JP2002209201A - Video receiving terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video receiving terminal that can reproduce a video contents file while downloading them through a network and normally reproduce a video image even after a communication fault is recovered. SOLUTION: A buffer management section 20 compares a data quantity of the stored video contents with a prescribed threshold value. When the result of comparison indicates that the data quantity is the threshold value or below, a CODEC control section 9 gives a control signal to a decoding section 6 to stop the operation of its timer 18. After communication recovers, when the buffer management section 20 discriminates that the data quantity of the received video contents is the threshold value or cover, the CODEC control section 9 gives the control signal to the decoding section 6 to restart the timer 18. Since the count of the timer is coincident with a time stamp of the received data, video data by a reproduction time equivalent to a communication stop time are not fast-forwarded but correctly reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A video receiving terminal that downloads a video content file and reproduces the file has a configuration as shown in FIG.

In FIG. 6, reference numeral 1 denotes a video distribution server, 2 denotes a network, and 3 denotes a video receiving terminal. The video communication terminal 3 includes a communication unit 4 that communicates with a video distribution server via the network 2, a decoding unit 6 that reproduces multiplexed data of a video content file, and a terminal control unit 5 that controls the communication unit 4 and the decoding unit 6. Schematically configured.

A terminal control unit 5 controls a communication unit 4 to download a video content file from the video distribution server 1, a protocol control processing unit 7, extracts multiplexed data from the downloaded file, and supplies data to a decoding unit. A codec control processing unit 9 for performing operation control; a key input unit 11; a terminal management unit 8 for controlling the operation of each control processing unit in accordance with an instruction input from the key input unit 11 and managing an operation state of each unit; It is configured by a terminal control unit buffer 10 that transfers data between the processing unit 7 and the codec control processing unit 9.

[0005] The decoding unit 6 includes a separation unit buffer 14 for transferring data to and from the codec control processing unit 9, a timer 18 for controlling the data reading speed, a separation unit 15 for separating data into video data and audio data, and a video data. And a display 13 for displaying a signal output from the video decoder, an audio decoder 16 for reproducing audio data, and a speaker 12 for reproducing a signal output from the audio decoder 16.

The operation of downloading the video content file and playing back the file in the above configuration will be described below.

First, a user designates a video content file with the key input unit 11. The terminal management unit 8 analyzes the specified contents, instructs the protocol control processing unit 7 to download, and instructs the codec control processing unit 9 to prepare for data reception. Protocol control processing unit 7
Starts downloading a video content file from the video distribution server 1 through the communication unit 4.

The received file is written into the control unit buffer 10, and the control unit buffer 10 notifies the codec control processing unit 9 that the file has been received. Upon receiving the notification, the codec control processing unit 9 reads the data written in the control unit buffer 10 and
And instructs the decoding unit 6 to perform a reproducing operation.

In the decoding section 6 which has received the reproduction instruction, the activation is started after the timer 18 is initialized.
The separation unit 15 reads the data in the separation unit buffer 14 so that the timer value and the time stamp on the data match at the timing specified by. The separation unit 15 separates the multiplexed data into audio and video data, and passes the data to the audio decoder unit 16 and the video decoder unit 17. Each decoder unit decodes the data passed from the separation unit 15 so that the time stamp and the timer value match, synchronizes the video and audio, and outputs the audio and video to the speaker 12 and the display 13.

In the above-mentioned operation, it is assumed that a communication error occurs during reproduction of a video while downloading a file from the video distribution server 1. In such a case, if retransmission processing is performed in the protocol control processing unit 7, data is no longer written to the control unit buffer 10, so that data transfer to the separation unit buffer 14 also stops. When the data in the separation unit buffer 14 runs out, the separation unit 15 that operates according to the instruction from the timer 18 detects an underflow of the data in the separation unit buffer 14 and stops the data separation processing.

Thereafter, when the communication error is recovered and the protocol control processing unit 7 writes data in the control unit buffer 10, the transfer to the separation unit buffer 14 is restarted. Timer 1
Upon detection of data in the separation buffer 14, the separation unit 15, which is instructed by the operation unit 8, compares the time stamp of the data with the timer value of the timer 18 to detect that data reproduction is delayed, and From the data on the separation unit buffer 14 to be passed to the unit 16 and the video decoder unit 17, the data required by the decoder is read irrespective of the timer until the time stamp matches. The audio data transferred from the separation unit 15 is skipped by the audio codec unit 16 until the time stamp and the timer value match, and the video data is fast forward reproduced by the video decoder unit 17 until the time stamp and the timer value match. .

FIG. 7 shows how an image is displayed in the above-described state according to the movement of the timer.
In a normal state, the timer value and the time stamp of the data match, so that the data is reproduced normally. However, when a communication error occurs and the data runs out, the timer operates but the video stops. When the communication error is recovered and the data transfer is resumed, the video is fast-forwarded until the timer value and the data time stamp match, and when the timer value and the data time stamp match, the video is normally reproduced.

Therefore, once a communication error occurs, there is a problem that the video cannot be normally reproduced and the audio cannot be reproduced until the time stamp of the data to be downloaded matches the timer value. In order to solve this problem, it is necessary to download the video content file again, and there is a problem that the communication time until the completion of the reproduction becomes longer.

[0014]

As described above, in the conventional video receiving terminal, if an underflow of the downloaded data occurs, the time stamp in the data coincides with the timer value after the data transfer is resumed. Until then, there was a problem that images were not displayed properly.

The present invention has been made in view of the above circumstances, and when reproducing while downloading a video content file from a video distribution server, data is temporarily lost due to a communication error or a temporary failure, and the communication is performed. It is an object of the present invention to provide a video receiving terminal that can normally reproduce a video even after recovery from a failure.

[0016]

A video receiving terminal according to the present invention receives video content, decodes the received video content by a decoding unit, and reproduces and displays the decoded video. A comparing means for calculating a data amount of the video content and comparing the calculated data amount with a predetermined threshold value; and a first means for temporarily stopping decoding when the calculated data amount is determined to be equal to or less than the threshold value. Control signal supply means for supplying the control signal to the decoding unit, wherein the control signal supply means compares the data amount of the video content received after the decoding is temporarily stopped with exceeding the predetermined threshold value. When the means determines, a second control signal is supplied to the decoding unit to restart the decoding operation temporarily stopped by the first control signal.

In the above arrangement, when the comparison means detects an underflow of the received data due to a communication failure during the reception of the video content, the control signal supply means sends the first control signal to the decoding unit. , To instruct the decoding operation to stop. Thereafter, when the comparison unit detects that the data of the video content has been received by the restoration of the communication, the control signal supply unit issues a second control signal to the decoding unit to restart the decoding operation. To instruct.
The decoding unit is provided with a timer. The operation of the timer is stopped by the first control signal, and the stopped timer is restarted by the second control signal. As a result, since the value counted by the timer matches the time stamp of the received data, the video data for the reproduction time corresponding to the time during which communication is stopped can be correctly reproduced without being fast-forwarded.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of a video receiving terminal according to the present invention. In FIG. 1, the same parts as those of FIG.

The terminal control unit 5 includes a buffer control unit 2 in addition to a terminal control unit buffer 10 for transferring data between the protocol control processing unit 7 and the codec control processing unit 9.
0 is provided. The buffer management unit 20 has a function of grasping and managing the amount of data accumulated in the control unit buffer 10 and comparing the amount of data with a predetermined threshold. Here, the threshold value is set to a value such as 1/2 of the memory capacity of the separation unit buffer 14, for example.

FIG. 2 shows a data transfer procedure among the protocol control processing unit 7, the codec control processing unit 9, the buffer management unit 20, and the decoding unit 6 for explaining the operation of the buffer management unit 20.

When the protocol control processing unit 7 sets the data received by downloading in the terminal control unit buffer 10, the codec control processing unit 9 receives the data transfer notification 30 from the protocol control processing unit 7 and sets the buffer management unit 20 Start. The buffer management unit 20 adds the received data amount.

The codec control processing section 9 transfers the data stored in the control section buffer 10 to the separation section buffer 14 of the decoding section 6 and sends a reproduction start control signal 32 to the decoding section 6. give. Separation unit buffer 1
4, the data for reproduction is transferred to the separation unit 15. The separating unit 15 has a function of detecting the remaining data amount of the separating unit buffer 14, and compares a predetermined threshold value provided in advance with the remaining data amount of the separating unit buffer. As a result of the comparison, when the separating unit 15 determines that the remaining data amount is equal to or smaller than the threshold value, the separating unit 15 sends a data processing notification 33 to the codec control processing unit 9.

When the codec control processing unit 9 receives the data processing notification 33, it calls the buffer management unit 20 again and subtracts the data amount supplied to the decoding unit 6. Here, the buffer management unit 20 determines whether the amount of data in the control unit buffer 10 is equal to or less than a threshold value set in advance according to the capability of the terminal control unit 5. If the result of the determination is that it is equal to or greater than the threshold value, the codec control processing unit 9 performs data transfer 34 to the decoding unit 6.

Next, a data transfer procedure among the protocol control processing unit 7, the codec control processing unit 9, the buffer management unit 20, and the decoding unit 6 when a communication failure occurs will be described with reference to FIG.

In FIG. 3, when the data in the terminal control unit buffer 10 barely exceeds the threshold value due to a communication failure, the codec control processing unit 9
Receives the data processing notification 40 from the buffer management unit 2
0 is started, and the data amount supplied to the decoding unit 6 is subtracted to determine the data amount. If the result of the determination is that it is equal to or less than the threshold, that is, if the buffer management unit 20 detects a buffer underflow,
Instructs the decoding unit 6 to stop reproduction (pause) 41. Specifically, a control signal is supplied from the codec control processing unit 9 to the decoding unit 6.

Upon receiving the instruction, the decoding unit 6 sets the timer 18
And the decoding operation of each of the decoder sections 16 and 17 are stopped. The timer 18 holds the timer value (count value) at the time of stopping.

Thereafter, the communication is restored, and the protocol control processing unit 9 sets the data received by the download in the terminal control unit buffer 10. The codec control processing unit 9 receives the data transfer notification 42, calls the buffer management unit 20, adds the received data amount, and instructs the decoding unit 6 to start reproduction 43. Specifically, a control signal is supplied from the codec control processing unit 9 to the decoding unit 6. The decoding section 6 receives a control signal from the codec control processing section 9 and receives a timer 18 and each of the decoder sections 16 and 17.
Works again.

FIG. 4 shows a protocol control processing unit 7, a codec control processing unit 9, and a buffer management unit 2 after the data transfer from the video distribution server 1 to the video receiving terminal is completed.
0 is a diagram showing a data transfer procedure between the decoding unit 6 and 0. FIG.

In FIG. 4, the codec control processing unit 9 receives the data transfer notification 50 from the protocol control processing unit 7, and the buffer management unit 20 determines the end of the data from the content of the received data. When the data in the terminal control unit buffer 10 is barely equal to or greater than the threshold value and the codec control processing unit 9 receives the data processing notification 51 from the decoding unit 6, it calls the buffer management unit 20 and calls the buffer management unit 20.
The data amount after subtracting the data amount supplied to is determined. At this time, the buffer management unit 20 determines that the data is normal because the buffer management unit 20 detects the end of the data first even if the data amount after the subtraction is equal to or smaller than the threshold value as a result of comparison with the threshold value of the buffer management unit 20 Then, the codec control processing unit 9 performs data transfer 52 on the remaining data to the decoding unit 6.

FIG. 5 shows how an image is displayed according to the present embodiment in accordance with the communication state and the movement of the timer. When there is no communication error, the video is normally reproduced because the timer value and the data time stamp match. When a communication error occurs and there is no more data, the codec control processing unit 9 of the terminal control unit 5 controls the decoding unit 6 and stops the timer 18 and each of the decoders 16 and 17, so that the reproduction of the video is stopped. After that, the communication error was recovered,
When the data transfer is resumed, the codec control processing section 9 controls the decoding section 6 to activate the timer 18. As a result, the timer value matches the data timestamp,
The video is reproduced normally without fast-forwarding.

As described above, in this embodiment, when the control unit buffer 10 detects the underflow of the received data,
The codec control processing unit 9 instructs the decoding unit 6 to temporarily stop the timer 18 in the codec. Then, the control unit buffer 10 detects that the data amount equal to or larger than the preset data amount has been received from the server due to the restoration of the communication, and the codec control processing unit 9 instructs the decoding unit 6 to start the timer 18. As a result, the decoder units 16 and 17 can be operated so that the timer value and the data time stamp match, so that the video is immediately and normally reproduced. Therefore, according to the present embodiment, unlike the related art, there is no problem that the video is fast-forwarded and reproduced after the communication error is recovered.

In addition, various modifications can be made without departing from the spirit of the present invention.

[0034]

According to the video receiving terminal of the present invention, when a video content file is played back while being downloaded from a video distribution server, data is temporarily lost due to a communication error or a temporary failure, resulting in a communication failure. The video can be reproduced normally even after the recovery.

[Brief description of the drawings]

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

FIG. 2 is a sequence diagram showing a normal data transfer procedure.

FIG. 3 is a sequence diagram showing a procedure of data transfer from the occurrence of a communication error until after the communication error has been recovered;

FIG. 4 is a sequence diagram showing a procedure of data transfer after data transfer is completed.

FIG. 5 is a diagram showing a display state of a video and a relationship between a timer and data in each communication state according to the embodiment.

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

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

[Explanation of symbols]

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

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yasushi Unoki 70-F, Yanagicho, Kawasaki-shi, Kanagawa F-term in Toshiba Yanagicho Plant (reference) 5C053 FA30 GB06 GB21 JA22 KA04 KA30 LA05 5C064 BA07 BB05 BC20 BC23 BC27 BD08

Claims (2)

[Claims] 1. A video receiving terminal that receives video content, decodes the received video content by a decoding unit, and reproduces and displays the decoded video. A buffer for temporarily storing the received video content; Comparing means for reading the amount of data stored in the memory and comparing the read data amount with the predetermined threshold value; and when the comparing means determines that the read data amount is equal to or smaller than the threshold value, temporarily performs an operation for decoding. Control signal supply means for supplying a first control signal for stopping to the decoding unit, the control signal supply means comprising: a video content stored in the buffer after an operation for decoding is temporarily stopped; When the comparing means determines that the data amount of the data exceeds the predetermined threshold value, the second control is performed to restart the decoding operation temporarily stopped by the first control signal. A video receiving terminal for supplying a control signal to the decoding unit. 2. The decoding section includes a timer, the timer temporarily stops its operation by the first control signal, and resumes its operation by the second control signal, and temporarily stops. 2. The video receiving terminal according to claim 1, wherein a count value at the time is stored.