JP2004032607A - Digital video reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital video reproducing apparatus for displaying captions matching the reproduction speed of the video. <P>SOLUTION: A variable speed caption control section 7 analyzes the caption PES data outputted from a TS separator 2, according to a fast-forward reproduction instruction from a control section 6, reduces processing wait time, until a next caption is presented inversely proportional to the magnification of the fast-forward reproduction speed and makes it fast, in proportion to the magnification of a scroll speed according to the fast-forward speed, and inserts a control code CS, immediately before the display of the next caption for updating the caption PES data. Then, output is made to a TS multiplexer 3 for multiplexing with the other data, thus generating a transport/stream. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a digital video reproducing apparatus for reproducing received and recorded digital broadcast video and other digital video.
[0002]
[Prior art]
In a digital broadcasting system, information related to a program or the like is added to video and audio by a broadcasting station and compressed, and a transport stream multiplexed by MPEG2 (Moving Picture Experts Group2) is digitally modulated and transmitted. On the receiving device side, the received digital modulation signal is demodulated to generate a transport stream, which is separated into video, audio, and other information and analyzed to present a program or the like to the user. I have. Further, in BS / CS digital broadcasting, the broadcasting station stores information on superimposed text such as subtitles of a movie or emergency broadcast in a PES (Packetized Elementary Stream) separate from video and audio and transports the information. It is multiplexed and sent to the stream. The receiver separates this information from the transport stream and analyzes it to display subtitles and superimposed characters on the screen.
[0003]
Also, a digital signal recording device capable of recording a digital signal received by a receiving device has been developed. Various types of digital signal recording devices, such as a D-VHS, a hard disk, and a DVD-RAM, are known. In any case, a digital signal received by a receiving device is recorded so that, for example, a conventional analog VHS video can be recorded. Similarly, a program broadcast once can be reproduced any number of times. Some digital signal recording apparatuses have a fast-forward reproduction function for reproducing an image at, for example, twice the normal speed.
[0004]
By the way, as shown in FIG. 3, the caption PES data storing information on captions and superimposed text includes a stream ID, PTS (Presentation Time Stamp), DTS (Decoding Time Stamp), data group ID, and one data group data. Contains. The data group data includes one or a plurality of data units. The data group data includes data indicating caption management data and data indicating caption text data, and these are distinguished by the data group ID.
[0005]
The subtitle management data includes information indicating basic attributes of the subtitles, such as the language_tag (language identification) of the subtitles and the display format (resolution, vertical writing, horizontal writing, etc.). However, it is transmitted once every 5 seconds, and serves as a criterion for determining whether or not a program has subtitles. Further, the caption management data includes information such as TMD (time control mode), num_language (number of languages), DMF (display mode), ISO_639_language_code (language code), and TCS (character encoding method). In the subsequent data unit, caption data that is not related to actual screen presentation is described by an 8-unit code defined by ARIB STD-B3 and ARIB STD-B24. The caption data not related to the screen presentation is a control code of SWF, SDF, SDP, SSM, SHS, and SVS among the eight unit codes.
[0006]
On the other hand, in the data unit of the caption sentence data, the contents of the caption and the superimposed text to be actually displayed are described by an 8-unit code. Further, TMD and STM (presentation start time) are included, and the STM stores a value indicating a time to be synchronized when time synchronization is designated by TMD.
[0007]
Captions to be displayed on the screen can be displayed in synchronization with video by following the TMD in the caption text data and the PTS in the data group containing the caption text data (PTS synchronization). On the other hand, the superimposed text can be displayed at a specific time in synchronization with the TMD and STM in the caption text data (STM synchronization).
[0008]
In addition, using a control code such as “TIME” or “CS” (clear screen) among the eight unit codes, it can be described so that the subsequent presentation of subtitles is delayed. For example, if a subtitle is presented on the screen for a while after the subtitle is presented, and this subtitle is to be erased several seconds later, after specifying an 8-unit code for displaying the subtitle, 'TIME', ' 02/0 '(meaning that it is the code of the 0 point in the 2nd section in the 8-unit code; the same applies hereinafter), and then a value in the range of 04/0 to 07/15 is specified, and the After specifying the delay time (display time) in units of 0.1 second with the lower 6 bits, a control code 'CS' which is an 8-unit code for performing screen erasure is specified. In addition, some of the 8-unit codes have a function such as 'SCR' for scrolling one line of subtitles from the right to the left of the screen at a specified speed, and 'FLC' for blinking (flashing) a specific subtitle.
[0009]
[Problems to be solved by the invention]
As described above, some digital signal recording devices have a fast-forward playback function. For example, a transport stream in which subtitle PES data is multiplexed is recorded by a digital signal recording device, and fast-forward playback is performed on the transport stream. In this case, the video is fast-forward reproduced, but the subtitle does not correspond to the fast-forward video, so that the subtitle and the like are not displayed.
[0010]
The present invention has been made in view of the above circumstances, and has as its object to provide a digital video playback device capable of displaying subtitles and the like in correspondence with fast-forwarding of video.
[0011]
[Means for Solving the Problems]
A digital video reproducing apparatus according to the present invention includes means for extracting video data and additional character-related data from a digital signal read from a recording medium, and prevents the video data and additional character-related data from being based on time synchronization information of the additional character-related data when a fast-forward reproduction instruction is given. Means for changing character display control information in the additional character-related data based on reproduction speed information; and means for extracting the video data based on reproduction speed information. .
[0012]
With the above configuration, the character display control information in the additional character-related data is changed and the video data is extracted based on the reproduction speed information without being affected by the time synchronization information of the additional character-related data. Subtitles and the like can be displayed according to the playback speed.
[0013]
The image processing apparatus may further include means for generating a digital signal in which the changed additional character-related data and the extracted video data are multiplexed, and an interface for transmitting the digital signal to a video display device. According to this, the reproduced video can be viewed on a digital broadcast receiving device or the like connected to the digital video reproducing device via, for example, an IEEE1394 interface.
[0014]
It is preferable that the character management information included in the original digital signal is appropriately thinned out so that the transmission interval of the character management information in the additional character related data after the change is not shorter than the specified minimum transmission interval. .
[0015]
If there is a character display clear command as the character display control information of the original digital signal, the character display clear command may be deleted, and the character display clear command may be inserted before the next display character. According to this, for example, the previous subtitle can be deleted immediately before the next subtitle is displayed (that is, the previous subtitle display is maintained until the next subtitle display is started), and fast-forward playback is performed. The visibility of the caption at the time can be improved.
[0016]
The timer starts when the character display clear command is deleted, and inserts the character display clear command when the process of inserting the character display clear command is not performed before the next display character within a predetermined time. It is good to be constituted to perform. As described above, if the previous subtitle display is maintained until the next subtitle display is started, if there is no next subtitle display, subtitles that do not match the scene will continue to be displayed, but time management as described above By doing so, it is possible to prevent subtitles that do not fit the scene from continuing to be displayed.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a digital video reproducing apparatus according to an embodiment of the present invention will be described with reference to FIGS.
[0017]
FIG. 1 is a block diagram showing a digital video reproducing apparatus 10 according to this embodiment. In this figure, thick arrows indicate a flow of a transport stream and PES (Packetized Elementary Stream) data, and thin arrows indicate a control signal. Shows the flow. The recording medium device 1 is, for example, an HDD, a D-VHS, a DVD-RAM, or the like, and reads a transport stream from a recording medium using a signal reader (not shown) and outputs the transport stream to the TS separator 2. Further, the transport stream received via the IEEE 1394 interface 4 can be recorded in the recording medium device 1.
[0018]
The TS separator 2 separates the transport stream received from the recording medium device 1 into video PES data, subtitle (including superimposed) PES data, and other data (for example, audio PES data and program information).
[0019]
The TS multiplexer 3 multiplexes the video PES data from the variable-speed video controller 8, the subtitle PES data from the variable-speed subtitle controller 7, and other data from the TS separator 2 again to form a transport stream. Is output.
[0020]
The IEEE 1394 interface 4 outputs the transport stream output from the TS multiplexer 3 to an external device (for example, a digital broadcast television or a digital STB (Set Top Box)), or a transport stream received from the external device. Is given to the recording medium device 1.
[0021]
The operation unit 5 is a button or the like provided on the remote control transmitter or the digital video reproduction device 10 and gives commands to the control unit 6 such as reproduction, stop, and fast-forward reproduction. The control unit 6 controls each block of the digital video reproduction device 10 according to a command from the operation unit 5.
[0022]
The variable-speed video control unit 8 analyzes the video PES data output from the TS separator 2 according to the fast-forward playback instruction from the control unit 6, and according to the fast-forward speed, for example, an I-picture (intra-frame code) in MPEG2 encoded data. , And outputs video PES data for fast-forward reproduction by extracting only the encoded image.
[0023]
The variable-speed subtitle control unit 7 analyzes the subtitle PES data output from the TS separator 2 based on the fast-forward playback instruction from the control unit 6, changes the content of the subtitle PES data according to the fast-forward speed, and outputs a TS multiplexer. Output to 3.
[0024]
Hereinafter, specific contents of the variable speed subtitle control at the time of fast forward will be described with reference to the flowchart of FIG. Note that the variable-speed caption control unit 7 analyzes each input caption PES data, and as a result, discards the caption PES data or outputs the updated caption PES data to the TS multiplexer 3. In the following description, it is assumed that the playback speed of the fast-forward playback instruction from the control unit 6 is N times that of the normal playback, and the specified minimum transmission interval of the caption management data is 0.3 seconds.
[0025]
The variable speed subtitle controller 7 receives the subtitle PES data output from the TS separator 2 (step S1). The subtitle PES data is developed on a work memory (not shown), sequentially read out, written into a separately prepared work memory through the following steps, and output to the TS multiplexer 3.
[0026]
The variable speed subtitle controller 7 determines whether the received subtitle PES data is subtitle management data (step S2). The determination as to whether or not the data is caption management data is made by referring to the lower 4 bits of the data group ID. If the data is caption management data, it is determined whether the data group ID is the same as the previously received caption management data (step S3). If the data group ID is the same (YES in step S3), It is determined whether 0.3 seconds have passed since the last time the caption management data was received (step S4). If 0.3 seconds have not elapsed, the received subtitle PES data is discarded (step S5). This is a process for preventing the PES including the caption management data from being transmitted during the specified minimum transmission interval of the caption management data of 0.3 seconds. If 0.3 seconds have elapsed, the specified minimum transmission interval of the subtitle management data has been exceeded, and the process proceeds to step S20 without discarding the subtitle management data. Similarly, if it is determined in step S3 that they are not the same, the caption PES data is transmitted to the TS multiplexer 3 as it is because it is unreceived caption management data and cannot be discarded (step S20).
[0027]
If the received subtitle PES data is subtitle sentence data (NO in step S2), it is determined whether the value of TMD is '01' (real time) (step S6). TMD '01' specifies the display processing of time synchronization of subtitles and superimposed characters. If the value of TMD is '01', it is updated to '00' (free) to perform PTS synchronization or STM synchronization. (Step S7).
[0028]
Hereinafter, in steps S8 to S18, the analysis is sequentially performed for each data unit and for each 8 unit code in the data unit, and the 8 unit code is changed as necessary.
[0029]
The variable-speed caption control unit 7 determines whether the eight-unit code in the data unit is the control code 'TIME' and the next one byte is the eight-unit code '02 / 0 '(step S8). If YES, the value of the lower 6 bits of one byte following the 8-unit code '02 / 0 'is set to 1 / N (step S9). For example, if the byte following 'TIME' and '02 / 0 'is hexadecimal' 52 'and the playback speed is triple speed (N = 3), the lower 6 bits of hexadecimal' 52 'are Since the decimal number is '18', 18/3 = 6. Therefore, the 8-unit code in the data unit is updated so that the one byte following 'TIME' and '02 / 0 'becomes hexadecimal' 46 '.
[0030]
Next, it is determined whether there is an SCR indicating scrolling in the extended control code CSI in the 8-unit code (step S10). If there is “SCR”, the process proceeds to step S11. In step S11, a process of updating the decimal value consisting of the lower 6 bits of each byte from the second byte next to the extended control code CSI to immediately before 03/11 indicating the intermediate character to a value multiplied by N is performed. (Step S11). For example, if there is a hexadecimal number “39” 30 ”following“ CSI ”and“ 03/1 ”, followed by 03/11 indicating an intermediate character, this means that the scroll speed is in decimal. Since it is 90 dots / second ('39' → 9, '30' → 0, decimal 90), if the reproduction speed is triple (N = 3), the scroll speed is decimal. It will be 270 dots / second. For this purpose, following the 'CSI' and '03 / 1 ', incorporate the hexadecimal number' 32 '' 37 '30'('32' → 2, '37' → 7, '30' → 0 , Decimal number 270), followed by an update of 03/11 indicating an intermediate character.
[0031]
If NO in step S10, it is determined whether an 8-unit code control code 'CS' exists (step S12). If the control code 'CS' exists, CS_FLAG is set to '1' and the control code 'CS' is deleted (step S17). On the other hand, if the control code 'CS' does not exist, it is determined whether or not it is another control code (step S13). If NO, it is determined whether it is a character code (step S14). If it is a character code, it is determined whether CS_FLAG is '1' (step S15). If CS_FLAG is '1', a control code 'CS' is inserted before the character code and CS_FLAG is set to '0'. (Step S16).
[0032]
The above-mentioned control code 'CS' indicates erasure of subtitles on the screen. If this control code 'CS' exists in the original data, the control code 'CS' is deleted in step S17, If there is a code, the process of inserting the control code 'CS' before the character code in step S16 is performed, so that the previous subtitle is erased immediately before the next subtitle is displayed (that is, the next subtitle display is started. (The display of the previous subtitle is maintained until the current subtitle is displayed), and the visibility of the subtitle at the time of fast forward reproduction can be improved.
[0033]
After step S16, it is determined whether or not the data unit is at the end (step S18). If YES in step S13 and NO in steps S14 and S15, the process proceeds to step S18 without passing through step S16. If it is not the end of the data unit (NO in step S18), the process returns to step S8 to check the next 8-unit code in the data unit. If it is the end, it is determined whether there is a next data unit (step S19). If there is, the process returns to step S8 to check the leading 8-unit code of the next data unit. If there is no next data unit, the PES subjected to the change processing as described above is transmitted to the TS multiplexer 3 (step S20).
[0034]
As described above, if the previous subtitle display is to be maintained until the next subtitle display is started (CS_FLAG is “1” during fast-forward playback), and if there is no next subtitle display, the scene Unsuitable subtitles will continue to be displayed (for example, subtitles will be displayed even after switching to commercials). In order to avoid this, if CS_FLAG is “1” at the time when a predetermined period (for example, 5 seconds) has elapsed from when CS_FLAG is set to “1”, the data unit with the control code “CS” inserted is transmitted. Is also good. When switching from fast-forward playback to normal-speed playback, CS_FLAG is set to “0” and a data unit including (not deleted) a control code “CS” is transmitted.
[0035]
As described above, during fast-forward playback, the transmission interval of caption PES data including caption management data is set to be equal to or longer than the specified minimum transmission interval (0.3 seconds). The subtitle management data is discarded, and the TMD of the subtitle management data is changed so that PTS synchronization and STM synchronization are not performed. The control code 'CS' is inserted immediately before the next subtitle display to update the subtitle PES data. On the other hand, the disadvantage that the subtitle display period becomes too long due to the subtitle display time management is also avoided. Also, for the subtitle scroll display, the scroll speed is increased in proportion to the reproduction speed.
[0036]
In this embodiment, the subtitle PES data updated as described above is multiplexed with the video PES data and other data by the TS multiplexer 3 and transmitted as a transport stream. However, if the digital video reproducing apparatus 10 is of a digital broadcast television integrated type, the multiplexing by the TS multiplexer 3 is not necessarily required, and the variable-speed subtitle control is performed. What is necessary is just to supply data from the section 7 and the variable speed video control section 8 to the MPEG decoder.
[0037]
【The invention's effect】
As described above, according to the present invention, subtitles and superimposed characters can be displayed in accordance with the video playback speed. If the character display clear instruction is deleted and the character display clear instruction is inserted before the next display character, the previous subtitle display can be maintained until the next subtitle display starts, and fast forward playback The visibility of the caption at the time can be improved. In addition, in the case of maintaining the previous subtitle display until the next subtitle display is started, if the time management is performed and the character display clear command is inserted, the subtitles that are not suitable for the scene will continue to be displayed. Can be avoided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a digital video reproducing apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating caption control processing.
FIG. 3 is an explanatory diagram showing the structure of subtitle PES data.
REFERENCE SIGNS LIST 1 recording medium device 2 TS (transport stream) separator 3 TS (transport stream) multiplexer 4 IEEE1394 interface 5 operation unit 6 control unit 7 variable-speed subtitle control unit 8 variable-speed video control unit

Claims (5)

Means for extracting video data and additional character-related data from the digital signal read from the recording medium; and, when a fast-forward playback instruction is given, not to be based on time synchronization information of the additional character-related data and to be based on playback speed information. A digital video reproducing apparatus comprising: means for changing character display control information in the additional character related data; and means for extracting the video data based on reproduction speed information. 2. The digital video reproducing apparatus according to claim 1, wherein a means for generating a digital signal obtained by multiplexing the changed additional character related data and the extracted video data is provided, and an interface for transmitting the digital signal to a video display device. And a digital video reproducing apparatus comprising: 3. The digital video playback device according to claim 1, wherein the transmission interval of the character management information in the additional character-related data after the change is included in the original digital signal so as not to be shorter than a specified minimum transmission interval. A digital video reproducing apparatus characterized in that the character management information is thinned out as needed. In the digital video reproducing apparatus according to any one of claims 1 to 3, if a character display clear command is present as character display control information of the original digital signal, the command is deleted, and the character display clear command is deleted before the next display character. A digital video playback apparatus characterized in that a character display clear command is inserted into the digital video playback apparatus. 5. The digital video reproducing apparatus according to claim 4, wherein when a character display clear command is deleted, time counting is started, and a process of inserting a character display clear command before a next display character within a predetermined time is performed. A digital video playback device configured to perform a process of inserting a character display clear command when there is no such command.

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