KR0149776B1 - Video telephone having plural video codec and method of operating the same - Google Patents

Abstract

[Technical field to which the invention described in the claims belongs]

The present invention relates to a video telephone having an H.261 video codec and a non-standard video codec and having a plurality of video codecs selectively using one of the video codecs in response to a transmission protocol, and a method of operating the same.

[Technical Clause Problem to Solve]

The present invention provides a video telephone having a standard video codec and a non-standard video codec having improved image quality, and having a plurality of video codecs selectively using video codecs in accordance with various connection conditions.

[Summary of the solution of the invention]

The present invention may vary depending on the method of implementing the original image compression algorithm, but basically includes an H.261 video codec 70 and a non-standard video codec 200, and H.242 protocol procedure for video communication. In the MBE capability message content, the video codec is converted into a non-standard video codec 200 or an H.261 video corresponding to the sub-code in the interchanged message by exchanging a country code and a company code which is a sub-code value of the non-standardized message value. The video codec is selected by the codec 70.

[Important Uses of the Invention]

The present invention can be importantly used in video telephones in ISDN networks.

Description

Video phone with multiple video codecs and its operation method

1 is a block diagram of a conventional video telephone.

2 is a block diagram of a video telephone according to a preferred embodiment of the present invention.

3 is a flow chart according to a preferred embodiment of the present invention.

In particular, the present invention relates to a video telephone apparatus including a H.261 video codec and a non-standard video codec, and a video telephone having a plurality of video codecs selectively using one of the video codecs in response to a transmission protocol, and a method of operating the same. It is about.

Recently, the development and dissemination of video telephones capable of communicating video and data together in addition to the existing voice communication service for the Integrated Services Digital Network (ISDN) has been accelerated. have. Conventional conventional video telephones according to this trend are equipped with H.261 video codec applying DCT (Discrete Cosine Transform) band image compression and reconstruction algorithm recommended by ITU, an international standardization organization, as shown in FIG. It is common to construct.

1 is a block diagram of a conventional video telephone.

The controller 10 controls the overall operation of the video telephone.

The ROM 20 stores a system program.

The user interface 40 outputs input data from the user to the controller 10.

The H.261 video codec 70 compresses and encodes the video signal input from the camera and monitor input / output unit 60 in accordance with International Telecommunication Unit (ITU) Recommendation H.261. In this case, the received image data are decoded and outputted to the camera and monitor input / output unit 60. The video signal processed at this time is a color video signal.

An audio codec 80 encodes a voice signal input from a microphone (not shown) at the time of transmission, and decodes the received voice data and outputs it to a speaker (not shown).

The H.221 synthesizer / separator 90 receives encoded video and audio data from the audio codec 20 and the video codec 30, respectively, and formats and outputs the H.221 frame format to receive the received H.221. The video and audio data of the frame format are recovered and output to the audio codec 80 and the H.261 video codec 70.

The ISDN interface unit 50 provides an interface between the H.221 synthesis / separation unit 90 and an ISDN network through a network termination device (NT).

A conventional video telephone having the above-described configuration, after connecting to the other party through the ISDN interface unit 50, compresses the audio data input from the audio codec 80, and the camera and monitor in the H.261 video codec 70. After compressing the image data input through the input / output unit 60, the data is formatted in the H.221 frame format by the H.221 synthesis / separation unit 90 and transmitted to the counterpart. In addition, the received data is separated into compressed video data and compressed audio data by the H.221 synthesis / separation unit 90 and sent to the audio codec 80 and the H.261 video codec 70, respectively. The compressed voice data received by the controller 80 is decompressed and output as voice data, and the compressed video data received by the H.261 video codec 70 is decompressed and displayed by the camera and the monitor input / output unit 60.

However, the conventional video telephone described above has a disadvantage in that the video information network defined in a narrow band ISDN having a limited transmission rate (64 Kbps to 1920 Kbps) is communicated because only a standardized video compression and reconstruction algorithm is applied.

In addition, the BRI-class ISDN video telephone of 2B + 1D, which is mainly used, has a problem in that it is unable to communicate high-definition video due to the deterioration of image quality due to quantization error and reduction of frame rate.

Accordingly, an object of the present invention is to provide a standard video codec and a non-standard video codec with improved image quality so as to solve the above object, and according to various connection conditions, a video telephone having a plurality of video codecs selectively using video codecs In providing.

Another object of the present invention is to provide a method of operating a video telephone having an H.261 video codec and a non-standard video codec.

The present invention for achieving the above object is a video telephone,

And an H.261 video codec which operates in response to a predetermined selection signal, compresses and encodes an image input signal according to ITU Recommendation H.261, and decodes and outputs the received image data.

Non-standard that is operated in response to the selection signal, has a predetermined image compression and decompression algorithm, compresses and encodes an image input signal according to the image compression algorithm, and decodes and outputs the received image data according to the image extension algorithm. Video codec,

An audio codec which encodes an input voice signal and decodes and outputs received voice data;

The video and audio data encoded from the audio codec and the non-standard video codec or the H.261 video codec are respectively formatted in the ITU Recommendation H.221 frame format, and received and reconstructed the video and audio data in the H.221 frame format. H.221 interfacing means for applying audio codecs and non-standardized video codecs or H.261 video codecs;

ISDN interfacing means for performing an interface between the H.221 interfacing means and ISDN;

Control means for controlling the overall operation of the video telephone, and selectively outputting the selection signal to the H261 video codec and non-standard video codec according to the video codec selection information of the protocol that communicates with the call-to-hope partner in the protocol exchange procedure of the video phone. and,

It consists of system software and storage means for storing data.

The present invention provides a H.261 video codec that compresses and encodes an image input signal according to ITU Recommendation H.261, decodes and outputs received image data, and predetermined image compression and decompression algorithms. In a video telephone operating method comprising a non-standard video codec for compressing and encoding a video input signal according to the video compression algorithm, and decoding and outputting the received video data according to the video extension algorithm,

A mode initialization step of exchanging an H242 protocol with a call connecting party;

A protocol determination step of determining whether there is an unstandardized mode message by searching for a relative H242 protocol received in the mode initialization step;

When the protocol determination step determines that there is a non-standardized mode message within a predetermined time, the non-standardized mode is performed to switch to the non-standard operation mode and output a selection signal for enabling the non-standard video codec to perform the non-standardized operation mode. Steps,

If the bar standardization mode message is not found within a predetermined time as a result of the determination of the protocol, the standardization mode performing step of switching to the H261 operation mode and outputting a selection signal for enabling the H261 video codec is performed to perform the H261 operation mode. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a video telephone according to an embodiment of the present invention.

The control unit 10 controls the overall operation of the video telephone, and transmits the selection signal to the H.261 video codec and the non-standard video according to the video codec selection information of the protocol that communicates with the call-to-be desired partner in the protocol exchange procedure of the video telephone. Optional output to codec.

The ROM 20 stores a system program.

The RAM 30 stores various data used in the operation of the video telephone.

The user interface 40 outputs input data from the user to the controller 10. The H.261 video codec 70 compresses and encodes a video signal input from the camera and monitor input / output unit 60 in accordance with International Telecommunication Unit (ITU) Recommendation H.261 during transmission. In this case, the received image data are decoded and outputted to the camera and monitor input / output unit 60. The video signal processed at this time is a color video signal.

The H.261 video codec 70 operates in response to a predetermined selection signal, compresses and encodes a video input signal according to ITU Recommendation H.261, and decodes and outputs the received video data.

The non-standard video codec 200 operates in response to the selection signal, has a predetermined image compression and decompression algorithm, compresses and encodes an image input signal according to the projection compression algorithm, and compresses the received image data into the image extension algorithm. Decode and output according to.

The audio codec 80 encodes an input voice signal, and decodes and outputs received voice data.

The H.221 synthesizer / separator 90 converts the encoded video and audio data from the non-standard video codec 200 or the H.261 video codec 70 and the audio codec 80 into the ITU Recommendation H.221 frame format. It formats and restores the received video and audio data in the H.221 frame format and applies it to the audio codec 80 and the non-standardized video codec 200 or the H.261 video codec 70.

The ISDN interface unit 50 performs an interface between the H.221 synthesis / separation unit 90 and the ISDN.

3 is a flow chart according to a preferred embodiment of the present invention.

Hereinafter, the operation of a preferred embodiment of the present invention will be described in detail with reference to the configuration of FIG. 2 and the flowchart of FIG. 3.

First, the control unit 10 multiplexes an audio signal and a video signal with a BAS code in a H.221 frame structure in a state in which a transmission line is connected through a call setup step, and transmits the signal from a counterpart. Thereafter, the BAS code, in which the audio signal and the video signal are multiplexed and transmitted, initializes the transmission mode between the video telephones in step 301 of FIG. 3 by a procedure of the H.242 protocol. Thereafter, the controller searches for the BAS code transmitted from the counterpart during the adjustment time to determine whether the non-standardized mode message has been received.

In this case, if the non-standardized mode message has not been received for a predetermined time, the control unit 10 recognizes the operation mode as the standard video codec operation mode in step 305, and in step 307 recognizes the selection signal in the enabled state as the H.261 video. It is applied to the codec 70 to enable the H.261 video codec 70 to match the video data compression and reconstruction algorithm with the other party and to end the routine.

However, if it is determined in step 303 that the non-standardized mode message has been received, the controller 10 enables the non-standard video codec 200 by applying the operation mode to the non-standard video codec 200 in step 311. Match the video data compression and decompression algorithm with the other end and terminate the routine.

In the above-described process, the non-standardized mode message means a message determined to recognize that the video code is equipped with the same non-standard video codec if the country code and the company code match among the BAS code values received from the opposite terminal. Subsequently, it may be transmitted as information of the type identifier code.

The present invention may vary depending on the method of implementing the original image compression algorithm, but basically includes the H.261 video codec 70 and the non-standard video codec 200, and the H.242 protocol procedure for video communication. In the MBE capability message, the video codec is replaced with the non-standard video codec 200 or the H.261 video codec corresponding to the subcode in the interchanged message by exchanging a country code and a company code which is a subcode value of an unstandardized message value. Select (70) to achieve video communication.

Therefore, as described above, the present invention includes a non-standard video codec having an improved non-standard video codec in image compression and reconstruction rate in addition to the H.261 video codec applying the ITU recommended DCT band image compression and reconstruction algorithm. Since it performs video communication with the counterpart video phone, it has the advantage of much improved video information transmission compared to video communication through H.261 video codec. In addition, the present invention has the advantage that it is possible to send and receive high-definition video because it uses an improved non-standard video codec in the image compression and reconstruction rate.

Claims (3)

In a video telephone, an H.261 video codec which operates in response to a predetermined selection signal, compresses and encodes a video input signal according to ITU Recommendation H.261, and decodes and outputs the received video data. A non-standard video codec having a predetermined image compression and decompression algorithm, compressing and encoding an image input signal according to the projection compression algorithm, and decoding and outputting the received image data according to the image extension algorithm; An audio codec that encodes an input audio signal and decodes and receives received audio data, and encodes video and audio data encoded from the audio codec, a non-standard video codec, or an H.261 video codec, respectively. And restore the received video and audio data in the H.221 frame format. H.221 interfacing means for applying to a video codec and non-standardized video codec or H.261 video codec, ISDN interfacing means for providing an interface between the H.221 interfacing means and ISDN, and controls the overall operation of the video telephone. And a control section for outputting the selection signal to the H261 video codec and the non-standard video codec according to the video codec selection information of the protocol communicated with the call connection requesting party in the protocol exchange procedure of the video telephone. A video telephone having a plurality of video codecs, characterized by comprising system software and storage means for storing data. 2. The video telephone of claim 1, wherein the video selection information of the protocol is provided in the MBE capability message of the H242 protocol. H.261 video codec which compresses and encodes video input signals according to ITU Recommendation H.261 and decodes and outputs received video data, and has a predetermined video compression and decompression algorithm. The video input signals are converted according to the video compression algorithm. A method of operating a video telephone having a non-standard video codec that compresses and encodes and decodes and receives received video data according to the video extension algorithm, the method comprising: a mode initialization step of exchanging an H242 protocol with a call-connecting partner; A protocol determination step of determining whether there is an unstandardized mode message by searching for a counterpart H242 protocol received in the mode initialization step, and when it is determined that there is a non-standardized mode message within a predetermined time as a result of the determination of the protocol determination step, returns to the non-normal operation mode. Choice to switch to enable non-standard video codecs And outputting an arc with non-normalized mode performing step for performing a non-standardized operating mode. If the non-standardized message is not detected within a predetermined time as a result of the determination of the protocol, the standardized mode performing step of switching to the H261 operation mode and outputting a selection signal for enabling the H261 video codec is performed to perform the H261 operation mode. Operating method of a video telephone having a plurality of video codecs characterized in that.