JPH0951356A - Av data buffering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the quantity of hardware and software necessiteted at the time of overflow by allowing a control means to control the state of the inside of a buffer memory. SOLUTION: An AV data buffering device 1 receiving requiring AV data through a communication line and outputting it to an AV data processor 12 while storing the piece of AV data is provided with a data input means 7, a buffer control means 8 and the control means 9. Then the device 1 judges the data request of the AV data processor 12 from the stored data quantity by preceding and requires new data. In this case, the state of the inside of the buffer memory is grasped by a state control part in the control means 9 without being occupied by the control of the buffer memory (included in the buffer control means 8). Then the buffer memory 11 is easily prevented from becoming free or overflow while the control means 9 executes another processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention requests AV data, which is image (video) data such as a movie or audio (audio) data such as music, through a communication line, and receives AV data received through the communication line. The present invention relates to an AV data buffering device that is configured as a part of an AV data processing device that reproduces a video stream or that is connected between an AV data processing device and a communication line. For example, a video-on-demand terminal device. Is used in.

[0002]

2. Description of the Related Art Generally, when transmitting AV data such as video data and audio data using a communication line,
For the purpose of reducing the amount of data on a communication line, AV data is encoded and divided into a plurality of packets for transmission. Then, the terminal which receives and reproduces the encoded AV data uses the FIFO format buffer memory,
It absorbs the speed difference between the transmission speed and the decoding / reproduction speed. As a method for buffering AV data, as disclosed in Japanese Patent Laid-Open No. 2-67847, "Packet Transmission Method", it is judged that the amount of data in the buffer memory is less than a certain amount, and A method of controlling reading from the memory is used.

[0003]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2-678
No. 47 “Packet transmission method” is an asynchronous transmission method in which packets are unilaterally continuously sent from the other side, and when AV data to be packet-transmitted is processed, the data amount is constant. When the amount becomes smaller, the data processing is temporarily stopped so that the amount of data in the buffer memory becomes larger than a certain amount. And
In the case of synchronous transmission in which the packet requested from the terminal side is sent from the host station, it is detected that the amount of data in the buffer memory is less than a certain amount,
I was requesting data from the host station.

However, in this case, until the amount of data in the buffer memory has once exceeded a certain amount, it cannot be detected that the amount of data has decreased, and the next data request is not made. There was a risk that the data in the memory would run out and the data to be processed would be interrupted. In addition, as a countermeasure against this, increasing the packet size can be considered, but in this case, there is a fear that the buffer memory may overflow.

As another method, it is conceivable that the control means in the terminal constantly monitors the state of the buffer memory to avoid the occurrence of overflow, but in this case, the control means has the buffer memory. Since it is occupied by the management of
There is a problem that the processing efficiency becomes poor.

In the case of synchronous transmission in which the packet requested from the terminal side is sent from the host station as described above,
It was difficult to prevent the data in the buffer memory from becoming empty and overflow. Further, if it is attempted to prevent this, the control means will be occupied by the buffer memory management, so another control means will be required to perform other processing, and there will be problems such as an increase in the amount of hardware. there were. Therefore, an object of the present invention is to control the buffer memory so as not to occupy the buffer memory management and to prevent overflow of the buffer memory and empty data.

[0007]

As means for achieving the above object, an AV data buffering device for receiving requested audiovisual data via a communication line and outputting the audiovisual data to an AV data processing device is supplied. It has a data input means for notifying that the input of the image and sound data is completed, and a buffer memory for accumulating the image and sound data supplied from the data input means, and the data amount in the buffer memory is greater than a predetermined value. Buffer management means for notifying that the data amount has increased and also for notifying the data amount when the data amount has decreased below a predetermined value, and a state for holding a state value of the data amount in the buffer memory with respect to the predetermined value. A management unit is provided, and the input completion state of the audiovisual data notified from the data input unit and the buffer management unit are set. The data amount in the buffer memory is constituted by the control means for judging the necessity of the data request from the notified data increase or decrease and the status value of the status management unit, It is intended to provide an AV data buffering device characterized by making a request for new data when is less than a predetermined value.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The AV data buffering apparatus of the present invention receives requested AV data via a communication line and outputs the AV data as shown in FIG.
The AV data buffering device 1 outputs data to the AV data processing device 12 while accumulating the data. The data input means 7, the buffer management means 8 and the control means 9 are provided, and the data request of the AV data processing device 12 is judged in advance from the accumulated data amount and a new data request is made. is there.

Here, each means will be described in detail with reference to FIG. The data input means 7 is a host station 6
It is means for receiving the AV data sent from the device via the communication line and the communication interface 2, and writing it in the buffer memory 11 in the buffer management means 8. And AV
When the data input is completed, it has a function of notifying the control means 9 of the input completion.

The buffer management means 8 has a buffer memory 11 for accumulating AV data, and is a means for notifying the control means 9 of a state change of the amount of data in the buffer memory 11. Then, when the amount of data in the buffer memory 11 exceeds the fixed amount of memory capacity, the control means 9 is notified of the increase of the data, and when the amount of data in the buffer memory 11 becomes less than the fixed amount of memory capacity, The control means 9 is notified of the data reduction.

The control means 9 has a state management part 10 for holding a state value that the amount of data in the buffer memory 11 is larger or smaller than a certain value, and notifies from the data input means 7 and the buffer management means 8 and this. It is means for requesting new data from the host station 6 by looking at the status value of the status management unit 10. The status value held by the status management unit 10 changes according to the notification (data increase, data decrease) from the buffer management means 8.

By holding the state value of the amount of data in the buffer memory 11 in the state management unit 10, the control means 9 keeps track of the state in the buffer memory 11 without being occupied by the management of the buffer memory 11. You can figure it out. Therefore, it is possible to easily prevent the buffer memory 11 from becoming empty or overflowing while the control unit 9 executes other processing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of the AV data buffering device of the present invention, an example of a video-on-demand terminal device is given, and its configuration is shown in FIG. 1 and described below. In the figure, the AV data buffering device 1 is connected to a communication interface 2 for communicating with a host station 6 via a communication line, and further, an operation panel 3 for a user to select information and received data. An AV data processing device 12 having a decoding device 4 for decoding and a reproducing device 5 for reproducing the decoded data is connected.

The AV data buffering device 1 comprises a data input means 7, a buffer management means 8 and a control means 9. Each of these means is shown in FIG. It has the configuration and operation described above, and the description thereof is omitted here. Then, the decoding device 4 of the AV data processing device 12 sequentially reads the data from the buffer memory 11 inside the buffer management means 8, decodes it, and outputs it to the reproducing device 5. In the playback device 5,
The decoded AV data is output to a display device or an audio signal reproducing device (not shown) to display and output images and sounds.

Here, the AV data buffering device 1
The operation will be described with reference to the flowchart shown in FIG. 3, focusing on the processing contents of the control means 9. When the user makes a request for desired AV data using the operation panel 3 (step s0), the control means 9 sets the initial value 0 to the state management unit 10 (step s1), and the communication interface 2
And access the host station 6 via the communication line to request the first data from the host station 6 (step s
2). Then, the notification from the data input means 7 or the buffer management means 8 is waited for (step s3), and other processing is performed until any notification is received (step s).
4).

The AV data requested from the host station 6 is sent to the data input means 7 via the communication line and the communication interface 2.
Then, the AV data is supplied from the data input means 7 to the buffer memory 11 in the buffer management means 8 and accumulated therein. At the same time, the buffer memory 11
AV data accumulated in the AV data processing device 12 is sequentially processed.
Is output to the decoding device 4. Therefore, the amount of data in the buffer memory 11 is constantly changing.

When the amount of data in the buffer memory 11 exceeds a certain value (predetermined value), the buffer managing means 8 notifies the controlling means 9 of the increase in data (step s5).
The state management unit 10 is set to 1 (step s6) and holds that the data amount in the buffer memory 11 is large.

Thereafter, when the input of the AV data packet supplied from the host station 6 is completed and the data input means 7 notifies the control means 9 of the completion of the data input (step s7), the control means 9 (others). Then, the setting value of the state management unit 10 is checked (step s8). At this time,
If the setting value of the state management unit 10 is 0, it means that the amount of data in the buffer memory 11 does not exceed a certain value (there is a vacant area), so that the host station 6 is notified via the communication interface 2. On the other hand, new data is requested (step s11).

Further, when the set value of the state management unit 10 is 1, it means that the amount of data in the buffer memory 11 exceeds a certain value (the free area has no margin).
Even if the input of V data is completed, the host station 6 is not requested for new data. Then, when the amount of data in the buffer memory 11 becomes equal to or less than a certain value (when the amount of data in the buffer memory 11 decreases), the buffer managing unit 8 notifies the control unit 9 of the data reduction (step s).
9), the setting value of the state management unit 10 is set to 0 (step s10), and new data is requested from the host station 6 via the communication interface 2 (step s11).

The state management unit 10 uses the buffer memory 1
Since the data amount in 1 is a value indicating whether the data amount is larger or smaller than a fixed value, when the state management unit 10 is 0 (when the data amount is smaller than the fixed value), the data is further reduced from the buffer management means 8. Is not notified, the state management unit 1
When 0 is 1 (when the data amount is larger than a certain value), the buffer management means 8 does not notify the data increase. The request for data to the host station 6 is made only when the amount of data in the buffer memory 11 is less than a certain value, so that the buffer memory 11 does not overflow due to the input of data.

Further, when the data in the buffer memory 11 becomes less than a certain value, the host station 6 is immediately requested for the data, so that the buffer memory 11 does not become empty. Then, the control means 9 needs to perform the processing relating to the data input / output only when the state change is notified from the data input means 7 and the buffer management means 8. Therefore, other processing is performed in parallel while waiting for the notification. It is possible (step s4).

[0022]

According to the AV data buffering device of the present invention, since the control means manages the state in the buffer memory, the data in the buffer memory will not be emptied or overflowed. You can reduce the amount of hardware and software required. Further, since the processing is not occupied by the control of the buffer memory, other processing can be performed in parallel by the control means, and the control means for other processing can be eliminated, thus reducing the amount of hardware. The effect is that it can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a video-on-demand terminal device to which an embodiment of an AV data buffering device of the present invention is applied.

FIG. 2 is a configuration diagram showing an embodiment of an AV data buffering device of the present invention.

FIG. 3 is a flowchart showing the operation of an embodiment of the AV data buffering device of the present invention.

[Explanation of symbols]

 1 AV Data Buffering Device 2 Communication Interface 3 Operation Panel 4 Decoding Device 5 Playback Device 6 Host Station 7 Data Input Means 8 Buffer Management Means 9 Control Means 10 State Management Unit 11 Buffer Memory 12 AV Data Processing Device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04Q 11/04

Claims (1)

[Claims] 1. An AV data buffering device for receiving requested audiovisual data via a communication line and outputting the audiovisual data to an AV data processing device, the data notifying that the input of the supplied audiovisual data has been completed. It has an input means and a buffer memory for accumulating the image and sound data supplied from the data input means, and when the data amount in the buffer memory exceeds a predetermined value, it is notified as a data increase, and the data amount is increased. It has a buffer management means for notifying as a data decrease when it decreases below a predetermined value, and a status management section for holding a status value of the amount of data in the buffer memory with respect to the predetermined value, and is notified by the data input means. The input completion state of the audiovisual data, the data increase or decrease notified by the buffer management means, and the state management unit And a control unit that determines whether or not a data request is necessary from the state value, and when the image / acoustic data is in an input completed state and the data amount in the buffer memory is less than a predetermined value, a new AV characterized by requesting data
Data buffering device.