JP2003018574A - Information receiving terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a data reproducing operation to be always restarted in a normal state after a communication fault is recovered and to allow a reproduction interrupting time to be shortened by always holding a stable buffering operation without depending upon a reproducing rate of the data. SOLUTION: An image receiving terminal 30 comprises a terminal controller 50 newly having a buffer managing unit 20 and a threshold value calculating unit 21. In this case, the calculating unit 21 decides a reproducing rate of receiving data at the time of starting a communication, and sets a first threshold value in response to the reproducing rate. Thereafter, the managing unit 20 executes a flow control of the received data based on the threshold value set in response to the reproducing rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information receiving terminal having a function of reproducing a video content file while downloading it from a video distribution server connected via a communication network.

[0002]

2. Description of the Related Art Conventionally, an information receiving terminal provided with this kind of function is constructed, for example, as follows. FIG. 6 is a block diagram showing the functional configuration thereof, where 1 is a video distribution server, 2 is a network, and 3 is an information receiving terminal.

The information receiving terminal 3 has a communication section 4 for communicating with a video distribution server via the network 2, a decoding section 6 for decoding and reproducing multiplexed data of a video content file, and these communication sections 4 And a terminal control unit 5 that controls the decoding unit 6.

First, the terminal control section 5 includes a protocol control processing section 7, a terminal management section 8, a codec control processing section 9, and
The control unit buffer 10 and the key input unit 11 are provided. The protocol control processing unit 7 controls the communication unit 4 to download the video content file from the video distribution server 1. The codec control processing unit 9 extracts the multiplexed data from the downloaded file,
The extracted multiplexed data is transferred to the decoding unit 6 and the operation of the decoding unit 6 is controlled. The terminal management unit 8
It controls the operation of each control processing unit based on the instruction input from the key input unit 11, and manages the operation state of each unit.
The control unit buffer 10 transfers data between the protocol control processing unit 7 and the codec control processing unit 9.

Next, the decoding unit 6 includes a separating unit buffer 14 and
The separation unit 15, the audio decoder unit 16, the video decoder unit 17, and the timer 18 are provided. Separator buffer 14
Receives and temporarily stores the multiplex data transferred from the codec control processor 9 of the terminal controller 5. Separation unit 15
Separates the multiplexed data read from the separation unit buffer 14 into video data and audio data. The audio decoder unit 16 decodes the separated audio data, reproduces an audio signal, and outputs it from the speaker 12. The video decoder unit 17 decodes the separated video data to reproduce a video signal, and displays the video signal on the display 13. The timer 18 specifies the timing for reading the multiplexed data from the demultiplexing unit buffer 14 to the demultiplexing unit 15.

In such an information receiving terminal, downloading of a video content file and decoding / reproduction thereof are performed as follows. That is, the user inputs the key input unit 1
When the video content file is designated and input by 1, the designated content is analyzed by the terminal management unit 8, and the terminal management unit 8 instructs the protocol control processing unit 7 to download and the codec control processing unit 9 as well. Preparation for data reception is instructed. Upon receiving this instruction, the protocol control processing unit 7 starts downloading the corresponding video content file from the video distribution server 1 through the communication unit 4.

The received video content file is once written in the control unit buffer 10. Control unit buffer 1
When receiving the above-mentioned video content file, 0 notifies the codec control processing unit 9 that the file has been received. The codec control processing unit 9 that has received this reception notification
Reads out the video content data written in the control unit buffer 10 and transfers it to the separation unit buffer 14, and at the same time instructs the other circuit units of the decoding unit 6 to perform a reproducing operation.

In the decoding unit 6 that has received the reproduction instruction, the timer 1
8 is initialized and activated, and the separation unit 15 causes the separation unit buffer 14 to operate according to the timing instructed by the timer 18.
The data of the video content file is read from. This data is read out so that the timer value of the timer 18 and the time stamp included in the data of the video content file match. The demultiplexing unit 15 demultiplexes the read multiplexed data into audio data and video data, and the audio decoder unit 16 and the video decoder unit 17 respectively.
Hand over to. The audio decoder unit 16 and the video decoder unit 17 decode the audio data and the video data, respectively, so that the time stamp and the timer value of the multiplexed data passed from the separation unit 15 match. Then, after synchronizing the decoded video signal and audio signal, the speaker 12 and the display 13 are respectively synchronized.
Output to.

Now, it is assumed that a communication error occurs during the downloading and reproducing operation of the video content file as described above. In this case, since the protocol control processing unit 7 performs the retransmission process, the reception data is not written in the control unit buffer 10 and the transfer of the multiplexed data to the demultiplexing unit buffer 14 is also stopped. When there is no data accumulated in the separation unit buffer 14, the separation unit 1
Reference numeral 5 detects the data underflow in the separation unit buffer 14 and stops the data separation processing.

After that, when the communication error is recovered and the protocol control processing unit 7 writes the data in the control unit buffer 10, the data transfer from the control buffer 10 to the separation unit buffer 14 is restarted. When the demultiplexing unit 15 reads the multiplexed data from the demultiplexing unit buffer 14, the demultiplexing unit 15 compares the time stamp of the demultiplexed data with the timer value of the timer 18 to recognize that the reproduction of the received data is delayed. Then, until the time stamp matches the timer value of the timer 18, the multiplexed data is continuously read from the demultiplexing unit buffer 14, the multiplexed data is separated into audio data and video data, and the audio codec unit 16 and the video codec unit are separated. Supply to 17. The audio codec unit 16 skips the audio data until the time stamp matches the timer value of the timer 18. On the other hand, the video codec section 17 performs fast-forward reproduction of the video data until the time stamp of the video data matches the timer value.

FIG. 7 shows the relationship between the communication state and the reproduction operation. As is clear from the figure, in the state where the communication is normally performed, the time stamp of the received data and the timer value of the timer 18 match each other, so that the data is normally reproduced. On the other hand, when a communication error occurs and the received data is interrupted, the timer 18 continues the time counting operation as it is, but the video reproduction operation by the video codec unit 17 is stopped. Then, when the communication error is recovered and the transfer of the received data is restarted, the video is reproduced at fast forward in the period until the time stamp of the received data matches the timer value of the timer 18. Then, when the time stamp of the received data matches the timer value of the timer 18, the video will be reproduced normally thereafter.

That is, once a communication error occurs,
During the period until the time stamp of the data downloaded after the communication error is recovered coincides with the timer value of the timer 18, the video is fast-forwarded and reproduced, and the audio is interrupted.

In order to solve this problem, the present inventors have proposed the means disclosed in Japanese Patent Application No. 2000-002410. That is, the terminal control unit 5 is provided with a management unit for the control unit buffer, and in this management unit, the control unit buffer 1
The data amount of the video content stored in 0 is compared with a preset threshold value. When the amount of accumulated data falls below the threshold value due to the influence of communication failure such as communication error, the codec control processing unit 9 gives a control signal to the decoding unit 6 to stop the operation of the decoding unit 6 including the timer 18. . After that, when the communication error is recovered and the accumulated data amount is recovered to be equal to or more than the threshold value, the codec control processing unit 9 gives a control signal to the decoding unit 6 and the decoding unit 6 including the timer 18.
Restart the operation of.

By taking such means, the timer 18 of the decoding unit 6 also stops the time counting operation during the period when the amount of data stored in the control unit buffer 10 is underflowing due to a communication error, and the communication error is recovered. Then, when the underflow is eliminated, the timer 18 restarts the time counting operation. For this reason, even if the reproduction operation of the video data and the audio data is interrupted due to the influence of the communication error, the time stamp of the received data immediately after the restart of the reproduction operation and the timer value of the timer 18 can always be made to coincide with each other. It is possible to reproduce the video data corresponding to the interruption period at a normal speed without fast-forwarding. For voice data,
It becomes possible to play back without causing audio interruption.

[0015]

However, such an information receiving terminal has the following problems to be improved. That is, the reproduction rate of the video content file is not always constant, but changes depending on the type of content and its content. Therefore, for example, if a threshold value for determining the amount of data stored in the control unit buffer 10 is set corresponding to the maximum value of the reproduction rate, when a content having a low reproduction rate is received and reproduced, The playback interruption time of video data and audio data becomes longer than necessary. For example, immediately after the communication is interrupted, the reproduction operation is stopped at an early timing although the data that can be reproduced by the decoding unit 6 actually remains. Also,
After the communication is recovered, the decoding unit 6 cannot start the reproducing operation until the control unit buffer 10 stores the received data equal to or more than the threshold value, so that a waiting time longer than necessary occurs before the reproducing operation is restarted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable the data reproducing operation to be always restarted in a normal state after recovery from a communication failure.
Another object of the present invention is to provide an information receiving terminal capable of shortening the reproduction interruption time while always maintaining a stable buffering operation regardless of the data reproduction rate.

[0017]

In order to achieve the above object, an information receiving terminal according to the present invention determines a buffer for temporarily storing received information content and a data amount of the information content stored in this buffer. A comparison means for comparing with a threshold value, and a decoding / playback control means for controlling the decoding / playback operation according to the determination result of this comparison means, wherein the decoding / playback control means has the data amount of the information content stored in the buffer. When the comparison means determines that the value has decreased below the threshold value, the first control signal is given to the decoding section to stop the decoding and reproducing operation of the information content, and thereafter the information stored in the buffer is stored. When the comparison means determines that the data amount of the content has recovered to the threshold value or more, a second control signal is given to the decoding section to send the information. And it is controlled so as to restart the decoding reproduction operation of the content. Further, a threshold setting means is further provided, and the threshold setting means variably sets the threshold according to the reproduction rate of the received information content.

Therefore, according to the present invention, even if the decoding / reproducing operation of the information content is interrupted due to the influence of the communication error, the time counting operation of the timer of the decoding section is also stopped during this interrupting period, so that the decoding / reproducing operation is restarted. Sometimes it is possible to play the content in a normal form from the beginning. For example, when receiving and playing back video data and audio data as information content, the video data corresponding to the playback operation interruption period can be played back at a normal speed without fast-forwarding. It is possible to reproduce without causing.

Further, according to the present invention, the threshold value is variably set so as to always have an optimum value according to the reproduction rate of the received information content. Therefore, regardless of the reproduction rate, it is possible to always maintain a stable buffering operation and restart the decoding and reproduction of the content in the shortest interruption time.

For example, when reproducing information content having a high reproduction rate, stable buffering operation can be performed without causing excessive underflow.
On the other hand, when playing back information content with a low playback rate, the decoding / playback operation can be stopped after continuing the decoding / playback operation of the residual data until a sufficiently late timing when communication is interrupted. The decoding / reproducing operation can be restarted when a relatively small amount of received data is accumulated in the buffer.

Further, as a concrete configuration of the threshold value setting means, at the start of reception of the information content, a reproduction rate of the information content is judged and the threshold value is set in accordance with the judged reproduction rate. And, during the reception period of the information content, the reproduction rate is determined from the information indicating the reproduction rate included in the stream of the received information content, and the threshold value is set according to the determined reproduction rate. Can be considered.

According to the former, when the information content is started to be received, the threshold value is set according to the reproduction rate of the information content to be received, so that the communication failure occurs at any time during the information content receiving period. However, the decoding / reproducing operation can be controlled by the optimum threshold value.

On the other hand, according to the latter, even if the reproduction rate is changed during the reception period of the information content, the threshold value can be reset according to the change. For this reason,
The decoding / reproducing operation can always be controlled by the optimum threshold value.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a video receiving terminal which is an embodiment of an information receiving terminal according to the present invention. In the figure, the same parts as those in FIG. 7 are designated by the same reference numerals and detailed description thereof will be omitted.

In the terminal control unit 50 of the video receiving terminal 30,
Protocol control processing unit 7, terminal management unit 8, codec control processing unit 9, control unit buffer 10, and key input unit 11
In addition to the buffer management unit 20 and the threshold value calculation unit 21
Is newly provided.

The buffer management unit 20 includes the control unit buffer 1
It has a function of grasping and managing the amount of data accumulated in 0 and comparing the amount of data with the first threshold value for the control unit. Specifically, the data amount of the video content accumulated in the control unit buffer 10 is periodically detected to
Compare with the threshold of. Then, when the amount of accumulated data falls below the first threshold value due to the influence of communication failure such as communication error, the decoding unit including the timer 18 by giving the first control signal from the codec control processing unit 9 to the decoding unit 6. The operation of 6 is stopped. After that, when the communication failure such as a communication error is recovered and the accumulated data amount is recovered to be equal to or more than the threshold value, the codec control processing unit 9 gives a second control signal to the decoding unit 6 and includes a decoding unit including a timer 18. The operation of 6 is restarted.

The threshold calculation unit 21 sets a first threshold for the control unit used by the buffer management unit 20 and gives it to the buffer management unit 20. The stream of the received video content file is set. The threshold value is calculated from the reproduction rate set in. For example, the first threshold value is set to the amount of data that can store 2 seconds of the video content file in the control unit buffer 10.

Next, the operation of the video receiving terminal configured as described above will be described. First, when the communication operation is normally performed, the following control processing operation is performed. Figure 2
FIG. 7 is a sequence diagram showing the processing procedure and its contents.

That is, when the communication is started, the protocol control processing unit 7 writes the download data of the video content file received by the communication unit 4 in the control unit buffer 10 and notifies the codec control processing unit 9 of the data transfer. Give 19 Upon receiving the data transfer notification 30 from the protocol control processing unit 7, the codec control processing unit 9 activates the buffer management unit 20.

The buffer management unit 20 adds the data amount of the received video content file and determines whether the received data at this time is the first received data after the communication is started. Then, if it is the first received data, the threshold calculation unit 21 is instructed to calculate the first threshold.

When the threshold calculation unit 21 receives the calculation instruction, the control unit controls, for example, 2 seconds of the video content file based on the reproduction rate set in the stream of the received video content file. The amount of data that can be stored in the buffer 10 is calculated, and the calculated amount of data is set as the first threshold value for the control unit.

For example, if the reproduction rate of the video content file that has just started to be received is 32 Kbps, then (32 Kbps / 8) x 2 sec = 8 Kbyte (1).

On the other hand, when the reproduction rate of the video content file that has started to be received is 128 Kbps, (128 Kbps / 8) × 2 sec = 32 Kbyte (2)

When the first threshold value is calculated in this way, the threshold value calculation unit 21 gives the calculated first threshold value to the codec control processing unit 9. As a result, the codec control processing unit 9 thereafter executes the flow control of the received data based on the first threshold value.

That is, the codec control processing unit 9 transfers the received data of the video content file stored in the control unit buffer 10 to the separating unit buffer 14 of the decoding unit 6 as shown in FIG.
23, and a control signal 25 for instructing the start of reproduction is given to the decoding section 6. Then, in the decoding unit 6, the received data held in the separation unit buffer 14 is transferred to the separation unit 15. The separation unit 15 monitors the remaining amount of data in the separation unit buffer 14 and compares the remaining amount of data with a preset second threshold value for the separation unit. Then, as a result of this comparison, when the remaining amount of data decreases below the second threshold value, the separation unit 15 notifies the data processing notification 22.
To the codec control processor 9.

When the data processing notification 22 is received, the codec control processing unit 9 gives a subtraction instruction to the buffer management unit 20. Upon receiving this instruction, the buffer management unit 20
The data amount previously supplied to the decoding unit 6 is subtracted from the received data amount accumulated in the control unit buffer 10. Then, the amount of accumulated data in the control unit buffer 10 after the subtraction is set to the first value previously set by the threshold value calculation unit 21.
Is compared with the threshold value of 1. As a result of this judgment,
If the data amount is equal to or larger than the threshold value, the codec control processing unit 9 reads the data from the control unit buffer 10 and transfers the data to the decoding unit 6.

Similarly, thereafter, during the period when the amount of data stored in the control unit buffer 10 is equal to or more than the first threshold value,
The reception data accumulated in the control unit buffer 10 is transferred to the separation unit buffer 14 by a predetermined amount in the order of reception, and the decoding unit 6 executes a reproduction process of the transferred reception data.

A communication error occurs in this state, and the protocol control processing unit 7 causes the control unit buffer 1 to go with it.
It is assumed that the input of received data to 0 is cut off. Then, the buffer management unit 20 performs the following control processing. FIG. 3 is a sequence diagram showing the control procedure and contents.

That is, when the input of the received data to the control unit buffer 10 is cut off, the remaining amount of data in the control unit buffer 10 gradually decreases. Then, when the remaining amount of data in the control unit buffer 10 falls below the first threshold value, the buffer management unit 20 determines that an underflow has occurred in the control unit buffer 10, and notifies the codec control processing unit 9 to that effect. Notice. Upon receiving the notification of the occurrence of the underflow, the codec control processing unit 9 gives the control signal 24 for instructing the decoding unit 6 to pause the reproduction processing operation. Receiving the stop instruction 24, the decoding unit 6 stops the decoding operations of the audio decoder 16 and the video decoder 17, respectively, and stops the time counting operation of the timer 18, and holds the timer value (count value) at the time of the stop. To do.

On the other hand, when the communication is subsequently recovered and the reception of the video content file is restarted by the protocol control processing unit 9, the input of the received data to the control unit buffer 10 is restarted. At this time, the data transfer notification 19 is sent from the protocol control processing unit 9 to the codec control processing unit 9.
Is given, and upon receipt of this notification, the codec control processing unit 9
Gives a data addition instruction to the buffer management unit 20.

Therefore, the buffer management unit 20 adds the newly accumulated data amount to the accumulated data amount of the control unit buffer 10 and compares the accumulated data amount after the addition with the first threshold value. Then, when the amount of accumulated data recovers to the first threshold value or more, the control signal 25 instructing the start of reproduction is given from the codec control processing unit 9 to the decoding unit 6. In the decoding unit 6, upon receiving the reproduction start control signal 25 from the codec control processing unit 9, the decoders 16 and 17 restart their operations. At this time, the timer 18 also restarts the time counting operation with the timer value (count value) held at the time of stop as the initial value.

By the way, the flow control of the reception data due to the communication failure described above is performed based on the threshold value which differs depending on the reproduction rate of the reception data. For example, the reproduction rate of the video content file being received is 128 Kbps, and 2 seconds worth of the file is stored in the control unit buffer 10.
In the case of accumulating the data in the memory, the first threshold value is set to 32 Kbytes as shown in the equation (1). Therefore, when the reproduction rate is high as in this case, the control unit buffer 1
The decoding / reproducing operation can be stopped before the accumulated data amount of 0 falls into an excessive underflow state, whereby a stable buffering operation can be performed.

On the other hand, when the reproduction rate of the video content file being received is, for example, 32 Kbps and 2 seconds of the file is stored in the control unit buffer 10, the first threshold value is (2) ) 8Kbyt as shown in the formula
Set to e. Therefore, even if a communication failure occurs and the input of the received data to the control unit buffer 10 is cut off, the decoding unit 6 continues the decoding and reproducing operation until the remaining amount of data in the control unit buffer 10 falls below 8 Kbytes. I can continue. On the other hand, when the communication failure is recovered, the immediate decoding unit 6 can resume the decoding / reproducing operation when the amount of data stored in the control unit buffer 10 exceeds 8 Kbytes. That is, when the reproduction rate of the received data is low, the decoding reproduction interruption period can be shortened as much as possible.

Incidentally, if the threshold is fixedly set to 32 Kbytes, which is the value when the reproduction rate is 128 Kbps, when the video content file with the reproduction rate of 32 Kbps is received, the remaining amount of data in the control unit buffer 10 becomes small. The decoding / reproducing operation is stopped as soon as it drops to less than 32 Kbytes, and the decoding / reproducing operation is not restarted until the amount of data accumulated in the control unit buffer 10 exceeds 32 Kbytes. Therefore, the decoding / reproduction interruption period becomes unnecessarily long when a communication failure occurs. The length is 3 seconds in the above example.

FIG. 5 shows the effects of this embodiment described above.
In other words, the length of the decoding / reproduction interruption period due to the difference in the reproduction rate is defined as
It is shown together with the communication state and the relationship between the timer and the received data.

The control processing of the protocol control processing unit 7, the codec control processing unit 9 and the buffer management unit 20 after the reception of the video content file is completed is performed as follows. FIG. 4 is a sequence diagram showing the processing procedure and contents.

That is, during reception of the video content file, the buffer management unit 20 monitors the end of data reception based on, for example, the content of the header of the received data. When the download of the video content file is completed in this state and the buffer management unit 20 detects the end of data reception, the codec control processing unit 9 causes the control unit buffer 10 to store the amount of data in the first threshold value thereafter. Even if the number is reduced to less than this, it is judged to be normal and the transfer of the received data remaining in the control unit buffer 10 is continued, and the decoding unit 6 continues.
To perform decryption / reproduction processing. In this way, the downloaded video content file is surely decoded and reproduced until the end.

As described above, in this embodiment, the buffer control unit 20 and the threshold value calculation unit 21 are newly provided in the terminal control unit 50 of the video receiving terminal 30, and the threshold value calculation unit 21 starts communication. The reproduction rate of the received data is judged and a first threshold value corresponding to this reproduction rate is set. Then, in the buffer management unit 20 thereafter,
The flow control of the received data is executed based on the threshold value set according to the reproduction rate.

Therefore, according to this embodiment, even if the decoding / reproducing operation of the information content is interrupted due to the influence of the communication error, the time counting operation of the timer of the decoding section is also stopped during this interrupting period. When resuming, the video data can be reproduced at a normal speed without fast-forwarding from the beginning, and the audio data can be reproduced without causing audio interruption.

In addition, the threshold value is variably set so as to always have an optimum value according to the reproduction rate of the received video content file. Therefore, for example, when reproducing a video content file having a high reproduction rate, a stable buffering operation can be performed without causing excessive underflow. On the other hand, when reproducing a video content file having a low reproduction rate, the decoding and reproducing operation of the residual data can be continued until a sufficiently late timing when a communication failure occurs, and the controller buffer 10 stores the communication data after the communication is restored. The decoding / reproducing operation can be restarted when a relatively small amount of received data is accumulated. That is, the decoding / reproduction interruption period can be shortened as much as possible when the reproduction rate of the received data is low.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the first threshold value is set at the start of receiving the video content file. However, the playback rate of the stream is monitored during the reception of the video content file, and every time the playback rate changes. Alternatively, the first threshold may be variably set according to the reproduction rate. By doing so, even if the reproduction rate is changed during the reception period of the video content file, the threshold value can be reset according to the change. Therefore, the flow control of the received data can always be performed with the optimum threshold value.

Further, in the above-mentioned embodiment, the optimum threshold value is obtained by calculation based on the reproduction rate of the received data. However, if the reproduction rate of the information content to be received is known in advance, these values are calculated. The optimum threshold value corresponding to each reproduction rate is stored in the memory in advance, and the corresponding threshold value is selectively read from the memory based on the type of the received data or the identification information of the reproduction rate. It may be set.

In the above embodiment, the case of receiving and reproducing the video content file has been described as an example.
The present invention can also be applied to the case of receiving and reproducing other media data having real-time property such as audio contents.

In addition, the threshold setting procedure and its contents,
The types and configurations of the information receiving terminals, the configurations of the terminal management unit and the decoding unit, the contents of the control processing thereof, and the like can be variously modified and implemented without departing from the scope of the present invention.

[0055]

As described above in detail, in the information receiving terminal according to the present invention, the decoding / reproducing control means determines that the data amount of the information content accumulated in the reception buffer has fallen below the threshold value. In the case where the comparison means determines that the decoding / reproducing operation of the information content by the decoding unit is stopped, and then the data amount of the information content accumulated in the buffer has recovered to the threshold value or more, It is controlled so that the decryption / reproduction operation of the information content by the decryption unit is restarted. Further, further comprising a threshold value setting means, by this threshold value setting means,
The threshold value is variably set according to the reproduction rate of the received information content.

Therefore, according to the present invention, the data reproducing operation can always be resumed in a normal state after the communication failure is recovered, and the stable buffering operation is always maintained and reproduced regardless of the data reproducing rate. It is possible to provide an information receiving terminal capable of shortening the interruption time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a video receiving terminal which is an embodiment of an information receiving terminal according to the present invention.

FIG. 2 is a sequence diagram showing a control processing procedure and its contents of a terminal control unit and a decoding unit when a communication operation is normally performed.

FIG. 3 is a sequence diagram showing a control processing procedure and its contents of a terminal control unit and a decoding unit when a communication error occurs.

FIG. 4 is a sequence diagram showing a control processing procedure of the terminal control unit and the decoding unit when the download of the video content file is completed and the contents thereof.

FIG. 5 is a diagram showing a length of a decoding / reproduction interruption period due to a difference in reproduction rate, together with a decoding / reproduction (display) state of a video content file, a communication state, and a relationship between a timer and received data.

FIG. 6 is a block diagram showing a schematic configuration of a conventional video receiving terminal.

FIG. 7 is a diagram showing a relationship between a video display state and a timer and data in each conventional communication state.

[Explanation of symbols]

1 ... Video distribution server 2 ... Network 3 ... Video receiving terminal 4 ... Communication section 5 ... Terminal control unit 6 ... Decoding section 7 ... Protocol control processing unit 8 ... Terminal management unit 9 ... Codec control processing unit 10 ... Control unit buffer 11 ... Key input section 12 ... Speaker 13 ... Display 14 ... Separator buffer 15 ... Separation part 16 ... Audio decoder section 17 ... Video decoder section 18 ... Timer 20 ... Buffer management unit 21 ... Threshold detector

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Claims (3)

[Claims] 1. A receiving unit for receiving information content, and a decoding unit having a timer, wherein the decoding unit decodes the received information content while associating the time stamp with the timer value of the timer. In an information receiving terminal for reproducing, a buffer for temporarily accumulating the received information content, comparing means for comparing a data amount of the information content accumulated in the buffer with a threshold value, and information content accumulated in the buffer When the comparison means determines that the data amount of the information content has fallen below the threshold value, the decoding / reproducing operation of the information content by the decoding unit is stopped, and then the data amount of the information content accumulated in the buffer is When the comparison means determines that the information content has recovered to the threshold value or more, the decryption unit re-encrypts the information content. Decoding / reproducing control means for resuming live operation, and according to a reproducing rate of the received information content,
An information receiving terminal, comprising: threshold setting means for variably setting the threshold. 2. The threshold value setting means determines a reproduction rate of the information content at the start of reception of the information content and sets a threshold value according to the determined reproduction rate. The information receiving terminal according to claim 1. 3. The threshold value setting means extracts information indicating a reproduction rate included in a stream of the received information content during a reception period of the information content, and extracts the reproduction rate extracted and read. The information receiving terminal according to claim 1, wherein the threshold value is set on the basis of the represented information.