JP2004040150A - Apparatus, method and system for reproducing compressed data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce MPEG (Moving Picture Experts Group) data at an accurate position, without taking much time for preparing a database. <P>SOLUTION: Prior to starting reading of the MPEG data, the MPEG data are equally divided into a plurality of data, the frame numbers of intra-frames around the position of equally divided data are obtained (step S2), and an interpolation function for interpolating the position of the overall MPEG file for the frame number of an intra-frame between the divided position is generated, by using some of the obtained frame numbers (step S4). When the frame number of a frame of a read request destination of the MPEG data is transmitted, the frame number is substituted for the interpolation function to determine the position for the entire MPEG file, the frame number of an intra-frame near the frame number from that is identified (step S5), and the MPEG data are reproduced at the intra-frame having the identified frame number (step S6). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a compressed data reproducing apparatus, method, and system, and more particularly, to a compressed data reproducing apparatus, method, and system for MPEG (Moving Picture Experts Group) data and the like.
[0002]
[Prior art]
Conventionally, to reproduce MPEG data from a designated time, a presentation time stamp (I-Frame) assigned to a reproducible intra-frame (I-frame) for detecting a reproduction start position has been used. (PTS) or the like, the entire reproduction number is stored in a database in advance, or the approximate reproduction start position is obtained from the total reproduction time obtained by searching for the file size and the PTS at the beginning and end of the MPEG data. It was playing from the I frame.
[0003]
[Problems to be solved by the invention]
However, the conventional technique has a problem that it takes a long time to create a database when the MPEG data is a file having a long total reproduction time.
[0004]
Further, there is a problem that if only the approximate reproduction start position is obtained, the MPEG data cannot be reproduced from an accurate position.
[0005]
Accordingly, it is an object of the present invention to enable MPEG data to be reproduced from an accurate position without taking time to create a database.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the present invention provides a storage unit for storing compressed data including a plurality of frames, and a reading unit for reading compressed data stored in the storage unit from a commanded intra frame. A compressed data reproducing apparatus comprising: before starting reading of compressed data by the reading means, divides the compressed data stored in the storage means into a plurality of pieces; By obtaining the position of the entire MPEG file with respect to the frame number, and using some of the obtained frame numbers, creating an interpolation function for compensating the position of the entire MPEG file with respect to the frame number of the intra frame between the division positions. The frame number of the frame to which the compressed data read request is sent. At this time, the frame number of the intra frame close to the position with respect to the whole MPEG file obtained by substituting the frame number into the interpolation function is determined, and the reading means is instructed to read from the intra frame of the determined frame number. It is characterized by comprising reproduction instruction means.
[0007]
According to another aspect of the present invention, there is provided a compressed data reproducing apparatus comprising: storage means for storing compressed data including a plurality of frames; and reading means for reading the compressed data stored in the storage means from a commanded intra frame. Prior to the start of reading compressed data by the reading unit, the compressed data stored in the storage unit is equally divided into a plurality of pieces, and the frame numbers of intra frames around each division position are acquired. In advance, when the frame number of the frame of the compressed data read request destination is transmitted, a binary tree search is performed to determine a frame number of an intra frame close to the frame number, and an intra frame of the determined frame number Reproduction command means for instructing the reading means to read from the memory.
[0008]
Further, the display device of the present invention transmits the frame number of the frame to which the compressed data is requested to be read to any one of the compressed data reproducing devices, and the compressed data reproducing device responds to the transmission of the frame number. The read compressed data is displayed.
[0009]
Furthermore, a compressed data reproducing system according to the present invention includes any one of the above compressed data reproducing devices and a display device.
[0010]
The present invention also relates to a compressed data reproducing method for reading compressed data including a plurality of frames from a commanded intra frame, wherein the compressed data is divided into a plurality of pieces before starting reading the compressed data. Interpolation that divides and obtains the frame numbers of the intra frames around each division position, and uses some of the obtained frame numbers to compensate for the position in the entire MPEG file with respect to the frame number of the intra frame between the division positions A function is created, and when the frame number of the frame of the compressed data read request destination is sent, the frame number is substituted into the interpolation function and a frame number of an intra frame close to the frame number is set. Identify and read from the determined intra-frame of the frame number To.
[0011]
Further, the present invention is a compressed data reproducing method for reading compressed data including a plurality of frames from a commanded intra frame, wherein the compressed data is divided into a plurality of pieces before starting reading the compressed data. Divide and obtain the frame numbers of the intra frames around each division position, perform a binary tree search when the frame number of the frame of the compressed data read request destination is transmitted, and find , The frame number of the intra frame is determined, and the frame number is read from the intra frame of the determined frame number.
[0012]
Still further, the display method of the present invention transmits a frame number of a frame to which a request for reading the compressed data is transmitted to a compressed data reproducing apparatus that realizes any of the above compressed data reproducing methods, and transmits the frame number. Accordingly, the compressed data read by the compressed data reproducing device is displayed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
(Embodiment 1)
[Description of configuration]
FIG. 1 is a block diagram illustrating a schematic configuration of the compressed data reproduction system according to the first embodiment of the present invention.
[0015]
FIG. 1 shows a home server 10 storing MPEG data, which is compressed data, as described below, and issues commands to the home server 10 such as reproduction, high-speed reproduction, stop, and pause of the MPEG data. 10 shows a client personal computer (PC) 20 for displaying the MPEG data distributed from 10 on a monitor or the like.
[0016]
The home server 10 distributes to the client PC 20 the file storage unit 11 storing the MPEG data, the MPEG read unit 12 for reading the MPEG data from the file storage unit 11, and the MPEG data read by the MPEG read unit 12. The communication control unit 13 and the MPEG data stored in the file storage unit 11 in response to a request from the client PC 20 are divided into, for example, 16 equal parts, and the I-Frame frame numbers and frame numbers near some division positions , A playback command section 14 for creating a database file including the position of the entire MPEG file, a database 15 for storing the database file created by the playback command section 14, and a database 15 stored in the database 15 when the MPEG data is played. One database file And a memory 16 to be written to specifically.
[0017]
The client PC 20 includes a communication control unit 21 that receives the MPEG data distributed from the home server 10, an MPEG decoder 22 that decodes the MPEG data received by the communication control unit 21, and a data that is decoded by the MPEG decoder 22. And a GUI (Graphical User Interface) 23 for displaying, for example, a request for distributing MPEG data to the home server 10 and the like.
[0018]
FIGS. 2 and 3 are schematic structural diagrams of MPEG data stored in the file storage unit 11 of FIG.
[0019]
As shown in FIG. 2, the MPEG data includes a PACK 101, PESs 102 to 106, and the like. The PES includes Video (video) PESs 102 to 104 and 106 and Audio (audio) PES 105.
[0020]
As shown in FIG. 3, PTSs (Presentation Time Stamp) for reproducing the Video and Audio recorded therein are recorded in the PESs 102 to 106 and the like. FIG. 3 shows an example in which the PTS of the PES 201 is 9009, the PTS of the PES 202 is 12012, and the PTS of the PES 203 is 15015. Various information including a PES header is stored in the Video PES 202 as illustrated.
[0021]
Here, for example, when the frame number of the frame to which the reading of the MPEG data is requested is sent from the client PC 20 side, it is not known whether or not this frame number is of the I-frame. If the corresponding PTS is 10000, the PTS located in the vicinity is read from the I-frame of 12012.
[0022]
[Description of operation]
FIG. 4 is an explanatory diagram of the operation of the reproduction command unit 14 of FIG.
[0023]
The operation of the compressed data reproduction system of FIG. 1 will be described with reference to FIG.
[0024]
First, the home server 10 stores MPEG data in the file storage unit 11. In this state, when the client PC 20 outputs an MPEG data distribution request including the frame number of the frame to which MPEG data is requested to be read through the GUI 23 in order to reproduce the MPEG data, the reproduction command unit 14 Prior to the reproduction of the MPEG data, it is determined whether or not a database file has already been created and stored with reference to the database 15 (step S1).
[0025]
If the result of the determination is that a database file is not stored in the database 15, the reproduction command unit 14 creates a database file (step S2).
[0026]
Specifically, a database file is created as follows. That is, the playback command unit 14 divides the MPEG data stored in the file storage unit 11 into 16 equal parts, for example, and splits the I-Frame PES near each division position and the entire I-frame MPEG data to which the PES is assigned. Create a database file containing the signals for
[0027]
As a result of the determination, if the database file is stored with reference to the database 15, the database file is read from the database 15, and if the database file is created by the reproduction command unit 14, the database file is read. Is written into the memory 16 (step S3).
[0028]
Then, the reproduction command unit 14 refers to the database file written in the memory 16 and determines, for example, an N-order interpolation function based on the N frame numbers around the frame number of the frame to which MPEG data is requested to be read and their positions. Is created (step S4).
[0029]
Then, the position information of the entire MPEG file is obtained by substituting the frame number of the frame of the read request destination of the MPEG data specified by the client PC 20 into the N-order interpolation function, and the I-Frame frame number close to the position is obtained. The position of the entire MPEG file is determined (step S5).
[0030]
Next, the reproduction command section 14 commands the reading of the MPEG data from the frame of the determined frame number, and the MPEG reading section 12 reads the MPEG data stored in the file storage section 11 according to the command, and performs the communication control. The data is distributed to the client PC through the unit 13 (step S6).
[0031]
At the same time, the MPEG data read by the MPEG reading unit 12 is also output to the reproduction command unit 14. When the I-Frame is detected by referring to the PES of the MPEG data output from the MPEG reading unit 12, the reproduction command unit 14 acquires the position and the frame number of the I-frame, and additionally records it in the memory 16. (Step S7).
[0032]
Then, the reproduction command section 14 determines whether or not a command to end the reproduction of the MPEG data has been issued from the client PC 20 (step S8).
[0033]
As a result of the determination, if the command to end the reproduction of the MPEG data has not been issued from the client PC 20, the process returns to step S 6. If the command to end the reproduction of the MPEG data has been issued from the client PC 20, the database file in the memory 16 is read. The result is stored in the database 15 and the processing shown in FIG.
[0034]
The database file in the memory 16 may be stored in the database 15 even when a command to temporarily stop or stop the playback of the MPEG data is issued from the client PC 20.
[0035]
Further, in the present embodiment, the case where the MPEG data is divided into 16 equal parts has been described as an example. However, the present invention is not limited to this. For example, the MPEG data may be divided into ten equal parts, twenty equal parts, or not equally divided. Further, for example, if the divided area is too large to perform effective position detection even after being divided into 16 equal parts, when the frame number of the compressed data read request destination is received, a more appropriate For example, the area may be divided into 16 equal parts to improve the reliability of the interpolation function.
[0036]
(Embodiment 2)
FIG. 5 is an explanatory diagram of the operation of the reproduction command unit 14 according to the second embodiment of the present invention.
[0037]
Note that the configuration of the compressed data reproduction system of the present embodiment is the same as that of FIG. The method of creating the database file is also the same as described in the first embodiment.
[0038]
First, as described in the first embodiment, the reproduction command unit 14 determines whether or not a database file has already been created and stored with reference to the database 15 (step S11).
[0039]
If the database file is not stored in the database 15 as a result of the determination, the playback command unit 14 obtains the position of the entire MPEG file corresponding to the I-frame frame number near the start and end of the MPEG data, and Are the detection start position and the detection end position (step S12).
[0040]
On the other hand, if the database file is stored in the database 15 as a result of the determination, the database 15 is referred to for the position with respect to the entire MPEG file corresponding to the I-frame frame number in which the frame number of the read request destination is narrowest. These are used as the detection start position and the detection end position (step S13).
[0041]
Then, an I-frame frame number near the midpoint between the detection start position and the detection end position is obtained (step S14).
[0042]
Then, it is determined whether or not the length between the detection start position and the detection end position has become equal to or less than Skbyte (step S15).
[0043]
Here, S is, for example, approximately equal to the length of the GOP. This is because most of MPEG data basically has only one I-frame in a GOP, so it is rare that an I-frame exists within a narrower range. There is no need to do it.
[0044]
As a result of the determination, when the length between the detection start position and the detection end position is equal to or smaller than Skbyte, the reproduction of the MPEG data is started from the I-frame near the middle point between the detection start position and the detection end position. Then, the processing illustrated in FIG. 5 ends (step S19).
[0045]
On the other hand, as a result of the determination, if the length between the detection start position and the detection end position is not equal to or smaller than Skbyte, the frame number of the read request destination is set near the middle point between the detection start position and the detection end position. It is determined whether the frame number is larger than the I-frame frame number (step S16).
[0046]
If the frame number of the read request destination is larger than the frame number of the I-frame near the middle point between the detection start position and the detection end position, the detection of the frame number of the I-frame near the middle point is started. The process returns to step S14 as the position (step S17).
[0047]
On the other hand, if the frame number of the read request destination is not larger than the frame number of the I-frame near the middle point between the detection start position and the detection end position, the frame number of the I-frame near the middle point is detected. The process returns to step S14 as the end position (step S18).
[0048]
After the end of the process shown in FIG. 5, the process is the same as the process of step S6 in FIG.
[0049]
【The invention's effect】
As described above, according to the present invention, it is not necessary to previously store the frame numbers of all the intra frames, so that the database creation time can be reduced even if the file is long, and the reproduction start approximate position can be reduced. Therefore, the compressed data can be reproduced from an accurate position in response to the compressed data read request.
[0050]
In particular, since the database file is created to update the database while the compressed data is being reproduced, the detection time required to detect the read destination of the compressed data can be reduced, and the detection level can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a schematic configuration of a compressed data reproduction system according to a first embodiment of the present invention.
FIG. 2 is a schematic structural diagram of MPEG data stored in a file storage unit 11 of FIG.
FIG. 3 is a schematic structural diagram of MPEG data stored in a file storage unit 11 of FIG.
FIG. 4 is an explanatory diagram of an operation of a reproduction command unit 14 of FIG. 1;
FIG. 5 is an explanatory diagram of an operation of a reproduction command unit 14 according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Home server 11 File storage unit 12 MPEG reading unit 13 Communication control unit 14 Playback instruction unit 15 Database 16 Memory 20 Client PC
21 Communication control unit 22 MPEG decoder 23 GUI

Claims (16)

A compressed data reproducing apparatus comprising: storage means for storing compressed data including a plurality of frames; and reading means for reading compressed data stored in the storage means from a commanded intra frame,
Prior to starting the reading of the compressed data by the reading unit, the compressed data stored in the storage unit is divided into a plurality of parts, and the frame numbers of the intra frames around each division position are obtained. Using some of the numbers, an interpolation function for compensating the position in the entire MPEG file with respect to the frame number of the intra frame between the division positions is created, and the frame number of the frame to which the compressed data is requested to be read is sent. When the frame number is substituted into the interpolation function, the position of the frame number of the intra-frame, which is close to the frame number, with respect to the frame number of the intra-frame is determined, and the read-out means is read from the intra-frame of the determined frame number. Characterized by comprising a reproduction command means for commanding Over data reproducing apparatus. A compressed data reproducing apparatus comprising: storage means for storing compressed data including a plurality of frames; and reading means for reading compressed data stored in the storage means from a commanded intra frame,
Prior to the start of reading compressed data by the reading unit, the compressed data stored in the storage unit is equally divided into a plurality of parts, and the frame numbers of intra frames around each division position are obtained. A binary tree search is performed when the frame number of the compressed data read request destination frame is sent, a frame number of an intra frame close to the frame number is determined, and the frame number is read from the intra frame of the determined frame number. A compressed data reproducing apparatus, comprising: a reproducing instruction unit for instructing the reading unit. 3. The compressed data reproducing apparatus according to claim 1, further comprising a database for storing a position of a file including each frame number of the intra frame acquired by said reproducing instruction means. Further, a memory for saving a file stored in the database is provided, and the frame number determined by the reproduction command means is overwritten on the memory. 4. The compressed data reproducing apparatus according to claim 3, wherein the means obtains the position of the file from the frame number of the intra frame to be read, and overwrites the file in the memory. 5. The compressed data reproducing apparatus according to claim 4, wherein the reproducing command unit returns the file stored in the memory to the database after reading the compressed data by the reading unit. 6. The compressed data reproducing apparatus according to claim 1, further comprising communication control means for distributing the compressed data read by said reading means. A frame number of a frame to which the read request of the compressed data is requested is transmitted to the compressed data reproducing apparatus according to any one of claims 1 to 6, and the compressed data reproducing apparatus reads the frame number in response to the transmission of the frame number. A display device for displaying the output compressed data. Further, communication control means for receiving compressed data from the compressed data, decoding means for decoding the compressed data received by the communication control means, and display means for displaying the compressed data decoded by the decoding means The display device according to claim 7, further comprising: A compressed data reproduction system comprising: the compressed data reproduction device according to claim 1; and the display device according to claim 7. A compressed data reproduction method for reading compressed data including a plurality of frames from a commanded intra frame,
Prior to starting the reading of the compressed data, the compressed data is equally divided into a plurality of parts, the frame numbers of the intra frames around each division position are obtained, and the division position is obtained by using some of the obtained frame numbers. An interpolation function for compensating the position in the entire MPEG file with respect to the frame number of the intra frame between them is created, and when the frame number of the requested frame for reading the compressed data is sent, the frame number is A compressed data reproducing method characterized by determining a frame number of an intra frame that is close to the frame number by substituting the frame number into an interpolation function, and reading out the frame number from the determined frame number. A compressed data reproduction method for reading compressed data including a plurality of frames from a commanded intra frame,
Prior to starting the reading of the compressed data, the compressed data is equally divided into a plurality of parts, the frame numbers of the intra frames around each division position are obtained, A compressed data reproducing method characterized by performing a binary tree search when a number is sent, determining a frame number of an intra frame close to the frame number, and reading the frame number from the intra frame of the determined frame number. 12. The compressed data reproducing method according to claim 10, wherein each frame number of the intra frame and position information for the entire file are stored. Obtain the calculated frame number and overwrite the file, and when reading the compressed data, obtain the frame number of the intra frame of the compressed data to be read and the position with respect to the entire file, and overwrite the file 13. The compressed data reproducing method according to claim 12, wherein: 14. The compressed data reproducing method according to claim 10, wherein the read compressed data is distributed. 15. A frame number of a frame to which a read request of the compressed data is requested is transmitted to a compressed data reproducing apparatus for realizing the compressed data reproducing method according to any one of claims 10 to 14, and according to the transmission of the frame number. A display method comprising displaying compressed data read by the compressed data reproducing device. The display method according to claim 15, further comprising receiving compressed data from the compressed data, decoding the compressed data, and displaying the decoded data.

Images