisition unit 153. If the TV size of the display device 114 is 30 inches or more, the process proceeds to step S207. On the other hand, if the TV size of the display device 114 is not 30 inches or more, the process proceeds to step S210.

In step S207, the special reproduction position control unit 152 selects the 8K representative image 701a having a high resolution, and controls the decoder block 116 so that the representative image 701a is displayed on the display device 114. As a result, the display device 114 displays the representative image 701a at the time of special reproduction.

In step S208, the special reproduction position control unit 152 determines whether or not the display resolution of the display device 114 is a resolution of 4K based on the display device information acquired by the display device information acquisition unit 153. If the display resolution of the display device 114 is a resolution of 4K, the process proceeds to step S209. On the other hand, if the display resolution of the display device 114 is not the resolution of 4K, the process proceeds to step S211.

In step S209, the special reproduction position control unit 152 determines whether or not the TV size of the display device 114 is 30 inches or more based on the display device information acquired by the display device information acquisition unit 153. If the TV size of the display device 114 is 30 inches or more, the process proceeds to step S210. On the other hand, if the TV size of the display device 114 is not 30 inches or more, the process proceeds to step S211.

If it is determined in step S206 that the TV size of the display device 114 is not 30 inches or more, or if it is determined in step S209 that the TV size of the display device 114 is 30 inches or more, the special reproduction position control is performed in step S210. The unit 152 selects a representative image 701b of 4K having a medium resolution, and controls the decoder block 116 so that the representative image 701b is displayed on the display device 114. As a result, the display device 114 displays the representative image 701b at the time of special reproduction.

If it is determined in step S208 that the display resolution of the display device 114 is not 4K resolution, or if it is determined in step S209 that the TV size of the display device 114 is not 30 inches or more, the special reproduction position control unit is determined in step S211. The 152 selects a 2K representative image 701c having a low resolution, and controls the decoder block 116 so that the representative image 701c is displayed on the display device 114. As a result, the display device 114 displays the representative image 701c at the time of special reproduction.

In step S212, the special reproduction position control unit 152 reads the next GOP601 and returns to step S202.

From the above, the video recording / playback device 100 selects and displays the representative image 701 having the optimum resolution within the performance range of the display device 114 based on the displayable format of the display device 114. Therefore, the processing load of the video recording / playback device 100 can be reduced without displaying a video having a resolution higher than the performance of the display device 114.

In addition, in FIG. 11, the representative image 701 may be selected by further adopting the special reproduction speed and the ratio of subtitles as shown in FIG.

In the present invention, the embodiments can be appropriately modified or omitted within the scope of the invention.

100 Video recording / playback device, 101 system control unit, 102 recording / playback drive unit, 103 optical disk, 104 tuner unit, 110 stream control unit, 111 video / audio decoder unit, 112 still image encoder unit, 113 digital interface unit, 114 display unit, 115 Display device communication unit, 116 decoder block, 120 memory unit, 130 operation unit, 151 representative image generation control unit, 152 special playback position control unit, 153 display device information acquisition unit, 2012K broadcast, 202 4K broadcast, 2038K broadcast , 300 root directory, 301 disk directory, 302 stream management directory, 310 playback control information file, 320 stream information file, 400 packets, 401 header information, 402 ID, 503 num_of_playlist, 508 num_of_playitem, 509 stream file name, 510 start time, 511 end time, 512 num_of_stream, 513 stream information file name, 514 attribute information management table, 515 access point management table, 600 video stream, 601 GOP, 610 I picture, 611 P picture, 612 B picture, 620 display time information, 630 Video attribute information, 631 AUD, 632 SPS, 633 PPS, 634 SEI, 640 coded video data, 641 slices, 700 representative image control information, 701 representative images, 721 Data_type, 722 Marker_ID, 723 num_of_Picture, 724 pictures. offset_byte, 732 pic_size, 733 pic_width, 734 pic_height, 735 pic_codec, 736 sub-file_rate, 737 sub-file_rate, 737 sub-file_fontsize, 737 sub-file_fontsize, 738 sub-file_fontsize, 738 902 resolution classification.

Claims (8)

A video recording / playback device capable of recording / reproducing high-resolution digital broadcast programs having a resolution higher than a predetermined resolution.
It is possible to control the generation of at least one representative image encoded by the still image compression method for each coded compression unit of the digital broadcast program, and record the metadata information in the coded compression unit for the generated representative image. A representative image generation control unit that controls recording in a user-specific area,
A special playback position control unit that selects the representative image corresponding to the special playback during special playback different from the normal playback speed and controls the display of the selected representative image.
A video recording / playback device. The representative image generation control unit controls to generate a plurality of the representative images, and controls to record the plurality of the representative images in the user's own area.
The special reproduction position control unit selects the high-resolution representative image when the special reproduction speed is slower than a predetermined speed, and when the special reproduction speed is equal to or higher than a predetermined speed, the special reproduction position control unit selects the representative image. The video recording / playback device according to claim 1, wherein the representative image having a lower resolution than the predetermined resolution is selected. The representative image generation control unit controls to record the ratio of subtitles in the representative image or the font size of the subtitles in the representative image in the user's own area.
The special reproduction position control unit selects the high-resolution representative image when the ratio occupied by the subtitle exceeds a predetermined ratio or when the font size of the subtitle is smaller than the predetermined font size. The video recording / playback device according to claim 1 or 2, wherein the image recording / playback device is characterized by the above. Further, a display device information acquisition unit for acquiring the display image size and display resolution of the display device for displaying the representative image is provided.
The representative image generation control unit controls to generate a plurality of the representative images, and controls to record the plurality of the representative images in the user's own area.
The special reproduction position control unit selects the high-resolution representative image when the display image size is equal to or larger than a predetermined display image size or the display resolution is equal to or higher than a predetermined display resolution. When the display image size is smaller than the predetermined display image size, or the display resolution is lower than the predetermined display resolution, the representative image having a lower resolution than the predetermined resolution is selected. The video recording / playback device according to claim 1, wherein the image recording / playback device is characterized by the above. It is a video recording / playback method capable of recording / playing back a high-resolution digital broadcast program having a resolution higher than a predetermined resolution.
(A) Control is performed to generate at least one representative image encoded by the still image compression method for each coded compression unit of the digital broadcast program, and the generated representative image is used as metadata information in the coded compression unit. The process of controlling to record in the user's own area where can be recorded, and
(B) A step of selecting the representative image corresponding to the special reproduction at the time of special reproduction different from the normal reproduction speed, and controlling the display of the selected representative image.
A video recording / playback method. In the step (a), control is performed to generate a plurality of the representative images, and control is performed to record the plurality of the representative images in the user's own area.
In the step (b), the representative image having the high resolution is selected when the special reproduction speed is slower than a predetermined speed, and the special reproduction speed is equal to or higher than the predetermined speed. The video recording / playback method according to claim 5, wherein the representative image having a low resolution lower than a predetermined resolution is selected. In the step (a), the ratio of the subtitles in the representative image or the font size of the subtitles in the representative image is controlled to be recorded in the user's own area.
In the step (b), when the ratio occupied by the subtitle exceeds a predetermined ratio, or when the font size of the subtitle is smaller than the predetermined font size, the high-resolution representative image is selected. The video recording / playback method according to claim 5 or 6, characterized in that. (C) Further provided with a step of acquiring the display image size and display resolution of the display device for displaying the representative image.
In the step (a), control is performed to generate a plurality of the representative images, and control is performed to record the plurality of the representative images in the user's own area.
In the step (b), when the display image size is equal to or larger than the predetermined display image size, or the display resolution is equal to or larger than the predetermined display resolution, the high-resolution representative image is selected and the display is performed. When the image size is smaller than the predetermined display image size, or the display resolution is lower than the predetermined display resolution, the representative image having a lower resolution than the predetermined resolution is selected. The video recording / playback method according to claim 5, wherein the image is recorded and reproduced.

Images