Patent Publication Number: US-2010118199-A1

Title: Video/Audio Processor and Video/Audio Processing Method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2008-288176, filed on Nov. 10, 2008; the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a video/audio processor and a video/audio processing method. 
     2. Description of the Related Art 
     Conventionally, with respect to a video/audio processor, there is proposed a method in which a position of a speaking person in video is detected and volume of a plurality of speakers is controlled based on the detected position of the speaking person in the video in order to enhance feeling of presence at a time that monaural audio is outputted (JP-A 11-313272(KOKAI)). 
     BRIEF SUMMARY OF THE INVENTION 
     However, in a conventional video/audio processor, volume of not only audio of a speaking person but also of sound effects such as BGM is controlled. Thus, a viewer is given a sense of incompatibility. In view of the above, an object of the present invention is to provide a video/audio processor and a video/audio processing method capable of providing a viewer with natural feeling of presence at a time that monaural audio is outputted. 
     A video/audio processor according to an aspect of the present invention includes: a position calculation unit configured to calculate from a video signal a position of a speaking person in a screen; and an adjustment section configured to adjust a signal level of a specific frequency of an audio signal inputted to a plurality of speakers in correspondence with the position of the speaking person calculated in the position calculation unit, for each of the plurality of speakers independently. 
     A video/audio processing method according to an aspect of the present invention includes: calculating from a video signal a position of a speaking person in a screen; and adjusting a signal level of a specific frequency of an audio signal inputted to a plurality of speakers in correspondence with the position of the speaking person calculated in the calculating a position of a speaking person, for each of the plurality of speakers independently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing an example of a constitution of a video/audio processor according to a first embodiment. 
         FIG. 2  is a diagram showing an example of a speaker disposition. 
         FIG. 3  is a diagram showing an example of a constitution of a position calculation unit. 
         FIG. 4A  is a view showing an example of a block disposition according to the first embodiment. 
         FIG. 4B  is a view showing another example of a block disposition according to the first embodiment. 
         FIG. 5A  is a table showing an example of a relation between an area and a block. 
         FIG. 5B  is a table showing another example of a relation between an area and a block. 
         FIG. 6  is a diagram showing an example of a constitution of an audio processing unit. 
         FIG. 7A  is a graph showing an attenuation amount of a signal level in Ch A. 
         FIG. 7B  is a graph showing an attenuation amount of a signal level in Ch B. 
         FIG. 7C  is a graph showing an attenuation amount of a signal level in Ch C. 
         FIG. 7D  is a graph showing an attenuation amount of a signal level in Ch D. 
         FIG. 8  is a flowchart showing an operation of a video/audio processor according to the first embodiment. 
         FIG. 9  is a diagram showing an example of a constitution of a video/audio processor according to a modification example of the first embodiment. 
         FIG. 10  is a diagram showing an example of a constitution of a position calculation unit according to the modification example of the first embodiment. 
         FIG. 11  is a diagram showing an example of a constitution of a video/audio processor according to a second embodiment. 
         FIG. 12  is a diagram showing an example of a constitution of an audio processing unit. 
         FIG. 13  is a diagram showing an example of a constitution of an amplifying section. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 
     First Embodiment 
       FIG. 1  is a diagram showing an example of a constitution of a video/audio processor  1  according to a first embodiment.  FIG. 2  is a diagram showing an example of disposition of speakers  50 A to  50 D. The first embodiment will be described in an example of a video display apparatus such as a CRT (Cathode Ray Tube) or a liquid crystal TV as the video/audio processor  1 . 
     The video/audio processor  1  according to the first embodiment includes a signal processing unit  10 , a position calculation unit  20 , a video display unit  30 , an audio processing unit  40 , speakers  50 A to  50 D. 
     The signal processing unit  10  demodulates a video signal and an audio signal inputted from an antenna  101  or an external apparatus  102 . The external apparatus  102  is a video tape recording/reproducing apparatus, a DVD recording/reproducing apparatus or the like. The signal processing unit  10  inputs the demodulated video signal to the position calculation unit  20  and the video display unit  30 . The signal processing unit  10  inputs the demodulated audio signal to the audio processing unit  40 . 
     The video display unit  30  generates video from the video signal inputted from the signal processing unit  10 . Then, the video display unit  30  displays the generated video. 
     The position calculation unit  20  detects a mouth of a speaking person from the video signal inputted from the signal processing unit  10 . The position calculation unit  20  calculates position coordinates of the detected mouth of the speaking person. The position calculation unit  20  judges to which area among areas described later in  FIG. 5A  the calculated position coordinates belong. The position calculation unit  20  inputs a judgment result to the audio processing unit  40 . It should be noted that the position calculation unit  20  detects the mouth of the speaking person under a condition that a face of the speaking person is ivory colored and that the mouth has motion. 
       FIG. 3  is a diagram showing an example of a constitution of the position calculation unit  20 . The position calculation unit  20  includes a memory  201 , a difference video generation section  202 , a color space extraction section  203 , an AND circuit  204 , a counting section  205 , and a comparison section  206 . 
     A video signal of one frame is stored in the memory  201 . The video signal stored in the memory  201  is inputted to the difference video generation section  202  in a delayed manner by one frame. The difference video generation section  202  generates a difference signal between the video signal inputted from the signal processing unit  10  and the video signal inputted from the memory  201  in a delayed manner by one frame. 
     The difference video generation section  202  generates an absolute value signal obtained by calculating an absolute value of the difference signal. Further, the difference video generation section  202  performs an offset processing and a filtering processing on the absolute value signal in order to remove noise. Then, the absolute value signal after the offset processing and the filtering processing is inputted to the AND circuit  204  as a detection signal. 
     In other words, the difference video generation section  202  inputs the detection signal corresponding to a pixel having a difference between frames, that is, a pixel having motion, to the AND circuit  204 . It should be noted that the difference video generation section  202  inputs the detection signal to the AND circuit  204  synchronously with a clock signal inputted from a clock signal generation section  207 . The difference video generation section  202  inputs the detection signal to the AND circuit  204 , in an arbitrary order, starting from a pixel in the upper left of the video. 
     The color space extraction section  203  includes a memory  203   a . A threshold value of a color difference signal determined by an experiment or the like is stored in the memory  203   a  in advance. The threshold value of the color difference signal is used for detection of the mouth of the speaking person. In the first embodiment, a threshold value of a color difference signal SC is set at a value to detect an ivory color. In the first embodiment, an HSV space is used as a color space. Further, for a color difference signal, a hue and a chroma are used. 
     The color space extraction section  203  judges for each pixel whether or not the inputted color difference signal of the video signal is within a range of the threshold value stored in the memory  203   a . If the color difference signal of the video signal is within the range of the above-described threshold value, the color space extraction section  203  inputs a detection signal to the AND circuit  204 . The color space extraction section  203  inputs the detection signal to the AND circuit  204  synchronously with the clock signal inputted from the clock signal generation section  207 . 
     In other words, the color space extraction section  203  inputs a detection signal corresponding to an ivory colored pixel to the AND circuit  204 . The color space extraction section  203  inputs the detection signal to the AND circuit  204  in the same order as in the difference video generation section  202 . It should be noted that in the first embodiment, the color space extraction section  203  detects an ivory colored region. However, after the ivory colored region is detected, a red color can be detected from the ivory colored region. Thereby, the mouth of the speaking person can be detected more effectively. Meanwhile, a skin color is different by person. Therefore, it is a matter of course that a plurality of colors can be set to be detected. 
     The AND circuit  204  obtains a logical multiplication of the detection signals inputted from the difference video generation section  202  and the color space extraction section  203 . In other words, when the detection signals inputted from the difference video generation section  202  and the color space extraction section  203  are inputted, a signal is inputted to the counting section  205 . As a result that the logical multiplication of the detection signal inputted from the difference video generation section  202  and the detection signal inputted from the color space extraction section  203  is obtained in the AND circuit  204 , the pixel having the ivory color and motion, that it, the pixel corresponding to the mouth of the speaking person can be detected effectively. 
     The counting section  205  counts the number of signals inputted from the AND circuit  204 . The number of signals is counted for each block described later in  FIG. 4A . The counting section  205  judges the pixel of which position in the video the signal inputted from the AND circuit  204  corresponds to, based on the clock signal inputted from the block signal generation section  207 . 
       FIG. 4A  is a diagram showing an example of a block arrangement according to the first embodiment. In this example, an example is shown in which a screen of the video display unit  30  is divided into sixteen equal parts, each of sixteen equally divided regions being one block. In other words, the screen of the video display unit  30  is constituted with sixteen blocks in total from a block B 1  to a block  1316 . 
     The arrangement of the blocks shown in  FIG. 4A  is an example. It is possible, for example, as shown in  FIG. 4B , to divide so that areas of blocks belonging to a center region of video, that is, blocks B 6 , B 7 , B 10  and B 11  are small and areas of blocks belonging to an outer peripheral region of the video, that is, from a block B 1  to a block B 5 , a block B 8 , a block B 9 , and a block B 12  to a block B 16  are large. Usually, the speaking person is projected in the center region of the video. Thus, making the area of each block in the center region of the video small leads to effective detection of the mouth of the speaking person in the screen. 
     The counting section  205  judges to which block the signal inputted from the AND circuit  204  belongs. The counting section  205  counts the number of the signals inputted from the AND circuit  204  for each block. Then, the counting section  205  inputs a count number for each block together with a block code to the comparison section  206 . 
     The comparison section  206  calculates a sum of the count numbers for each area described later in  FIG. 5A . The comparison section  206  compares the calculated sums of the count numbers and inputs a code of the area having the highest sum of the count numbers to the audio processing unit  40 . 
       FIG. 5A  is a table showing an example of a relation between the area and the block. An area  1  is constituted with the blocks B 1 , B 2 , B 5  and B 6 . An area  2  is constituted with the blocks B 3 , B 4 , B 7  and B 8 . An area  3  is constituted with the blocks B 9 , B 10 , B 13  and B 14 . 
     Further, an area  4  is constituted with the blocks B 11 , B 12 , B 15  and B 16 . An area  5  is constituted with the blocks B 2 , B 3 , B 6  and B 7 . An area  6  is constituted with the blocks B 6 ,  37 , B 10  and B 11 . An area  7  is constituted with blocks B 10 , B 11 , B 14  and B 15 . An area  8  is constituted with the blocks B 5 , B 6 , B 9  and B 10 . An area  9  is constituted with the blocks B 7 , B 8 , B 11  and B 12 . 
     The relation between the area and the block shown in  FIG. 5A  is an example, and is altered depending on the number and disposition of speakers connected to the video/audio processor  1 . For example, when one speaker is each disposed on the right and the left of the video display unit  30 , areas can be set as shown in  FIG. 5B . Further, an area and a block can be corresponded one-to-one. In this case, the mouth of the speaking person is detected for each block. 
     The audio processing unit  40  inputs the audio signal inputted from the signal processing unit  10  to the speakers  50 A to  50 D. A path for inputting the audio signal to the speaker  50 A is referred to as Ch (channel) A. A path for inputting the audio signal to the speaker  50 B is referred to as Ch B. A path for inputting the audio signal to the speaker  50 C is referred to as Ch C. A path for inputting the audio signal to the speaker  50 D is referred to as Ch D. The audio processing unit  40  attenuates a signal level of a specific frequency of the audio signal inputted to the speakers  50 A to  50 D in correspondence with the area code inputted from the position calculation unit  20 . 
       FIG. 6  is a diagram showing an example of a constitution of the audio processing unit  40 . The audio processing unit  40  includes an audio signal processing section  401 , a BPF (band pass filter)  402 , a frequency judgment section  403 , a filter control section  404 , a notch filter  405  (adjustment section), selectors  406 A to  406 D and amplifiers  407 A to  407 D. 
     The audio signal processing section  401  inputs the audio signal inputted from the signal processing unit  10  to the selectors  406 A to  406 D. The audio signal processing section  401  judges whether the audio signal is monaural or stereo. When a judgment result indicates monaural, the audio signal processing section  401  controls the selectors  406 A to  406 D to switch connection destinations of the amplifiers  407 A to  407 D to the notch filter  405 . Meanwhile, when the judgment result indicates stereo, the audio signal processing section  401  controls the selectors  406 A to  406 D to switch the connection destinations of the amplifiers  407 A to  407 D to the audio signal processing section  401 . 
     The BPF  402  passes an audio signal of a frequency band (about 0.5 kHz to 4 kHz) of human conversation sound among the audio signals received by the audio processing unit  40 . 
     The frequency judgment section  403  judges a frequency of the highest signal level from a spectrum of the audio signal passed through the BPF  402 . 
     The notch filter  405  is a 4-channel notch filter including Ch A to Ch D. The notch filter  405  distributes an inputted audio signal to Ch A to Ch D. Then, the notch filter  405  attenuates a specific frequency of the audio signal, independently for Ch A to Ch D. 
     An attenuation amount of the audio signal and the specific frequency in the notch filter  405  are controlled by the filter control section  404 . Further, attenuation of the audio signal in the notch filter  405  is realized by adjusting a Q value of the notch filter  405 . 
     The audio signal attenuated in Ch A is inputted to the selector  406 A. The audio signal attenuated in Ch B is inputted to the selector  406 B. The audio signal attenuated in Ch C is inputted to the selector  406 C. The audio signal attenuated in Ch D is inputted to the selector  406 D. 
     The filter control section  404  includes a memory  404   a . In the memory  404   a  is stored table data in which the area codes explained in  FIG. 5  are corresponded with the attenuation amounts of the signal levels of the audio signals in Ch A to Ch D of the notch filter  405 . 
     The filter control section  404  sets a center frequency of the notch filter  405  at the frequency judged in the frequency judgment section  403 . Further, the filter control section  404  refers to the table data stored in the memory  404   a . Then, the filter control section  404  controls the attenuation amount of the notch filter  405  to be the value corresponding to the area code inputted from the position calculation unit  20 . 
     The attenuation amounts of the signal levels of the audio signals in Ch A to Ch D are determined in correspondence with distances from center positions of respective areas to the respective speakers  50 A to  50 D. In the first embodiment, as the distances from the position of the speaking person to the respective speakers  50 A to  50 D get far (long), the attenuation amounts of the notch filter  405  are made large (deep). 
     For example, when the speakers  50 A to  50 D are disposed as in  FIG. 2  and a person B is the speaking person, attenuation amounts of the signal levels in Ch A to Ch D are as shown in  FIG. 7A  to  FIG. 7D . 
       FIG. 7A  is a graph showing the attenuation amount of the signal level in Ch A.  FIG. 7B  is a graph showing the attenuation amount of the signal level in Ch B.  FIG. 7C  is a graph showing the attenuation amount of the signal level in Ch C.  FIG. 7D  is a graph showing the attenuation amount of the signal level in Ch D. 
     In Ch C corresponding to the speaker  50 C, which is the farthest in distance from the person B, as a result of adjustment of the Q value, the attenuation amount of the signal level is set deepest. In contrast, in Ch B corresponding to the speaker  50 B, which is the nearest in distance from the person B, as a result of adjustment of the Q value, the attenuation amount of the signal level is set smallest (shallowest). 
     As stated above, as a result that the attenuation amount of the notch filter  405  is increased as the distances between the center positions of the areas and the respective speakers  50 A to  50 D get longer, it is possible to assign audio to a neighborhood of the position of the speaking person effectively. Consequently, an effect can be obtained that audio sounds from the neighborhood of the position of the speaking person. Besides, the frequency of the highest signal level of the frequencies passed through the BPF  402  is attenuated. Therefore, as for sound effects and the like other than the audio of the speaking person B, it is possible to effectively restrain change of assignment of audio. 
     It should be noted that the notch filter  405  can be controlled by using an attenuation ratio instead of the attenuation amount as a control parameter by the filter control section  404 . 
     The amplifiers  407 A to  407 D each amplify the audio signal inputted from the selectors  406 A to  406 D by a predetermined gain. 
     The speakers  50 A to  50 D each convert the amplified audio signal inputted from the amplifiers  407 A to  407 D into an acoustic wave and radiate into the air. 
     Next, an operation will be described.  FIG. 8  is a flowchart showing an operation of a video/audio processor  1  according to the first embodiment. 
     A signal processing unit  10  receives a video signal (step S 11 ). An audio processing unit  40  receives an audio signal (step S 12 ). A difference video generation section  202  generates an absolute value signal obtained by calculating an absolute value of a difference signal of the video signals between frames (step S 13 ). The difference video generation section  202  performs an offset processing and a filtering processing on the generated signal and inputs to an AND circuit  204  as a detection signal. 
     A color space extraction section  203  of a position calculation unit  20  judges whether or not a color difference signal of the video signal is within a range of a threshold value stored in a memory  203   a  (step S 14 ). If the color difference signal of the video signal is within the rage of the threshold value, the color space extraction section  203  inputs a detection signal to the AND circuit  204 . 
     When the detection signals inputted from the difference video generation section  202  and the color space extraction section  203  are inputted, the AND circuit  204  inputs a signal to a counting section  205  (step S 15 ). 
     The counting section  205  of the position calculation unit  20  counts the number of the signals inputted from the AND circuit  204  for each block. 
     A comparison section  206  of the position calculation unit  20  calculates a sum of the count numbers for each area (step S 16 ). Next, the comparison section  206  compares the sums of the count numbers calculated for each area. The comparison section  206  inputs an area code of the area having the largest sum of the count numbers from a comparison result to the audio processing unit  40  (step S 17 ). 
     An audio signal processing section  401  of the audio processing unit  40  judges whether the audio signal inputted from the signal processing unit  10  is monaural or stereo (step S 18 ). 
     When the audio signal is monaural, the audio signal processing section  401  switches the connection destinations of the selectors  406 A to  406 D to the notch filter  405  (step S 19 ). 
     A filter control section  404  sets a center frequency of the notch filter  405  at a frequency judged in a frequency judgment section  403 . Further, the filter control section  404  refers to table data stored in a memory  404   a . Then, the filter control section  404  sets an attenuation amount of the notch filter  405  at a value corresponding to an area code inputted from the position calculation unit  20 . 
     The notch filter  405  distributes the audio signal inputted from the signal processing unit  10  to Ch A to Ch D. The notch filter  405  attenuates signal levels of a specific frequency of the audio signals distributed to Ch A to Ch D and inputs the audio signals to the selectors  406 A to  406 D, in correspondence with an instruction from the filter control section  404 . 
     The audio signals inputted from the notch filter  405  to the selectors  406 A to  406 D are amplified in amplifiers  407 A to  407 D and outputted from speakers  50 A to  50 D (step S 20 ). 
     When the audio signal is stereo, the audio signal processing section  401  switches the connection destinations of the selectors  406 A to  406 D to the audio signal processing section  401 . 
     The audio signals inputted from the audio signal processing section  401  are amplified in the amplifiers  407 A to  407 D. The audio signals after amplification are outputted from the speakers  50 A to  50 D (step S 20 ). The video/audio processor  1  continues processings from the steps S 11  to S 20  while video signals and audio signals are being inputted. 
     As stated above, in the first embodiment, it is constituted so that in a case of a monaural audio signal, a signal level of a specific frequency of the audio signal is attenuated by the notch filter  405  in correspondence with a position of a speaking person in video. Thus, assignment of audio can be changed so that a voice can sound from the position of the speaking person. Besides, a frequency of the highest signal level of frequencies passed through the BPF  402  is attenuated. Thus, it is possible to effectively restrain change of assignment of audio with respect to sound effects and the like other than the audio of the speaking person. As a result, it is possible to provide a viewer with natural feeling of presence at a time that monaural audio is outputted. 
     Further, in a case that an audio signal is stereo, the audio signal is directly inputted to the amplifiers  407 A to  407 D without being passed through the notch filter  405 . Thus, in the case that the audio signal is stereo audio, feeling of presence in stereo audio can be obtained. It should be noted that though the mouth position of the speaking person is calculated in the first embodiment, it can be constituted to calculate only the position of the speaking person. 
     Modification Example of First Embodiment 
     A modification example of the first embodiment is different from the first embodiment in a constitution for detecting a mouth position of a speaking person. In the modification example of the first embodiment, an embodiment will be described in which the mouth position of the speaking person is detected after an edge of a face and positions of eyes of the speaking person are detected. 
       FIG. 9  is a diagram showing an example of a constitution of a video/audio processor  2  according to the modification example of the first embodiment. It should be noted that the video/audio processor  2  according the modification example of the first embodiment is different from the video/audio processor  1  explained in  FIG. 1  in a constitution of a position calculation unit  20 A. Thus, in the following explanation, the position calculation unit  20 A will be described and the same reference numerals and symbols are given to the same components as the components explained in  FIG. 1  and duplicate explanation will be omitted. 
       FIG. 10  is a diagram showing an example of a constitution of the position calculation unit  20 A. The position calculation unit  20 A includes an edge detection section  211 , a face detection section  212 , an eye detection section  213 , a lip detection section  214 , a motion vector detection section  215  and a lip motion detection section  216 . 
     The edge detection section  211  detects an edge of video from an inputted video signal. In such edge detection, there is used a phenomenon that signal levels of a luminance signal SY and a color difference signal SC (Pb, Pr) of the video signal change at an edge portion. The edge detection section  211  inputs a luminance signal SY and a color difference signal SC of a detected edge portion to the face detection section  212 . 
     The face detection section  212  detects a region of an ivory colored portion from the video signal. In the detection of the ivory colored region, with a hue of the color difference signal SC inputted from the edge detection section  211  being a standard, the luminance signal SY of the edge portion is masked with the color difference signal SC of the edge portion. 
     Next, the face detection section  212  judges whether or not the ivory colored region is a face from a shape of the detected ivory colored region. The judgment of whether or not the ivory colored region is the face can be done by means of pattern matching with a stored facial edge pattern. It is better to store a plurality of facial edge patterns. 
     When judging the detected ivory colored region is the face, the face detection section  212  calculates a size (vertical and horizontal measurement) of the detected face. The face detection section  212  inputs the video signal of the detected face region together with the calculated size of the face to the eye detection section  213 . 
     The eye detection section  213  detects edges of both eyes from the video signal of the face region inputted from the face detection section  212 . In this detection of the edges, with a hue by the color difference signal SC being a standard, an edge detection signal obtained by the luminance signal SY is mask-processed. Next, the eye detection section  213  calculates position coordinates of the detected edges of the both eyes. 
     The lip detection section  214  calculates position coordinates of a mouth from the position coordinates of the edges of the both eyes and the size of the face which are inputted from the eye detection section  213 . 
     The motion vector detection section  215  detects from the luminance signal SY of the video signal a motion vector of the present frame for each block of the video, with a previous frame being a standard, and inputs the motion vector to the lip motion detection section  216 . It should be noted that a gradient method, a phase correlation method or the like can be used as a detection method of the motion vector. 
     The lip motion detection section  216  judges whether or not the mouth is moving. In this judgment, it is judged whether or not a motion vector exists at position coordinates of the mouth calculated in the lip detection section  214 . 
     When judging that the mouth is moving, the lip motion detection section  216  judges to which area explained in  FIG. 5A  the calculated position coordinates of the mouth belongs, and inputs a code of the area to an audio processing unit  40 . 
     As described above, in the modification example of the first embodiment, after the edge of the face and the positions of the eyes of the speaking person are detected, the mouth position of the speaking person is detected. It should be noted that an effect thereof is similar to that of the first embodiment. 
     Second Embodiment 
       FIG. 11  is a diagram showing an example of a constitution of a video/audio processor  3  according to a second embodiment. In the first embodiment, there is described the embodiment in which the signal levels of the audio signals are attenuated as the distances between the center positions of the areas and the respective speakers  50 A to  50 D get longer. In the second embodiment, there will be described an embodiment in which an amplifying section  405 A is included instead of the notch filter  405  and a signal level of an audio signal is amplified in correspondence with distances between center positions of areas and respective speakers  50 A to  50 D. 
     It should be noted that the video/audio processor  3  according to the second embodiment has an audio processing unit  40 A with a constitution different from the constitution in the video/audio processor  1  explained in  FIG. 1 . Thus, in the following explanation, the audio processing unit  40 A will be described and the same components as the components explained in  FIG. 1  will be given the same reference numerals and symbols and duplicate explanation will be omitted. 
       FIG. 12  is a diagram showing an example of a constitution of the audio processing unit  40 A. The audio processing unit  40 A includes an audio signal processing section  401 , a BPF  402 , a frequency judgment section  403 , a control section  404 A, the amplifying section  405 A (adjustment section), selectors  406 A to  406 D and amplifiers  407 A to  407 D. 
     It should be noted that with regard to the components except the control section  404 A and the amplifying section  405 A the constitution of the audio processing unit  40 A is the same as the constitution of the video/audio processor  1  explained in  FIG. 6 . Therefore, in the following explanation, the control section  404 A and the amplifying section  405 A will be described, and the same components explained in  FIG. 1  are given the same reference numerals and symbols and duplicate explanation will be omitted. 
       FIG. 13  is a diagram showing an example of a constitution of the amplifying section  405 A. The amplifying section  405 A includes a distributing device  501 , distributing devices  502 A to  502 D, BPFs (band-pass filters)  503 A to  503 D, amplifying devices  504 A to  504 D and combining devices  505 A to  505 D. 
     The distributing device  501  distributes an audio signal inputted from a signal processing unit  10  to the distributing devices  502 A to  502 D. The distributing devices  502 A to  502 D further distribute the audio signals distributed in the distributing device  501 . The BPFs  503 A to  503 D pass audio signals with a specific frequency band or frequency of the one audio signals distributed in the distributing devices  502 A to  502 D. 
     The amplifying devices  504 A to  504 D amplify the audio signals passed through the BPFs  503 A to  503 D. 
     The combining device  505 A combines the audio signal amplified in the amplifying device  504 A and the other audio signal distributed in the distributing device  502 A. The combining device  505 A inputs the combined audio signal to a selector  406 A. 
     The combining device  505 B combines the audio signal amplified in the amplifying device  504 B and the other audio signal distributed in the distributing device  502 B. The combining device  505 B inputs the combined audio signal to a selector  406 B. 
     The combining device  505 C combines the audio signal amplified in the amplifying device  504 C and the other audio signal distributed in the distributing device  502 C. The combining device  505 C inputs the combined audio signal to a selector  406 C. 
     The combining device  505 D combines the audio signal amplified in the amplifying device  504 D and the other audio signal distributed in the distributing device  502 D. The combining device  505 D inputs the combined audio signal to a selector  406 D. 
     The control section  404 A includes a memory  404   b . In the memory  404   b  is stored table data in which area codes described in  FIG. 5  are corresponded with amplification amounts of signal levels of audio signals in the amplifying devices  504 A to  504 D. 
     The control section  404 A sets center frequencies of the BPFs  503 A to  503 D of the amplifying section  405 A at frequencies judged in the frequency judgment section  403 . Further, the control section  404 A refers to the table data stored in the memory  404   b . Then, the filter control section  404 A controls amplification amounts of the amplifying devices  504 A to  504 D to be values corresponding to the area codes inputted from the position calculation unit  20 . 
     The amplification amounts of the signal levels of the audio signals in the amplifying devices  504 A to  504 D are determined in correspondence with the distances from the center positions of the respective areas to the respective speakers  50 A to  50 D. In the second embodiment, the amplification amounts in the amplifying devices  504 A to  504 D are increased as the distances between a speaking person and the respective speakers  50 A to  50 D get near (short). 
     It should be noted that the amplifying section  405 A can be controlled by using an amplification ratio instead of the amplification amount as a control parameter by the control section  404 A. 
     As described above, in the second embodiment, the amplification amounts in the amplifying section  405 A are increased as the distances between the center positions of the areas and the respective speakers  50 A to  50 D get short. Therefore, it is possible to assign audio to a neighborhood of a position of the speaking person effectively. Consequently, an effect can be obtained that audio sounds from the neighborhood of the position of the speaking person. Other effects are the same as in the first embodiment. 
     Other Embodiments 
     It should be noted that the present invention is not limited to the above-describe embodiments, but can be concretized with components being modified in a range not departing from the gist of the present invention in a practical phase. For example, though the embodiment is described with the example of the video display apparatus such as a liquid crystal television in the first embodiment, the present invention can be applied also to a reproducing apparatus, a recording/reproducing apparatus or the like for DVD or video tape.