JP3785107B2 - Moving picture and audio data recording / reproducing apparatus and reproducing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moving picture and audio data recording / reproducing apparatus and a reproducing method for encoding a moving picture and audio data to generate an MPEG (Moving Picture Expert Group) -2 stream, and decoding and reproducing the MPEG-2 stream.
[0002]
[Prior art]
In TV broadcast recording using a personal computer or the like, an encoding method such as MPEG-2 or MPEG-1 is used. Among these, the structure of the inter-frame predictive encoding in the MPEG-2 system is shown in FIG. In this figure, GOP (Group of Pictures) is composed of 7 frames. The I picture 111 is a frame encoded within a frame, and an image can be generated independently. The P picture 113 is a frame encoded with reference to a temporally previous frame (I picture 111 or P picture 113). The B picture 112 is a frame encoded with reference to the I picture 111 and the P picture 113.
[0003]
In order to perform special reproduction (intra-stream seek) of an MPEG-2 stream encoded by using such correlation in the time axis direction, reproduction must be performed from the beginning of the GOP.
[0004]
In the conventional playback method, the MPEG-2 stream recorded at a fixed bit rate has a substantially constant data amount per GOP. Therefore, in order to perform special playback, the position on the MPEG-2 stream is determined from time or the like. After calculating and moving the position on the MPEG-2 stream, GOP is detected and special reproduction is performed.
[0005]
However, the MPEG-2 stream recorded at a variable bit rate varies in data amount per GOP, and the position on the MPEG-2 stream cannot be calculated from the average bit rate of the MPEG-2 stream and the indicated playback time. It is difficult to carry out special reproduction by the above method.
[0006]
As a method for solving this problem, there is a method of generating an index indicating the relationship between the position of the frame on the MPEG-2 stream and time separately from the MPEG-2 stream, and performing special reproduction using this index. It is considered.
[0007]
However, the moving image and audio data recording / reproducing apparatus generates an MPEG-2 stream and an index indicating the relationship between the frame position on the MPEG-2 stream and time, and simultaneously reproduces the MPEG-2 stream being generated. However, when the playback position is changed for special playback, since the index has not yet been completed, there is a problem that special playback cannot be performed in a portion of the MPEG-2 stream being generated where the index cannot be acquired.
[0008]
Japanese Patent Laid-Open No. 10-234003 and Japanese Patent Laid-Open No. 9-46712 are conventional techniques for performing special reproduction without using an index.
[0009]
In the above publication, a special medium having information for special reproduction is used, and special reproduction can be performed by using a device having a special mechanism for reproducing the medium. Therefore, there is a problem that cannot be applied to a device that records and reproduces data in the standard MPEG-2 format, such as a personal computer.
[0010]
[Problems to be solved by the invention]
In the prior art, an index is indispensable for special reproduction of a variable bit rate MPEG-2 stream, and there is a problem that special reproduction cannot be performed when the index is invalid.
[0011]
The present invention has been made to solve the above-described problem. In a device that records and reproduces moving images and audio data in a standard MPEG-2 format on a hard disk such as a personal computer, the present invention encodes moving images and audio data. An MPEG-2 stream and an index indicating the relationship between the frame position on the MPEG-2 stream and time are written to the hard disk, and the MPEG-2 stream is reproduced at the same time, and at all positions of the MPEG-2 stream. It is an object of the present invention to provide a moving image and audio data recording / reproducing apparatus and reproducing method capable of special reproduction.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a moving image and audio data recording / reproducing apparatus of the present invention encodes a moving image and audio data to generate encoded data, and the code for performing special reproduction. Index generating means for generating an index indicating the relationship between the position of the encoded data and time, a determination means for confirming the validity of the index, and decoding the encoded data to reproduce moving image and audio data If the index is valid, special reproduction is performed according to the index. If the index is not valid, special reproduction is performed by searching for a frame from the size of the encoded data, the entire time, and the designated reproduction time. And reproducing means for performing.
[0013]
According to the present invention, special playback is efficiently performed using an index when the index is valid, and special playback can be performed at all positions of the MPEG-2 stream by performing frame search when the index is not valid. Thus, convenience can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 is a block diagram showing an embodiment of a recording / reproducing apparatus to which the present invention is applied. The home server 1 has the following configuration. TV broadcast data input via the antenna 11 is received by the TV tuner 12. The received moving image and audio data are encoded by the MPEG-2 encoder 13, and at the same time, an index indicating the relationship between the frame position on the MPEG-2 stream and time is generated. The encoded MPEG-2 stream 15 and the generated index 16 are written into the hard disk device 14. Home server 1 is connected to personal computer 2 via LAN 3.
[0016]
The personal computer 2 reads the MPEG-2 stream 15 and the index 16 from the home server 1 via the LAN 3. The MPEG-2 stream 15 is decoded by the MPEG-2 decoder 22 and displayed on the display screen of the display device 23. The LAN 3 may be either wired or wireless. The MPEG-2 encoder 13 and the MPEG-2 decoder 22 may be realized by either hardware or software.
[0017]
The personal computer 2 has a built-in hard disk device 21. In addition to the MPEG-2 stream and index fetched from the home server via the LAN 3, the hard disk device 21 is an MPEG-2 stream fetched from the home server via the LAN 3, but the index becomes invalid because of editing. MPEG-2 streams and MPEG-2 streams that do not have an index imported from the outside can also be stored.
[0018]
FIG. 2 is a diagram showing an MPEG-2 stream recorded on the hard disk device 14. It is composed of a pack 32 having a plurality of PES (packetized elementary stream) packets 31 in which an elementary stream obtained by encoding moving image and audio data is packetized with a variable length. A pack header 35 is provided at the head of the pack 32. The pack header 35 includes a start code 33 indicating start and an SCR (system clock reference) 34.
[0019]
FIG. 3 is a diagram showing the configuration of video data. One packet of the video packet 31 is composed of a plurality of GOPs 41 each consisting of 7 frames of [IBBPBBP].
[0020]
FIG. 4 is a diagram showing the index 16, and the index 51 generated for each unit time indicates the position of the corresponding pack 32 on the MPEG-2 stream. In the example of FIG. 4, indexes 0, 1, 2,..., N, n + 1 are generated every 0.5 seconds.
[0021]
FIG. 5 is a diagram showing a state in which the MPEG-2 stream 15 and the index 16 generated by the home server 1 are being generated. Reference numeral 61 denotes a portion of the MPEG-2 stream 15 being generated written to the hard disk device 14, and 62 denotes a portion of the MPEG-2 stream 15 being generated that has not yet been written to the hard disk device 14. Reference numeral 63 denotes a portion of the index 16 being generated written to the hard disk device 14, and 64 denotes a portion of the index 16 being generated that has not yet been written to the hard disk device 14.
[0022]
The home server 1 uses a disk cache to efficiently write to and read from the hard disk device 14. During recording, the MPEG-2 stream 15 having an enormous amount of data due to the effect of the disk cache is immediately written to the hard disk device 14, and there are few portions held in the disk cache. On the other hand, since the data amount of the index 16 is extremely small, it is difficult to write the data to the hard disk device 14 and the portion held in the disk cache increases. Therefore, on the hard disk device 14 storing the MPEG-2 stream 15, there is a mismatch where the index 63 does not exist even if the MPEG-2 stream 61 exists. In the present invention, even if this index does not exist, special reproduction of the MPEG-2 stream is possible, and the contents thereof will be described below.
[0023]
FIG. 6 is a diagram for explaining a software function for performing special reproduction. The file reader 71 reads the MPEG-2 stream 15 stored on the hard disk device 14 of the home server 1 via the LAN 3 and sends it to the demultiplexer 72. The demultiplexer 72 separates the MPEG-2 stream 15 sent from the file reader 71 into video data 76 and audio data 77, sends the video data 76 to the video decoder 73, and sends the audio data 77 to the audio decoder 74. The video decoder 73 decodes the encoded video data 76 and displays an image on the display screen of the display device 23 of the personal computer 2. The audio decoder 74 decodes the encoded audio data 77 and reproduces sound from a speaker (not shown) of the personal computer 2. The user input device 75 gives an instruction to change the reproduction time of the MPEG-2 stream 15 by operating a slider on the display screen.
[0024]
The MPEG-2 stream 15 may be in either the hard disk device 14 of the home server 1 via the LAN 3 or the hard disk device 21 built in the personal computer 2.
[0025]
FIG. 7 shows an example of the display screen of the personal computer 2. A video screen 82 is displayed on the display screen 81, and there is a slider 83 for indicating the current display position and changing the playback time in special playback. By operating the slider 83, time shift reproduction is performed.
[0026]
FIG. 8 is a flowchart of the seek process of the file reader 71 when the playback time of the MPEG-2 stream 15 having the index of the present invention is changed. When the playback time is changed by operating the slider 83, seek processing S91 is called. In the seek process, an index corresponding to the reproduction time designated by the slider 83 is obtained in step S92. Subsequently, in step S93, the validity of the index obtained in step S92 is confirmed (index existence confirmation).
[0027]
In the seek process, when it is determined that the index is valid (exists), the pack 32 indicated by the index 51 corresponding to the reproduction time designated by the slider 83 is positioned in step S97 (see FIG. 4). In step S96, the MPEG-2 stream 15 recorded in either the hard disk device 14 or 21 is read out, and the MPEG-2 stream 15 is decoded by the MPEG-2 decoder 22 to resume video reproduction.
[0028]
On the other hand, in the seek process, when it is determined that the index is not valid (does not exist), the designated reproduction is performed based on the reproduction time designated by the slider 83 and the average bit rate of the MPEG-2 stream 15 in step S94. Calculate the estimated position of the pack 32 on the MPEG-2 stream 15 in time. Subsequently, in step S95, the pack 32 near the reproduction time designated by the slider 83 is searched from the estimated position of the MPEG-2 stream 15. In step S96, the MPEG-2 stream 15 recorded in either the hard disk device 14 or 21 is read out, and the MPEG-2 stream 15 is decoded by the MPEG-2 decoder 22 to resume video reproduction.
[0029]
FIG. 9 is a flowchart of the seek process of the MPEG-2 stream 15 having no index according to the present invention. When the playback time is changed by operating the slider 83, seek processing S100 is called.
[0030]
In the seek process, the estimated position of the pack 32 on the MPEG-2 stream 15 at the designated reproduction time is calculated from the reproduction time designated by the slider 83 in step S101 and the average bit rate of the MPEG-2 stream 15. Subsequently, in step S102, the pack 32 close to the reproduction time designated by the slider 83 is searched from the estimated position on the MPEG-2 stream 15. In step S103, the MPEG-2 stream 15 recorded in the hard disk device 21 is read out, and the MPEG-2 stream 15 is decoded by the MPEG-2 decoder 22 to resume video reproduction.
[0031]
【The invention's effect】
According to the present invention, when the index is valid, efficient and accurate special reproduction is performed using the index, and when the index is not valid or there is no index, special reproduction is performed by frame search to improve convenience. ing.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of a recording / reproducing apparatus to which the present invention is applied.
FIG. 2 is a block diagram of an MPEG-2 stream according to the present invention.
FIG. 3 is a configuration diagram of video data according to the present invention.
FIG. 4 is a diagram of an index generated by a recording / reproducing apparatus to which the present invention is applied.
FIG. 5 is a diagram showing the relationship between an MPEG-2 stream and an index generated by a recording / playback apparatus to which the present invention is applied.
FIG. 6 is a block diagram of MPEG-2 playback software of the personal computer of the present invention.
FIG. 7 is a playback screen of the personal computer of the present invention.
FIG. 8 is a flowchart of MPEG-2 stream seek processing with an index of the present invention.
FIG. 9 is a flowchart of seek processing of an MPEG-2 stream without an index according to the present invention.
FIG. 10 is a configuration diagram of a frame obtained by encoding a conventional MPEG-2 stream in a time axis direction.
[Explanation of symbols]
3 LAN
11 TV antenna 12 TV tuner 13 MPEG-2 encoder 14 Hard disk device (remote)
15 MPEG-2 stream 16 Index 21 Hard disk device (local)
22 MPEG-2 decoder 31 PES packet 32 pack 33 start code 34 system clock reference (SCR)
41 GOP
51 Index 76 Encoded video data 77 Encoded audio data 111 I picture 112 B picture 113 P picture

Claims (4)

Encoding means for encoding moving images and audio data to generate encoded data;
Index generating means for generating an index indicating a relationship between a position of the encoded data and time for performing special reproduction;
Determining means for confirming the validity of the index;
When the encoded data is decoded and moving image and audio data are reproduced, if the index is valid, special reproduction is performed according to the index, and if the index is not valid, the size of the encoded data and the whole A moving image and audio data recording / reproducing apparatus, comprising: a reproduction means for searching for a frame and performing special reproduction based on the time and the designated reproduction time. The index generation means records the relationship between the position of the encoded data and time as an index in order to start reproduction from a predetermined screen (frame) of the encoded data. Recording / playback apparatus for moving image and audio data. 2. The moving image and audio data recording / reproducing according to claim 1, wherein the index generating means records, as an index, a relationship between a position and time of the encoded data to which a screen (frame) per unit time belongs. apparatus. Encoding moving image and audio data to generate encoded data, and generating an index indicating the relationship between the position of the encoded data and time,
If the index is generated, special reproduction is performed according to the index if the index has been generated, and if the index is not generated, the size of the encoded data, the entire time, and the indicated reproduction time, And a special reproduction by searching for a moving image and audio data.

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