JP4266427B2 - Recording / reproducing apparatus, recording / reproducing method, and computer-readable storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording / reproducing apparatus, a recording / reproducing method, and a computer-readable storage medium used in the recording / reproducing apparatus, which are suitable for use when recording / reproducing a stream signal in which a plurality of programs are time-division multiplexed. .
[0002]
[Prior art]
In recent years, digital broadcasting has attracted attention as a next-generation broadcasting system. With the digitalization of broadcasting systems, it has become easier to install various functions in television receivers. Among them, the development of a recording / reproducing device such as a hard disk, which has a high-speed, large-capacity, high-speed random access, a built-in recording / reproducing unit that can write and read simultaneously, and uses this recording / reproducing unit as a delay device has been developed. ing.
[0003]
This recording / reproducing apparatus is capable of reproducing and watching a user with a certain time delay while recording a currently broadcast program, for example. For example, if a sports broadcast is extended, the sports broadcast will be viewed as it is, and dramas etc. broadcasted simultaneously on other channels will be recorded on the recording medium, and the recorded program will be played back from the beginning after the sports broadcast ends. By this, it is possible to watch a program currently being broadcast with an arbitrary delay.
[0004]
The recorded program can be provided with special playback functions such as slow playback and search playback, and can be displayed as if the currently broadcast program can be specially played back.
[0005]
As such a recording / reproducing method, for example, as disclosed in Japanese Patent Laid-Open No. 8-297922, a time stamp is recorded for each transport stream at the time of recording in order to match the speed of the bit stream to be reproduced with the speed of decoding. There is a method in which the reproduction is performed while controlling the reading of the bit stream so that it matches the time stamp on the playback side.
[0006]
FIG. 3 is a block diagram showing a conventional recording / reproducing apparatus.
In FIG. 3, a broadcast signal input from an input terminal 301 is converted into a bit stream signal in which a plurality of program (program) signals are digitized and time-division multiplexed by a tuner unit 303 and output to a stream separator 305. Is done. As a bit stream format of the digitized program signal, a transport stream such as H222 standardized by ITU-T is known. As the image signal and the audio signal, a signal compressed by the MPEG2 method or the like is used. In addition, the standardized bit stream includes data as time information indicating the arrival time of a packet called PCR or SCR.
[0007]
The bit stream separator 305 outputs the transport stream of the program that the user wants to watch to the terminal a of the changeover switch 313 according to the control signal output from the controller 327, and changes the transport stream of the program that the user wants to record to the changeover switch 307. To terminal a. The counter 309 is a time stamp counter to be added at the time of recording.
[0008]
The changeover switch 307 adds the value output from the counter 309 as a time stamp to the transport stream to be recorded, and then outputs it to the recording / playback unit 325. The recording / reproducing unit 325 outputs a transport signal to be reproduced simultaneously to the header separator 315 and the memory 311 while recording a transport signal to be recorded on the recording medium based on the control signal output from the controller 327.
[0009]
The header separator 315 separates the time stamp added to the transport and outputs the time stamp value to the comparator 319. The comparator 319 compares the time stamp value output from the transport separator 319 with the value of the counter 317, and outputs the comparison result to the controller 321. The controller 321 reads the transport stream from the memory 311 when the time stamp value matches the counter 317 value, and stops reading from the memory 311 if they do not match.
[0010]
The transport stream read from the memory 311 is output to the terminal b of the changeover switch 313. The change-over switch 313 connects to the terminal a if the user wants to watch the program currently being broadcast, and connects to the terminal b if the user wants to watch the recorded program, and decodes the selected transport stream. To the device 323. The decoder 323 performs decoding processing, and outputs a video signal to the display 329 and an audio signal to the speaker 311.
[0011]
FIG. 4 shows a state when only a transport stream to be recorded is extracted from a multiplexed transport stream and a time stamp is added.
As shown in FIG. 4 (a), bit streams for a plurality of programs of video transport streams V1, V2, V3,... And audio transport streams A1, A2, A3,. It is multiplexed.
In FIG. 4B, the video transport stream V1 and the audio transport stream A1 of the program to be recorded are extracted.
[0012]
FIG. 4C shows a state where a time stamp is added to the beginning of the extracted transport stream. At the time of recording, only the video transport stream V1 and the audio transport stream A1 to which a time stamp is added are recorded. In this example, a 4-byte time stamp header is added to each 188-byte transport stream.
[0013]
In this way, by controlling the reading while looking at the value of the added time stamp, the decoding processing speed and the reading speed of the recording / reproducing unit are made to coincide with each other, so that excess or deficiency of data at the time of decoding is eliminated.
[0014]
[Problems to be solved by the invention]
However, in the above conventional example, since a time stamp is always added to each transport stream to be recorded, the amount of information to be recorded has increased. In particular, in the above conventional example, since a 4-byte time stamp is added to a 188-byte transport stream, the amount of information increases by about 2%.
[0015]
The present invention has been made in order to solve the above-described problems, and without increasing the amount of information at the time of recording, the decoding processing speed is matched with the reading speed of the recording / playback unit, and the data at the time of decoding is The purpose is to be able to eliminate excesses and deficiencies.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, in the recording / reproducing apparatus according to the present invention, first calculation means for obtaining a transmission rate based on the time information of the stream signal into which the time information is inserted, and the stream signal as a recording medium Recording / reproducing means for recording at a predetermined rate, storage means for storing the reproduced stream signal, time information of the reproduced stream signal, and a transmission rate obtained by the first calculating means. Based on the second calculation means for obtaining the time information according to the predetermined rate based on the above, the time information of the reproduced stream signal is compared with the time information according to the predetermined rate obtained by the second calculation means. And a control means for controlling reading of the storage means in accordance with the comparison result of the comparison means.
[0017]
In the storage medium according to the present invention, the first arithmetic processing for obtaining the transmission rate based on the time information of the stream signal into which the time information is inserted, and the stream signal is recorded on the recording medium and reproduced at a predetermined rate. The predetermined rate based on the recording / reproduction process, the storage process for storing the reproduced stream signal in the storage means, the time information of the reproduced stream signal, and the transmission rate obtained in the first calculation process A second calculation process for obtaining time information according to the comparison, a comparison process for comparing the time information of the reproduced stream signal with the time information according to the predetermined rate obtained by the second calculation process, A program for executing control processing for controlling reading of the storage means in accordance with the comparison result of the comparison processing is stored.
The recording / reproducing method according to the present invention also includes a first calculation step for obtaining a transmission rate based on the time information of the stream signal into which the time information is inserted, and the stream signal is recorded on a recording medium and reproduced at a predetermined rate. The predetermined rate based on the recording / reproducing step, the storing step for storing the reproduced stream signal in the storage means, the time information of the reproduced stream signal and the transmission rate obtained in the first calculating step. A second calculation step for obtaining time information according to the comparison, a comparison step for comparing the time information of the reproduced stream signal with the time information according to the predetermined rate obtained in the second calculation step; And a control step for controlling reading of the storage means in accordance with the comparison result of the comparison step.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a recording / reproducing apparatus according to an embodiment of the present invention.
In FIG. 1, a broadcast signal input from an input terminal 101 is converted by a tuner unit 103 into a transport stream signal in which a plurality of digitized program (program) signals are time-division multiplexed, and is sent to a stream separator 105. Is output. In the stream separator 105, based on the control signal output from the controller 137, the transport stream signal of the program that the user wants to watch is output to the terminal a of the changeover switch 127, and the transport stream signal of the program that the user wants to record is And output to the recording / reproducing unit 135 and the PCR separator 107.
[0019]
The PCR separator 107 separates the PCR as time information inserted into the transport stream, outputs it to the rate calculator 111, and resets the value of the counter 109. The counter 109 counts the number of bytes in the transport stream between the PCR and the next PCR, and outputs it to the rate calculator 111. The rate calculator 111 calculates the byte rate of the separated transport stream from the PCR value and the counter 109 value.
[0020]
Here, the transport rate is the number of bytes between the bytes including the last bit of two consecutive PCR fields of the same program in the transport stream encoded in these two identical PCR fields. Defined as divided by the time difference. The arithmetic expression is defined in the ITU-TH222 standard as shown in Expression (1).
[0021]
transport_rate = [(I′−I ″) * system clock frequency] / [PCR (I ′) − PCR (I ″)] (1)
Where I ′ is the index number of the byte containing the last bit of the most recent PCR base field applied to the program to be decoded, and I ″ is the PCR number immediately following that applied to the program to be decoded. Defined as the index number of the byte containing the last bit of the source field, where I ″ is less than I ′.
[0022]
In other words, the byte rate is obtained by dividing the value obtained by multiplying the number of bytes between PCRs by the system clock frequency by the difference between the PCR and the next PCR value. In this way, the transmission rate of the transport stream obtained by the rate calculator 111 is recorded in the register 113. The register 113 outputs to the controller 137 and to the PCR calculator 119. The register 113 may have a plurality of registers corresponding to each program.
[0023]
On the other hand, as an operation on the playback side, the recorded transport stream is read from the recording / playback unit 135 at a specified byte rate by a control signal output from the controller 137, and sent to the PCR separator 117 and the memory 115. Is output. The PCR separator 117 separates the PCR from the transport stream to be reproduced, outputs the latest PCR value to the comparator 121, and outputs the previous PCR value to the PCR calculator 119.
[0024]
The PCR calculator 119 calculates the current PCR value from the transport stream transmission rate output from the register 113 and the previous PCR value output from the PCR separator 117, and outputs the calculated PCR value to the comparator 121. . The arithmetic expression of the PCR calculator 119 is obtained by Expression (2) obtained by modifying Expression (1).
PCR (I ′) = PCR (I ″) + [(I′−I ″) * system clock frequency] / transport_rate (2)
[0025]
The comparator 121 compares the PCR value separated from the transport stream with the PCR value obtained from the PCR calculator 119 and outputs the comparison result to the controller 123. In the controller 123, if the PCR value obtained by the calculation is smaller than the PCR value separated from the transport stream, the memory reading is stopped, and the null transport stream is connected to the terminal b of the changeover switch 125 and the null transport stream is converted to the PCR. Is inserted just before the transport stream that contains.
[0026]
When the PCR value obtained by the calculation is equal to the PCR value separated from the transport stream, the transport stream is read as it is by controlling the memory 115, the terminal a of the changeover switch 125 is connected, and the recorded transport stream is select. The null transport stream is defined in the TU-TH222 standard.
[0027]
FIG. 2 shows a state in which a null transport stream is inserted before PCR.
FIG. 2A shows the state of the transport stream read from the recording / playback unit 135.
FIG. 2B shows a state in which a null transport stream is inserted for rate adjustment before PCR and a predetermined byte rate is achieved.
[0028]
As described above, the video signal and the audio signal are decoded in the decoder 129 from the transport stream having a predetermined byte rate by inserting the null transport stream into the transport stream before the PCR, and the video signal is The audio signal is output to the speaker 131 and the audio signal is output to the speaker 133.
[0029]
The controller 137 may be realized by a microcomputer or the like, and may include a bit rate calculator 111, a register 113, and a PCR calculator 119.
[0030]
Next, a storage medium according to another embodiment of the present invention will be described.
The system shown in FIG. 1 can be configured by hardware, but can be configured by a computer system including a CPU and a memory. In the case of a computer system, the memory constitutes a storage medium according to the present invention. The storage medium stores a program for executing a processing procedure for controlling the operation described in the above embodiment.
[0031]
Further, as this storage medium, a semiconductor memory such as ROM and RAM, an optical disk, a magneto-optical disk, a magnetic medium, etc. may be used, and these may be a CD-ROM, floppy disk, magnetic tape, magnetic card, nonvolatile memory card, etc. It may be configured and used.
[0032]
Therefore, the above-described embodiment can also be realized by using this storage medium in another system or apparatus other than the system or apparatus shown in FIG. 1, and reading and executing the program code stored in this storage medium by the system or computer. A function equivalent to that of the embodiment can be realized, an equivalent effect can be obtained, and the object of the present invention can be achieved.
[0033]
Also, when the OS running on the computer performs part or all of the processing, or the program code read from the storage medium is an extension function board inserted in the computer or an extension connected to the computer Even when the CPU or the like provided in the extended function board or the extended function unit performs part or all of the processing based on the instruction of the program code after being written in the memory provided in the functional unit, While equivalent functions can be realized, equivalent effects can be obtained, and the object of the present invention can be achieved.
[0034]
【The invention's effect】
As described above, according to the present invention, the transmission rate of a program to be recorded is obtained, time information such as a PCR value corresponding to the reproduction rate is obtained at the time of reproduction, and this time information and the time information in the reproduction stream signal are obtained. By controlling the reading of the storage means according to the comparison result, it is possible to decode the processing speed and playback time without decoding an unnecessary program without recording an extra time stamp and without increasing the amount of information only for the necessary program. Recording / reproduction can be performed while matching the reading speed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a recording / reproducing apparatus according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a transport stream according to the embodiment of the present invention.
FIG. 3 is a block diagram showing a conventional recording / reproducing apparatus.
FIG. 4 is a configuration diagram of a conventional transport stream.
[Explanation of symbols]
105 Stream Separator 107 PCR Separator 109 Counter 111 Rate Calculator 113 Register 115 Memory 119 PCR Calculator 121 Comparator 125 Changeover Switch 123, 137 Controller 135 Recording / Reproducing Unit 129 Decoder

Claims (6)

First computing means for obtaining a transmission rate based on the time information of the stream signal into which the time information is inserted;
Recording and reproducing means for recording the stream signal on a recording medium and reproducing it at a predetermined rate;
Storage means for storing the reproduced stream signal;
Second computing means for obtaining time information corresponding to the predetermined rate based on the time information of the reproduced stream signal and the transmission rate obtained by the first computing means;
Comparing means for comparing time information of the reproduced stream signal with time information corresponding to the predetermined rate obtained by the second calculating means;
A recording / reproducing apparatus comprising: control means for controlling reading of the storage means in accordance with a comparison result of the comparison means.   2. The recording / reproducing apparatus according to claim 1, further comprising insertion means for inserting a null signal immediately before the time information of the stream signal read from the storage means.   3. A recording / reproducing apparatus according to claim 2, further comprising decoding means for decoding the stream signal into which the null signal is inserted.   In the stream signal, a plurality of programs are time-division multiplexed and the time information is inserted for each program. The first calculation means determines the transmission rate of the program based on the time information of the same program. The recording / reproducing apparatus according to claim 1, wherein the recording / reproducing apparatus is obtained. A first calculation process for obtaining a transmission rate based on the time information of the stream signal into which the time information is inserted;
A recording / reproducing process for recording the stream signal on a recording medium and reproducing the stream signal at a predetermined rate;
A storage process for storing the reproduced stream signal in a storage means;
A second calculation process for obtaining time information corresponding to the predetermined rate based on the time information of the reproduced stream signal and the transmission rate obtained in the first calculation process;
A comparison process for comparing the time information of the reproduced stream signal with the time information corresponding to the predetermined rate obtained in the second calculation process;
A computer-readable storage medium storing a program for executing control processing for controlling reading of the storage means in accordance with a comparison result of the comparison processing. A first calculation step for obtaining a transmission rate based on the time information of the stream signal into which the time information is inserted;
A recording / reproducing step of recording the stream signal on a recording medium and reproducing it at a predetermined rate;
A storage step of storing the reproduced stream signal in a storage means;
A second calculation step for obtaining time information corresponding to the predetermined rate based on the time information of the reproduced stream signal and the transmission rate obtained in the first calculation step;
A comparison step of comparing time information of the reproduced stream signal with time information corresponding to the predetermined rate obtained in the second calculation step;
And a control step of controlling reading of the storage means in accordance with the comparison result of the comparison step.

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