JP5642529B2 - Image reproducing apparatus and image reproducing method - Google Patents

Description

  The present invention relates to an image playback apparatus and an image playback method used in a video on demand (VOD) system that provides video information according to a user's request, and in particular, so-called trick play such as fast forward playback and rewind playback. The present invention relates to an image reproducing apparatus and an image reproducing method capable of selecting a target image in operation.

  2. Description of the Related Art Conventionally, a video on demand (VOD) system is known as a system that distributes various contents in response to a request from a user. In this VOD system, stream data is received from the server and played back. However, the communication state of the stream data is not always stable, and if the stream data is played back directly, it may become unstable. The received stream data is buffered once on the playback device side, and when a certain amount of stream data is accumulated, playback starts with a time lag from reception.

JP-A-8-251542 International Publication WO2007 / 148777

  However, as is clear from normal video, it is difficult to match the target point in one trick play. Actually, the target scene is finally reached after repeating trick play several times, too much or too close. Playback from is possible. In such a case, the VOD system has a problem that communication with the server is increased and the burden is increased, and a certain amount of buffering is performed each time trick play is performed, so that waiting time increases.

  To solve this problem, for example, in Patent Document 1, when trick play is performed, a target scene can be searched using buffered data. However, the technique described in Patent Document 1 has a difficulty when the data of the scene intended by the user is not stored in the buffer. For example, there is a possibility that the server may be burdened, for example, the video cannot be reproduced smoothly without being accurately connected as the content data, or the data needs to be retransmitted in order to reproduce the content without interruption.

In Patent Document 2, it is easy to find a target scene by jumping to a chapter position during trick play operation. However, at the time of playback at the jump destination, a predetermined amount of buffering is eventually performed and a waiting time is required. For example, when there is a video desired by the user between chapters, the user frequently Trick play operation is required, and there is a risk of server burden.
As described above, with the techniques described in Patent Documents 1 and 2, it is difficult to drastically solve the above-described problems.

  The present invention has been made in view of the above problems, and its object is to reduce the amount of data retransfer and reduce the server load, and during trick play, the user can easily search for a desired image. Another object of the present invention is to provide an image reproducing apparatus and an image reproducing method capable of seamlessly reproducing received content.

  That is, the image reproducing device according to the present invention sequentially writes the image data for moving images received from the server via the network into the ring buffer, and the image data from the read address set behind the write leading address. Is read and the moving image is played back, and the image data or the image data related to the image data is intermittently received from the image data read by receiving operation information related to playback by the user or fast-forward playback. An image information storage unit that acquires and stores image-related data, and a selection that displays the image indicated by the series of image data stored in the image information storage unit or the image-related information indicated by the image-related data so that the user can select it. The display unit and the image data indicated by the image selected by the user or the image-related information are displayed on the ring bar. If it is not in the file, the most past image data that can be independently displayed on the ring buffer is specified from the writing leading edge address at the time of the selection, and the past image is displayed from the image data indicated by the image or the image related information. An image data receiving unit that receives image data up to the data from the server; And a moving image reproduction unit that reproduces a moving image from the read address by writing the image data and moving the read address to the backward writing tip address.

  If it is such, when it goes too much by trick play, for example, between the image data indicated by the image or the image related information indicating the vicinity of the reproduction position selected by the user and the oldest image data on the ring buffer Since only the minimum necessary image data is received from the server, there is no need to connect to the server unnecessarily. Therefore, data transfer and data storage processing can be suppressed to the minimum, and server load and user waiting time can be greatly reduced.

Moreover, since each image or image related information corresponding to the image data at a plurality of points in time is stored and displayed so as to be selectable by the user, the user can easily search for a desired scene. . In addition, since the received image data is seamlessly connected to the past image data that can be independently displayed in the ring buffer, it is possible to seamlessly reproduce a moving image.
The image data stored in the image information storage unit is preferably an I picture.

The present invention may be an image reproduction method as described below. That is, the image data for moving image received from the server via the network is sequentially written in the ring buffer, and the image data is read from the read address set behind the write leading address to reproduce the moving image. A playback method,
An image information accumulating step for intermittently acquiring and accumulating image data or image related data related to the image data from the image data read by receiving operation information related to reproduction or fast-forward reproduction by a user; A selection display step for selectively displaying the image indicated by the series of image data stored in the information storage step or the image related information indicated by the image related data to the user, and the image or the image related information is selected by the user; When the image data indicated by the image or the image-related information is not in the ring buffer, the image data indicated by the image or the image-related information is the most independently displayable on the ring buffer from the write leading edge address at the time of selection. The past image data is specified, and the image data indicated by the image or the image related information An image data reception step of receiving the image data to the image data of Sa from the server,
The write leading address is retracted by the amount of image data received in the image data receiving step, and the received image data is written from the retracted writing leading address, and the read is performed at the retracted writing leading address. And a moving image reproduction step of reproducing a moving image from the read address by moving an address.

  According to the image reproducing device and the image reproducing method of the present invention, the data transfer capacity is reduced to reduce the server load, and the user can easily search for a desired image during trick play, and the received moving image can be seamlessly displayed. It is possible to play back.

1 is a schematic diagram showing an overall configuration of a video on demand (VOD) system in which an image reproduction apparatus according to an embodiment of the present invention is used. 1 is a schematic configuration diagram of an image reproduction device according to an embodiment of the present invention. It is a functional block diagram which shows the internal structure of the image reproduction apparatus which concerns on one Embodiment of this invention. It is a schematic explanatory drawing about the operation | movement of the write front address and read address of the image data in a ring buffer. It is the schematic which shows the relationship between the state of a ring buffer, and the image on a time axis. It is a figure which shows the state in which the image was arranged so that selection was possible. It is a figure which shows the state in which the image relevant information was arranged so that selection was possible. It is a schematic explanatory drawing which shows operation | movement of a ring buffer when the image which does not exist in a ring buffer is selected. It is a schematic explanatory drawing which shows operation | movement of a ring buffer when the image which does not exist in a ring buffer is selected. It is a flowchart which shows the internal operation | movement of an image reproduction apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

FIG. 1 is a schematic diagram showing an overall configuration of a video on demand (VOD) system in which an image reproduction apparatus 1 according to an embodiment of the present invention is used, and FIG. 2 is an embodiment of the present invention. It is a schematic block diagram of the image reproduction apparatus 1 which concerns on a form. FIG. 3 is a block diagram showing the internal structure of the image playback device 1 according to an embodiment of the present invention.
As shown in FIG. 1, a server 2 and an image playback device 1 are connected via a network 3 to constitute a VOD system.

  The server stores various moving image contents (also referred to as moving image data) so that the moving image content in response to a request from the user can be distributed to an image playback device operated by the user via the network. It has become. Here, for example, description will be made on the assumption that HTTP, which is a request-response type protocol that supports a Range header, is used as a communication protocol, and that MPEG format is handled as moving image data. Of course, it is not limited to these specific forms.

  The image reproducing apparatus 1 is, for example, a television, a PC, a DVD recorder, a Blu-ray disc recorder, or the like. As shown in FIG. 2, the image reproducing apparatus 1 has a recording unit 11, a receiving unit 12, a transmitting unit 13, and a display unit 14. The encoder 15 and the decoder 16 are provided so that the CPU 10 controls each part. Here, a plurality of image reproducing apparatuses 1a, 1b... 1n are connected.

The recording unit 11 includes an external memory such as a hard disk and a memory card in addition to an internal memory such as a ROM and a RAM.
The receiving unit 12 receives a signal related to operation information performed by the user using a remote controller (not shown) and image data sent from the server.
The transmission unit 13 transmits information related to the content selected by the user to the server based on the user operation information.
The display unit 14 is, for example, a display, and can display information and a status such as time, day of the week, recording or reproduction in addition to an image.
The encoder 15 converts the input analog signal into an MPEG encoded digital signal.
The decoder 16 decodes the MPEG encoded data read from the recording unit.

  Accordingly, the image reproduction apparatus 1 is described in terms of functional aspects including software operations by the CPU and the like, as shown in FIG. 3, a data control unit 100, a ring buffer 101, an image information storage unit, An index data storage unit 102, a moving image reproduction unit 103, an index display unit 104 as a selection display unit, and an image data reception unit 105 are provided.

The data control unit 100 writes the image data downloaded from the server 2 in the ring buffer 101 and stores the image or image related information corresponding to the image data at a plurality of time points in the index data storage unit 102.
The ring buffer 101 is set in a predetermined area such as the RAM, and the storage areas are logically connected in a circular manner.

  The index data storage unit 102 serving as an image information storage unit intermittently extracts a plurality of frame image data from the moving image data downloaded from the server 2 and stores the frame image data in a predetermined area such as the RAM. .

  By the way, the moving image data here is in the MPEG format, and is therefore divided in GOP units. This GOP is composed of three types of frame image data of I-picture, P-picture, and B-picture, and only I-picture can be displayed independently independently of the preceding and following frame image data. The other image frame data is represented by difference information from the previous and subsequent image frame data. Therefore, one or more I-pictures are always included in a GOP, and the head is I-picture.

  Therefore, the index data storage unit 102 extracts and stores the I-pitch sequentially or intermittently. The frame image data may be any data that can be displayed independently, and other than MPEG, the data is naturally in a different format. Further, in place of the frame image data, image-related information that suggests the frame image data, for example, an elapsed time from the beginning of reproduction may be used.

  The moving image reproduction unit 103 performs a process of reproducing the downloaded image data as a moving image by continuously displaying the downloaded image data on the display 4.

  The index display unit 104 displays an image corresponding to the I-picture on the display 4 so that the user can select it.

  The image data receiving unit 105 calculates a necessary reception amount by the data control unit 100 based on the moving image reproduction status by the moving image reproducing unit 103, and requests the server 2 to download based on this calculation.

  FIG. 4 is a schematic explanatory view of the operation of the writing leading edge address W and the reading address R of the image data in the ring buffer 101. In FIG. 4, the time axis is set from the left side to the right side in each figure, and it is assumed that the write leading address W and the read address R move from the left side to the right side as time passes.

  As shown in FIG. 4A, since nothing is written in the ring buffer 101 in the initial state, the write leading address W and the read address R are located at the left end (0 address) of the ring buffer. ing.

  Then, when the user views a certain content, the write leading address W of the ring buffer 101 first moves from the left side to the right side as shown in FIG. 4B based on the user operation information. To go. As a result, image data is written to the ring buffer 101 by the amount corresponding to the write leading address W (accumulation of unreproduced data).

  Next, as shown in FIG. 4C, when the writing leading edge address W writes a certain amount (for example, 4 MB) of image data in the ring buffer, the reading address R follows the writing leading edge address W. However, it moves from the left side of the figure to the right side. In this manner, moving image reproduction is performed by displaying the image data continuously reproduced by the read address R on the display.

  Normally, since the writing speed of the writing tip address W is set faster than the progress (reproduction) speed of the reading address R, the writing tip address W that has reached the right end of the ring buffer 101 is shown in FIG. Then, new data is written from the left end of the ring buffer 101 as shown in FIG. Then, as shown in FIG. 4E, when the write leading address W catches up with the reading address R, the writing leading address stops writing once and stops at that address.

  After that, as shown in FIG. 4F, only the read address R reads the image data in the ring buffer 101 and reproduces it. Then, as shown in FIG. 4G, the read address R that has reached the right end of the ring buffer 101 further reads and reproduces new data from the left end of the ring buffer 101. In this manner, writing to the ring buffer 101 and data reproduction are performed, and display on the display 4 is performed.

  At this time, corresponding to the movement of the read address R, each image or image related information corresponding to the image data at a plurality of time points of the content being reproduced is stored in the index data storage unit 102. For example, as shown in FIG. 5, the frame image data (I-picture) at the head of each GOP of the moving image content is stored in the RAM sequentially by the index data storage unit 102 along with or subsequent to the reproduction.

  As shown in FIG. 6, the image data stored in this way is displayed on the display 4, for example, so that the user can select it. That is, when the user selects the displayed I-picture, a scene desired to be viewed can be found at a glance.

  Further, as described above, the data stored in the index data storage unit 102 is not limited to the I-picture, and the image related information such as the data position and time in the moving image corresponding to the image data at a plurality of times of the content. It may be. When the image related information is stored, as shown in FIG. 7, I-picture information, time (time corresponding to the I-picture), address position on the ring buffer 101, presence / absence flag in the buffer (ring buffer) 101) and the like can be displayed in the form of a table. As a result, the user can search for a scene that the user wants to see at a glance by looking at the information displayed in a selectable manner. The image selected by the user exists in the ring buffer 101, that is, the data stored in the index data storage unit 102, and the image selected by the user exists at the address in the ring buffer 101. If this is the case, the read address R may be moved to the address of the selected image or the like, and playback may be started again from there.

  Further, in FIG. 8A, for example, when the address in the ring buffer 101 can be designated as an address from address 1 to address 100, the read address R is set to the address 20 in the ring buffer 101. Yes, the writing tip address is at address 70, the addresses from address 1 to address 20, and addresses from address 70 to address 100 are reproduced data, and further, data in the areas from address 20 to address 70 are stored. The state of the ring buffer 101 which is so-called unreproduced data to be reproduced from now on is shown.

  Here, as shown in FIG. 8B, when the user selects an image or the like that is not stored in the ring buffer 101, that is, although it is not already stored in the ring buffer 101, the index data is stored. When the user selects an I-picture corresponding to address 15 as data stored in the section 102, the data position of the selected I-picture is specified in the Range header and a GET request is made to the server. . On the other hand, the most recent I-picture in the ring buffer 101, that is, the data position of the I-picture closest to the current writing tip address is stored separately (assuming that it is the same here). The difference data amount between the selected I-picture and the past I-picture is calculated. Then, the writing leading edge address W and the reading address R are moved to an address retreated from the address of the past I-picture by the difference data amount. Next, the data transmitted from the server is written from the writing tip address. When the moving image data up to the stored data position is received, the connection with the server is disconnected.

  Thereafter, as shown in FIG. 8C, the writing leading edge address W is moved to the address position (address 15) of the image or the like selected by the user. As a result, all the data in the ring buffer 101 becomes unreproduced data, and when the read address R reads the data in the ring buffer 101, the display 4 starts from the content corresponding to the image data from address 15 on the display 4. Is displayed.

When a certain amount of reading is performed, that is, when the reading address R advances and the difference address between the writing tip address W and the reading address R becomes less than a predetermined amount (for example, 4 MB), the server 2 and the image reproduction are performed again. The connection with the apparatus 1 is established, and the reception of the image data is resumed. As shown in FIG. 9B, the write leading address W starts to move. It is not always necessary to wait for the size to be less than 4 MB. For example, after obtaining data to be reacquired, if a writable area appears in the ring buffer, the subsequent data is requested and received and written. The tip address W may be advanced.
FIG. 10 is a flowchart for explaining the internal operation of the image reproduction apparatus.

  First, while the user is viewing a desired moving image content, in the image reproduction device 1, content data is written into the ring buffer 101, and the I-picture of the reproduced content is accumulated by the index data storage unit 102. (Step S1).

  It is determined whether trick play such as rewind playback or fast forward playback has been performed by the user (step S2). If trick play has not been performed (NO in step S2), content data writing and I-picture (or image-related information) accumulation are continued as the content is viewed.

  On the other hand, when trick play is performed (YES in step S2), the image (or image related information) related to the I-picture accumulated up to the read address R is displayed on the display 4 (step S3). Then, the user confirms and selects an image (or image related information) related to I-picture (step S4). Next, it is determined whether an image (or image related information) related to the I-picture selected by the user is written in the ring buffer 101 (step S5).

  When the image (or image related information) related to the I-picture selected by the user is in the ring buffer 101 (YES in step S5), the read address R in the ring buffer 101 is the image or image selected by the user. The image data is moved to the recording position corresponding to the related information (step S6). Then, normal playback is started without connecting to the server.

  On the other hand, if the image (or image related information) related to the I-picture selected by the user is not in the ring buffer 101 in step S5 (NO in step S5), first, the write leading address at that time is stored. Is done.

  Next, the server requests transmission of stream moving image data starting from the image (or image related information) related to the I-picture selected by the user (step S8).

  On the other hand, a difference data amount between the I-picture selected by the user and the past I-picture is calculated. Then, the writing tip address and the reading address are moved to an address retreated from the most previous I-picture address by the difference data amount (step S9).

Next, the data transmitted from the server is written from the writing leading edge address (step S10). When the moving image data up to the stored data position is received, the connection with the server is disconnected (steps S11 and S12). Then, the write address is moved to the write tip address set in step S9.
The reproduction is started from the reading address (step S13).

As described above, in the image reproduction device according to the present embodiment, the content reception amount is calculated based on the difference address between the recording position of the image data indicated by the image selected by the user or the image-related information and the writing leading edge address W. Therefore, since it is not necessary to connect to the server 2 unnecessarily, data transfer or data storage processing is not performed, and the load on the server 2 can be reduced. Furthermore, among the moving image content, each image or image-related information corresponding to the image data at a plurality of time points is accumulated and displayed so as to be selectable to the user, so that the user can easily search for a desired scene. Become. Further, since the content to be received is received based on the address positions of the writing tip address W and the reading address R in the ring buffer 101, the image data corresponding to the content written in the ring buffer 101, and the reception The image data corresponding to the selected content is seamlessly connected, and the content can be reproduced seamlessly.
In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Image reproduction storage 2 Server 3 Network 100 Data control part 101 Ring buffer 102 Index data storage part 103 Movie reproduction part 104 Index display part 105 Data request part W Write front address R Read address

Claims (3)

The video data received from the server via the network is sequentially written in the ring buffer, and the video data is read from the read address set behind the write leading address, and the video is played back. An image playback device,
An image information storage unit that intermittently acquires and stores image data or image-related data related to the image data from the image data read by receiving operation information related to playback or fast-forward playback by the user,
A selection display unit that displays the image indicated by the series of image data stored in the image information storage unit or the image related information indicated by the image related data so as to be selectable to the user;
When the image or image-related information is selected by the user and the image data indicated by the image or image-related information is not in the ring buffer, independent display on the ring buffer is performed based on the writing leading edge address at the time of selection. An image data receiving unit that identifies the most possible past image data and receives image data from the image data indicated by the image or image-related information to the most past image data that can be independently displayed from a server;
The write leading address is retracted by the amount of image data received by the image data receiving unit, and the received image data is written from the retracted writing leading address, and the read is performed at the retracted writing leading address. An image reproducing apparatus comprising: a moving image reproducing unit that moves an address and reproduces a moving image from the read address.   The image reproducing apparatus according to claim 1, wherein the image data stored in the image information storage unit is an I picture. An image reproduction method for sequentially writing image data for a moving image received from a server via a network in a ring buffer, reading the image data from a read address set behind the write leading address, and reproducing the moving image An image information storage step for intermittently acquiring and storing image data or image-related data related to the image data from the image data read by receiving operation information related to reproduction or fast-forward reproduction by a user; ,
A selection display step of displaying the image indicated by the series of image data stored in the image information storage step or the image related information indicated by the image related data so as to be selectable to the user;
When the user selects the image or the image related information and the image data indicated by the image or the image related information is not in the ring buffer, the writing at the time of the selection is performed from the image data indicated by the image or the image related information. The most recent image data that can be independently displayed on the ring buffer is specified based on the leading edge address, and image data from the image data indicated by the image or the image related information to the most past image data that can be independently displayed is a server. Receiving image data from
The write leading address is retracted by the amount of image data received in the image data receiving step, and the received image data is written from the retracted writing leading address, and the read is performed at the retracted writing leading address. And a moving image reproduction step of reproducing a moving image from the read address by moving an address.