Patent Publication Number: US-2011058790-A1

Title: System and method for recording and playing audio/video

Description:
BACKGROUND 
     1. Technical Field 
     Embodiments of the present disclosure relate to multimedia technology, and particularly to a system and method for recording and playing audio/video (AV). 
     2. Description of Related Art 
     Display devices, such as monitors and projectors, have been widely used to display image files such as slide show presentations from computers. In some cases, it is desirable to record such presentations together with audio captured by a microphone during the presentations. Current AV recording systems are not universal and may only work with certain applications in a computer, which is inconvenient and may necessitate having many different methods and/or devices to cover all recording needs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of one embodiment of an application environment of a system for recording and playing audio/video (AV). 
         FIG. 2  is a schematic diagram of one embodiment of the system in  FIG. 1 . 
         FIG. 3  is a flowchart of one embodiment of a method for recording and playing AV implementing a system, such as that of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of one embodiment of an application environment of a system  10  for recording and playing audio/video (AV). The system  10  may be connected to a computer  11 , a display device  12 , a microphone  13 , a camera  14 , and a speaker  15 . The system  10  is operable to record video signals from the computer  11  and/or captured images from the camera  14 , while at the same time recording audio captured by the microphone  13  to combine into one AV file. The system  10  is further operable to play video on the display device  12  and play audio over the speaker  15 . The display device  12  may be a monitor or a projector. In one embodiment, the system  10  may be further connected to a network  16 . The system  10  may transmit the recorded AV to at least one network terminal device  17  (only one shown in  FIG. 1 ) via the network  16 , and receive AV from the network terminal device  17  to play. The network  16  may be an intranet (e.g., a network within a company) or an extranet (e.g., the Internet). 
       FIG. 2  is a schematic diagram of one embodiment of the system  10  in  FIG. 1 . The system  10  may include a video splitter  200 , a video switch  202 , a video converter  204 , a video decoder  206 , an AV compressor  208 , an audio decoder  210 , a processor  212 , a storage device  214 , an AV de-compressor  216 , an audio encoder  218 , and a video encoder  220 . 
     The video splitter  200  duplicates an input of an original video signal received from the computer  11  into two outputs, consisting of a first original video signal and a second original video signal. In one embodiment, the original video signal may be a video graphics array (VGA) signal. The video splitter  200  outputs the first original video signal to the video converter  204 , and outputs the second original video signal to the video switch  202 . 
     The video converter  204  converts the first original video signal into an analog video signal. In one embodiment, the video converter  204  converts the first original video signal into a composite video signal. 
     The video decoder  206  decodes the analog video signal into a digital video signal, and outputs the digital video signal to the AV compressor  208 . In one embodiment, the video decoder  206  converts the analog video signal into an 8-bit digital video signal. 
     The audio decoder  210  receives an analog audio signal captured by the microphone  13  and decodes the analog audio signal into a digital audio signal. The audio decoder  210  outputs the digital audio signal to the AV compressor  208 . 
     The AV compressor  208  compresses the digital audio signal and the digital video signal to obtain a compressed AV file, and outputs the compressed AV file to the processor  212 . In one embodiment, the AV compressor  208  may apply a moving pictures experts group (MPEG) compression algorithm, such as MPEG-1, MPEG-2, or MPEG-4, to compress the digital audio signal and the digital video signal. The AV compressor  208  may further compress video data captured by the camera  14 . 
     In AV recording process, the processor  212  stores the compressed AV file into the storage device  214 . In one embodiment, the processor  212  may transfer the compressed AV file to the network terminal device  17  via the network  16 . As such, the compressed AV file can be displayed on the network terminal device  17 . 
     In AV playing process, the processor  212  retrieves a compressed AV file from the storage device  214 , and transfers the retrieved compressed AV file to the AV de-compressor  216 . In one embodiment, the processor  212  may receive a compressed AV file from the network terminal device  17  via the network  16 , and transfer the received compressed AV file to the AV de-compressor  216 . 
     The AV de-compressor  216  decompresses the retrieved/received compressed video file to obtain a digital audio signal and a digital video signal. The AV de-compressor  216  outputs the digital audio signal to the audio encoder  218 , and outputs the digital video signal to the video encoder  220 . 
     The audio encoder  218  encodes the digital audio signal into an analog audio signal, and outputs the analog audio signal to the speaker  15  to play. 
     The video encoder  220  encodes the digital video signal into an original video signal, and outputs the original video signal to the video switch  202 . 
     The video switch  202  selectively connects the video splitter  220  to the display device  12  or connects the video encoder  220  to the display device  12 . If the video switch  202  connects the video splitter  220  to the display device  12 , the second original video signal can be displayed on the display device  12 . If the video switch  202  connects the video encoder  220  to the display device  12 , the original video signal can be displayed on the display device  12 . In one embodiment, the video switch  202  may be a logic switch. 
       FIG. 3  is a flowchart of one embodiment of a method for recording and playing AV implementing a system, such as that of  FIG. 2 . Blocks S 301 - 307  illustrate one embodiment of an AV recording process. Blocks S 308 - 311  illustrates one embodiment of an AV playing process. Depending on the embodiments, additional blocks may be added, others removed, and the ordering of the blocks may be changed. 
     In block S 301 , the video splitter  200  duplicates an original video signal received from the computer  11  into a first original video signal and a second original video signal. The first original video signal is output to the video converter  204 . The second original video signal is output to the video switch  202 . In one embodiment, the original video signal may be a video graphics array (VGA) signal. Depending on the embodiment, the original video signal may be other types of video signals, such as a digital visual interface (DVI) signal or a hi-definition multimedia interface (HDMI) signal. 
     In block S 302 , the video switch  202  connects the video splitter  200  to the display device  12 , so that the second original video signal can be displayed on the display device  12 . 
     In block S 303 , the video converter  204  converts the first original video signal into an analog video signal. In one embodiment, the video converter  204  converts the first original video signal, such as a VGA signal, into a composite video signal. In another embodiment, the video converter  204  may convert the first original video signal into a separate video (S-Video) signal. 
     In block S 304 , the video decoder  206  decodes the analog video signal into a digital video signal, and outputs the digital video signal to the AV compressor  208 . In one embodiment, the video decoder  206  converts the analog video signal into an 8-bit digital video signal. Depending on the embodiment, the video decoder  206  may convert the analog video signal into digital signals in different formats, such as a 10-bit digital video signal, a 16-bit digital video signal, or a 20-bit digital video signal. 
     In block S 305 , the audio decoder  210  receives an analog audio signal captured by the microphone  13  and decodes the analog audio signal into a digital audio signal. The audio decoder  210  outputs the digital audio signal to the AV compressor  208 . 
     In block S 306 , the AV compressor  208  compresses the digital audio signal and the digital video signal to obtain a compressed AV file, and outputs the compressed AV file to the processor  212 . In one embodiment, the AV compressor  208  may apply a moving pictures experts group (MPEG) compression algorithm, such as MPEG-1, MPEG-2, or MPEG-4, to compress the digital audio signal and the digital video signal. In one embodiment, the AV compressor  208  may further compress video data captured by the camera  14 . The video data may be firstly transmitted from the camera  14  to the processor  212 , and secondly transmitted from the processor  212  to the AV compressor  208 . 
     In block S 307 , the processor  212  stores the compressed AV file into the storage device  214 . In one embodiment, via the network  16 , the processor  212  may transfer the compressed AV file stored in the storage device  214  to the network terminal device  17 , such as a personal computer. As such, the compressed AV file can be displayed on the network terminal device  17 . 
     In the AV playing process, in block S 308 , the processor  212  retrieves a compressed AV file from the storage device  214 , and transfers the retrieved compressed AV file to the AV de-compressor  216 . Depending on the embodiment, the processor  212  may receive a compressed AV file from the network terminal device  17  via the network  16 , and transfer the received compressed AV file to the AV de-compressor  216 . 
     In block S 309 , the AV de-compressor  216  decompresses the retrieved/received compressed AV file to obtain a digital audio signal and a digital video signal. The AV de-compressor  216  outputs the digital audio signal to the audio encoder  218 , and outputs the digital video signal to the video encoder  220 . 
     In block S 310 , the audio encoder  218  encodes the digital audio signal into an analog audio signal, and outputs the analog audio signal to the speaker  15  to play. Meanwhile, the video encoder  220  encodes the digital video signal into an original video signal, and outputs the original video signal to the video switch  202 . 
     In block S 311 , the video switch  202  connects the video encoder  220  to the display device  12 , so that the original video signal can be displayed on the display device  12 . 
     Although certain inventive embodiments of the present disclosure have been specifically described, the present disclosure is not to be construed as being limited thereto. Various changes or modifications may be made to the present disclosure without departing from the scope and spirit of the present disclosure.