JP2010183624A - Audio/video amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio/video amplifier which measures a display delay time from video signal generation to actual image display, and automatically sets a delay time of an audio signal so as to synchronize the display with sound. <P>SOLUTION: Test image data 110 is stored in a memory 11. This test image data generates clear intensity changes such as a sudden screen change from pitch-black to pure white. The test image is output to an image display apparatus 2 such as a PDP, and a delay time until actual image display after output is measured. As the intensity of the screen suddenly changes when the image is actually displayed, the change is detected by an optical sensor 20. By setting the delay time to an audio signal processing part 13 and delaying the audio signal, the image is synchronized with sound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an audio / video amplifier capable of canceling a difference between video and audio when an audio / video source is reproduced.

  With the widespread use of high-definition television broadcasting and home theater systems, large display devices such as PDP (plasma display) and DLP (micromirror projector) have been put into practical use. However, such a large display requires processing such as discretization of the input video signal into a dot matrix, so there is a delay between displaying the video signal and actually displaying it on the screen (display (Delay time) was large and a delay of about 1 to 2 frames (1/30 to 1/15 seconds) occurred.

  On the other hand, the audio signal also requires a certain amount of time for processing such as decompressing the compressed digital signal and converting it to analog, but it is not as large as the time delay for the above video display, and the video and audio were reproduced as they were However, there is a problem that the video and the audio are shifted due to the large delay of the video.

  On the other hand, a technique for detecting a shift in processing time in an audio / video signal processing apparatus has been proposed (for example, Patent Document 1). In the technique of Patent Document 1, an audio / video signal in which a change in luminance and a change in volume occur simultaneously is input, processed in a separate system, and the volume change timing and video of the output audio signal are processed. By measuring the timing shift of the luminance change of the signal, the processing time shift is measured.

Japanese Patent Laid-Open No. 10-285483

  As described above, the technique for detecting the difference between the processing time of the video signal and the processing time of the audio signal in the transmission path (signal processing circuit) is disclosed in Patent Document 1, but this document only discloses the measurement technique. However, since it is not disclosed to automatically measure and correct this, it cannot be applied to an audio / video amplifier used by a general user.

  An object of the present invention is to provide an audio / video amplifier capable of automatically measuring a display delay time and correcting it.

  The present invention is an audio / video amplifier for inputting at least an audio signal of audio / video signals and reproducing the input audio signal, an audio processing unit for reproducing the input audio signal, and a test video. A test video generating means for generating and inputting the video signal to the video display device for displaying the video signal; a sensor for detecting a change in the video displayed by the video display device; and after generating the test video, the sensor, The time until the change of the image displayed on the image display device is detected is detected as the image delay time, and the audio delay time, which is the time for delaying the reproduction of the audio signal, is calculated correspondingly, and this audio delay time is calculated. A control unit for setting the audio processing unit to the audio processing unit. Parts detects the type of the input audio signal, wherein the control unit is characterized in that to change the audio delay time for each type of the audio signal detected by the audio processing unit.

  In the above invention, as the change of the image, for example, the luminance may be changed. In this case, a sensor such as a phototransistor for detecting brightness may be provided in the vicinity of the screen of the video display device. Further, it may be a color change. The type of the audio signal is the format of the audio signal, for example, PCM, DTS (trademark), Dolby (trademark), or the like. The change in the content of the audio signal is a change from a silent state to a constant volume level, a frequency change from the first frequency to the second frequency, or the like.

  In the above invention, when a video signal (test video) is input from the outside, the audio signal is input at the same time in a general AV amplifier, since the video signal is input as an analog signal (for example, a component signal). If a change in the signal is detected, a special processing circuit is required, whereas the audio signal is input as a digital signal, so the function of the digital signal processing circuit originally detects the signal type, etc. This is because detection is easy.

  As described above, according to the present invention, it is possible to detect a delay time from when a video signal is reproduced to when the video is actually displayed, and in order to eliminate a shift due to the delay time, an audio signal can be detected. Since the audio delay time can be automatically set so as to delay the video, even if a video display device having a long display delay time is used, the video and the audio can be reproduced.

Block diagram of an AV amplifier according to an embodiment of the present invention Block diagram of the audio signal processing unit of the AV amplifier Flow chart showing operation of the AV amplifier Flow chart showing operation of the AV amplifier

    FIG. 1 is a block diagram of an AV (audio / video) amplifier according to an embodiment of the present invention. FIG. 2 is a configuration diagram of an audio signal processing unit of the AV amplifier.

  The AV amplifier 1 includes a plurality (four) of audio input terminals 22 and video input terminals 23, and any one of them is selected by the audio selector 12 and the video selector 16. The audio selector 12 and the video selector 16 are switched by the control unit 10 in conjunction with each other.

  A video playback device 4 such as a DVD player is connected to the audio input terminal 22 and the video input terminal 23.

  The video signal selected by the video selector 16 is input to the video display device 2 via the video output terminal 26. The video display device 2 is, for example, a PDP (plasma display) or a DLP (micromirror) display.

  The video selector 16 includes a test video input terminal 24 in addition to the four external video input terminals 23. The test video input terminal 24 has a signal generation IC 27 for generating a video signal of the test video. Is connected. In the test mode using the test video, the input of the video selector 16 is switched to the test video input terminal 24. At this time, the signal generation IC 27 generates a test video (test video signal) according to an instruction from the control unit 10, and the test video is output to the video display device 2 via the video selector 16.

  In the embodiment of FIG. 1, a test video input terminal 24 is provided in the video selector 16 and the signal generation IC 27 is connected to the test video input terminal. However, the signal generation IC 27 is connected to the output side of the video selector 16. The signal generating IC 27 normally passes the input video signal, and in the test mode, the signal from the video selector 16 is cut off and the generated test video is output to the video display device side. Also good.

  Here, the test mode is a mode for measuring a time difference (display delay time) from when a video signal is input to the video display device 2 until the video is actually displayed. In this measurement, a first test mode using a test video reproduced by the control unit 10 and a second test mode using a video signal input from the outside (video playback device 4) via the video input terminal 23 are used. There is. The first test mode or the second test mode is set by a predetermined operation by the user.

  The audio signal selected by the audio selector 12 is input to the audio signal processing unit 13. The audio signal processing unit 13 is configured as shown in FIG. A DIR (digital interface receiver) 30 controls the input of an audio signal and detects the type (PCM, DTS, Dolby, etc.) of the input audio signal. The type of the detected audio signal is transmitted to the control unit 10.

  The decoder 31 converts the input audio signal into a linear PCM signal. The decoder 31 has a buffer memory 32, and once buffers the input audio signal in the buffer memory 32, the decoder 31 executes the decoding process. The audio signal delay time is determined by how many audio signals are buffered in the buffer memory 32. In this AV amplifier, the buffer amount is controlled to synchronize the actually displayed video and the actually output audio. The control unit 10 determines the buffer amount and instructs the decoder 31. The decoded audio signal is given effects such as reverberation by the post processor 33.

  Although the buffer memory 32 is connected to the decoder 31 in FIG. 2, it may be configured to be connected to the DIR 30 or the post processor 33. The buffer memory may be configured as an internal memory of the decoder 31 or the post processor.

  The audio signal to which the effect is given by the post processor 33 is output to the D / A converter 14 at the next stage. The audio signal converted into an analog signal by the D / A converter 14 is amplified by the amplifier 15 and output to the speaker 3 via the speaker terminal 25. The amplifier 15 incorporates an electronic volume, and controls the volume of the audio signal based on a volume control signal input from the control unit 10.

  The control unit 10 is configured by a microcomputer having a memory 11. In addition to a program for controlling the operation of the AV amplifier 1, the memory 11 stores test video data 110, which will be described later, a decoding processing time 111 for each type of audio signal, and the like. The test video data is, for example, a video in which a clear luminance change occurs on a screen that changes from black to white, and may be stored as digital video data, and may be an OSD (for displaying characters or the like on the screen). On-screen display) control data may be stored.

  The memory 11 also has a delay time storage area 112 for storing a display delay time of the video display device 2 and an audio delay control time for each type of audio signal calculated by subtracting the decoding processing time from the display delay time. Has been.

  At that time, the control unit 10 instructs the decoder 31 on the audio delay control time corresponding to the type of the audio signal. The decoder 31 buffers data for the designated audio delay control time in the buffer memory 32. As a result, the audio signal is delayed by the audio delay control time (buffer amount) + decoding processing time, that is, the display delay time, and the display delay and the audio delay coincide with each other to achieve synchronization.

  In addition to the audio selector 12, the video selector 16, the audio signal processing unit 13, and the amplifier 15, an optical sensor 20 is connected to the control unit 10 through an operation unit 17, a display unit 18, and a sensor connection terminal 21. Yes. The operation unit 17 includes a power switch for turning on / off the amplifier, a select switch for switching the AV source, a volume switch for adjusting the volume, a normal operation mode, and a (first and second) test mode. And a mode change-over switch 170 for switching between and. The display unit 18 displays the currently selected AV source, volume value, mode, and the like.

  The mode switch 170 may be constituted by a button switch, for example. In this case, every time the button is turned on, the control unit 10 may operate so as to switch the mode in the order of normal mode → first test mode → second test mode → normal mode.

  The optical sensor 20 is a sensor that is provided toward the video display device 2 and has a function of detecting at least a change in luminance of the display screen of the video display device 2. The detection value of the optical sensor 20 is input to the control unit 10 via the sensor terminal 21.

  3 and 4 are flowcharts showing the operation in the test mode. FIG. 3A shows the operation in the first test mode, and FIG. 4 shows the operation in the second test mode. FIG. 3B shows an operation for setting the audio delay control time calculated in the test mode in the decoder 31.

  First, in FIG. 3A, in the first test mode, the test video data 110 stored in the memory 11 is reproduced (s1) and the timer is started simultaneously (s2). This timer uses a soft timer in which the control unit 10 counts time with an internal clock. Thereafter, the optical sensor 20 is monitored, and when the optical sensor 20 detects a change in luminance of the screen of the video display device 2 (s3), the timer is stopped (s4). The count value of this timer is the display delay time of the video display device 2. The audio delay control time is calculated by subtracting the audio signal decoding processing time from the measured display delay time (s5). This audio delay control time is calculated for each type of audio signal. The measured display delay time and the calculated audio delay control time are stored in the delay time storage area 112 (s6).

  Then, the audio delay control time is set in the decoder 31 of the audio signal processing unit 13 (s7). As described above, the audio delay control time varies depending on the type of the audio signal, but here, the audio delay control time of a typical audio signal type (for example, DTS) may be set.

  FIG. 5B is a flowchart showing an operation when an AV source is input from the outside in the normal mode. When an audio signal is input (s10), the DIR (digital interface receiver) 30 detects the type of the audio signal (s11). This type is transmitted from the DIR 30 (audio signal processing unit 13) to the control unit 10. The control unit 10 reads the audio delay control time corresponding to this type from the delay time storage area 112 (s12), and sets the audio delay control time in the decoder 31 of the audio signal processing unit 13 (s13). The decoder 13 delays the set audio delay control time in addition to the time necessary for decoding the audio signal, outputs the audio signal, and matches the video and audio timings.

  In the operation of the second test mode of FIG. 4, the test video is generated when the video playback device 4 such as a DVD player plays back a medium (DVD disc or the like) dedicated to the test mode. This test mode video is a video that has a clear brightness change, such as the entire screen suddenly changing from black to white, and the type or content of the audio signal changes in synchronization with the timing of the video signal brightness change. is there. When the type of the audio signal (PCM, DTS, Dolby, etc.) changes, the DIR 30 of the audio signal processing unit 13 immediately detects this and notifies the control unit 30. Therefore, this detection timing is used as the test video generation timing. be able to. In addition, even when the content of the audio signal such as the volume value changes, this can be detected by monitoring this with the decoder 31.

  When a test audio / video signal is input (s21), it is monitored whether the type or content of the audio signal changes (s22). When the type or content of the audio signal changes (s22), the timer is started at the timing when the luminance of the video signal input synchronously changes (s23). Thereafter, the optical sensor 20 is monitored, and when the optical sensor 20 detects a change in luminance of the screen of the video display device 2 (s24), the timer is stopped (s25). The count value of this timer is the display delay time of the video display device 2. The audio delay control time is calculated by subtracting the audio signal decoding processing time from the measured display delay time (s26). This audio delay control time is calculated for each type of audio signal. The measured display delay time and the calculated audio delay control time are stored in the delay time storage area 112 (s27).

  Then, the audio delay control time is set in the decoder 31 of the audio signal processing unit 13 (s28). As described above, the audio delay control time varies depending on the type of the audio signal, but one type of signal (for example, DTS) is stored in the control unit 10 by previously storing the difference in the delay control time for each type of video. By calculating the audio delay control time, delay control times for other video types can be determined.

  In the second test mode of FIG. 4, the dedicated media is played back by the video playback device 4, but the display delay time is measured by playing back a general media (recording movies or the like). You may do it.

  In the second test mode, the display audio time taking into account both the display delay of the video display device 2 and the time difference between the video signal output from the video playback device 4 and the audio signal is measured by measuring the shift using the audio signal as a trigger. Can be measured.

  In the above embodiment, the audio delay control time is calculated by subtracting the decoding processing time from the display delay time. However, since the decoding processing time is sufficiently shorter than the display delay time, the display is not performed. It is also possible to set the delay time as it is as the audio delay control time.

DESCRIPTION OF SYMBOLS 1 ... AV amplifier 2 ... Video display apparatus 4 ... Video reproduction apparatus (DVD player)
DESCRIPTION OF SYMBOLS 10 ... Control part 11 ... Memory 110 ... Test video storage area 111 ... Decoding processing time storage area 112 ... Delay time storage area 13 ... Audio signal processing part 30 ... DIR (digital interface receiver)
DESCRIPTION OF SYMBOLS 31 ... Decoder 32 ... Buffer memory 16 ... Video selector 20 ... Optical sensor 24 ... Test image input terminal 170 ... Mode change switch

Claims (1)

An audio / video amplifier for inputting at least an audio signal of audio / video signals and reproducing the input audio signal,
An audio processing unit for reproducing the input audio signal;
Test video generation means for generating a test video and inputting the video signal to a video display device for displaying the video signal;
A sensor for detecting a change in video displayed by the video display device;
After the test video is generated, the sensor detects the time until the change of the video displayed by the video display device is detected as the video delay time, and the time for delaying the reproduction of the audio signal corresponding to this time A control unit that calculates an audio delay time and sets the audio delay time in the audio processing unit;
With
The audio processing unit detects the type of the input audio signal,
The control unit is an audio / video amplifier that changes the audio delay time for each type of audio signal detected by the audio processing unit.

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