US 5579239 Remote video transmission system
ABSTRACT – A remote video transmission system for digitizing and compressing an audio/visual signal, transmitting that signal over low band width lines, such as land telephone lines, cellular telephone lines, or radio frequencies, decompressing the digitized data and converting it to an audio/visual signal for broadcast. Components of this system include: A remote unit, a host unit, and a playback unit. The remote unit is capable of digitizing and compressing the audio/visual signal as well as transmitting the compressed, digitized data. Data may be divided and sent to multiple ports for output. Data may also be edited prior to transmission. The host unit is automated to receive data transmitted from the remote unit and reassemble the data if it has been divided. The playback unit stores and automatically catalogs transmitted data files. The player unit also decompresses the digitized data files and converts them to an audio/visual signal which may then be broadcast. The audio/visual signal can either be NTSC, PAL, or Y/C video.
FIELD OF THE INVENTION
This invention relates to capturing a video signal at one location and transmitting that signal to another location over telephone lines, cellular, radio and other telemetric frequencies.
Advances in the information highway promotes the United States as a world leader in the computer, video and broadcast industries. This invention adds to that information highway.
Transmission of a real time video signal from a remote location to a base location is conventionally done by one of two methods: Microwave or satellite. Equipment associated with these methods is extremely expensive and has significant limitations. The large amount of equipment necessary for satellite technology for remote transmission requires that the equipment be installed in trucks having an integral satellite dish. The signal is received from the video camera, beamed to the satellite, and then beamed to the base location for broadcast. The enormous amount of equipment and the sophisticated technology required makes satellite transmission extremely expensive and impractical for many applications. Satellite transmission does, however, send real time broadcast quality signals. The costs associated with satellite transmission are justifiable for large events such as sporting events where transmission could be made from a single location over a sustained period of time. It is not practical, however, for coverage such as news coverage where short segments from many different locations are necessary. An example would be in covering a natural disaster. Speed in obtaining and broadcasting video footage is a competitive requirement in news gathering situations.
The required set up time and inaccessibility of the satellite truck are significant additional limitations to satellite type transmission.
Microwave transmission technology overcomes some of the limitations of satellite technology but has several additional limitations of its own. Microwave transmission systems are less expensive and require less equipment. With a microwave system, a video signal is obtained and transmitted from the remote location at microwave frequencies from a vehicle mounted transmitting antenna to a base antenna for broadcast.
Difficulties have been encountered using this technology in aligning the antenna on the vehicle with the base antenna. Obstructions between the transmitting antenna and the base antenna may also prevent passage of the signal. Setup limitations also inhibit the use of microwave transmission systems in obtaining short segments of video at one location, transmission of that signal, moving to another location, transmission, movement, etc. Transmission is also limited to accessibility of the vehicle to the location of the subject matter.
The limitations of satellite and microwave technology have forced video broadcasters to devise alternative means of transmission, which may include: Setting up a remote microwave or satellite transmission post and transporting segments on video tape to it from multiple remote locations. More often, broadcasters capture video segments on tape and then manually transport those tapes back to the station as quickly as possible for broadcast.
With the establishment and advancements in cellular technology, television broadcasters have begun sending teams into remote locations for reports transmitted via cellular telephone. Cellular technology provides the ability to access a location and immediately report information back to the station. This use of cellular telephones transmits voice messages only and excludes video transmission altogether. Cellular technology has also been used to transmit data such as facsimile and computer file transmissions from one location to another. Cellular telephones have been quick to transmit data received from a facsimile machine or computer having a modem to a second fax machine or computer. Cellular combined with computer technology has never been used, however, to transmit a broadcast quality video signal.
A need, therefore, exists in the art for a highly portable, cost-effective method and apparatus for capturing and transmission of broadcast quality video from a remote location to a base location. A need also exists for a capture and transmission apparatus over cellular, land lines, or radio or other frequencies. Additionally, with the current FCC limitations regarding cellular transmissions from airborne craft an additional need is evidenced for video over the radio or other telemetric frequencies.
SUMMARY OF THE INVENTION
It is the purpose of the present invention to provide a method and means for capturing full-color, full-motion audio/video signals, digitizing and compressing the signals into a digitized data file, and transmitting the signals over telephone lines, cellular, radio and other telemetric frequencies.
A second object includes splitting the digitized, compressed, audio/video signal prior to transmission in order to reduce transmission time.
A further object is to provide an apparatus that will transmit audio/video files for immediate broadcast over radio frequencies, cellular telephone frequencies, or land telephone lines.
An apparatus to accomplish this purpose includes a remote unit, a host unit, and a player or a basic embodiment includes a remote and a combined host/player unit. This apparatus provides the capability of digitizing and compressing a signal which is then transmitted over low band width lines.
The remote unit includes means for digitizing and compressing a video signal, storage of the digitized and compressed data file, and transmission of this data file over telephone lines, cellular, radio and other telemetric frequency. The remote unit may also split the data file prior to transmission for multiple simultaneous transmissions in order to reduce transmission time. The host unit is automated to receive the transmitted data file, recombine it if it has been split, and store the recombined data file to the playback unit. The playback unit stores and automatically catalogs transmitted data files. The playback unit also decompresses the digitized data file and converts it to an audio/visual signal for broadcast.
In one preferred embodiment, an audio/visual signal is input into the remote unit from a video camera at a remote location. The remote unit is a combination portable personal computer having one or more computer interfaces and a corresponding number of cellular telephones. Computer software loaded on a hard disk drive in the remote unit instructs it to capture the input signal to a video capture card within the remote unit. The video capture card takes the audio/visual signal, digitizes it into a computer data file, and compresses that data file. Once digitized and compressed, the data file is captured in the computer’s memory by a capture module on the video capture card. A software sequence then instructs the computer central processing unit to store the captured data file on the computer’s hard disk drive. After the video file has been captured, it may be edited as desired prior to transmission to the host unit.
Once stored, a computer program sequence removes the digitized data from the hard drive, breaks the data file, and sends it to one or more computer interfaces which transmit the data file, using a corresponding number of cellular telephones, to the host unit. The data file is split and organized so as to reduce the amount of time of transmission of the data file.
A software sequence installed on the remote unit automatically catalogs data files stored in the system hard drive. These files are cataloged visually on a computer monitor for easy visual recognition. A single frame of video from each stored data file is displayed on the monitor in a catalog array to allow the operator the ability to quickly identify the file and select a file for retrieval or transmission to the host unit as required.
In an alternate embodiment, a basic one, the signal is not divided before it is transmitted. In this alternate embodiment, only a single interface and a single cellular phone are necessary.
The host unit is a desktop personal computer with installed communications software and one or more computer interfaces connected to a corresponding number of telephone lines. The interfaces are set to receive transmitted data files from the remote unit.
If the data files have been split for transmission, a software program recombines the split file back to its original single data file. A computer monitor is connected to the host unit for viewing of the stored data files at the host unit. A software program also copies this recombined data file to a network hard disk drive of the playback unit. The host unit and the playback unit are interfaced to allow transfer of data files. The computer to computer interface between the host unit and the playback unit is a computer network in the preferred embodiment, however, any known port to port connection could be substituted.
The playback unit is the interface between captured video and the master control which outputs the signal. Once the recombined data file has been stored on the networked hard disk drive of the playback unit, the data file may then either remain stored for later use or retrieved for broadcast.
Stored data files may be edited at the host location as desired.
For broadcast, a video card located in the playback unit retrieves the stored data file, decompresses the file, and converts the digitized data to VGA. The video card in the playback unit is similar to the video card in the remote unit with the exception that the card in the playback unit does not have a capture module.
Once the data file has been decompressed and converted to digital, a converter card converts the VGA signal to the desired signal for broadcast (NTSC, PAL, Y/C video, etc.) Hardware playback of the signal or output of the signal is to a monitor or VCR for storage on conventional video tape or immediate broadcast.
Other features and advantages of the invention will become apparent in view of the drawings and following detailed description.