KR100387577B1 - Apparatus for removing audio noise in video cdp and method therefor - Google Patents

Abstract

PURPOSE: An apparatus for removing an audio noise in a video CDP and a method therefor are provided to remove an audio noise generated due to an audio data error by detecting the error from extended digital audio data and holding the normally output voice signals before the error is generated. CONSTITUTION: A digital signal processor(100) corrects a data error from signals reproduced from a pickup part for outputting the compressed audio/video bit stream data. An audio decoder(101) extends the compressed audio bit stream data into the original audio signal. An audio data error detector(102) detects a data error from the audio data output from the audio decoder. A digital-to-analog converter(103) converts the digital audio signals output from the audio data error detector into analog audio signals. A voice signal pre-value holding unit(104) holds the analog audio signals output from the digital-to-analog converter. An audio signal switching unit(105) selectively outputs the audio signal output from the digital-to-analog converter or the held audio signals. An audio amplifier(106) amplifies the audio signals output from the audio signal switching unit for outputting the amplified audio signal to an output terminal(107).

Description

Apparatus and method for removing audio noise in video CDP

The present invention relates to noise removal due to deterioration of audio data in video CDP. In particular, the present invention relates to audio data error by detecting an error from extended digital audio data and holding and outputting a previously outputted audio signal when an error occurs. The present invention relates to an apparatus and method for removing audio noise in a video CDP for removing audio noise generated therefrom.

1 is a configuration diagram of an audio reproducing apparatus in a conventional video CD. The pickup unit 2 reproduces video / audio data recorded on the disc 1, and a signal reproduced by the pickup unit 2 as shown in FIG. A high frequency amplifying section 3 for amplifying and converting the digital signal into a digital signal, and a digital signal processing section for correcting an error of the video / audio data output from the high frequency amplifying section 3 and outputting the compressed video / audio bit stream data. (4), an audio decoder 5 which expands and outputs the audio bit stream data output from the digital signal processor 4, and converts the audio data output from the audio decoder 5 into an analog signal and outputs the analog signal. The digital / analog converter 6 and the analog / audio signal output from the digital / analog converter 6 are amplified and input to the audio signal output terminal 8. The application was made up of an audio amplifier 7.

The operation of the conventional video CDP configured as described above is as follows.

First, the pickup unit 2 reproduces the video / audio data recorded on the disc 1 and transmits the high frequency signal to the high frequency amplifier 3 as a high frequency signal. The high frequency amplifier 3 transmits the applied reproduction high frequency to a predetermined level. After amplifying the digital signal, the digital signal is converted into a digital signal and applied to the digital signal processor 4.

The digital signal processor 4 applies the compressed audio / video bit stream data according to the reproduced data applied to the MPEG decoder unit (not shown). The MPEG decoder unit decodes the video bit stream data through the video decoder. The audio bit stream data is decompressed by the audio decoder 5 to the original audio signal.

The expanded audio data is converted into an analog audio signal by the digital / analog converter 6, amplified to a predetermined level by the audio amplifier 7, and then output to the audio signal output terminal 8 to reproduce the audio.

At this time, if the disk is heavily scratched or fingerprinted, the digital signal processor primarily performs data error correction, but if the disk is severely damaged, it is impossible to correct all data errors.

In this case, when the video and audio signals without error correction are output, audio sound may be broken or noise may be severe, and a part of the image may be broken.

In this case, since the video image is scanned on the monitor by one picture unit, if the part of the image corresponding to one screen is partially lost, the screen of the damaged part is hidden by displaying the previous screen once more without displaying the screen. .

Therefore, even if part of the image is lost, it is not displayed on the actual monitor.

However, in the case of the audio signal, since the flow of the continuous voice signal has little time correlation, it is impossible to completely correct and output the broken audio sound, thereby outputting the noise.

Therefore, the conventional video CDP does not compensate for the loss of the compressed audio bit stream data due to the damage of the disk, and outputs it to the output, thereby causing noise in the audio sound.

Accordingly, the present invention is to solve the above problems of the conventional video CDP, an object of the present invention is to detect the error from the extended digital audio data and to hold and output the audio signal that was previously output when the error occurs audio Disclosed are an apparatus and method for removing an audio noise in a video CDP for removing audio noise caused by a data error.

The technical means for achieving the object of the present invention is an audio data error detection means for detecting a data error from the extended audio data and generating an audio data and audio data output control signal, and outputted from the audio data error detection means. Digital / analog converting means for converting and outputting a digital audio signal into an analog audio signal, a voice signal pre-value holding means for temporarily holding an audio signal output from the digital / analog converting means, and outputting from the audio data error detecting means Audio signal switching means for selecting and outputting an audio signal output from the digital / analog converting means or an audio signal held by the audio signal pre-value holding means according to the audio output control signal to be output; Amplifies the audio signal to a predetermined level comprises a means for amplifying the audio output to the output terminal.

A method for achieving the object of the present invention comprises a first process of storing the first to third audio data continuously input in units of 16 bits and comparing the stored first to third audio data, and the second comparison If the audio data exists between the first and third audio data, the audio data is judged to be normal audio data, and the first audio data is output and the second and third audio data are sequentially shifted for error detection of the next input audio data. A second step of retrieving a second audio data value if the second audio data does not exist between the first and third audio data and outputting the first audio data normally when the second audio data is 0; and the second audio. If the data value is non-zero, retrieve the status flag and if it is 1, the second audio data is not available because the previous output audio value is normal A fourth process of replacing the value with the first audio data and outputting the first audio data and controlling the output of the held voice signal; and if the status flag is not 1, a data error occurs continuously. The fifth step is to set the value to 0 and control to output the previous value held as an audio signal until the finishing data is continuously inputted and the status flag becomes 1.

Hereinafter, described in detail with reference to the accompanying drawings of the present invention.

2 is a block diagram of an audio noise removing device in a video CDP according to the present invention.

As shown, the present invention is a digital signal processing unit 100 for correcting the data error from the signal reproduced in the pickup unit and output as compressed audio / video bit stream data, and output from the digital signal processing unit 100 The audio decoder 101 which expands and compresses the compressed audio bit stream data into the original audio signal, detects a data error from the audio data output from the audio decoder 101, and outputs the audio data and the audio output control signal. An audio data error detector 102, a digital / analog converter 103 for converting the digital audio signal output from the audio data error detector 102 into an analog audio signal, and outputting the analog audio signal; and the digital / analog converter. The audio signal pre-value holding unit 104 for holding the audio signal output from the 103 and the image According to the audio data output signal output from the audio data error detection unit 102, an audio signal output from the digital / analog converter 103 or an audio signal held by the audio signal pre-value holding unit 104 is selected and output. An audio signal switching unit 105 and an audio amplifying unit 106 for amplifying the audio signal output from the audio signal switching unit 105 to a predetermined level and outputting the audio signal to the output terminal 107.

The operation and effects of the audio noise removing device in the video CDP according to the present invention configured as described above are as follows.

First, the audio / video data reproduced by the pickup unit is processed by the digital signal processing unit 100 and compressed into video bit stream data, which is applied to a video decoder (not shown) to extend and process a video signal. The bit stream data is extended by the audio decoder 101 and input to the audio data error detection unit 102 together with the data transfer clock BCK and the L and R channel separation signals LRCK as the original audio data.

The audio data error detection unit 102 detects an error of the input audio data and transmits the audio output control signal to the audio signal switching unit 105 as a high signal when an error occurs in the audio data. When the audio data is normal, the audio output control signal is transmitted as the low signal to the audio signal switching unit 105, and at the same time, the audio data is transferred to the digital / analog conversion unit 103.

The operation of the audio data error detection unit 102 will be described in more detail with reference to FIGS. 3 and 4 below.

First, the audio data error detection unit 102 stores the first audio data input in units of 16 bits in the first memory as the M1 value (S1, S2), and subsequently stores the second audio data that is input in the second memory as the M2 value. (S3, S4), and the third audio data of 16-bit unit input next is stored in the third memory as M3 value (S5, S6).

The stored M1, M2, and M3 values are compared (S7) to determine whether there is an error in the audio data.

That is, when the audio data M1, M2, M3 are continuous, the audio signal within 20 KHZ cannot be changed rapidly because it has a 16-bit continuous value according to the sampling frequency of 44.1 KHZ.

Therefore, except for the case where M2, which is the median value of audio data, is 0, M2 has a value between M1 and M3 as shown in (a) and (b) of FIG.

On the other hand, as shown in (c) and (d) of FIG. 4, when M2 is larger or smaller than M1 and M3, not M1 and M3, it may be determined as an error of audio data.

Therefore, as shown in FIG. 3, when M2, M2, and M3 are compared in step S7, when M2 becomes a value between M1 and M3, it is judged as normal audio data, and M1 audio data is output to output a digital / analog converter. 103, and at the same time, M1 audio data can be outputted with the audio output control signal as a low signal (S9).

In order to detect an error of the next audio data, the M2 audio data is shifted and stored as M1 audio data, and the M3 audio data is shifted and stored as M2 audio data and the state flag N is set to 1 (S10 and S11). ).

On the other hand, if the M2 audio data is not between M1 and M3, it is determined whether the M2 value is 0 (S12). If the M2 value is 0, the normal audio data is judged, and the M1 audio data is outputted. The signal is transmitted to the analog converter 103, and at the same time, the M1 audio data can be outputted with the audio output control signal as the low signal (S9).

In order to detect an error of the next audio data, the M2 audio data is shifted and stored as M1 audio data, and the M3 audio data is shifted and stored as M2 audio data and the state flag N is set to 1 (S10, S11). ).

When the M2 audio data value is not 0, the status flag N is searched (S13). When the search result status flag N is 1, M1 data is outputted and M2 data is converted to M1 data. At the same time, the M3 data is shifted to the M2 data, and then the audio output control signal is output as a high signal so that the previous voice signal held by the voice signal pre-value holding unit 104 is output, thereby preventing noise from being output.

In addition, when the state flag is not 1, it is determined that the previous value is not outputted correctly, and the M1, M2, and M3 values are all set to 0 (S16), and then normal audio data is continuously The audio output control signal is output as a high signal until the state flag N becomes 1 so that the held previous voice signal is output, thereby preventing noise from being output.

Meanwhile, the digital / analog converter 103 converts the input digital audio data into an analog audio signal corresponding thereto and transmits the converted digital audio data to the audio signal switching unit 105. The voice signal pre-value holding unit 104 is a multiplier ( The analog audio signal output from the digital-to-analog converter 103 is temporarily held by the 104a and the condenser 104b.

On the other hand, the audio signal switching unit 105 is an audio signal or audio signal pre-value holding unit 104 output from the digital / analog converter 103 in accordance with the audio output control signal output from the audio data error detection unit 102 When the audio output control signal is a low signal, the audio signal output from the digital / analog converter 103 is switched and output, and the audio output control signal is high. In the case of a signal, the audio signal held by the voice signal pre-value holding unit 104 is switched to output the audio noise even when the compressed audio data is damaged.

The switched audio signal is output through the audio amplifier 106 and the audio output terminal 107 sequentially.

As described above, the present invention has an effect of preventing noise from being output by retrieving the extended audio data and outputting the audio signal previously output normally when an error occurs in the audio data.

In addition, by preventing the output of audio noise, there is an effect that can prevent the damage to the amplifier or speaker caused by the sudden rise of the audio signal.

1 is a system configuration diagram of a conventional video CDP.

2 is a block diagram of an audio noise canceling device in a video CDP according to the present invention.

3 is a flowchart of a process for removing audio noise in a video CDP according to the present invention.

4 is a waveform diagram illustrating an audio data error detection process in the present invention.

*** Explanation of symbols for the main parts of the drawing ***

101: audio decoder 102: audio data error detection unit

103: digital / analog converter 104: voice signal pre-value holding unit

105: audio signal switching unit

Claims (4)

Audio data errors that are continuously input in 16-bit units are stored in M1, M2, and M3 according to the input time sequence, and the data values of M1 and M3 are compared to detect errors of M2 and output audio data. Sudan, Digital / analog conversion means for converting and outputting an audio digital audio signal output from said audio error data detection means into an analog audio signal; Voice signal pre-value holding means for temporarily holding an audio signal output from said digital / analog conversion means; And audio switching means for selecting and outputting an audio signal output from the digital / analog converting means or an audio signal held by the audio signal pre-value holding means according to a result detected by the audio data error detecting means. Audio noise reduction device in video CDP. The method of claim 1, And an audio amplifying means for amplifying the audio signal output from the audio signal switching means to a predetermined level and outputting the audio signal to an output terminal. The method of claim 1, The M1, M2, M3 is the audio noise canceling device in a video CD (CDP), characterized in that M1 is the most advanced data in time and the order of M2, M3. The method of claim 1, The error detecting means determines that the signal is normal when the value of M2 exists between the values of M1 and M3, and determines that it is an error if the value of M2 does not exist between the values of M1 and M3. Audio Noise Reduction Device