KR20070061780A - Method of video data transmitting - Google Patents

Abstract

A method of video data transmitting by means of video data reconstruction on the receiving end of the communication channel per time unit, based not only on the data, transmitted directly via the channel, but on all previously transmitted, decoded and stored video data.

Description

Video data transmission method {METHOD OF VIDEO DATA TRANSMITTING}

Both US Pat. No. 5,321,776 to Shapiro and US Pat. No. 5,764,807 to Pearlman et al. Are incorporated herein by reference.

See also US patent application ___________, entitled "METHOD OF DATA COMPRESSION INCLUDING COMPRESSION OF VIDEO DATA," filed June 29, 2005 by Andrey V. Zurov et al.

This application claims the benefit of Provisional Patent Application No. 60 / 584,364, filed June 30, 2004.

The description of two such applications is hereby incorporated by reference in its entirety.

The present invention mainly relates to a technique for transmitting video data over low bit-rate communication channels in a real time mode.

The main problem in transmitting video data over low bit rate communication channels is maintaining high image quality. This problem is solved by various methods of digital video data compression. The main method is frame sequence coding by MPEG procedure. This procedure is based on the display of digital video data received from an image source as a collection of group of pictures (GOPs), each starting with a key frame (I-frame) and through the same image scene. It includes a limited number of predictive frames (P-frames) that are typically connected to a frame. I-frames constitute the first frame of the scene, followed by GOP P-frames that are very similar to each other. The next stage of the MPEG procedure is the compression of GOP digital video data. I-frame compression is one of the known methods, e.g., of digital data organized according to the influence of these coefficients on image quality with coefficients corresponding to lower spatial frequencies located at the beginning of the flow. As a flow is performed by a method of two-dimensional spectral decomposition with the following representation of the resulting spectral coefficients. Compression of a GOP P-frame is based on the high predictability of each next P-frame when compared to the preceding GOP frame. This procedure, known as predictive coding, includes the following; The image of the frame serving as the next content prediction source of the coded frame is divided into rectangular blocks of pixels. Then, a search for an image block of the same size that is closest in the content of the block of the preceding frame is made for the coded frame. After such blocks are found, their position is fixed on the coded frame for the preceding frame by setting the displacement vector. For image portions of a coded P-frame where prototypes from the previous frame cannot be found based on predetermined criteria, a standard coding procedure similar to the coding of a GOP I-frame is applied. Thus, the predictive coding algorithm uses the GOP data volume as a GOP I-frame, a P-frame without prototype from the preceding GOP frame as well as a volume containing an array of displacement vectors of the encoded image block for each GOP P-frame. To substantially reduce the volume of the encoded image block.

The MPEG procedure ensures universal and relatively high level video data compression. However, for individual applications such as video data from meetings or video survey data of slow-moving or periodically replaying objects over low-bit communication channels in real-time mode, the algorithm of the bit flow configuration has been improved to improve the image quality transmitted. Can be.

It is an object of the present invention to improve video image transmission quality. Reduce the data volume per transmission of the flow of frames located at such a distance when the number of frames coming from the image receiver (from the video camera) exceeds the number of coded frames that can be transmitted over the communication channel in the same time period. Is achieved through build up of the number of frames transmitted per unit of time.

In order to ensure the high quality of video data transmitted over a low bit rate communication channel, it is first necessary to understand and specify all the key factors that determine the perception of the video range by a specter. Many experiments conducted by the authors on the personal peculiarities of human perception are based on the sheer volume of video data received by specters per unit of time, but due to the smoothness of image detail transformations. It has been proved that the quality of video information is less determined. In other words, even if each given frame is of full quality, the specter can be used to produce images where small details may be omitted or distorted when compared to images in which delays produce a "slide-show" effect in the video sequence. Quality has much higher estimates. Considering the work of video data transmitted in real time, the problem of high video image quality turns out to be unwieldy because the bit rate of encoded video data of desired quality and frame rate exceeds the channel capacity. This is because a valid method known to the user does not provide a solution for this situation.

The core of the present invention is a method of transmitting video data by video data reconstruction on the receiving end of a communication channel per unit of time based on all previously transmitted, decoded and stored video data as well as data transmitted directly through the channel. The advantage of the claimed method assists in avoiding a "slide-show" effect when the transmitted image is repeated periodically, for example in a video conference range.

The method of transmitting video data according to the invention has two possible sequence of steps: According to the first aspect of the invention, the claimed method means coding of video data as a sequence of key frames and prediction frames, The selection and coding of the first frame of the sequence precedes the transmission of the coded frame over its low bit rate communication channel, its decoding and the storage of results at the transmitting and receiving ends of the communication channel. The next frame F (J) assigned to the coding is selected from the sequence of frames proceeding out of the video data source. The number J of this frame in this source frame sequence is calculated by the formula J = INT (NQ / W), where N is the video data source frame rate, Q is the number of bits transmitted over the channel, and W is the communication The capacity of the channel, INT (x) is a function for calculating the integer part. After that, the coding type for the frame should be set. For this purpose, the array of frames transmitted, decoded and stored at the transmitting end is searched for the frame R (r) closest to the current frame assigned to the coding. If the difference value D1 between the previously transmitted and decoded frame and the current frame assigned to the coding determined by any method does not exceed the predetermined threshold Th, the current frame F (J) is the communication channel. It is coded as a predictive frame for the pre-selected and transmitted frame R (r) transmitted and stored at the receiving and transmitting ends of the < RTI ID = 0.0 > If not, the current frame will be coded as a key frame according to the procedure described above.

According to a second aspect of the invention, the claimed method refers to the coding of video data as a sequence of key frames and predictive frames, wherein the selection and coding of the first frame of the sequence as a key frame comprises a low bit rate communication channel. Precedes the transmission of the coded frame, its decoding and the storage of results at the transmitting and receiving ends of the communication channel. The next frame F (J) assigned to the coding is selected from the sequence of frames proceeding out of the video data source. The number J of this frame in this source frame sequence is calculated by the formula J = INT (NQ / W), where N is the video data source frame rate, Q is the number of bits transmitted over the channel, and W is the communication The capacity of the channel, INT (x) is a function for calculating the integer part. After that, the coding type for the frame should be set. For this purpose, an array of frames transmitted at the transmitting end, decoded and stored is searched for the frame R (r) closest to the current frame assigned to the coding. If the difference value D1 between the pre-transmitted and decoded frame and the current frame assigned to the coding determined by any method exceeds the predetermined threshold Th, the group of frames preceding the current frame is pre-transmitted frame. Will be searched for the frame F (j) closest to (R (s)). If the difference value D2 between these two frames does not exceed the threshold Th, the selected frame F (j) is stored at the receiving and transmitting end of the communication channel and is sent to the preceding prototype frame (instead of the current frame). Will be coded as a predictive frame for R (s)). If not, the current frame F (J) will be coded like a key frame as described above.

1 shows a first aspect of the claimed method.

2 shows a second aspect of the claimed method.

3-16 illustrate alternative and / or detailed concepts of the present application.

According to a first aspect of the invention for implementing the claimed method of transmitting video data over a low bit rate communication channel, it is necessary to calculate a numerical value indicating a criterion of selection of coding type for frames of a video sequence. . As shown in Fig. 1, the first step to achieve this method is to enter a defined numerical threshold Th (1). Obviously any frame sequence received by the communication channel from the source output may be encoded in at least two different ways: 1) as key frames independent of other frames and 2) as predictive frames for preceding coded frames. It can be displayed as a collection of frames that are allocated. At the beginning of each video scene as well as at the beginning of the video data transfer, a frame F (J) appears, which is chosen to be coded as a key frame because of the content. This coding 2 performs the second step of the sequence of operations for the claimed method. The coded frame then advances to the input of the communication channel and is transmitted (3) to perform the next step of the method. During the data transmission process, the number of bits Q substantially passing through the channel is determined, after which the image of the transmitted frame R (r) is decoded (4) and stored at the transmitting end of the channel. The next frame assigned to coding from the sequence due to the fact that the duration of the transmission of the coded frame over the low bit communication channel exceeds the time interval between adjacent frames of the video sequence received by the communication channel from the output of the video data outlet. The number of times J will be determined before the end of the previous frame transmission. This calculation (5) is done by J = INT (NQ / W), where N is the video data source frame rate, Q is the number of bits transmitted over the communication channel during the preceding frame transmission, and W is the communication The capacity of the channel. After defining the number of next frames assigned to the coding, it is necessary to determine the type of coding to determine whether this frame is coded as a predictive frame or key frame for some pre-transmitted frame. Obviously the second coding type is preferred, less desirable for the data volume transmitted for the image, while the quality is the same. In order to select the coding type for the next frame of the video sequence, the absolute difference between each frame that is previously transmitted and decoded and stored at the transmitting end of the channel frames R (r) and the frame F (J) assigned to the coding ( The value of D1) is calculated. From the set of values obtained for D1, the minimum value is selected (6) and compared with the value Th (7). If the value D1 does not exceed Th, the next frame F (J) assigned to coding will be encoded as the predictive frame 8 for the frame R (r) where D1 has the minimum value. If the condition D1 <Th is not satisfied, frame F (J) will be encoded as a key frame (9). Frames that are coded in one way or another go through the communication channel and the data transfer process proceeds until the last frame is sent from the video data source.

The quality of the transmitted video image can be further improved by implementing the claimed method according to the second aspect of the present invention as shown from FIG. When entering source data as required by the second aspect of the present invention, data input 1 of value Th will involve the selection of a p parameter in the range of 0 to 1 and its input (10). . Steps 2-4 and 5-8 of the operation sequence as required by the second aspect of the present invention have already been described above. According to a second aspect of the invention, the saving 11 of the number of preceding frames J 0 = J for the frame sequence of the video data source will occur before step 5.

The situation when step 7 of the video data transmission method as required by the second aspect of the present invention results in the non-compliance of the condition D1 <Th will be described more closely. This means that the frame to be coded and transmitted is not encoded as a predictive frame. At the same time, there is no match frame received from the video data source until the end of the preceding frame transmission, but pre-encoded similar to one of the frames received from the source at the input of the communication channel during the video data pass from the preceding frame. One of the transmitted set frames may still find a frame. To define this frame, each frame R (r), previously decoded and stored at the transmitting end of the channel on the one hand, and within the range of the numbers of J0 + p (J-J0) <j <J on the other hand The absolute difference D2 between each frame F (j) received from the video data source at will be calculated. From the set of D2 values received by these means, the minimum value will be selected (12) and compared with the value Th (13). If the value D2 does not exceed Th, frame F (j) will be coded as a predictive frame for frame R (s) of minimum D2 value (14). If D1 <Th is not satisfied, frame F (J) is coded as a key frame (9). Frames encoded by either method go through the communication channel and the data transfer process proceeds until the last frame is sent from the video data source.

Continuing attention to the present application, the following describes a comet video technology codec operation plan as shown in FIG. 3, which is made up of three blocks.

Video Codec

Audio Codec

Network Kernel

All three blocks interact to ensure that the audio and video encoding is in sync, as well as to automatically adjust the codecs when changing the communication channel or when the connection is terminated.

Video codec

The video codec performs encoding and decoding using wavelets of video flows. A given processor has the following work cycles:

Pretreatment

Encoding Key Frames

Compensation Model

Decoding Key and Compensated Frames

After treatment

Preprocessing-Video image preparation required for the next encoding, i.e. improvement of quality (based on available from previous frame statistics)

The encoding of the key frame is performed based on the developed video compression methods using wavelet technology.

Compensation methods make it possible to transmit a larger number of frames due to the fact that only the differences between the frames are transmitted. This method will be closely related to pretreatment. Compensation methods are also closely related to the network kernel because they are mostly dependent on network disturbances. Encoding of the compensated frames is performed based on the wavelet technique.

Decoding of key and compensation frames is realized using back-encoding using wavelet technology.

Post-processing aims at improving video quality by applying filters to the video image for improved sharpness and color spectrum.

1. Key frame packaging is shown in FIG.

The packaging process consists of seven steps as shown in FIG.

Description of step 1.1 as shown in FIG. 5 : A static frame is input in an RGB format. The frame consists of three planes of red, green and blue that together form an image. Using one-to-one functions as standard, the static frame is converted to another format called YUV, this time as long as it is the brightness component Y and two color subcarriers modulated by the color signals U and V. Three planes as unity. The most commonly used formulas for the YUV conversion are:

Y = 0.299 * R + 0.587 * G + 0.114 * B

U = 0.564 * (B-Y)

V = 0.649 * (R-Y)

This presentation of the image is more beneficial for later analysis.

Description of step 1.2 as shown in Fig. 6 : A static frame in YUV format is input. With the help of two filters based on wavelets, the image is resolved into two components, high and low frequencies. The transformation is one-to-one and the output is presented as a graph and the coefficients are placed at the contacts of the graph as a decomposition result. Arcs are connections between coefficients. Wavelet filters are used to graph the frames into graphs. Wavelet filters have been selected experimentally and are optimal for video packaging (but wavelet filters can be easily modified if needed). Wavelet filters are hard coded programmatically on the sending side as well as on the receiving side (they will be similar on both sides).

Description of step 1.3 as in FIG. 7 : In order to package the data in steps 4 and 5 the graph in step 3 must meet certain requirements.

Except for the top, each graph contact has a "parent". Check the graph from step 2 in step 3 and complete it. If necessary, mark it as "parent" for contacts that do not have anything.

The step 0.4 as shown in FIG 8. Description: This starts from step to begin the packaging process. To perform the analysis in step 5, the graph from step 3 is subjected to a unique process and converted into bit planes, which are unique machine representations.

Description of Step 1.5 as in Fig. 9 : From Step 4 the bit planes and the data contained therein are analyzed. Based on this analysis, the data in the bit planes are organized according to their validity. Then, according to the compression ratio value used in this step, all data meaningless in this step is discarded. (The larger the compression ratio value, the more data is discarded). The remaining data is classified into four different data flows.

Description of step 1.6 as in FIG. 10 : In order to achieve greater data compression, the data in flows are organized in a special way and further statistical analysis is performed.

Description of step 1.7 as in FIG. 11 : The organized flows are unified into an integrated structure, ie a packaged frame. This structure is sent for sending over the network.

2. Frame construction (compensation method) (shown in FIG. 12).

Step 1. Compare the difference with the previous frame ( difference ).

Description : A static frame is entered. The difference with the previous frame is determined. There can be two variants: to set the difference from the previous frame or to the difference from the previous base frame. The first variant presupposes a small car, but when there is no difference in communication, the next frame will not be constructed. The second variant presupposes a larger difference and would not be important without the frames.

Step 2. Treatment of the car

Description : The car is processed to eliminate unnecessary data and make it more compact.

Step 3. Packaging of the Car

Description : A variant of the key frame packaging method is used for packaging.

Audio codec

The audio codec encodes the audio flow in synchronization with the video flow. Sound encoding means the original realization of a psycho-acoustic model of sound encoding. This realization enabled the transmission of human voices using the 1400 BPS channel.

Well-timed delivery of data to the network kernel (as shown in FIG. 13) must be ensured, the network must be monitored for network disturbance detection, and adjustment of video and audio compressors based on accumulated statistics do. The figure shows the structure of a one-way data transmission channel (the requirements for this channel are listed below). This channel consists of three flows.

-Video channel

Audio Channel

Control channel

The video channel performs video frame delivery from the video compressor.

The audio channel performs audio flow delivery from the audio compressor.

The control channel performs a wide range of service functions:

     Perform connection of two or more users of client programs before a communication session begins.

     Synchronize video and audio flows.

     network.

     Network disturbances and data loss notifications.

     Perform a short message exchange (chat) between users.

14 shows requirements and functional specifications for the development of a program system for video conferencing over the Internet.

All system users must register with the website by entering their name, email and password for system login. After users are registered, the system assigns a unique number (UID) to each user.

After the user is registered with the system, the user can upload the PS to his computer and install it.

The client may pay by credit card for additional services (options) in the system. Payment is performed through the cyber cache system and registered with the charging server.

Client application

The client application has the following features:

1. View and search users in the database. This option is available in all versions of PS.

2. Request authentication to add users to the contact list. The user is added to the contact list after authentication. This option is available in all versions of PS.

3. Send short messages to the user from the contact list. This option is available in all versions of PS.

4. Chat with the user from the contact list. This option is available in all versions of PS.

5. Can convert video and audio flows and examine video and audio flows examine audio and video flows from authorized users. This option is available in all versions of PS.

6. Have a point-to-point video conference with another user of the system authorized to conduct the video conference. Video conferencing is available to users who have paid for this option.

7. Video translation for multiple users. This option is available to users who have paid for authentication of the video translation.

Hardware requirements for the client:

    -Intel PC with PII Celeron 600 MHz processor and

    -64 Mb or more memory

    -Sound card

    -Video camera

    -56BPS standard modem for dial-up connection

    Network card for accessing 10 / 100MB networks

Software Requirements for Clients:

-OS Windows 98 OSR1, Windows Me, Windows 2000

 A set of direct show drivers (cameras and sound cards must be compatible with the drivers)

TCP / IP protocol driver

Server applications

1. Connection Server.

The access server is the entry point for all users of the system. Perform the following functions.

-UID and password request for registration with the system

Secure persistent connections with users during sessions

-Test your status

-Maintain a list of users who are online at the moment

Data communication between the client and higher-level services (described below).

-Stored in the message DB in case of sending short messages to users and failing

2. Redirector

The redirector is a thin layer between the access server and the higher level services. Balance the load of the top services.

3. Directory Servers

Directory servers store a distributed database of users and their contact lists. The redirector server is responsible for the load on these servers.

4. Message DB

The message DB is a server of unsent messages. Any message that could not be delivered to the recipient by the access server for some reason is sent to the message DB. When a user logs in to the system, the access server checks the availability of unsent messages addressed to this user and sends them to the user if there are any.

5. Billing system

Your system accounts for storage. There is a personal account for each registered system user. If this is empty by default, the user can only access free system services after the user has registered with the system. If the user wants to pay for additional services, the user can do this using a credit card (via the cybercache system). When the user logs in to the system, the access server requests the billing system for its status and assigns access to additional services based on the user's status.

In one embodiment server hardware requirements:

-Server with PIII 600MHz or higher processor

-128Mb or more memory

In one embodiment server software requirements:

-OS Windows 2000 Server

MSSQL Server 2000

15 shows functional specifications for the development of a program system for the compression and transmission of video images.

The purpose of this project is to develop a program system (also known as PS) for the compression and transmission of video images using the low bandwidth channels of wireless communications of all existing standards. The given PS is intended to perform video conferencing and video transmission in real time mode using wireless communication and will be used as a prototype for hardware implementation. The developed technology, which is fundamental to the PS, must be adaptable and scalable to wide channels (56 BSP and above). This fact will enable PS to be extended to video movie broadcasting systems.

Structural Measures of the Program System

Client side

The client side is an independent program installed on the user's PC that allows the user to send real-time video images to another user with the same program installed on his or her PC or to perform a real-time video conference with the other user. Connection to another user is realized using a wireless communication channel (direct connection) or using the Internet (or other TCP / IP networks). In the case of a connection using the Internet (or other TCP / IP networks), the client side may contact the server program and request about the users currently connected to the network.

On the client side,

-Video compressor

Encode the video flow from the video camera and send it to the network kernel

Decode the video flow from the network kernel and send it to your display

Receive network disturbance statistics from the network kernel to correct video flow parameters.

-Audio compressor

Encode the audio flow from the soundmap and send it to the network

Decode the audio flow from the network kernel and send it to the soundmap

Receive network disturbance statistics from the network kernel and correct audio flow parameters

Network kernel

Realize connection between two users

Realize network data reception and transmission

Realize control of the integrity of the transmitted data

Realize network monitoring and send network disturbance statistics to audio and video compressors

A description of the data transfer principle can be found in the network kernel description.

Client Hardware Requirements:

-Portable PC with PII Celeron 600MHz Process

-Sound card with 64Mb or more memory

-Sound card

-Video camera

-Connection device for connection to a wireless communication channel

-A standard modem 56 BPS for dial-up connection or

Plan-schedule of tasks on the project

Work on the project is realized in six steps.

First stage conciliatory and preparatory. Presentation of the current version of the program.

At this stage the following work should be achieved:

The developer prepares program modules and technical documentation of the current version of the program for video compression for presentation.

-The developer sets the task for the employee and enables the employee to understand the project requirements properly.

The developer presents the current version of the program. During the presentation, the developer demonstrates the following:

1. Client side with possibility of direct connection by using mobile phone and connecting via internet.

2. Realization of a video compressor that operates in compliance with the hardware and software described in the given requirements specification.

3. Confer with a compensation mechanism and transmit video and audio flows in conference mode to achieve satisfactory quality at 3 frames per second using a full duplex wireless communication channel with a bandwidth above 9500BPS. Of video and audio compressors.

4. Realization of the current version of the user interface.

5. Realization of chat functions.

6. Create test record sheets of the current version of the program to ensure video flow transmission using the 9600 K5 channel.

Step 2 << Development of a new version >>

Server-side complete realization.

-Development, coordination and introduction of new versions of users.

-Realization of the area of interest

Realization of two versions of compensation models. Ensure interaction between these methods and the network kernel, automatically changing the settings of the methods in accordance with network disturbance statistics.

Realization of an audio compressor (estimated audio flow bandwidth 1500 BPS)

Testing of the system with different OS, communication network standards and hardware.

-New version of the presentation.

-Create a test record sheet for the current version of the program.

Deliver the source code to the customer on the paper media

Step 3 << Preliminary work to realize the hardware version of the codec >>

The user should have a mechanism to adjust for his arbitrarily different channel bandwidth, and easy-to-understand functions for qualitative adjustment of video and audio flows. All specific settings of the video and audio compressors can be realized automatically without the user.

The user can customize the volume setting panel and the video camera parameter settings.

The user must be informed by the program about an incoming call and can block unwanted calls.

-The user can arbitrarily chat function.

Server-side.

The server program is designed for the purpose of facilitating the discovery and access of client-side users using an Internet connection (or any other TCP / IP network). The server side is a scalable database of program users that can register and trace connections of all users to the client side of the network. When connected to the network, each program user can register with the server, add other users to his address book, and view the current status of any user listed in the address book. If the requested user is currently online, the server side can secure fast access to this user without any adjustments.

The main task of the billing system is to settle users' accounts for channel usage time. Payments for channel usage are collected every minute. For example, the cost of one minute is determined for each channel with the possibility of introducing a special rate on vacation. Each client has a personal account. Money is transferred from the client's credit card to this account. Account replenishment is done by real money transfer or by getting free time within the frames of the advertising campaign. Video broadcast servers send requests to the billing server using the http protocol. One billing server can serve several video broadcast servers.

In one embodiment server hardware requirements:

-Server with PE 6D0 MHz or higher processor

-128Mb or more memory

In one embodiment server software requirements:

-OS Windows 2000 Server

In one embodiment server side requirements:

-The server should have a standard scalable database that supports an infinite number of.

The server has to handle about 10D requests per second from client programs.

The network kernel (such as FIG. 13 or 16) must ensure timely delivery of data, monitor the network for network disturbance detection purposes, and make adjustments of the video and audio compressors based on the accumulated statistics. 3 shows the structure of a one-way data transmission channel (the requirements for this channel are listed below). This channel consists of three flows:

-Video channel

-Audio channels

Control channel

The video channel performs video frame delivery from the video compressor.

The audio channel performs audio flow delivery from the audio compressor.

The control channel performs a wide range of service functions:

Perform connection of two or more users of the client programs before the communication session begins.

Synchronize video and audio flows.

- network.

-Notification of network disturbances and data loss.

Perform a short message exchange (chat) between users.

In one embodiment network kernel requirements:

Control of data adequacy

Continuous network monitoring

-Accumulation of network disturbance statistics and ability of operation by video and audio compressor settings.

Availability of intelligent algorithms to work with compensation.

-Realization of chat function.

-Scalability.

-Possibility to send one video flow to many.

interface

The user interface (GUI) should provide a convenient and intuitively understandable form of managing client programs. The GUI must ensure an easy way of operation by program setting and a simple and convenient connection to other users.

In one embodiment, the requirements of a user interface (GUI) are:

The user interface should be simple and intuitive.

-The interface should have a beautiful modern design.

The user interface should consist of two dialogs for viewing incoming and outgoing video flows.

The user must have the possibility to increase the size of the dialogs up to the size of the screen and return the dialogs to the reset state.

The video compressor should be flexibly adjustable during the video flow encoding process based on the statistics tracked during the encoding process and the statistics accumulated in and received from the network kernel.

In one embodiment the video compressor requirements:

The video compressor must realize simultaneous encoding and decoding of the video flow in conference mode, including pre and post processing in accordance with the software and hardware requirements mentioned above.

The video compressor should provide a symmetrical way of encoding and decoding.

-The number of frames processed per second must be at least 5 followed by a satisfactory quality using a channel with a bandwidth of 9600 BPS.

The compensation model should ensure a gradual qualitative increase of the static image.

The compensation model should be able to handle possible network disturbances.

The compensation model is two variants, for networks that guarantee data delivery (for hardware implementations using these networks) and for networks that do not guarantee data delivery (networks of the Internet type).

Audio compressor

The audio compressor performs encoding and decoding using wavelets of audio flows. The realization of a given module must be ahead in two directions: the use of standardized audio flow compression algorithms available on the market and an analysis of the possibilities of developing your own audio codec based on wavelet technology.

Audio compressor requirements in one embodiment:

The audio compressor must realize simultaneous encoding and decoding of the audio flow with video in conference mode in accordance with the software and hardware requirements mentioned above.

The audio compressor must provide a symmetrical way of encoding and decoding.

Audio compressor operation should be synchronized with video when

Sound quality should be sufficient to understand human voice.

-The audio data volume should not exceed 240D BPS using 9600 BPS bandwidth channels. The ideal volume is 1000 BPS.

The audio compressor should be able to handle possible network disturbances.

Network card for accessing 10 / 100MB networks

In one embodiment, the software requirements of the client:

-OS Windows 98 OSR 1, Windows Me, Windows 2000

A set of direct show drivers (cameras and sound cards must be compatible with the drivers)

-TCP / IP protocol driver through wireless communication channel

In one embodiment, the requirements for data communication channels are:

-Digital wireless communication channel

Given wireless channels must provide full-duplex communications with bandwidths above 9600 BPS.

A direct dial-up connection between two computers (or via the Internet using ASP), or

Local 10/100 MB network for direct connection between two computers

Video compressor

The video compressor performs encoding and decoding using wavelets of video flows. A given processor has the following work cycles.

- Pretreatment

Encoding of key frames

Compensation Models

Decoding of the key and compensated frames

- After treatment

Preprocessing-Video image preparation required for the next encoding, i.e. improvement of quality (based on what is available from previous frames statistics).

The encoding of the key frame is performed based on the developed video compression methods using wavelet technology.

Compensation methods make it possible to transmit a larger number of frames due to the fact that only the differences between the frames are transmitted. This method will be closely related to pretreatment. Compensation methods are also closely related to the network kernel because they are mostly dependent on network disturbances. Encoding of the compensated frames is also performed based on the wavelet technique.

Decoding of key and compensation frames is realized using back-encoding using wavelet technology.

Post-processing aims at improving video quality by applying filters to the video image for improved sharpness and color spectrum.

In the description of the invention there is provided a specific and most preferred implementation of this method. Although these method steps and their specific parameters have been described in detail, it does not mean that the invention is limited to the description provided. Additional advantages of the claimed method and its modifications may also be realized in accordance with the general inventive concepts of the applicants.

Claims (2)

A method of transmitting video data over a low bit-rate communication channel using coding of video data as a sequence of keys and predictive frames: Coding a frame of a frame sequence to be incoming from the video data source as a key frame; Transmitting a coded frame over the low bit rate communication channel; Decoding a frame transmitted over the low bit rate communication channel; Determining the number J of the next frame F (J) allocated to coding in a frame sequence from the video data source by calculating an integer portion of ratio NQ / W, where N is the video data source frame rate Where Q is the number of bits transmitted on the low bit rate communication channel and W is the capacity of the communication channel; Determining the number r of decoded frames R (r) in the frame sequence transmitted over the low bit rate communication channel corresponding to the minimum value D1 of the difference between F (J) and R (r) frames. ; Coding said F (J) frame as a predictive frame for an R (r) frame according to a value of D1 not exceeding a predetermined threshold Th; Transmitting a coded F (J) frame over the low bit rate communication channel. A method of transmitting video data over a low bit rate communication channel using coding of video data as a sequence of key and predictive frames: Coding a frame of a frame sequence to be incoming from the video data source as a key frame; Transmitting a coded frame over the low bit rate communication channel; Decoding a frame transmitted over the low bit rate communication channel; Determining the number J of the next frame F (J) assigned to coding in a frame sequence from the video data source by calculating an integer portion of non-NQ / W, where N is the video data source frame rate and Q is the low Determining a number of bits transmitted over a bit rate communication channel, where W is the capacity of the communication channel; Determining the number r of decoded frames R (r) in the frame sequence transmitted over the low bit rate communication channel corresponding to the minimum value D1 of the difference between F (J) and R (r) frames; The video in the range of J0 + p (J−J0) <j <1 corresponding to the minimum value D2 of the difference between the F (j) and R (s) frames according to the value of D1 exceeding a predetermined threshold Th Determining the number j of frames F (j) in the frame sequence coming from the data source, where J0 is the number of precoded frames in the frame sequence coming from the video data source, and p is the range 0 < an adaptation parameter in p <1, wherein s is the number of frames R (s) decoded in the frame sequence transmitted over the low bit rate communication channel; Coding the F (j) frame as a predictive frame for an R (s) frame that conforms to a value of D2 that does not exceed the threshold Th; Transmitting a coded F (J) frame over the low bit rate communication channel.

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