KR100203271B1 - The video telephone audio codec bit-rate automated control apparatus - Google Patents

Abstract

The present disclosure relates to an audio codec bitrate automatic control apparatus of a video telephone. The apparatus of the present invention encodes and outputs video data inputted from a video input device such as a camera according to H.263 recommendation, and compares the data amount and the default value in frame units by receiving the encoded video data. A code amount checker for selecting a bit rate of the audio codec, an audio codec for encoding audio data input from an audio input device such as a microphone according to the G.723 recommendation according to the bit rate selected by the code amount checker, and each configuration A control unit for controlling the interconnection of the multiplexers; a multiplex / separation unit for multiplexing and outputting the control signal and the encoded video data and audio data according to the H.223 recommendation; and the multiplexed control signals, video data and audio data It consists of a modem that transmits to the other party through the telephone line. Therefore, the present invention can reduce or increase the code amount of the audio data according to the code amount of the video data, thereby enabling the use of the transmission channel more efficiently than the conventional one, and providing an effect of improving the quality of the video telephone.

Description

Audio Codec Bitrate Automatic Control of Video Phone

The present invention relates to a video telephone, and in particular, in a transmission channel having a constant bit rate, it is possible to lower or increase the bit rate of the audio codec according to the amount of video data, thereby efficiently using the transmission channel and improving the quality of the video telephone. The present invention relates to an audio codec bitrate automatic control device of a video telephone.

Recently, an Integrated Service Digital Network (ISDN) has been disclosed that transmits information such as voice (telephone), facsimile, data, and images in large quantities and at the same time using a single digital line. H.221 was recommended as a way to multiplex video, voice, and other data to realize video telephony and video conferencing in ISDN. Video telephony and video conferencing equipment for ISDN are called H.320 terminals under the name of the Recommendation. Of course, Recommendation H.324 is currently in progress as a way to implement video telephony using low bitrate PSTN public telephone networks. As described above, the video telephone apparatus compresses and encodes the image information input through the video input means such as the camera and the audio information input through the audio input means such as the microphone and transmits the encoded information to the connected video telephone. In a video codec and an audio codec which compress and encode image information and audio information, one bitrate is fixed and used.

However, since the code amount of video data is different for each screen in the video codec, there is a problem in that a channel having a constant bit rate cannot be efficiently used. Therefore, the present invention transmits more video data by selectively adjusting the bit rate of the audio codec according to the video data amount in the video telephone, and if the video data amount is small, the bit rate of the audio codec can be transmitted 1. We present audio codec bitrate automatic control device of video telephone that can be selected without fixing with branches.

1 is a block diagram showing an audio codec bitrate automatic adjustment apparatus of a video telephone according to a preferred embodiment of the present invention;

2 is a flow chart for explaining the operation of the device of FIG.

Explanation of symbols for main parts of the drawings

11: video input device 12: audio input device

13: video codec 14: code amount check unit

15: audio codec 16: control unit

17: Multiple / Separator 18: Modem

Accordingly, the apparatus for automatically adjusting the audio codec bit rate of a video telephone according to the present invention includes a video codec for compressing and encoding an input video data into a transferable form, and a video coded from the video codec. A code amount checker for reducing the bit rate of the audio data when the amount of the code is large and increasing the bit rate of the audio data when the amount of the code is small, and the code of the plurality of bit rates. A bit rate is automatically adjusted by the quantity checking unit, an audio codec for compressing and encoding audio data input in accordance with the adjusted bit rate in a transferable form, a control unit for controlling the interconnection of each component, and a control signal of the control unit. And the compressed and encoded video data and audio data. Mux / split section for multiplexing, and a modem for transmitting to the other party connected to the data multiplexed by the multiplexing / separating unit.

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

1 is a block diagram showing an audio codec bitrate automatic adjustment apparatus of a video telephone according to the present invention. As shown, the apparatus of the present invention is an H.324 system that implements a video telephone using a general telephone line of a PSTN, and the H.324 system includes an input device 11 such as a camera and an audio input device 12 such as a microphone. Equipped with. In addition, a video codec 13 for encoding video data input from the video input device 11 and performing encoding according to Recommendation H.263 and a video coded video frame-by-frame coded by the video codec 13 are preset. A code amount checking unit 14 for checking the code amount compared with the default value and selecting the audio bit rate is provided. The code amount checker 14 is connected to an audio codec 15 that performs encoding in accordance with Recommendation G.723 so that the audio data input from the audio input device 12 conforms to a mode selected from a plurality of bit rate modes. On the other hand, the control unit 16 of the H.245 recommendation for controlling the interconnection with each configuration, and the encoded video data and audio codec applied through the control signal and the code amount checker 14 of the control unit 16 A multiplex / separation section 17 for multiplexing the encoded audio data applied from (15) in accordance with H.223 Recommendation is connected. In general, the multiplex / separator 17 also separates the multiplexed video data, audio data, and additional information transmitted from the connected counterpart video telephone. The multiple / separation section 17 is configured to connect a modem 18 of V. 34 recommendation for a network interface with a general telephone line.

Operation of the audio codec bitrate automatic adjustment apparatus of the video telephone according to the present invention configured as described above will be described in more detail with reference to FIG.

FIG. 2 is a flowchart for describing an operation of the apparatus of FIG. 1.

First, in the H.324 system implementing the video telephone, the video input unit 11 inputs video data obtained through a camera or the like into the video codec 13. The audio input unit 12 inputs audio data obtained through a microphone or the like into the audio codec 15. The video codec 13 compresses and encodes the input video data based on the H.263 recommendation, and outputs it to the code amount checker 14. The code amount checker 14 receives the encoded video data from the video codec 13 and checks the code amount in units of frames to select the bit rate mode of the audio codec 15. This will be described in more detail with reference to FIG. 2.

In FIG. 2, the code amount checker 14 first determines whether the initial state of the bit rate set in the audio codec 15 is 5.3 kbps (step 101). It is determined whether the video data amount is smaller than the default value (for example, 10000 bits) (step 102). In step 102, the code amount checking unit 14 changes the bit rate of 5.3 kbps set in the audio codec 15 to 6.4 kbps so that the audio codec 15 can transmit more audio data if the code amount in the frame unit is smaller than the default value (step 103). In step 102, the code amount checking unit 14 maintains the bit rate of 5.3 kbps set in the audio codec 15 as it is if the code amount in units of frames is not smaller than the default value, and repeats step 102. On the other hand, the code amount checker 14, if the initial state of the bit rate set in the audio codec 15 in step 101 is 6.3kbps or the bit rate of the audio codec 15 is changed to 6.3kbps in step 103, the video codec 13 In step 104, it is determined whether the amount of video data encoded in units of frames to be applied is greater than the default value. In step 104, the code amount checking unit 14 changes the bit rate of 6.3 kbps set in the audio codec 15 to 5.3 kbps so that the video data can be transmitted by reducing the amount of audio data if the code amount of the frame unit is larger than the default value. (Step 105). In step 104, the code amount checking unit 14 keeps the bit rate of 6.3 kbps set in the audio codec 15 as it is if the code amount in units of frames is not larger than the default value, and repeats step 104. If the bit rate of the audio codec 15 is changed to 5.3 kbps by the step 105, the code amount checker 14 performs step 102 for the code amount of the next frame applied from the video codec 13.

Again, in FIG. 1, the audio codec 15 encodes audio data input from an audio input device 12 such as a microphone based on the G.723 recommendation. Here, the audio codec 15 has two bit rate modes of 5.3 kbps and 6.3 kbps. Of the two modes, 5.3kbps has a small amount of data, which means good compression efficiency but poor sound quality, while 6.3kbps has a large amount of data, which reduces compression efficiency but good sound quality. Thus, in the H.324 system of the PSTN video telephone, it is used to set one of two modes of the audio codec 15 according to the amount of video data compressed and coded in the video codec 13 of H.263 as shown in FIG. do. Therefore, if a large amount of data is generated in the video codec 13, the audio codec 15 generates a small amount of data of 5.3 kbps, and if a small amount of data is generated in the video codec 13, the audio codec 15 is generated. Generates a lot of data of 6.3 kbps. On the other hand, the control unit 16 compares the control signal associated with each component with the control signal transmitted from the other party's video telephone to control the interconnection of each component, and outputs the related control signal. The multiplex / separator 17 performs H.223 compression coded video data input through the control signal of the controller 16 and the code amount checker 14 and compressed coded audio data applied from the audio codec 15. Multiplexed according to the recommendation and output to the modem 18. The modem 18 of V.34 transmits the multiplexed control signals, video and audio data to the other party's video telephone via the general telephone line of the PSTN. Here, the process of receiving the data transmitted from the connected other party's video telephone so that the caller can see the other party's image and hear the voice is omitted since it is a known technique.

As described above, the present invention relates to an audio codec bitrate automatic adjustment apparatus of a video telephone, and accordingly, the transmission bitrate of the audio codec can be automatically adjusted according to the amount of video data compressed and coded in the video codec. Since more video or audio data can be transmitted, the use efficiency of the transmission channel is increased, and the quality of the video telephone is improved.

It is an object of the present invention to automatically adjust the bit rate of an audio codec according to the amount of video data in a visual telephone to transmit more video data, and to transmit more audio data when the amount of video data is small. The present invention provides an audio codec bitrate automatic control device of a video telephone that can increase the use efficiency of a channel having a predetermined transmission rate and improve the telephone quality.

Claims (5)

In the video telephone, A video codec for compressing and encoding the input video data into a transmittable form; A code amount that receives the compressed coded video data from the video codec and checks the code amount on a frame-by-frame basis to reduce the bit rate of the audio data when the code amount is large, and to adjust the bit rate of the audio data when the code amount is small. Check unit; An audio codec which automatically adjusts a bit rate of the plurality of bit rates by the code amount checker and compresses and encodes audio data input in accordance with the adjusted bit rate in a form that can be transmitted; A controller for controlling interconnection of each component; A multiplex / separator for multiplexing the control signal of the controller and the compressed and encoded video data and audio data; And And an audio codec bit rate automatic adjustment device of a video telephone including a modem for transmitting the data multiplexed in the multiplex / separation unit to a connected counterpart. The apparatus of claim 1, wherein the video telephone is implemented by a system of H.324 recommendation using a general telephone network. The apparatus of claim 1, wherein the audio codec can selectively use a plurality of bit rates of 5.3 kbps and 6.3 kbps. 4. The method of claim 3, wherein the code amount checker compares the video data amount in units of frames encoded in the video codec with a predefined default value and selects one of a plurality of bit rates of the audio codec according to the comparison result. An audio codec bitrate automatic control device for a video telephone. The frame rate checker of claim 4, wherein the code amount checker adjusts the bit rate to 6.3 kbps so as to generate a large amount of audio data in the audio codec when the amount of video data in a frame unit is smaller than a predetermined default value. And the bit rate is adjusted to 5.3 kbps so that the audio codec generates less audio data when the amount is larger than a predetermined default value.