Patent Publication Number: US-9426270-B2

Title: Control apparatus and control method to control volume of sound

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from Japanese Patent Application No. 2010-219866 filed in the Japan Patent Office on Sep. 29, 2010, the entire contents of which is hereby incorporated by reference. 
     BACKGROUND 
     The present disclosure relates to a control apparatus and a control method. 
     In recent years, apparatuses, such as personal computers (PCs), that allow caller-callee communication with an external apparatus between users while reproducing content data have been in widespread use. Among such apparatuses, some apparatuses allow a user to independently control the sound volume of content data and the sound volume of speech of the user by, for example, using a sound mixing function of an application regarding reproduction of content data and an application regarding voice communication. However, it is necessary for a user of such an apparatus to manually control the volume in accordance with, for example, communication conditions as necessary. Therefore, users who use such apparatuses experience inconvenience. 
     Accordingly, a technology for automatically controlling sound volume has been developed. For example, in order to output, while one type of sound is being output, sound corresponding to another type of sound data, Japanese Unexamined Patent Application Publication No. 11-45096 describes a technology for decreasing the volume of the one type of sound. 
     When outputting, while one type of sound is being output, sound corresponding to another type of sound data, a control apparatus that employs an existing technology for automatically controlling the volume (hereinafter referred to as an “existing control apparatus”) decreases the volume of the one type of sound. That is, if, for example, an existing control apparatus performs caller-callee communication with an external apparatus between users while reproducing content data, an existing control apparatus automatically decreases the volume of sound of reproduced content data (hereinafter referred to as “content sound”) every time speech of the user is output. Therefore, when an existing technology is used, it is not necessary for a user to manually control the volume of content sound and the volume of speech as necessary. As a result, the user can experience some level of convenience. 
     However, as described above, if, while one type of sound is being output, sound corresponding to another type of sound data is output, an existing apparatus decreases the volume of the one type of sound. Therefore, in an existing apparatus, even when the user does not want to decrease the volume of, for example, content sound, the volume is disadvantageously decreased automatically. 
     Thus, even when an existing technology is employed, it is very difficult to increase the convenience that the user experiences. 
     SUMMARY 
     Accordingly, the present disclosure provides novel and improved control apparatus and control method capable of improving the convenience of a user when the control apparatus performs caller-callee communication with a communication target apparatus. 
     In accordance with one aspect of the embodiments, an apparatus may include a control unit to selectively control volume of content sound and volume of speech sound according to a priority assigned to a user corresponding to speech sound and a priority assigned to content data. In addition, when volume control is to be performed on a priority basis, the control unit may selectively control the volume of the content sound and the volume of the speech sound based on the assigned priorities so that the volume of the sound having a higher priority becomes louder than the volume of the other sound. 
     In accordance with another aspect of the embodiments, a method may include selectively controlling, by a processor, volume of content sound and volume of speech sound according to a priority assigned to a user corresponding to speech sound and a priority assigned to content data. The method may further include that, when volume control is to be performed on a priority basis, the volume of the content sound and the volume of the speech sound are selectively controlled based on the assigned priorities so that the volume of the sound having a higher priority becomes louder than the volume of the other sound. 
     In accordance with another aspect of the embodiments, a non-transitory recording medium may be recorded with a computer-readable program having instructions executable by a processor. The program may include selectively controlling volume of content sound and volume of speech sound according to a priority assigned to a user corresponding to speech sound and a priority assigned to content data. The program may further include that, when volume control is to be performed on a priority basis, the volume of the content sound and the volume of the speech sound are selectively controlled based on the assigned priorities so that the volume of the sound having a higher priority becomes louder than the volume of the other sound. 
     According to the present disclosure, the convenience of a user can be improved when the control apparatus performs caller-callee communication with a communication target apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart of an example of a process according to a convenience improvement approach performed by a control apparatus according to an embodiment of the present disclosure; 
         FIG. 2  is a flowchart of an example of a priority-based volume control process performed by the control apparatus according to the embodiment of the present disclosure; 
         FIG. 3  illustrates an example of control of the volumes of content sound and speech sound performed by the control apparatus according to the embodiment of the present disclosure; 
         FIG. 4  is a flowchart of an example of a volume control process of speech sound performed by the control apparatus according to the embodiment of the present disclosure; 
         FIG. 5  is a block diagram of an example of the configuration of a control apparatus according to a first embodiment of the present disclosure; 
         FIG. 6  illustrates an example of the hardware configuration of the control apparatus according to the embodiment of the present disclosure; and 
         FIG. 7  is a block diagram of an example of the configuration of a control apparatus according to a second embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Note that as used herein, the same numbering will be used in describing components having substantially the same functional structure and, thus, descriptions thereof are not repeated. 
     In addition, the descriptions are made in the following order: 
     1. Technical Approach According to Embodiment of Present Disclosure 
     2. Control Apparatus According to Embodiment of Present Disclosure 
     3. Program According to Embodiment of Present Disclosure 
     1. Technical Approach According to Embodiment of Present Disclosure 
     Before describing an exemplary configuration of a control apparatus according to an embodiment of the present disclosure (hereinafter also referred to as a “control apparatus  100 ”), a convenience improvement approach according to the embodiment of the present disclosure is described. Note that a process in accordance with the convenience improvement approach according to the embodiment of the present disclosure described below can be regarded as a process in accordance with a control method according to the embodiment of the present disclosure. 
     In addition, the following description is made with reference to the case in which, for example, the control apparatus  100  performs a process for reproducing content data and caller-callee communication with at least one communication target apparatus at the same time. As used herein, the term “content data according to an embodiment of the present disclosure” refers to sound data or sound and image (still image/moving image) data. Examples of content data include music data and video data. In addition, an example of caller-callee communication according to an embodiment of the present disclosure is communication through voice call. However, caller-callee communication according to an embodiment of the present disclosure is not limited thereto. For example, caller-callee communication according to an embodiment of the present disclosure may be caller-callee communication using a captured image, which is a moving image obtained by image capturing, and voice (e.g., video call). Note that a captured image according to an embodiment of the present disclosure is, for example, a moving image obtained by image capturing (or a set of still images continuously captured in the time axis direction). 
     Brief Overview of Convenience Improvement Approach 
     As described above, if, while outputting one type of sound, an existing apparatus outputs sound corresponding to another type of sound data, the existing apparatus decreases the volume of the one type of sound. However, in the case in which an existing apparatus has a function of performing caller-callee communication with an external apparatus between users while reproducing content data, the existing apparatus may automatically decrease the volume of content sound although the user does not want to decrease the volume of the content sound. For example, a user does not want the volume of content sound to automatically decrease when a climactic scene of a movie (an example of a content item) is reproduced. In such an undesirable case, decreasing the volume automatically may impair user convenience. Accordingly, even when an existing control apparatus is used, user convenience is not necessarily increased. 
     In contrast, even when a climactic scene of a movie (an example of a content item) is reproduced, a user may want to the volume of content sound to automatically decrease. For example, a user sets the volume of content sound to automatically decrease if the user wants to put a priority on voice communication over the reproduced content. In such a case, as in the existing technology, when one type of sound is being output and if sound corresponding to another type of sound data is output, the volume of the one type of sound is decreased. In this way, the convenience of the user can be increased. 
     Therefore, according to an embodiment of the present disclosure, a control apparatus  100  selectively controls the volume of content sound and the volume of speech sound on the basis of a priority assigned to a user corresponding to the detected speech sound. More specifically, the control apparatus  100  selectively controls the volume of content sound and the volume of speech sound so that the volume of sound having a higher priority becomes louder. 
     As used herein, the term “priority according to an embodiment of the present disclosure” refers to an index used by the control apparatus  100  to determine which one of the volumes of content sound and speech sound is preferentially increased when the volumes of content sound and speech sound are controlled. For example, if a priority is assigned to one of content data and a user corresponding to speech sound, the control apparatus  100  determines that the one having the priority assigned thereto has a higher priority. In contrast, if priorities are assigned to both, the control apparatus  100  determines that the one having a higher priority has a higher priority. An example of the priority is a “step-wise” value, such as a value from 1 to 10. Note that the priority according to an embodiment of the present disclosure is not limited to the step-wise value. For example, any format that allows such determination can be employed. In addition, when the priority according to the embodiment of the present disclosure is expressed using a step-wise value, the larger value may represent a higher priority, for example. However, the smaller value may represent a higher priority. The following description is made with reference to the case in which the priority according to an embodiment of the present disclosure is expressed using a step-wise value, and the larger value represents a higher priority. 
     For example, content data includes a priority in the form of meta data. In the above-described case, the control apparatus  100  references the meta data of content data being reproduced as necessary. Thus, the control apparatus  100  can dynamically analyze the priority of content data, for example, on a per scene basis (when the content data represents video data) or on a per phrase basis (when the content data represents music data). At that time, for example, a priority assigned to content data is preset by the creator of the content data. However, the setter is not limited to a creator. For example, the control apparatus  100  may set the priority in accordance with, for example, a user operation. In addition, the above-described meta data may be included in, for example, content data or may be separated from content data (i.e., external meta data). 
     In addition, for example, the control apparatus  100  identifies a priority assigned to a user corresponding to speech sound on the basis of priority information stored in the control apparatus  100  or priority information sent from a communication target apparatus. As used herein, the term “priority information according to an embodiment of the present disclosure” refers to information including a user name and a priority associated with the user name. For example, a priority included in the priority information is set when the priority information is generated. However, the setting of the priority is not limited thereto. For example, the control apparatus  100  may set the priority in accordance with, for example, a user operation. 
     Furthermore, if a plurality of priority information items are present for the same user (e.g., priority information stored in the control apparatus  100  and priority information sent from a communication target apparatus), the control apparatus  100 , for example, selectively use one of the priority information items. In the above-described case, the control apparatus  100  selects one of the priority information items to be used on the basis of predetermined setting or setting set through a user operation (for example, the control apparatus  100  preferentially selects the priority information stored in the control apparatus  100 ). Note that the process performed by the control apparatus  100  when a plurality of priority information items are present for the same user is not limited to the above-described process. For example, the control apparatus  100  can compute the average value of the priorities set in the plurality of priority information items for the same user and uses the average value as a new priority. 
     In the control apparatus  100 , a technique for identifying the priority assigned to a user corresponding to speech sound is not limited to the above-described technique. For example, the control apparatus  100  can identify a priority assigned to a user corresponding to the speech sound on the basis of priority information and user information that is stored in the control apparatus  100  and that includes a user name and user identification information associated with the user name. More specifically, the control apparatus  100  identifies the user who gave speech on the basis of the user information and acquires the priority assigned to the identified user from the priority information. According to the embodiment of the present disclosure, examples of the information used for identifying a user and recorded in the user information include vocal print information regarding the user (the frequency and strength of the voice) and face information indicating the feature of the face of the user (e.g., skeletal information and information indicating a positional relationship among the eyes, nose, and mouth). For example, the control apparatus  100  compares the speech sound with the recorded user voice print information or compares face information extracted from a captured image with the recorded face information. By using any voice print authentication technique or face recognition technique, a user who gave speech can be identified. 
     As described above, by selectively controlling the volume of the content sound and the volume of speech sound in accordance with the set priority, the control apparatus  100  can increase the volume of the sound having a higher priority assigned thereto more than the volume of the other sound. Accordingly, by dynamically controlling the volume in accordance with the set priority, the control apparatus  100  can increase the volume of content sound more than the volume of speech sound or increase the volume of speech sound more than the volume of content sound. 
     Thus, the control apparatus  100  can control the volume of sound while reducing the probability of the occurrence of an undesirable situation and, therefore, user convenience can be increased. 
     While above description has been made with reference to an example in which the control apparatus  100  controls the volume of sound on a priority basis, the process performed by the control apparatus  100  according to an embodiment of the present disclosure is not limited thereto. For example, when the control apparatus  100  communicates with a communication target apparatus in caller-callee communication using a captured image and voice (e.g., a video call), the control apparatus  100  can further update the display ratio of an image of reproduced content data to a captured image in the caller-callee communication. According to the embodiment of the present disclosure, as an example of updating the display ratio in conjunction with selective control of the volume of sound, when the control apparatus  100  increases the speech sound of a communication partner user who speaks using the communication target apparatus, the control apparatus  100  also increases the display size of a captured image of the communication partner user. In contrast, for example, the control apparatus  100  may decrease the display size of the image of content data in conjunction with updating of the above-described captured image. It should be noted that according to the embodiment of the present disclosure, the process for updating the display size in conjunction with updating of selective control of the volume of sound is not limited to the above-described example. 
     Since the control apparatus  100  changes the display ratio in conjunction with the above-described selective volume control, the user of the control apparatus  100  can visually recognize which user of a communication target apparatus has the speech sound having a louder volume. Thus, by changing the display ratio in conjunction with the above-described selective volume control, the control apparatus  100  can further increase user convenience. 
     In addition, if priorities are not assigned to the content data and the user corresponding to the speech sound, the control apparatus  100  determines that, for example, the user corresponding to the speech sound has a priority higher than that assigned to the content data (an example of an exceptional process). Thereafter, the control apparatus  100  selectively controls the volume of the content sound and the volume of the speech sound. Therefore, even when priorities are not assigned to the content data and the user corresponding to the speech sound, the control apparatus  100  can increase the volume of the speech more than the volume of the content sound on the basis of the result of a predetermined determination. Note that while the above description has been made with reference to the case in which if priorities are not assigned to the content data and the user corresponding to the speech sound, the speech sound has a priority, the control apparatus  100  may control the volumes so that the content sound has a priority. By controlling the volume of the content sound and the volume of the speech sound on the basis of the result of predetermined determination, the control apparatus  100  can automatically control the volumes even when priorities are not assigned to the content data and the user corresponding to the speech sound. 
     Specific Example of Process According to Convenience Improvement Approach 
     A specific example of a process to realize the convenience improvement approach according to the embodiment of the present disclosure is described next.  FIG. 1  is a flowchart illustrating an example of a process according to the convenience improvement approach performed by the control apparatus  100  according to the embodiment of the present disclosure. 
     The control apparatus  100  sets the volume of content sound to a first reference value (step S 100 ) and sets the volume of speech sound to a second reference value (step S 102 ). 
     As used herein, the term “first reference value” according to an embodiment of the present disclosure refers to a value serving as a reference of the volume of content sound. In addition, the term “second reference value” according to an embodiment of the present disclosure refers to a value serving as a reference of the volume of speech sound. That is, the processes performed in steps S 100  and S 102  correspond to processes for setting the initial values of the volumes of content sound and speech sound. 
     In addition,  FIG. 1  illustrates an example in which the process in step S 102  is performed after the process in step S 100  has been performed. However, the process according to the convenience improvement approach is not limited thereto. For example, the control apparatus  100  may perform the process in step S 100  after the process in step S 102  has been performed. Alternatively, the control apparatus  100  may simultaneously perform the processes in steps S 100  and S 102 . 
     When the processes in steps S 100  and S 102  are performed, the control apparatus  100  determines whether the volume control according to the convenience improvement approach according to an embodiment of the present disclosure is performed (step S 104 ). At that time, the control apparatus  100  makes determination in step S 104  on the basis of, for example, the state of a hardware switch that determines on/off of volume control or a software switch that determines on/off of volume control on the basis of an external operation signal transmitted from an external operation device, such as a remote controller. However, the process performed by the control apparatus  100  according to an embodiment of the present disclosure in step S 104  is not limited thereto. 
     For example, the control apparatus  100  may detect a predetermined motion performed by the user and determine whether volume control is performed on the basis of the result of detection. In such a case, for example, the control apparatus  100  performs image processing on a captured image generated by an imaging device (an imaging unit described below) included in the control apparatus  100  or an external imaging device (an imaging apparatus described below) and detects a predetermined motion performed by the user in the captured image (e.g., the shape of the hand indicating on/off of volume control or a periodic motion). Thereafter, for example, the control apparatus  100  determines that volume control is to be performed if an ON operation for volume control is detected. At that time, if an ON operation for volume control is detected, the control apparatus  100  determines that volume control continues until, for example, an OFF operation for volume control is detected. However, the process performed by the control apparatus  100  is not limited thereto. For example, the control apparatus  100  may determine that volume control is performed only when an ON operation for volume control is detected. 
     In addition, the control apparatus  100  can determine whether volume control is performed on the basis of distance information generated by a sound input device (a sound input unit described below) included in the control apparatus  100  or an external sound input device (a sound input apparatus described below). The distance information indicates the distance between the sound input device or the external sound input device and the user. For example, if a distance indicated by the distance information is smaller than or equal to a predetermined threshold value (or smaller than the predetermined threshold value), the control apparatus  100  can determine that volume control is performed. In this case, for example, the control apparatus  100  determines that volume control is performed until the distance indicated by the distance information is larger than a predetermined threshold value (or larger than or equal to the predetermined threshold value). Note that the above-described distance information is generated by a distance sensor included in, for example, a sound input device or an external sound input device. However, the distance sensor is not necessarily included in a sound input device or an external sound input device, but may be an independent device. In such a case, a distance information generating unit (not shown) or a distance measuring unit (not shown) having a body separated from a sound input unit or a sound input unit (described below) generates the distance information. In addition, in this case, the distance information indicates a coarse distance between the sound input device (the sound input unit described below) included in the control apparatus  100  or the external sound input device (the sound input apparatus described below) and the user. 
     If, in step S 104 , it is determined that volume control is not performed, the control apparatus  100  completes the process according to the convenience improvement approach. Note that the process according to the convenience improvement approach shown in  FIG. 1  is not a process that is limited to being performed once, but the process according to the convenience improvement approach shown in  FIG. 1  can be periodically or non-periodically performed again by the control apparatus  100  even after the process has been completed once. 
     However, if, in step S 104 , it is determined that volume control is to be performed, the control apparatus  100  determines whether content data is being reproduced (step S 106 ). For example, if content data stored in a storage unit (described below) is being reproduced or content data transmitted from an external apparatus, such as a communication target apparatus or a server, is being reproduced, the control apparatus  100  determines that content data is being reproduced. At that time, for example, the control apparatus  100  can reproduce streaming content data or download content data transmitted from an external apparatus. 
     If, in step S 106 , it is determined that content data is not being reproduced, the control apparatus  100  repeats the processing from step S 104 . 
     However, if, in step S 106 , it is determined that content data is being reproduced, the control apparatus  100  determines whether speech sound is detected (step S 108 ). At that time, when, for example, the control apparatus  100  includes a sound input device (the sound input unit described below) and if a sound signal generated by the sound input device is detected, or when an external sound signal received from a communication target apparatus is detected, the control apparatus  100  determines that speech sound is detected. However, when, for example, the control apparatus  100  does not include such a sound input device and if a sound signal generated by an external sound input device (the sound input apparatus described below) or an external sound signal received from a communication target apparatus is detected, the control apparatus  100  determines that speech sound is detected. 
     If, in step S 108 , it is determined that speech sound is not detected, the control apparatus  100  repeats the processing from step S 104 . 
     However, if, in step S 108 , it is determined that speech sound is detected, the control apparatus  100  performs volume control on a priority basis (step S 110 ). 
     Example of Volume Control Process on Priority Basis 
       FIG. 2  is a flowchart of an example of a volume control process performed on a priority basis by the control apparatus  100  according to an embodiment of the present disclosure. That is,  FIG. 2  illustrates an example of a process performed in step S 110  shown in  FIG. 1 . 
     The control apparatus  100  determines whether a priority has been assigned to content data being reproduced (step S 200 ). The control apparatus  100  makes determination in step S 200  using the meta data of the content data. 
     (1) Case in which Priority is not Assigned to Content Data 
     If, in step S 200 , it is determined that a priority has not been assigned to the content data being reproduced, the control apparatus  100  determines whether a priority has been assigned to a user corresponding to the speech sound (step S 202 ). At that time, for example, the control apparatus  100  performs the process in step S 202  by identifying the priority assigned to the user corresponding to speech sound in caller-callee communication on the basis of priority information stored in the control apparatus  100  or priority information sent from the communication target apparatus. 
     If, in step S 202 , it is determined that a priority is assigned to the user corresponding to the speech sound, the control apparatus  100  performs the processes performed in steps S 206  and S 208  described below. 
     However, if, in step S 202 , it is determined that a priority is not assigned to the user corresponding to the speech sound, the control apparatus  100  determines that a priority that is higher than that for the content data being reproduced is assigned to the user corresponding to the speech sound (step S 204 ). Here, the process performed in step S 204  is a sort of an exceptional process in a priority basis volume control process. 
     When, in step S 202 , it is determined that a priority is assigned to the user corresponding to the speech sound or when the process in step S 204  is performed, the control apparatus  100  sets the volume of the content sound to a value lower than the second reference value (step S 206 ). In addition, the control apparatus  100  controls the volume of the speech sound (step S 208 ). 
     Note that in  FIG. 2 , the case in which the process in step S 208  is performed after the process in step S 206  has been performed is illustrated. However, the volume control process performed by the control apparatus  100  is not limited thereto. For example, the control apparatus  100  may perform the process in step S 206  after the process in step S 208  has been performed. Alternatively, the control apparatus  100  can simultaneously perform the processes in steps S 206  and S 208 . 
       FIG. 3  illustrates an example of control of the volumes of content sound and speech sound performed by the control apparatus  100  according to an embodiment of the present disclosure. 
     In  FIG. 3 , speech sound corresponding to a sound signal generated by the sound input device (the sound input unit described below) or the external sound input device (the sound input apparatus described below) is referred to as “first speech sound”, and speech sound corresponding to an external sound signal transmitted from a communication target apparatus (i.e., the speech of a communication partner) is referred to as “second speech sound”. Note that hereinafter, the first speech sound and the second speech sound shown in  FIG. 3  are collectively referred to as “speech sound”. In addition, in  FIG. 3 , an example in which the number of the second speech sounds is one, that is, an example in which the control apparatus  100  communicates with only one communication target apparatus is shown. Furthermore, in  FIG. 3 , an example in which the second reference value is lower than the first reference value is shown. However, a relationship between the first reference value and the second reference value according to an embodiment of the present disclosure is not limited thereto. For example, according to the embodiment of the present disclosure, the second reference value may be higher than the first reference value. 
     As indicated by “A” shown in  FIG. 3 , if a first speech sound or a second speech sound is detected, the control apparatus  100  controls the volume of the content sound and the volume of the speech sound. More specifically, for example, the control apparatus  100  sets the volume of the content sound to a value lower than the second reference value. In addition, for example, the control apparatus  100  sets the volume of the speech sound to a third reference value that is higher than the second reference value. As used herein, the term “third reference value” refers to a maximum value of the volume of speech sound set by the control apparatus  100  in the volume control process according to the embodiment of the present disclosure. In addition, for example, the third reference value may be a predetermined value or a value changeable through a user operation. 
     While  FIG. 3  illustrates an example in which the volume of the content sound and the volume of the speech sound are controlled, the volume control process performed by the control apparatus  100  according to the embodiment of the present disclosure is not limited thereto. For example, the control apparatus  100  can selectively control the volume of the content sound and the volume of the speech sound. For example, the control apparatus  100  may set the volume of the content sound to a value lower than the second reference value without controlling the volume of the speech sound. Alternatively, the control apparatus  100  may set the volume of the speech sound to the third reference value without controlling the volume of the content sound (in the case in which the first reference value&lt;the third reference value). That is, the control apparatus  100  can selectively control the volume of the content sound and the volume of the speech sound so that the sound having a higher priority is increased more. 
     As indicated by “B” shown in  FIG. 3 , if the first speech sound and the second speech sound are not detected, the control apparatus  100  determines whether the state in which speech sound is not detected continues for a predetermined period of time (a period of time indicated by “C” shown in  FIG. 3 ). If the control apparatus  100  determines that speech sound has not been detected for the predetermined period of time (the period of time indicated by “C” shown in  FIG. 3 ), the control apparatus  100  sets the volume of the content sound to the first reference value and sets the volume of the speech sound to the second reference value. Thus, the control apparatus  100  controls the volume of the content sound and the volume of the speech sound again. The reason why the control apparatus  100  controls the volume of the content sound and the volume of the speech sound again when the control apparatus  100  determines that the state in which speech sound is not detected continues for the predetermined period of time (the period of time indicated by “C” shown in  FIG. 3 ) is that in the case of caller-callee communication, there is a possibility of, after speech sound disappears, a subsequent speech sound being immediately detected. Thus, by setting a predetermined period of time for detection, frequent changes in the volumes of content sound and speech sound caused by frequent volume control operations can be prevented. 
     In addition, when the control apparatus  100  markedly increases the volume of the content sound and the volume of the speech sound, the control apparatus  100  gradually increases the volumes for a predetermined period of time (e.g., the periods indicated by “D” and “E” shown in  FIG. 3 ) (this operation is called “fade-in”). In addition, when the control apparatus  100  decreases the volume of the content sound and the volume of the speech sound, the control apparatus  100  gradually decreases the volumes for a predetermined period of time (e.g., the periods indicated by “D” and “E” shown in  FIG. 3 ) (this operation is called “fade-out”). At that time, for example, as indicated by “D” shown in  FIG. 3 , a predetermined period of time necessary to control the volume of the content sound can be set so as to be the same as a predetermined period of time necessary to control the volume of the speech sound. Alternatively, for example, as indicated by “E” shown in  FIG. 3 , these predetermined periods of time can be set to different values. 
     For example, the control apparatus  100  controls the volume of the content sound and the volume of the speech sound in a manner shown in  FIG. 3 . Note that in  FIG. 3 , the volume of the first speech sound is controlled in synchronization with the volume of the second speech sound. However, a volume control process of the volume of the speech sound performed by the control apparatus  100  according to an embodiment of the present disclosure is not limited thereto. For example, if a plurality of speech sounds are detected, the control apparatus  100  can control the volume of the speech sound corresponding to a user having a higher priority. 
     Example of Volume Control Process of Speech Sound 
       FIG. 4  is a flowchart of an example of a volume control process of speech sound performed by the control apparatus  100  according to the embodiment of the present disclosure. That is,  FIG. 4  illustrates an example of a process performed in step S 208  shown in  FIG. 2 . 
     As in step S 202  shown in  FIG. 2 , the control apparatus  100  determines whether a priority is assigned to a user corresponding to the speech sound (step S 300 ). 
     If, in step S 300 , it is determined that a priority is not assigned to the user corresponding to the speech sound, the control apparatus  100  sets the volume of the speech sound to the third reference value (step S 302 ). Thereafter, the control apparatus  100  completes the sound control process of speech sound. 
     However, if, in step S 300 , it is determined that a priority is assigned to the user corresponding to the speech sound, the control apparatus  100  determines whether a plurality of speech sounds have been detected (step S 304 ). If, in step S 304 , it is determined that a plurality of speech sounds have not been detected, the control apparatus  100  performs the process in step S 302  and, thereafter, completes the volume control process of speech sound. 
     However, if, in step S 304 , it is determined that a plurality of speech sounds have been detected, the control apparatus  100  sets the volume of the speech sound corresponding to the user having a higher priority assigned thereto to the third reference value (step S 306 ). Thereafter, the control apparatus  100  completes the volume control process of speech sound. 
     At that time, in step S 306 , the control apparatus  100  controls the volumes of the speech sound corresponding to one or more users having higher priorities and does not control the volumes of speech sounds corresponding to other users. However, the process performed in step S 306  according to the embodiment of the present disclosure is not limited thereto. For example, the control apparatus  100  can control the volumes of speech sounds in accordance with the priorities assigned to corresponding users. For example, by using a lookup table including a priority and the volume associated with the priority, the control apparatus  100  sets the volumes in accordance with the priorities assigned to the users. 
     For example, the control apparatus  100  performs the process shown in  FIG. 4 . Thus, even when a plurality of speech sounds are present, the control apparatus  100  can control the volumes of the speech sounds in accordance with the priorities assigned to the corresponding users. It should be noted that the volume control process of speech sound according to an embodiment of the present disclosure is not limited to the process shown in  FIG. 4 . 
     Referring back to  FIG. 2 , an example of a volume control process performed on a priority basis by the control apparatus  100  according to an embodiment of the present disclosure is described next. After the process in step S 208  is completed, the control apparatus  100  determines whether the state in which speech sound has not been detected for a predetermined period of time occurs (step S 210 ). In this case, the predetermined period of time in step S 210  corresponds to, for example, a period indicated by “C” shown in  FIG. 3 . 
     If, in step S 210 , it is determined that the state in which speech sound has not been detected for a predetermined period of time does not occur, the control apparatus  100  repeats the processes from step S 208 . However, if, in step S 210 , it is determined that the state in which speech sound has not been detected for a predetermined period of time occur, the control apparatus  100  completes the volume control process performed on a priority basis. 
     (2) Case in which Priority is Assigned to Content Data 
     An example of the volume control process performed on a priority basis when a priority is assigned to content data is described next. If, in step S 200 , it is determined that a priority is assigned to content data being reproduced, the control apparatus  100  determines whether a priority is assigned to the user corresponding to the speech sound, as in step S 202  (step S 212 ). 
     If, in step S 212 , it is determined that a priority is not assigned to the user corresponding to the speech sound, the control apparatus  100  performs the processes in steps S 216  and S 218  described below. 
     However, if, in step S 212 , it is determined that a priority is assigned to the user corresponding to the speech sound, the control apparatus  100  determines whether the priority assigned to the content data is higher than the priority assigned to the user corresponding to the speech sound (step S 214 ). 
     If, in step S 214 , it is determined that the priority assigned to the content data is higher than the priority assigned to the user corresponding to the speech sound, the control apparatus  100  performs the processes subsequent to step S 206 . 
     However, if, in step S 214 , it is determined that the priority assigned to the content data is not higher than the priority assigned to the user corresponding to the speech sound, the control apparatus  100  does not control the volume of the content sound (step S 216 ). In addition, the control apparatus  100  performs setting so that the volume of the speech sound is lower than the first reference value (step S 218 ). 
     Note that  FIG. 2  illustrates an example in which the control apparatus  100  does not control the volume of the content sound in step S 216 . However, according to the embodiment of the present disclosure, the process performed in step S 216  is not limited thereto. For example, if it is determined that the priority assigned to the content data is not higher than the priority assigned to the user corresponding to the speech sound, the control apparatus  100  may set the volume of the content sound to a value higher than the first reference value. In addition, if the second reference value is lower than the first reference value, the control apparatus  100  sets the volume of the speech sound to a value lower than the second reference value in step S 218 . 
     Note that in  FIG. 2 , the case in which the process in step S 218  is performed after the process in step S 216  has been performed is illustrated. However, the volume control process performed by the control apparatus  100  is not limited thereto. For example, the control apparatus  100  may perform the process in step S 216  after the process in step S 218  has been performed. Alternatively, the control apparatus  100  can simultaneously perform the processes in steps S 216  and S 218 . 
     After the process in step S 218  is completed, the control apparatus  100  determines whether the state in which speech sound has not been detected for a predetermined period of time occurs, as in step S 210  (step S 220 ). 
     If, in step S 220 , it is determined that the state in which speech sound has not been detected for a predetermined period of time does not occur, the control apparatus  100  stops processing until it is determined that the speech sound has not been detected for a predetermined period of time. However, if, in step S 220 , it is determined that the state in which speech sound has not been detected for the predetermined period of time occur, the control apparatus  100  completes the volume control process performed on a priority basis. 
     By performing, for example, the process shown in  FIG. 2 , the control apparatus  100  performs the volume control process on the basis of a priority assigned to the content data and/or a priority assigned to the user corresponding to the speech sound. However, it should be noted that the volume control process performed on a priority basis according to the embodiment of the present disclosure is not limited to the example shown in  FIG. 2 . 
     Referring back to  FIG. 1 , an example of a process for realizing the convenience improvement approach according to the embodiment of the present disclosure is described next. After the process in step S 110  (the volume control process performed on a priority basis) is completed, the control apparatus  100  repeats the processes from step S 100 . 
     The control apparatus  100  selectively control the volume of sound of content data being reproduced and the volume of the speech sound in caller-callee communication by performing, for example, the processes shown in  FIG. 1 . At that time, the control apparatus  100  selectively controls the volume of the content sound and the volume of the speech sound so that the volume of the sound having a higher priority becomes higher by performing, for example, the volume control process on a priority basis shown in  FIG. 2 . Accordingly, the control apparatus  100  can realize the convenience improvement approach according to the embodiment of the present disclosure by performing the process shown in  FIG. 1 . Thus, the convenience of a user can be increased when caller-callee communication is performed with a communication target apparatus. However, it should be noted that the process for realizing the convenience improvement approach according to an embodiment of the present disclosure is not limited to the process shown in  FIG. 1 . 
     2. Control Apparatus According to Embodiment of Present Disclosure 
     An example of the configuration of the control apparatus  100  according to the embodiment of the present disclosure that can perform the process associated with the convenience improvement approach according to the embodiment of the present disclosure is described next. 
     First Embodiment 
       FIG. 5  is a block diagram of an example of the configuration of a control apparatus  100  according to a first embodiment of the present disclosure. 
     In  FIG. 5 , a display system  200  and a communication target apparatus  300  are shown together with the control apparatus  100 . The display system  200  displays an image (a still image or a moving image) on a display screen, generates a captured image obtained by capturing an image in the display direction of the display screen, and inputs and outputs sound in order to realize caller-callee communication using voice. The communication target apparatus  300  is connected to the control apparatus  100  via a network  400 . As used herein, connection using the network  400  means that one of the apparatuses is communicating with another apparatus via the network  400  or the apparatuses are in communicable state with each other. In addition, examples of the network  400  include a wired network, such as a local area network (LAN) or a wide area network (WAN), a wireless network, such as a wireless WAN (WWAN) via a base station, and the Internet using a communication protocol, such as TCP/IP (transmission control protocol/Internet Protocol). Note that communication between the control apparatus  100  and the communication target apparatus  300  is performed not only using the network  400  but, for example, using direct connection. 
     By using the configuration shown in  FIG. 5 , a user who uses the control apparatus  100  and the display system  200  can communicate with a user of the communication target apparatus  300  over, for example, a video call using a captured image and voice. Note that the display system  200  shown in  FIG. 5  may be replaced with a sound input and output system (not shown) that includes, for example, a microphone and a speaker and that inputs and outputs sound in order to realize caller-callee communication using voice. In such a case, a user who uses the control apparatus  100  and the sound input and output system (not shown) communicates with the user of the communication target apparatus  300  through voice call. 
     In addition,  FIG. 5  illustrates an example of the display system  200  including a display apparatus  500  that performs a display operation, an imaging apparatus  600  that performs an image capturing operation, a sound output apparatus  700  that outputs sound, and a sound input apparatus  800  that receives sound. However, the configuration of the display system  200  according to the embodiment of the present disclosure is not limited to the above-described configuration. For example, the display system  200  may be an apparatus into which the display apparatus  500 , the imaging apparatus  600 , and the sound output apparatus  700  are integrated (e.g., a display apparatus having an imaging function and a sound output function). Alternatively, the display system  200  may be a single unit having, for example, a display function, an imaging function, a sound output function, and a sound input function. 
     In this configuration, by generating a captured image obtained by capturing an image in a display direction of the display screen using the display system  200 , an image of a user watching the display screen can be captured. Accordingly, by processing a captured image generated by the display system  200 , the control apparatus  100  can easily perform, for example, a face recognition process in order to identify the priority assigned to the user corresponding to the speech sound. 
     As shown in  FIG. 5 , the control apparatus  100  includes a storage unit  102 , a communication unit  104 , an input unit  106 , and a control unit  108 . 
     The control apparatus  100  can further include, for example, a read only memory (ROM) (not shown), a random access memory (RAM) (not shown), and an operation unit operable by a user (not shown). The control apparatus  100  connects such components with one another via a bus that functions as a data transmission path. 
     The ROM (not shown) stores, for example, a program and control data, such as computation parameters, used by the control unit  108 . The RAM (not shown) temporarily stores a program executed by the control unit  108 , for example. An example of the operation unit (not shown) is a button, a directional key, or a combination thereof. Note that the control apparatus  100  may be connected to an operation input device (e.g., a keyboard and a mouse) serving as an external unit of the control apparatus  100 . 
     Example of Hardware Configuration of Control Apparatus 
       FIG. 6  illustrates an example of the hardware configuration of the control apparatus  100  according to the embodiment of the present disclosure. In  FIG. 6 , an example of part of the hardware configuration of the control apparatus  100  for caller-callee communication using voice is shown. In addition, the communication target apparatus  300  that has a similar configuration (i.e., another control apparatus  100  serving as a communication partner) is shown in  FIG. 6 . That is, the hardware configuration of the control apparatus  100  according to the embodiment of the present disclosure is not limited to that shown in  FIG. 6 . For example, the control apparatus  100  includes a recording medium (not shown) functioning as the storage unit  102  and an input and output interface (not shown) functioning as the input unit  106 . In addition, in  FIG. 6 , an example of the control apparatus  100  that includes a sound output device  700 A (corresponding to a sound output unit described below) serving as the sound output apparatus  700  and formed from a speaker is shown. 
     A recording medium (not shown) is provided as a storage unit of the control apparatus  100 . The recording medium stores, for example, user information, priority information, content data, and an application. Examples of the recording medium include a magnetic recording medium, such as a hard disk, and a nonvolatile memory, such as an electrically erasable and programmable read only memory (EEPROM), a flash memory, a magnetoresistive random access memory (MRAM), a ferroelectric random access memory (FeRAM), or a phase change random access memory (PRAM). In addition, the control apparatus  100  can include a recording medium removable from the control apparatus  100  (not shown). 
     Examples of the input and output interface (not shown) include a sound input terminal, a sound output terminal, a universal serial bus (USB) terminal, a digital visual interface (DVI) terminal, a high-definition multimedia interface (HDMI) terminal, and a variety of processing circuits. 
     As shown in  FIG. 6 , the control apparatus  100  includes, for example, a communication module  150 , an MPU  152 , a content data processing circuit  154 , an analog-to-digital (AD) converter  156 , a sound mixer  158 , and an amplifier  160 . The communication target apparatus  300  includes, for example, a communication module  350 , an MPU  352 , a content data processing circuit  354 , an AD converter  356 , a sound mixer  358 , and an amplifier  360 . Since the components of the communication target apparatus  300  can have configurations that are the same as those of the corresponding components of the control apparatus  100  described below, description of the communication target apparatus  300  is not provided below. 
     The communication module  150  is provided as a communication unit of the control apparatus  100 . The communication unit  150  serves as a communication unit  104  that communicates with an external apparatus, such as the display system  200 , the communication target apparatus  300 , or a server (not shown), via the network  400  (or directly) wired or wirelessly. Examples of a communication interface (not shown) includes a communication antenna and an RF circuit, an IEEE 802.15.1 port and a transmitting and receiving circuit, an IEEE 802.11b port and a transmitting and receiving circuit, and a LAN terminal and a transmitting and receiving circuit. 
     Note that the control apparatus  100  can communicate a sound signal and an image signal with the display system  200  using, for example, the communication module  150  and/or an input and output interface (not shown). Accordingly, in the control apparatus  100  according to the embodiment of the present disclosure, the communication module  150  may function as the communication unit  104  and the input unit  106 . In addition, in  FIG. 6 , the control apparatus  100  includes only one communication module  150 . However, the configuration of the control apparatus  100  according to the embodiment of the present disclosure is not limited thereto. For example, the control apparatus  100  may include a plurality of communication modules, one of the communication modules may function as the communication unit  104 , and the other communication modules may function as the input unit  106 . 
     The MPU  152  is formed from an integrated circuit including a micro processing unit (MPU) and a plurality of circuits for realizing a variety of functions, such as a voice print authentication process, a face recognition process, and image processing. The MPU  152  functions as a control unit  152  that performs overall control of the control apparatus  100 . In addition, in the control apparatus  100 , the MPU  152  serves as, for example, a reproduction processing unit  110 , a detection unit  112 , a determination unit  114 , a volume control unit  116 , and a display control unit  118 . Note that while, in  FIG. 5 , the control apparatus  100  includes the content data processing circuit  154  and the sound mixer  158  separately from the MPU  152 , the configuration of the control apparatus  100  is not limited to such a configuration. For example, in the control apparatus  100  according to the embodiment of the present disclosure, the MPU  152  may have the function of the content data processing circuit  154  and the function of the sound mixer  158 . 
     For example, the MPU  152  executes a sound identifying program using voice print recognition and processes sound data  1  transmitted from the AD converter  156 . Thus, the MPU  152  identifies a user corresponding to the speech sound included in the sound data  1  (a user A in the example shown in  FIG. 6 ). Thereafter, the MPU  152  transmits user information regarding the identified user to the communication target apparatus  300  via the communication module  150  (refer to a signal line L 1 ) 
     In addition, for example, the MPU  152  executes a mixer control program that performs the volume control process on a priority basis. Thus, the MPU  152  controls the sound mixer  158  using the transmitted user information, user information transmitted from the communication target apparatus  300  via the communication module  150  (refer to a signal line L 2 ), and the priority of the content data being reproduced. 
     The content data processing circuit  154  performs a process regarding reproduction of content data. An example of the content data processing circuit  154  is an integrated circuit into which a variety of circuits, such as an encoder and a decoder, are integrated. The content data processing circuit  154  reproduces sound data  3  representing content sound and transmits the sound data  3  to the sound mixer  158 . 
     The AD converter  156  converts the sound signal  1  received from a sound input apparatus  800 A into the sound data  1 . The sound data  1  can include, for example, the speech sound of the user A and/or sound output from the sound output device  700 A. Thereafter, the AD converter  156  transmits the sound data  1  to the communication module  150  (refer to a signal line L 3 ). Thus, the sound data  1  is transmitted to the communication target apparatus  300 . In addition, the AD converter  156  transmits the sound data  1  to the MPU  152  and the sound mixer  158 . 
     Under the control of the MPU  152 , the sound mixer  158  controls the volumes of the sound data  1 , the sound data  2  that includes speech sound and transmitted from the communication target apparatus  300  via the communication module  150  (refer to a signal line L 4 ), and the sound data  3  representing the content sound. 
     The sound data controlled by the sound mixer  158  is converted into a sound signal and is amplified by the amplifier  160 . Thereafter, the sound signal is transmitted to the sound output device  700 A. Accordingly, the content sound and speech sound having the volumes controlled through the volume control process on a priority basis are output from the sound output device  700 A. 
     The control apparatus  100  has, for example, the configuration shown in  FIG. 6  and realizes the process according to the convenience improvement approach. However, it should be noted that the configuration of the control apparatus  100  according to an embodiment of the present disclosure is not limited to the configuration shown in  FIG. 6 . 
     Referring back to  FIG. 5 , an example of the configuration of the control apparatus  100  according to the first embodiment of the present disclosure is described. The storage unit  102  is provided as a storage unit of the control apparatus  100 . Examples of the storage unit  102  include a magnetic recording medium, such as a hard disk, and a nonvolatile memory, such as a flash memory. 
     The storage unit  102  stores, for example, user information, priority information, content data, and an application. In  FIG. 5 , as examples, user information  130 , priority information  132 , and content data  134  are stored in the storage unit  102 . 
     The communication unit  104  is provided as a communication unit of the control apparatus  100 . The communication unit  104  communicates with an external apparatus, such as the display system  200 , the communication target apparatus  300 , or a server (not shown), via the network  400  (or directly) wired or wirelessly. The control apparatus  100  communicates at least one communication target apparatus using the communication unit  104  and can perform caller-callee communication (caller-callee communication using voice or both a captured image and voice). In addition, the communication unit  104  performs communication under the control of the control unit  108 . 
     Examples of the communication unit  104  include a communication antenna and an RF circuit, and a LAN terminal and a transmitting and receiving circuit. However, the communication unit  104  is not limited thereto. For example, the communication unit  104  can have any configuration that is communicable with an external apparatus via the network  400 . 
     For example, the input unit  106  receives a captured image generated by the imaging apparatus  600  that captures an image and a sound signal generated by the sound input apparatus  800 . Thereafter, the input unit  106  transmits the received (input) captured image and sound signal to the control unit  108 . Examples of the input unit  106  include a sound input terminal, a sound output terminal, a USB terminal, a DVI terminal, an HDMI terminal, and a variety of processing circuits. However, the input unit  106  is not limited thereto. For example, the input unit  106  can have any configuration that can receive a captured image and a sound signal from an external apparatus wired or wirelessly. 
     In addition, upon receiving distance data generated by the sound input apparatus  800 , the input unit  106  transmits the distance data to the control unit  108 . 
     The control unit  108  is formed from an integrated circuit into which a variety of processing circuits, such as an MPU, a content data processing circuit, and a sound mixer, are integrated. The control unit  108  performs overall control of the control apparatus  100 . Furthermore, the control unit  108  includes a reproduction processing unit  110 , a detection unit  112 , a determination unit  114 , a volume control unit  116 , and a display control unit  118 . Thus, the control unit  108  plays a major role in the process according to the convenience improvement approach according to the embodiment of the present disclosure. 
     The reproduction processing unit  110  reproduces content data stored in the storage unit  102  or content data transmitted from an external apparatus, such as the communication target apparatus  300  or a server (not shown), and received by the communication unit  104 . 
     The detection unit  112  detects speech sound of a user in caller-callee communication on the basis of the sound signal transmitted from the input unit  106  and the external sound signal received by the communication unit  104 . 
     The determination unit  114  determines whether volume control is performed. More specifically, the determination unit  114  performs the process in step S 104  shown in  FIG. 1  on the basis of, for example, the state of a hardware switch or a software switch that determines on/off of volume control, a captured image, and distance information. 
     Note that in  FIG. 5 , the control apparatus  100  includes the determination unit  114 . However, according to the embodiment of the present disclosure, the configuration of the control apparatus  100  is not limited thereto. For example, the control apparatus  100  can have a configuration that does not include the determination unit  114 . In such a case, the control apparatus  100  performs the process according to the convenience improvement approach according to the embodiment of the present disclosure when it is determined that volume control is to be performed in step S 104  shown in  FIG. 1 . 
     The volume control unit  116  plays a major role in the volume control process performed on a priority basis. More specifically, the volume control unit  116  performs, for example, a process shown in  FIG. 2  on the basis of priorities assigned to the content data being reproduced by the reproduction processing unit and a user corresponding to the speech sound detected by the detection unit. Thereafter, the volume control unit  116  transmits a sound signal corresponding to a sound having a controlled volume to the sound output apparatus  700  via the communication unit  104 . Subsequently, the sound output apparatus  700  outputs the sound having the controlled volume. 
     In addition, when the volume control unit  116  controls the volume of content sound or the volume of the speech sound, the volume control unit  116  gradually increases or decreases the volume so that fade-in or fade-out is accomplished. 
     Furthermore, if the determination unit  114  determines that volume control is to be performed, the volume control unit  116  selectively controls the volume of the content sound and the volume of the speech sound. Since the volume control unit  116  controls the volume in accordance with the result of determination made by the determination unit  114 , the control apparatus  100  can selectively enable or disable volume control on the basis of the state of a hardware switch or a software switch, a predetermined motion performed by a user, or a distance between the user and the sound input apparatus  800 . 
     The display control unit  118  controls displaying of an image on a display screen. More specifically, if, for example, the reproduction processing unit  110  reproduces content data regarding the content including an image, the display control unit  118  causes the display apparatus  500  or a display unit (described below) included in the display control unit  118  to display the image. In addition, for example, when the control apparatus  100  performs caller-callee communication with the communication target apparatus  300  using a captured image and voice, the display control unit  118  displays the image represented by content data reproduced by the reproduction processing unit  110  and a captured image received from the communication target apparatus  300  by the communication unit  104  in a display screen at the same time. Alternatively, for example, when the control apparatus  100  performs caller-callee communication with the communication target apparatus  300  using a captured image and voice, the display control unit  118  may display a captured image received by the input unit  106  in the display screen in addition to the image represented by the content data. That is, the display control unit  118  displays a captured image used for caller-callee communication in the display screen together with, for example, an image represented by the content data. 
     In addition, when an image represented by content data and a captured image are displayed in a display screen at the same time, the display control unit  118 , for example, changes a display ratio of the image represented by content data to the captured image used for caller-callee communication in conjunction with selective volume control of the volume of the content sound and the volume of the speech sound performed by the volume control unit  116 . 
     According to the first embodiment of the present disclosure, the control apparatus  100  can realize the process according to the convenience improvement approach through the configuration shown in  FIG. 5 . Accordingly, by employing, for example, the configuration shown in  FIG. 5 , the control apparatus  100  can improve user convenience when caller-callee communication is performed with at least one communication target apparatuses. However, it should be noted that the configuration of the control apparatus  100  according to the first embodiment of the present disclosure is not limited thereto. 
     Second Embodiment 
       FIG. 7  is a block diagram of an example of the configuration of a control apparatus  100  according to a second embodiment of the present disclosure. As in  FIG. 5 , in  FIG. 7 , a communication target apparatus  300  connected via the network  400  is also shown. 
     As shown in  FIG. 7 , according to the second embodiment of the present disclosure, the control apparatus  100  has a configuration that is basically similar to that of the control apparatus  100  according to the first embodiment shown in  FIG. 5 . However, unlike the control apparatus  100  according to the first embodiment shown in  FIG. 5 , the control apparatus  100  according to the second embodiment does not include the input unit  106  and further includes a sound input unit  120 , an imaging unit  122 , a display unit  124 , and a sound output unit  126 . 
     The sound input unit  120  is provided as a sound signal generating unit of the control apparatus  100 . An example of the sound input unit  120  is a microphone. Note that the sound input unit  120  may be removable from the control apparatus  100 . 
     In addition, the sound input unit  120  can include a distance sensor that measures the distance between the sound input unit  120  and a user. Thus, the sound input unit  120  can generate distance information. However, the configuration of the control apparatus  100  is not limited to the configuration in which the sound input unit  120  includes a distance sensor. For example, the sound input unit  120  may have a distance sensor functioning as a distance information generating unit (not shown) separately from the body of the sound input unit  120 . 
     The imaging unit  122  is provided as an imaging unit of the control apparatus  100 . The imaging unit  122  captures an image in the display direction of the display screen of the display unit  124  and generates a captured image. Note that if the control apparatus  100  according to the second embodiment of the present disclosure does not have a function of performing caller-callee communication using a captured image and voice, the control apparatus  100  may have a configuration that does not include the imaging unit  122 . 
     An example of the imaging unit  122  is an imaging device including, for example, a pair including a lens and an image sensor and a signal processing apparatus. In the imaging device, an optical lens and an image sensor including a plurality of imaging elements, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) are included. The signal processing circuit includes, for example, an automatic gain control (AGC) circuit and an AD converter. The signal processing circuit converts an analog signal generated by the image sensor into a digital signal (image data) and performs a variety of signal processes. Example of the signal processes performed by the signal processing circuit include, for example, a white balance correction process, an interpolation process, a color tone correction process, a gamma correction process, an YCbCr conversion process, an edge enhancement process, and a coding process. 
     The display unit  124  is provided as a display unit of the control apparatus  100 . The display unit  124  displays various types of information and images. Examples of screens displayed on the display unit  124  include a content display screen displaying an image represented by content data, a screen displaying a captured image used for caller-callee communication, and an operation screen user for instructing the control apparatus  100  to perform a desired operation. Note that in the above-described screen in which a captured image used for caller-callee communication is displayed, the captured image and an image represented by content may be displayed in parallel or in an overlaid manner. 
     Examples of the display unit  124  include a liquid crystal display (LCD), an organic electroluminescence display, and an organic light emitting diode (OLED) display. 
     The sound output unit  126  is provided as a sound output unit of the control apparatus  100 . The sound output unit  126  outputs a variety of sounds, such as content sound, speech sound for caller-callee communication, and system sounds of the control apparatus  100 . 
     An example of the sound output unit  126  is a sound output device including a digital signal processor (DSP), an amplifier, and a speaker. 
     According to the second embodiment, the control apparatus  100  has a configuration basically similar to that of the control apparatus  100  according to the first embodiment shown in  FIG. 5 . Thus, like the control apparatus  100  according to the first embodiment, by employing the configuration shown in  FIG. 7 , the control apparatus  100  according to the second embodiment can realize the process according to the convenience improvement approach. Therefore, by employing, for example, the configuration shown in  FIG. 7 , the control apparatus  100  can improve the convenience of a user when caller-callee communication is performed with at least one communication target apparatuses. However, it should be noted that the configuration of the control apparatus  100  according to the second embodiment is not limited to the configuration shown in  FIG. 7 . For example, like the control apparatus  100  according to the first embodiment shown in  FIG. 5 , the control apparatus  100  according to the second embodiment may include the input unit  106 . 
     As described above, the control apparatus  100  according to an embodiment of the present disclosure selectively control the volume of the content sound and the volume of the speech sound on the basis of a priority assigned to the content data being reproduced and/or a priority assigned to the user corresponding to the detected speech sound. Thus, by dynamically controlling the volumes in accordance with the set priorities, the control apparatus  100  can increase the volume of the content sound to a volume louder than the volume of the speech sound. Alternatively, the control apparatus  100  can increase the volume of the speech sound to a volume louder than the volume of the content sound. 
     In this way, the control apparatus  100  can control the volumes while reducing the probability of the occurrence of the above-described undesirable situation and, therefore, the control apparatus  100  can increase user convenience in caller-callee communication with a communication target apparatus. 
     While the embodiments of the present disclosure have been described with reference to the control apparatus  100 , an embodiment of the present disclosure is not limited thereto. For example, the embodiment of the present disclosure is applicable to a variety of apparatuses, such a computer (e.g., a PC or a server), a display apparatus (e.g., a television receiver or a signage apparatus), a portable communication apparatus (e.g., a cell phone), a video/music playback apparatus (or a video/music recording and reproduction apparatus), a game console, and a set-top box. 
     While the embodiment of the present disclosure has been described with reference to the display system  200 , an embodiment of the present disclosure is not limited thereto. For example, the embodiment of the present disclosure is applicable to a variety of apparatuses, such as a computer (e.g., a PC), a display apparatus (e.g., a television receiver or a signage apparatus), and a portable communication apparatus (e.g., a cell phone). Note that the display system  200  according to the embodiment of the present disclosure may be a combination of an apparatus for displaying an image, an apparatus for capturing an image, an apparatus for generating a sound signal, and an apparatus for outputting sound. 
     3. Program According to Embodiment of Present Disclosure 
     By using a program that causes a computer to function as the control apparatus according to the embodiment of the present disclosure (e.g., a program that realizes the process according to the convenience improvement approach according to the embodiment of the present disclosure shown in  FIGS. 1, 2, and 4 ), the convenience of a user can be increased when caller-callee communication is performed with a communication target apparatus. 
     Although an exemplary embodiment of the present disclosure has been described with reference to the accompanying drawings, it should be appreciated that the present disclosure is not limited to such an exemplary embodiment. It is evident that many alternatives, modifications and variations will be apparent to those skilled in the art within the spirit and broad scope of the appended claims. That is, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and technical scope of the disclosure. 
     For example, the control apparatus  100  according to an embodiment of the present disclosure can separately include the reproduction processing unit  110 , the detection unit  112 , the determination unit  114 , the volume control unit  116 , and the display control unit  118  shown in  FIGS. 5 and 7  (e.g., the control apparatus  100  can be formed from independent processing circuits). 
     In addition, while the above description has been made with reference to a provided program (a computer-readable program) that causes a computer to function as the control apparatus according to an embodiment of the present disclosure, an embodiment of the present disclosure can also provide a recording medium, such as a non-transitory recording medium, having the above-described program recorded thereon. 
     The above-described configuration is only an example of the embodiment of the present disclosure and, therefore, is embraced within the technical scope of the present disclosure.