Video apparatus and method for controlling the same

This application claims the benefit of Korean Patent Application No. 10-2004-0057673, filed on July 23, 2004, which is hereby incorporated by reference as if fully set forth herein.

<u style="single">BACKGROUND OF THE INVENTION</u>

<u style="single">Field of the Invention</u>

The present invention relates to a video apparatus, and more particularly, to a video apparatus and a method for controlling the same, wherein a video signal and an audio signal are synchronized.

<u style="single">Discussion of the Related Art</u>

FIG. 1 is a block diagram showing the configuration of a conventional video apparatus, and FIG. 2 is a flow chart illustrating a video/audio processing method of the conventional video apparatus. A tuner 1 tunes a broadcast signal of a channel desired by the user (S11). The tuned broadcast signal is separated into a video signal, an audio signal, and supplementary information (S12). A video/audio processor 2 receives the separated video and audio signals and transforms the received video signal into video data that can be displayed through a display unit 3 and the received audio signal into audio data that can be outputted through a speaker 5, respectively (S13). A controller 7 stores the supplementary information in a memory 6 and outputs control signals to control the respective components of the video apparatus.

In this video apparatus, it is necessary to synchronize a video signal and audio signal inputted to the video apparatus with each other to remove a time difference between the video signal and the audio signal in the process of outputting the video signal and audio signal through the corresponding signal processings. The time difference between the video signal and the audio signal results from the fact that the processing of the video signal is more complicated than that of the audio signal and is performed for a longer period of time than that of the audio signal.

For an analog television (TV) which is a representative example of the video apparatus, the volume of the video signal is not larger than that of a digital TV and the delay thereof is thus not so severe as to disturb the viewer' s TV watching. However, for the digital TV, a large amount of video data must be processed, and the video data is subjected to very complex signal processings, such as decoding, deinterlacing, scaling, etc., after being received over a specific channel. As a result, the delay of the video signal is considerably severe.

In particular, for digital broadcasting of a satellite broadcasting type, a TV must receive a digital broadcast signal through a satellite antenna and set-top box (STB). At this time, the video signal delay of the STB itself is added to the internal video signal delay of the TV, resulting in a larger time difference between picture and sound. In this case, it is very inconvenient for the viewer to watch the TV.

<u style="single">SUMMARY OF THE INVENTION</u>

Accordingly, the present invention is directed to a video apparatus and a method for controlling the same that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a video apparatus and a method for controlling the same, wherein a video signal and an audio signal are synchronized.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a video apparatus comprises a video/audio processor for transforming a received video signal into a signal that can be displayed and a received audio signal into a signal that can be outputted, respectively; a controller for detecting an internal delay time and/or external delay time associated with the video signal and determining a delay time of the audio signal on the basis of the detected internal delay time and/or external delay time; and a delay for delaying the audio signal according to the delay time determined by the controller.

In another aspect of the present invention, a method for controlling a video apparatus comprises the steps of receiving a video signal and an audio signal; detecting an internal delay time and/or external delay time associated with the video signal; and delaying the audio signal on the basis of the detected internal delay time and/or external delay time to synchronize the video signal and the audio signal with each other.

Preferably, the step of detecting the internal delay time includes the step of reading the internal delay time from a memory.

Alternatively, the step of detecting the internal delay time may include the step of detecting the internal delay time on the basis of a time difference between a test signal sent to each internal device of the video apparatus and a signal fed back in response to the test signal.

Preferably, the step of detecting the external delay time includes the steps of receiving information regarding an external device which provides the video signal and audio signal to the video apparatus; and reading the external delay time from a memory on the basis of the received external device information.

Alternatively, the step of detecting the external delay time may include the steps of identifying a video source which provides the video signal and audio signal to the video apparatus; and reading an external delay time corresponding to the video source from a memory.

Preferably, the control method further comprises the step of determining, on the basis of the detected internal delay time and external delay time, whether the received video signal is delayed internal or external to the video apparatus.

<u style="single">BRIEF DESCRIPTION OF THE DRAWINGS</u>

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a block diagram showing the configuration of a conventional video apparatus;

FIG. 2 is a flow chart illustrating a method for controlling the conventional video apparatus;

FIG. 3 is a block diagram showing the configuration of a video apparatus according to the present invention;

FIG. 4 is a flow chart illustrating a first embodiment of a method for controlling the video apparatus according to the present invention; and

FIG. 5 is a flow chart illustrating a second embodiment of the method for controlling the video apparatus according to the present invention.

<u style="single">DETAILED DESCRIPTION OF THE INVENTION</u>

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

FIG. 3 is a block diagram showing the configuration of a video apparatus according to the present invention. As shown in this drawing, the video apparatus according to the present invention comprises a tuner 11 for receiving a broadcast signal of a selected channel, a demultiplexer (not shown) for separating the received broadcast signal into a video signal, an audio signal and supplementary information, and a video/audio processor 12 for processing the video signal and audio signal sent from the demultiplexer or a video signal and audio signal sent from an external device so that they can be outputted through a display unit 13 and speaker 15, respectively. The video apparatus further comprises a delay 14 for delaying the audio signal outputted from the video/audio processor 12 by a predetermined time and outputting the delayed audio signal to the speaker 15, a memory 16 for storing various operating programs, temporary information for the operation of the video apparatus, and internal delay time information of the video apparatus, and a controller 17 for determining a delay time of the delay 14 according to the internal delay time information and external delay time information inputted from an external device.

The video/audio processor 12 includes a decoder, deinterlacer, scaler IC, etc. to process the video signal.

The internal delay time information stored in the memory 16 includes respective video processing times of video processing associated devices of the video apparatus, and the total of the video processing times. The internal delay time information can be stored by a manufacturer in a manufacturing process of the video apparatus, because the video processing time of the video apparatus can be obtained through testing. The internal delay time information may include data processing times of the internal devices of the video apparatus detected by the controller 17.

The delay 14 includes a device for adjusting the delay time under control of the user or the controller 17. For example, the delay 14 includes at least one of a flip-flop, latch and shift register.

The controller 17 receives the external delay time information from the external device, for example, an STB for satellite broadcasting reception, through a spare terminal, usually not used, or a separate additional terminal. Since the STB is also a video processing device, the video processing time of the STB itself can be obtained in a similar manner to the above. The STB sends the delay time information thereof to the video apparatus connected therewith automatically or in response to the video apparatus' s request in consideration of compatibility with the video apparatus. That is, an STB operating program is implemented in the STB such that the STB sends the delay time information simultaneously with the video and audio signals when sending the video and audio signals to the video apparatus. Further, the STB sends the delay time information to the video apparatus according to a standard communication protocol (for example, Bluetooth, RS-232C, IIC, IEEE1394, USB, or the like) supportable by the video apparatus.

Preferred embodiments of a method for controlling the video apparatus according to the present invention will hereinafter be described.

FIRST EMBODIMENT

FIG. 4 is a flow chart illustrating a first embodiment of the method for controlling the video apparatus according to the present invention. First, the controller 17 determines whether the current mode of the video apparatus is an external input mode where the video apparatus receives a signal from an external device (for example, an STB) (S21).

If the current mode is determined not to be the external input mode at step S21, namely, if the video apparatus is receiving general broadcasting, the controller 17 reads internal delay time information stored in the memory 16 and determines the delay time of the delay 14 on the basis of the read internal delay time information. Thus, an audio signal from the delay 14 is synchronized with a video signal (S22). Since image reconstruction is carried out on a frame-by-frame basis due to the characteristics of the display unit 13, such as a plasma display panel (PDP) or liquid crystal display (LCD), the delay time of the delay 14 is set as a time corresponding to a frame unit, too. When the frame unit includes, for example, six frames, the delay time of the delay 14 is 0.12sec because one frame corresponds to 1/50sec (0.02sec).

If the current mode is determined to be the external input mode at step S21, namely, if the video apparatus is receiving video and audio signals from the STB, the controller 17 determines whether external delay time information from the STB has been inputted (S23). If the external delay time information from the STB has been inputted, the controller 17 sums up an internal delay time stored in the memory 16 and an external delay time inputted from the STB and adjusts the delay time of the delay 14 to the summed-up delay time (S24).

On the other hand, in the case where no external delay time information from the STB is determined to have been inputted at step S23, the controller 17 adjusts the delay time of the delay 14 to the internal delay time stored in the memory 6. As a result, an audio signal from the video/audio processor 12 is delayed by the internal delay time and then outputted (S22). Where no external delay time information from the STB is inputted, a constituent element capable of providing the delay time information may not exist in the STB, or a video processing delay may not be present in the STB itself or may be so negligible as not to adversely affect the TV watching.

As an alternative, in the video apparatus according to the present invention, the user may manually adjust the delay time of the audio signal through the use of a separate key for the audio delay additionally provided in a remote controller or an existing key of the remote controller, or by using a menu for the audio delay provided in a user menu.

For example, for the remote controller, the audio signal is delayed by a predetermined reference time whenever the user pushes an AUDIO DELAY' key. In the case of the user menu, the user can solve a misalignment between the video signal and the audio signal by delaying the audio signal by a desired time through an 'AUDIO TIMING ADJUST' menu. In this case, if the user issues an audio delay command through the AUDIO TIMING ADJUST menu, the controller 17 controls the delay 14 such that the audio output is delayed by the corresponding unit time. Therefore, the synchronization between the video signal and the audio signal can be made only with the addition of a user menu and an associated program, without a need for separate hardware.

According to the first embodiment, the control method can simultaneously compensate for the video signal processing delay of the external device, which is an essential constituent element to the digital broadcasting reception, as well as the video signal processing delay of the video apparatus itself. In this control method, the video signal processing delay compensation by the user is also possible. Therefore, it is possible to perfectly solve a misalignment between picture and sound being finally outputted.

SECOND EMBODIMENT

FIG. 5 is a flow chart illustrating a second embodiment of the method for controlling the video apparatus according to the present invention. The video apparatus can receive a general broadcast signal or a video signal and audio signal from an external device such as an STB, a cable receiver, digital versatile disc (DVD) player, a video cassette recorder (VCR), a personal computer (PC) or the like. The controller 17 determines whether the received video signal is delayed internal or external to the video apparatus and then delays the audio signal according to a result of the determination. The controller 17 can sequentially or simultaneously determine whether the video signal is delayed internal to the video apparatus and whether the video signal is delayed external to the video apparatus. In the second embodiment, an example is disclosed in which the controller 17 sequentially determines whether the video signal is internally delayed and whether the video signal is externally delayed.

First, if the video apparatus receives a video signal and an audio signal (S31), the controller 17 detects internal delay information of the video signal (S32). The internal delay information includes respective video processing times of video processing associated devices of the video apparatus, and the total of the video processing times.

In order to detect the internal delay information, the controller 17 can retrieve the internal delay information from the memory 16 or detect the internal delay information in real time. In order to detect the internal delay information in real time, the controller 17 detects data processing times of the internal devices of the video apparatus. That is, the controller 17 can detect the data processing time of each internal device on the basis of a time difference between a test clock sent to each device and a signal fed back in response to the test clock. Because the data processing time of the video apparatus is different depending on the volume of received data, it is effective to utilize the data processing time of each device detected in real time as the internal delay information.

After detecting the internal delay information, the controller 17 determines, on the basis of the detected internal delay information, whether the received video signal is delayed internal to the video apparatus (S33). Upon determining that the received video signal is delayed internal to the video apparatus, the controller 17 determines a delay time of the video signal from the internal delay information and then delays the audio signal inputted to the delay 14 by the delay time to synchronize the video signal and the audio signal with each other (S34). As a result, a time difference between the video signal to be displayed through the display unit 13 and the audio signal to be outputted through the speaker 15 is removed, so that the synchronized video signal and audio signal are displayed and outputted, respectively (S35) .

If the received video signal is determined not to be delayed internal to the video apparatus (S33), the controller 17 receives information regarding a video source (e.g., air, a cable, a satellite, or a recording medium) and/or the external device. The external device information includes at least one of a manufacturer name, model name and identification (ID) of the external device. The controller 17 then detects external delay information of the video signal (S36). In order to detect the external delay information of the video signal, the controller 17 can detect external delay information stored in the memory 16 corresponding to the video source information and/or the external device information, or read external delay information from the external device in real time. The external delay information stored in the memory 16 includes a delay time based on the manufacturer and model of the external device.

After detecting the external delay information, the controller 17 determines, on the basis of the detected external delay information, whether the received video signal is delayed external to the video apparatus (S37). If it is determined that the received video signal is delayed external to the video apparatus, the controller 17 determines the delay time of the video signal from the external delay information and then delays the audio signal inputted to the delay 14 by the delay time to synchronize the video signal and the audio signal with each other (S38) . Accordingly, a time difference between the video signal to be displayed through the display unit 13 and the audio signal to be outputted through the speaker 15 is removed, so that the synchronized video signal and audio signal are displayed and outputted, respectively (S35).

In addition, in the case where the received video signal is delayed internal and external to the video apparatus, the controller 17 delays the audio signal on the basis of the internal delay information and the external delay information to synchronize the video signal and the audio signal with each other.

As apparent from the above description, the video apparatus of the present invention can detect and remove a time difference between a video signal and an audio signal caused internal and external thereto. It is therefore possible to provide synchronized picture and sound to the user.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.