WO2005107272A1

WO2005107272A1 - A system and a method for sharing video input jacks

Info

Publication number: WO2005107272A1
Application number: PCT/US2005/003280
Authority: WO
Inventors: Dale Wayne King; Carlton Jethro Simmons; Ronald Thomas Keen
Original assignee: Thomson Licensing S.A.
Priority date: 2004-04-14
Filing date: 2005-02-03
Publication date: 2005-11-10

Abstract

The disclosed embodiments relate to a system and method for decoding video signals. A video unit (10) may comprise shared video input jacks (18) wherein the shared video input jacks (18) are adapted to receive a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack (36) regardless of whether the video signal is the composite video signal or the component video signal. The method may comprise the act of receiving a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack (36) regardless of whether the video signal is the composite video signal or the component video signal.

Description

A SYSTEM AND A METHOD FOR SHARING VIDEO INPUT JACKS

Cross Reference to Related Applications This application claims benefit of United States provisional patent application serial number 60/562,003, filed April 14, 2004, which is herein incorporated by reference.

FIELD OF THE INVENTION The present invention relates generally to decoding video signals on a video unit. More specifically, the present invention relates to a system for sharing video input jacks, and a method for decoding a video signal on a video unit that can accept multiple input video types on a single set of input jacks.

BACKGROUND OF THE INVENTION

This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

Modem video, units, such as cathrode ray tube ("CRT") televisions, LCD ("Liquid Crystal Display") monitors or televisions, plasma screen televisions, audio/video receivers, or video projectors, need to provide a variety of input jacks in order to facilitate the growing number of video output devices, such as video cassette recorders ("VCR") digital video disc ("DVD") players, computers, or satellite television receivers. There are a variety of video input signal types, both analog and digital.

Typically, the video unit will also have an audio input that corresponds to each of the video input types. This audio input may comprise one RCA jack for the left channel and one RCA jack for the right channel. In alternate embodiments, there may be other types of audio inputs.

With the growth over the past few years of the consumer video market, the number of video inputs on modern video units has grown tremendously. For example, a video unit may need five separate video inputs in order to accommodate a user that wishes to connect a VCR, a DVD player, a video camera, a satellite receiver, and a computer to a ^■ single video unit. Because each of these video sources may use either composite or component video, the video unit may have both a composite video jack and three component video jacks for each input. Each set of composite and component video jacks may also have two or more audio jacks that accompany it-resulting in a total of six jacks per video input. At six jacks per input, the video unit example described above with five inputs would have a total of thirty jacks. These thirty jacks may occupy a significant amount of space on the video unit. Reducing the number of jacks is desirable. SUMMARY OF THE INVENTION The disclosed embodiments relate to a system and method for decoding video signals. A video unit may comprise shared video input jacks wherein the shared video input jacks are adapted to receive a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack regardless of whether the video signal is the composite video signal or the component video signal. The method may comprise the act of receiving a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack regardless of whether the video signal is the composite video signal or the component video signal.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a block diagram of a video unit with shared video input jacks in accordance with embodiments of the present invention; and FIG. 2 is a diagram of shared video input jacks in accordance with embodiments of the present invention.

DETAILED DESCRIPTION One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system -related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

Composite video and component video are two analog video input signal types. Composite video is a video type that is used in most present consumer video equipment, such as the televisions and VCRs discussed above as well as camcorders, digital cameras, and a variety of other video recording and display devices.

Typically, composite video is transmitted over a wire with RCA- style plugs on either side. These RCA plugs can be inserted into RCA- style jacks in both the video unit that will display the video as well as the video output device. In alternate embodiments, the RCA-style plug may be integrated into the video output device. In this case, the transmission wire and the output device may be a single unit.

Composite video combines the color, luminance, and synchronization elements of a video image into a single, combined video signal. Typically, composite video is comprised of four hundred and eighty visible lines in an interlaced format. When video is displayed in an interlaced format, a display may show the odd lines during one scan of the display, and then show the even lines during the next scan of the display. The complete video image may be created on the display in each video field by repeating this process thirty times per second. This type of video input signal may be referred to as 480i because, as described above, it has four hundred and eighty visible lines and is interlaced.

Composite video may also be referred to as 1 H because composite video is the base line for rating the horizontal sync frequency of a video signal. Horizontal sync frequency is the number of times per second that an electron beam within the display can trace a pattern horizontally across the display from one side to the other and then back.

Turning now to component video, which is a newer video input type that separates brightness and color into separate signals.

Specifically, component video consist of a luminance signal, referred to as Υ," a blue color difference signal referred to as "Pb", and red color difference signal, referred to as "Pr". Typically, breaking the video signal into three parts produces higher quality video at the display. Similar to composite video, each of the component video signals is typically transmitted over RCA-style cables. This means that both the video unit and the video output device will typically have RCA jacks.

Unlike composite video, component video may support a wide variety of video signal formats. First, component video may support 480i or 1 H. In this case, the component video signal may be no higher resolution than a composite video signal. Component video may also support 480p, which is also referred to as 2H. As with 480i video signals, a 480p video signal comprise a video signal that has 480 lines of video. However, unlike 480i, the 480p video signal is not interlaced. Rather, all of the 480 displayable lines may be displayed in each vertical field. Showing all of the displayable lines at once is known as progressive scanning, and 480p gets its name from the fact that it has four hundred and eighty displayable lines that are progressively scanned. 480p is also known as 2H because the horizontal sync frequency of 480p is twice that of 480L Component video is also capable of transmitting a 1080i video signal. 1080i video signals consist of one thousand and eighty displayable lines of video in an interlaced scan. 1080i video signals are also referred as 2.14H because the horizontal sync frequency of the 1080i video signal is approximately 2.14 times that of 480i.

Lastly, component video is capable of transmitting 720p video signals. 720p video signals comprise seven hundred twenty displayable lines of video in a progressive scan. 720p video signals are also referred to as 3H because the horizontal sync frequency of the 720p video signal is approximately three times that of 480i video signal. Those skilled in the art will appreciate that component video is also capable of displaying video signals at a variety of other horizontal sync frequencies and with a variety of other numbers of displayable lines, such as 1080p, without affecting the underlying nature of the invention.

As discussed above, it may be desirable to reduce the number of video input jacks on a video unit. One method to accomplish this is to use shared video input jacks. As described above, both composite and component video may be transmitted over wires that have RCA-style plugs and may be inserted into RCA-style jacks on the video unit. As such, the number of video input jacks can be reduced if one of the component video input jacks is also used as the input jack for composite video signals. In one embodiment of the invention, the composite video may be coupled to the luminance input jack. In this case, however, it may be difficult for the video unit to determine whether the input video signal is a composite video signal or the luminance component of a component video signal. If the video unit is not able to make this determination, it may not be able to properly display the video signal.

One way to overcome this potential issue is for the user to set the input video type. This may be done through some type of user interface. However, many consumers, especially those inexperienced with video equipment, may either not understand the need to select an input video type or may not understand how to set the input video type. In this case, the input video signal may be displayed incorrectly. The input video display may also be displayed incorrectly if the user is unaware of the need to select a video input type and the default video input type either composite or component does not match the input signal type.

In one embodiment of the invention the default or user-selected video input type may be changed based on the horizontal sync rate of the input video signal. Recall from above that while both composite and component video may have a horizontal sync frequency of 1 H, only component video may have a horizontal sync frequency of 2H, 2.14H, or 3H. As described in more detail below, the video unit may be able to use this feature of component video signals to ensure that a component video signal with a horizontal sync frequency of 2H or above is decoded as a component video signal.

In another embodiment of the invention, the video unit may be configured to detect the presence of a blue color difference signal or a red color difference signal. Because composite video does not have separate wires to transmit the blue color difference signal and the red color difference signal, the video unit may be able to determine that the input video signal is a component signal if the blue color difference signal or the red color difference signal is detected through the input jacks for those signal types. In one embodiment of the invention, the blue color difference signal or the red color difference signal is detected by detecting the presence of the blue color difference signal or the red color difference signal itself. In an alternate embodiment of the invention, the presence of a blue color difference signal or a red color difference signal may be detected by detecting the physical presence of a plug in the input jack corresponding to that component of the input video signal.

FIG. 1 is a block diagram of a video unit with shared video input jacks in which embodiments of the present invention may be employed.

The diagram is generally referenced to by the reference numeral 10.

The video unit 10 may comprise a display 12, a video processor 14, a detection circuit 16, shared video input jacks 18, and a user interface 20.

The display 12 may include any type of video display. Examples include, but are not limited to CRT televisions, LCD screens, plasma screens, digital light processing ("DLP") systems, or projectors. The display 12 may display the video input signal and may be used in conjunction with the user interface 20 to select a video input type. The display 12 may be coupled to the video processor 14. The video processor 14 may convert a video signal into the form necessary to be displayed on the display unit 12. The video processor 14 may also contain logic or programming to permit the user to set-up the video unit 10. This set-up process may include selecting a video input type for a particular video input. The video processor 14 may also be coupled to the user interface 20. The user interface 20 may permit the user to interface with the video processor 14 and to select the video input type for a particular video input.

The video processor 14 may also be coupled to the detection circuit 16. The detection circuit 16 may be configured to determine whether the input video is a composite video signal or a component video signal. As described above, in one embodiment this determination may be made by detecting the horizontal sync frequency of the video input signal entering the video unit 10 through a luminance jack (36 in FIG. 2). If the horizontal sync frequency is greater than 1 H, the detection circuit 16 may determine that the input video signal is a component video signal. In this case, the detection circuit 16 may send a signal to the video processor 14 informing the video processor 14 that the input video signal is a component video signal. When the video processor 14 receives this signal, it may override either the default video input type selection or the user selected video input type and set the video input type as component video. For example, if the user sets the input video type as composite video, but the detection circuit 16 determines that the input video signal has a horizontal sync frequency of 2H, the video processor 14 may override the user selection and decode the input video signal as a component video signal.

In another embodiment of the invention, the detection circuit 16 may determine whether the input video signal is a component video signal or a composite video signal by detecting the presence or absence of the blue color difference signal or the red color difference signal. In either of these cases, the detection circuit 16 may send a signal to the video processor 14 to override the video input type selected by the user if it does match the video input type determined by the detection circuit 16.

In yet another embodiment of the invention, the detection circuit 16 may determine whether the input video signal is a component video signal or a composite video signal by detecting the presence of a chrominance signal entering the video unit 10 through the luminance/composite input jack (36 in FIG. 2). Because chrominance is transmitted via both the blue color difference signal input jack and the red color difference signal input jacks in component video, the presence of a chrominance signal (also referred to as a chroma burst) in the video input signal entering the video unit 10 through a luminance/composite input jack may indicate that the video input type is composite video.

Lastly, the detection circuit 16 may be coupled to the shared video input jacks 18. FIG. 2 is a diagram of the shared video input jacks in which embodiments of the present invention may be employed. The diagram is generally referenced by the reference numeral 18. The shared video input jacks 18 will typically be RCA-style input jacks. Those skilled in the art, however, will appreciate the techniques disclosed in the present application may be practiced with other types of input jacks. The shared video input jacks 18 may comprise a set of audio input jacks 34 and a set of video input jacks 42. The set of audio input jacks 34 may include a left channel audio jack 30 and a right channel audio jack 32. The left channel audio jack 30 may be connected to a wire carrying an audio signal for the left channel speakers where as the right channel audio jack 32 may be connected to a wire carrying an audio signal for the right channel speakers. Those skilled in the art will appreciate the set of audio jacks 34 may be comprised of more than two audio jacks or may be absent entirely without affecting the underlying nature of the invention.

The shared video input jacks 18 may also comprise the set of video input jacks 42. The set of video input jacks 42 will typically consists of three video input jacks: the luminance/composite input jack (also referred to as the "Y/composite" input jack), a red color difference input jack 38 (also referred to as the "Pr" input jack), and a blue color difference input jack 40 (also referred to as the "Pb" input jack). As with the set of audio jacks 34, the set of video input jacks 42 will typically be RCA-style input jacks, however, in alternate embodiments the set of video input jacks 42 may be a different style of input jack without affecting the underlying nature of the invention. While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

1 . A video unit (10) comprising shared video input jacks (18) wherein the shared video input jacks (18) are adapted to receive a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack (36) regardless of whether the video signal is the composite video signal or the component video signal.

2. The video unit (10) set forth in claim 1 comprising: a detection circuit (16), coupled to the shared video input jacks (18), and adapted to detect a horizontal sync frequency of the video signal; and a video processor (14), coupled to the detection circuit (16) and adapted to decode the video signal as a component video signal if the horizontal sync frequency is greater than 1 H.

3. The video unit (10) set forth in claim 1 comprising: a user interface (20) adapted to provide an interface for a user to select whether the video signal comprises a component video signal or a composite video signal; and a video processor (14), coupled to the user interface (20), and adapted to decode the video signal in conformance with a user selection.

4. The video unit (10) set forth in claim 3 comprising a detection circuit (16) coupled to the video processor (14) and the shared video input jacks (18), and adapted to determine whether a received video signal comprises a composite video signal or a component video signal.

5. The video unit (10) set forth in claim 4 wherein the detection circuit (16) is adapted to determine whether the video signal comprises a composite video signal or a component video signal by detecting the horizontal sync frequency of the video signal.

6. The video unit (10) set forth in claim 4 wherein the detection circuit (16) is adapted to determine whether the video signal comprises a composite video signal or a component video signal by detecting the presence of a red color difference signal or a blue color difference signal.

7. The video unit (10) set forth in claim 4 wherein the detection circuit (16) is adapted to determine whether the video signal comprises a composite video signal or a component video signal by detecting the presence of a chroma burst at a luminance/composite input jack.

8. A method of decoding a video signal, the method comprising receiving a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack (36) regardless of whether the video signal is the composite video signal or the component video signal.

. The method set forth in claim 8, comprising: detecting a horizontal sync frequency of the video signal; and decoding the video signal as a component video signal if the horizontal sync frequency is greater than 1 H.

10. The method set forth in claim 8, comprising: providing an interface for a user to select whether the video signal comprises a component video signal or a composite video signal; decoding the video signal in conformance with a user selection unless a detection circuit (16) indicates that the user selection is incorrect; and if the detection circuit (16) indicates that the user selection is incorrect, decoding the video signal as composite video if the user selection is component video or decoding the video signal as component video if the user selection is composite video.

1 1. The method set forth in claim 10, comprising indicating via the detection circuit (16) that the user selection is incorrect if a horizontal sync frequency of the video signal is greater than 1 H and the user selection is composite video.

12. The method set forth in claim 10, cdmprising indicating via the detection circuit (16) that the user selection is incorrect if the detection circuit (16) detects the presence of either a red color difference signal or a blue color difference signal and the user selection is composite video.

13. The method set forth in claim 10, comprising indicating via the detection circuit (16) that the user selection is incorrect if the detection circuit (16) detects the presence of a chroma burst at a luminance/composite input jack and the user selection is component video.

14. The method set forth in claim 10, comprising overriding the user selection if the determination of the detection circuit (16) does not match the user selection.

15. A video unit (10) comprising means for receiving a video signal comprising either a component video signal or a composite video signal wherein at least a part of the video signal is received through a first input jack (36) regardless of whether the video signal is the composite video signal or the component video signal.

16. The video unit (10) set forth in claim 15 comprising: means for detecting a horizontal sync frequency of the video signal; and means for decoding the video signal as a component video signal if the horizontal sync frequency is greater than 1 H.

17. The video unit (10) set forth in claim 15, comprising: means for providing an interface for a user to select whether the video signal comprises a component video signal or a composite video signal; means for decoding the video signal in conformance with a user selection unless a detection circuit (16) indicates that the user selection is incorrect; and means for decoding the video signal as composite video if the user selection is component video or decoding the video signal as component video if the user selection is composite video if the detection circuit (16) indicates that the user selection is incorrect.

18. The video unit (10) set forth in claim 17, wherein the detection circuit (16) will indicate that the user selection is incorrect if a horizontal sync frequency of the video signal is greater than 1 H and the user selection is composite video.

19. The video unit (10) set forth in claim 17, wherein the detection circuit (16) will indicate that the user selection is incorrect if the detection circuit (16) detects the presence of either a red color difference signal or a blue color difference signal and the user selection is composite video.

20. The video unit (10) set forth in claim 17, wherein the detection circuit (16) will indicate that the user selection is incorrect if the detection circuit (16) detects the absence of either a red color difference signal or a blue color difference signal and the user selection is component video.