JP3140935B2 - Quality assurance method and information transmission system for transmission target information - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information transmission system for transmitting information at a high speed via a transmission line, and more particularly, to an information transmission system using a LAN or a high-speed modem.
Alternatively, the present invention relates to a technique for guaranteeing the quality of information to be transmitted (transmitted and received, the same applies hereinafter) in an asynchronous multimedia digital transmission system to a certain level or more.

[0002]

2. Description of the Related Art Recent digital information transmission systems include:
Various media such as voice, data, and images can be transferred to LAN, high-speed modem, or ATM (Asynchronous TransferModule).
e) Some technologies enable high-speed transmission. For example, in a system using the ATM technology, all information is divided into blocks each having a fixed length called a cell, and information to be transmitted and its destination are collectively transmitted in the cell. In this technique, the difference in bit rate is adjusted by the number of cells transmitted per second, so that the transmission path can be used without waste regardless of the type of transmission target information. But,
In such a system, when transmitting information that is temporally continuous such as moving images and audio, when the network is congested, or when the number of terminals connected to the network increases, the traffic volume of the network increases. On the receiving side, some of the cells are discarded. for that reason,
For example, in the case of a moving image, the image freezes, and in the case of a sound, there is a problem that the voice is interrupted. This is LAN
The same applies to communication lines using high-speed modems.

As a countermeasure against such a problem, the following method has conventionally been adopted. (1) Provide sufficient margin in network design. That is, when designing the number of lines, the band, and the like, a line having a capacity that exceeds the required capacity stochastically is designed. This prevents shortage of lines and bandwidth. (2) Prioritize a plurality of media to be transmitted. Among voices, moving images, data, etc., for example, by providing means for transmitting voice preferentially, the amount of information to be transmitted is reduced, and peaks are cut to prevent a temporary increase in traffic volume on the network I do. (3) Change the compression degree of the transmission target information according to the state of the network. If the network performance is degraded due to congestion of the line or the like, the compression degree of the transmission target information is changed according to the state.

[0004]

However, the above method (1) has a drawback that the network utilization is low, and an excessively large design poses a problem from the viewpoint of economy. On the other hand, if the margin in the line design is reduced, the probability of occurrence of audio breaks increases. In addition, the method (2) cannot be applied to a single type of transmission media, and has a disadvantage that the probability that an image stops when the highest priority is given to audio is increased. In the above method (3), the information transmission side uses a differential pulse code modulation (Differential pulse code modulatio).
Since n) and the like are required, the processing load on the transmission side increases. In addition, when the transmission target information is already compressed as in a video server, for example, it becomes difficult to apply the information.
Further, since it is necessary to grasp the network performance at the time of transmission, there is a disadvantage that the processing for that is required separately.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a method for transmitting information at high speed through a transmission line by dynamically changing the amount of information to be transmitted according to the traffic amount of the transmission line. An object of the present invention is to provide a technology for guaranteeing the quality of target information.

[0006]

The present invention first provides a quality assurance method for information to be transmitted. In this method, when transmitting transmission target information, a plurality of band compression data having different compression degrees are generated from one transmission target information, and the generated plurality of band compression data are sequentially transmitted to a transmission path in descending order of compression degree. Send. Here, the band-compressed data refers to data obtained by, for example, thinning out a certain number of samples (performing band compression) from transmission target information sampled at a predetermined sampling frequency. At this time, difference data between successive band compression data in the order of compression degree is simultaneously generated, and band compression data having the highest compression degree (band compression data having the highest degree of thinning).
And differential data in the next and subsequent orders, or at least one differential data selected in accordance with the highest compressed band compressed data and the current traffic volume of the transmission line among the plurality of band compressed data. The data may be sequentially transmitted to the transmission path. As the number of difference data with respect to the band compression data with the highest compression ratio increases, it becomes the same as the band compression data with the lower compression ratio, and the data obtained by integrating all the difference data is not compressed, that is, the time when it was sampled (Sampled data).

[0007] A reproduction start time is assigned in advance to each transmission target information, and the transmission completion prediction time of the next band compressed data or differential data based on the transmission time of each band compressed data or differential data is set to the subsequent transmission time. The transmission of the band-compressed data or the difference data is started when the reproduction start time assigned to the target information is not reached, and the transmission is stopped when the predicted transmission end time is after the reproduction start time. It is preferable to be able to transmit the maximum amount of information within a range that does not affect the transmission of the transmission target information.
On the other hand, the receiving side reproduces the transmission target information based on the band compression data or by integrating the band compression data and the difference data.

[0008] The present invention also provides an information transmission system for implementing the above method. In this information transmission system, the transmitting device compresses one piece of transmission target information with different degrees of compression to generate a plurality of band-compressed data and difference data between band-compressed data having successive degrees of compression, and Means for transmitting to a plurality of band-compressed data or the differential data transmission path, and the number of transmissions of the band-compressed data or the differential data after the next transmission after the transmission of the band-compressed data with the highest degree of compression to the traffic amount of the transmission path. Transmission amount control means for dynamically changing the transmission amount in response to the request.

The transmission amount control means monitors, for example, the transmission time of each of the band-compressed data or the difference data between the band-compressed data, and determines the estimated transmission end time of the next-order band-compressed data or the difference data between the band-compressed data. A monitoring unit to derive,
When the predicted transmission end time of the band-compressed data or the difference data between the band-compressed data does not reach the reproduction start time assigned to the subsequent transmission target information, the transmission unit transmits the band-compressed data or the difference data between the band-compressed data. A transmission control unit for permitting transmission and suspending the transmission when the predicted transmission end time is after the reproduction start time.

[0010] Also, the receiving apparatus, when the band compressed data received from the transmission path is one, the band compressed data,
When there are a plurality of band-compressed data, or when the band-compressed data and the difference data are combined, a unit for reproducing the transmission target information by integrating them is provided.

[0011]

According to the present invention, the band-compressed data having the highest compression degree is transmitted first on the transmission side, and the transmission time of the band-compressed data is monitored. As a result, the current traffic volume of the transmission path can be determined, and if there is a margin between the transmission end time of the band-compressed data and the reproduction start time of the subsequent transmission target information, the next band-compressed data is transmitted. When the information amount of each band compressed data is large, the difference data between the next band compressed data is transmitted after the transmission of the band compressed data with the highest compression degree is completed. This is repeated until the reproduction start time of the subsequent transmission target information is reached, and when the reproduction start time is reached, transmission of band compression data or difference data for the next transmission target information is started. On the receiving side, the transmission target information is reproduced based on the band compression data and the difference data.

In this way, the band compression data having the highest compression degree, that is, the information of the lowest quality, is always transmitted from the transmission side, and if the traffic volume of the transmission path is small and high-speed transmission is possible, it is continued. Data for improving the quality of information up to is transmitted. As a result, even when the traffic volume fluctuates, the transmission target information is not discarded as in the related art, and the problem of the interruption of the sound and the freeze of the image is solved. That is, the quality of the transmission target information is guaranteed. Also, it is not necessary to expect an excessive margin in the line design, and the efficiency of use of the transmission line is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a functional block diagram of an information transmission system according to one embodiment of the present invention. This information transmission system is configured by connecting a transmission device 1 and a reception device 2 via a transmission path such as a LAN. The transmission device 1 includes a media input unit 11, an analog / digital conversion unit (A / D conversion unit)
12, interpolation processing unit 13, information storage unit 14, communication processing unit 1
5 and a system processing unit 16. The receiving apparatus 2 includes a communication processing unit 21, a system processing unit 22, a digital / analog converter (D / A converter) 23, an integrated processing unit 24, and a media output unit 25. Have.

In the transmission device 1, the media input unit 11
Is a medium for inputting a medium to be transmitted, for example, audio or image which is analog data, and is constituted by, for example, a microphone or a video output device. A / D converter 12
Converts input speech and the like at a predetermined sampling frequency and converts the sampled data into sampled data. The interpolation processing unit 13 divides the sampled data into a plurality of blocks, and compresses the sampled data of each block with different compression degrees to generate a plurality of band-compressed data. The difference data between the band compression data in the order of successive compression degrees is generated. The information storage unit 14 is a memory that stores sampled data in block units and a plurality of band-compressed data or difference data of each block. The manner of storing these data will be described later. The communication processing unit 15 includes the method processing unit 1
6 and transmits the band-compressed data and the like obtained from the information storage unit 14 to the transmission path, receives a reception notification from the receiving device 2, and notifies the system processing unit 16 of the reception notification.

The system processing unit 16 sets a predetermined reproduction start time at the preceding stage of each block when storing the sampled data in block units in the information storage unit 14, or stores a communication start time described later. Time information setting section 16
1, a monitoring unit 162 that monitors the transmission time of the band-compressed data or the difference data and derives a predicted transmission end time, and the transmission-end predicted time of the band-compressed data or difference data is allocated to the subsequent transmission target information. The transmission control unit 1 that allows the communication processing unit 15 to transmit the compressed band data or the differential data when the reproduction start time has not been reached, and stops the transmission when the predicted transmission end time is after the reproduction start time.
63. The monitoring of the transmission time is performed, for example, based on a communication start time for each block, band compression data, or difference data and a reception notification from the receiving device 2.

On the other hand, in the receiving device 2, the communication processing unit 2
1 receives band-compressed data and the like transmitted from the transmission path and inputs the data to the system processing unit 22. The reception notification may be transmitted to the communication processing unit 15 (to the monitoring unit 162) of the transmission device 1. The D / A converter 23 converts the received band compressed data and the like into analog data. The integration processing unit 24 integrates the converted analog data and sends it to the media output unit 25. Each communication processing unit 1 of the present system
5 and 21, for the sake of convenience, errors on the transmission path are automatically corrected, and when the processing speed on the transmission side is too fast, transmission processing is suppressed by flow control. The buffer in the communication processing unit 15 of the transmission device 1 is made as small as possible. This is because the accuracy of the transmission start timing according to the present embodiment is reduced when the transmission appears to be completed and is actually stored in the buffer. Further, in the receiving device 2, the actual reproduction of the audio is performed by the media output unit 25
This is performed by an audio playback device connected to the FIFO output side of the. This device does not output anything when the FIFO is empty, and continuously reproduces audio as long as there is content.

Next, the operation of the information transmission system having the above configuration will be described with reference to FIGS. First, the transmission target medium will be described. FIGS. 2 to 5 show that an audio signal, which is an example of a transmission target medium, is sampled at a sampling frequency of 44 [KHz], and a plurality of band-compressed data and differential data are generated from the obtained sampled data. An example is shown below. For convenience, the audio signal is 1 [ms
[ec] unit. this is,
This is because the quality of the reproduced audio information is made comparable to that of a CD (Compact Disk).

FIG. 2A shows audio information before sampling.
When this is sampled at a sampling frequency of 44 [KHz], a sample of 44,000 [lines / second] is obtained as shown in FIG. Data consisting of this sample group is sampled data,
Data obtained by compressing the sampled data at a plurality of compression degrees having a mutual interpolation relationship is band-compressed data. FIG.
(C) shows a state in which the band compression data having the highest compression degree obtained from one sampled data and the difference data in the next and subsequent orders are divided.

FIG. 3 is an exploded view of each data in FIG. 2C. In the example of FIG. 3, the band compression data compressed at the highest compression degree is resolution 1, the band compression data compressed at the next highest compression degree is resolution 1 + resolution 2, and the third band compression data (no compression: original sample). Data) resolution 1
+ Resolution 2 + resolution 3 are defined. The band-compressed data of resolution 1 shown in FIG.
The band compressed data of resolution 1 + resolution 2 shown in FIG. 3C is obtained by compressing the above sampled data by 1/2. Further, the data of resolution 2 shown in FIG. 3B is difference data between the band-compressed data of resolution 1 + resolution 2 shown in FIG. 3C and the band-compressed data of resolution 1 shown in FIG. The data of the resolution 3 shown in FIG. 3D is obtained by combining the sampled data shown in FIG.
This is difference data from the band compression data of resolution 1 + resolution 2 shown in (c).

FIG. 4 shows a case where, in addition to the data (audio information) of each resolution shown in FIG. 3 and data of resolution 4 for performing stereo reproduction, these band compressed data and difference data are stored in an information storage unit. 14 shows an example of a file configuration in the case where the file is stored in the storage unit 14. Note that the data of resolution 4 corresponds to the sampled data shown in FIG. In the upper part of FIG. 4, such audio information is divided into blocks, and an area (hereinafter, a header part) for storing a reproduction start time of each block is provided in a preceding part of each block. The lower part of FIG. 4 is a detailed explanatory diagram of each block. In the illustrated example, data of resolutions 1 to 4 are arranged in order. FIG. 5 shows an example of a file configuration when the reproduction start time is actually recorded in each header section. In the illustrated example, the reproduction start time of the first audio information is 00: 00: 00.0.
00, the reproduction start time of the second audio information is 00: 00: 00.001, and so on, in the same manner, 00: 00: 00.002, 00: 00: 00.003, and so on.
On the other hand, the first audio information is band-compressed data having a resolution of 1 comprising 22 bytes, differential data having a data amount of 22 bytes and having a resolution of 2 by itself, differential data having a data amount of 44 bytes having a resolution of 3, and 88-byte data. .. Are sampled data of resolution 4 having a quantity, resolution 1 is transmitted at the fastest, and subsequently transmitted as resolution 2.

FIG. 6 shows an example of a file configuration when the transmission target medium is image information. In the case of image information, for example, information of resolution 1 is 160 dots * 120 dots,
The resolution 2 information may be 240 dots * 180 dots, the resolution 3 information may be 320 * 240 dots, and the resolution 4 information may be 640 * 240 dots. The information of each resolution is difference data of the data of the previous resolution.

Next, a procedure for actually transmitting media in the present system will be described with reference to FIGS. S indicates a processing step. FIG. 7 shows a transmitting device 1.
FIG. 6 is an explanatory diagram of a processing procedure in a method processing unit 16. The system processing unit 16 first stores the current time as the “communication start time” in the time information setting unit 161 when starting communication (S101, S102). One unit of media information is read from the information storage unit 14 (S103), and further subsequent media information (block) is read, and the reproduction start time stored in the header part of the block is read to perform "next time". It is stored in the time information setting unit 161 (S104). Here, a counter for counting the number of transmissions of each resolution (1 to 4) is set to “1” (S
105). Then, the time when the transmission of the data of resolution 1 is completed is compared with the reproduction start time of the next block (S1).
06) If the transmission end time of the resolution 1 is earlier than the reproduction start time of the next block (No in S106), the data of the resolution 2 is transmitted (S107). The same procedure is used to transmit data of resolution 3 and higher, and if the counter value matches the resolution number, all information (all samples sampled at the maximum sampling frequency) of the block has been transmitted. Therefore, the process returns to S106 (S108, S1
09). On the other hand, in S106, if the reproduction start time of the next block is earlier (Yes in S106), the transmission of the data of the block is terminated, and the preparation for transmission of the next unit block is started (S103).

The procedure in the system processing unit 22 of the receiving apparatus 2 is as shown in FIG. 8. First, after data of resolution 1 is received (S201, S202), the next data contains the same media information (block). Is determined (S202). This is because the header portion is not added to the data of resolution 2 or later, but the header portion is added at the preceding stage of each block, so that it can be easily identified. If the data is in the same block, the same determination is made for the next received data (resolution n). If the data is not in the same block, the data is determined to be the data in the next block. Start (S2
04).

In the above description, the transmission target medium is sampled at the maximum sampling frequency, and compressed at a plurality of compression levels based on the sampled data to generate a plurality of band-compressed data and differential data. This is an example of transmitting differential data sequentially from high-bandwidth compressed data.
First of all, the main focus is on generating a plurality of band-compressed data containing the same information from one transmission target medium and dynamically changing the number of transmissions according to the current traffic volume of the transmission path. Alternatively, other band-compressed data may be transmitted in the order of decreasing compression degree. If there is enough time before the reproduction start time of the subsequent block, band-compressed data having an appropriate compression degree is arbitrarily selected. May be.

In the sampling stage, the transmission target medium may be sampled using a plurality of sampling frequencies to directly generate a plurality of band-compressed data or similar data. In this case, the first data to be transmitted to the transmission path is data sampled at the minimum sampling frequency. Also,
If the integration of a plurality of data on the receiving device side does not lead to an improvement in the quality of information, the data received last in the same block may be adopted as the representative data of the block.

[0026]

As is apparent from the above description, according to the present invention, data transmitted from the transmission side is reproduced without being discarded at the reception side even when the traffic volume of the transmission path changes. Therefore, there is an effect that the quality is guaranteed regardless of the type of the transmission target information. This enables continuous information transmission in a system using an existing LAN, high-speed modem, or the like, and also enables an increase in network utilization. Furthermore, DPCM (di
Since there is no need to perform complicated compression processing such as fferential pulse codemodulation, the load on the transmission side is reduced.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an information transmission system according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a process in a case where an audio signal as a transmission target medium of the present embodiment is sampled at a maximum sampling frequency to generate band-compressed data.

FIG. 3 is a diagram illustrating an example in which three types of sampled data are extracted as resolutions 1 to 3 according to the present embodiment.

FIG. 4 is a diagram showing an example of a file configuration when an audio signal is stored in an information storage unit as data for each resolution according to the embodiment.

FIG. 5 is a diagram showing an example in which time information and the information amount of each resolution are specifically recorded in the file configuration example of FIG. 4;

FIG. 6 is a diagram showing an example of a file configuration when an image signal is stored in an information storage unit as data for each resolution according to the embodiment.

FIG. 7 is an explanatory diagram of a procedure on the transmitting device side when information is transmitted according to the embodiment.

FIG. 8 is an explanatory diagram of a procedure on the receiving device side when information transmission is performed according to the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission device 11 media input unit 12 A / D conversion unit 13 interpolation processing unit 14 information storage unit 15 transmission-side communication processing unit 16 transmission-side system processing unit 2 receiving unit 21 transmission-side communication processing unit 22 reception-side system processing unit 23 D / A conversion unit 24 Integration processing unit 25 Media output unit

Claims (7)

(57) [Claims] When transmitting information to be transmitted, a plurality of band-compressed data having different degrees of compression are generated from one piece of transmission-target information, and the plurality of band-compressed data thus generated are transmitted in the order of higher compression degree. Wherein the receiving side reproduces the transmission target information based on the band compressed data received from the transmission path. 2. When transmitting transmission target information, a plurality of band compressed data having different degrees of compression and difference data between successive band compression data in order of compression degree are generated from one transmission target information. The band compression data having a high degree of compression and the difference data in the next and subsequent orders are sequentially transmitted to the transmission line, and the receiving side integrates the band compression data and the difference data received from the transmission line to obtain the transmission target information. A quality assurance method for transmission target information characterized by reproduction. 3. When transmitting transmission target information, a plurality of band compressed data having different degrees of compression and differential data between successive band compression data in order of compression degree are generated and generated from one transmission target information. The band-compressed data having the highest compression degree among the plurality of band-compressed data and at least one differential data selected according to the current traffic volume of the transmission line are sequentially transmitted to the transmission line. And transmitting the transmission target information by integrating the band compression data and the difference data received from the path. 4. A reproduction start time is allocated in advance for each transmission target information, and the next predicted transmission end time of the next band compressed data or differential data based on the transmission time of each band compressed data or the differential data is set to a subsequent time. When the reproduction start time allocated to the transmission target information has not been reached, transmission of the band-compressed data or difference data is started, and when the transmission end predicted time is after the reproduction start time, the transmission is stopped. 4. The quality assurance method for transmission target information according to claim 1, wherein 5. An information transmission system for transmitting information between a transmitting device and a receiving device, wherein the transmitting device compresses one transmission target information at different compression degrees to generate a plurality of band-compressed data. Means for transmitting the generated plurality of band-compressed data to the transmission path in descending order of the degree of compression, and transmitting the number of transmitted band-compressed data in the next order after the end of transmission of the band-compressed data with the highest degree of compression. Transmission amount control means for dynamically changing according to the traffic volume of the path, wherein the receiving apparatus has means for reproducing the transmission target information based on the band compression data received from the transmission path. Information transmission system. 6. An information transmission system for transmitting information between a transmission device and a reception device, wherein the transmission device generates a plurality of band-compressed data by compressing one transmission target information with different compression degrees. Means for generating difference data between band-compressed data in successive band-compression order, means for sequentially transmitting band-compressed data having the highest degree of compression and difference data in the next and subsequent order to a transmission path, Transmission amount control means for dynamically changing the number of transmissions of the differential data after transmission is completed in accordance with the current traffic volume of the transmission line, wherein the receiving device comprises: And a means for integrating the difference data and reproducing the transmission target information. 7. The transmission amount control means monitors a transmission time of each band-compressed data or a difference data between the band-compressed data, and derives an estimated transmission end time of the next band-compressed data or the difference data. Unit, when the transmission end predicted time of the band-compressed data or the difference data does not reach the reproduction start time assigned to the subsequent transmission target information, the transmission unit permits the transmission of the band-compressed data or the difference data, 7. The data transmission device according to claim 5, further comprising: a transmission control unit that stops the transmission when the predicted transmission end time is after the reproduction start time.