FAST SWITCHING USING VARIABLE REFRESH RATE IN A REPEATER ENVIRONMENT

Switching from delivering a first video signal to a sink to delivering a second video signal to the sink is carried out. A repeater, connected to a previously authenticated sink, receives the first video signal outputted by a previously authenticated first source, and delivers the first video signal to the sink. The repeater receives a command to switch from the first video signal to the second video signal outputted by a second source. The repeater terminates receiving the first video signal, and delivers a temporary video signal to the sink so that the sink remains authenticated while the second source is being authenticated. The repeater sets the frame rate of the temporary video signal to a minimum variable refresh rate (VRR) supported by the sink. Upon completion of authentication of the second source, the repeater receives the second video signal and delivers the signal to the sink.

BACKGROUND OF THE INVENTION

Technical Field

The present embodiments relate to video distribution networks and, more particularly, to video distribution networks in which a repeater device or other device receives video signals from a video source device and delivers the video signals to a video sink device.

Background Art

Video distribution networks have become increasingly common in various commercial and residential environments. These video distribution networks typically receive video signals from one or more video sources and deliver video to one or more video sinks. For example, a typical home distribution network may include various sources such as the Internet, a streaming box, a gaming console, a Blu-Ray disc player, a media server, a digital video disc (DVD) player, a digital video recorder (DVR), a cable box, etc. Video from such video sources may be distributed using various repeater devices or network devices to deliver the video to one or more video sinks. Such video sinks may include a television display, a computer monitor, and/or a video projector.

To manage the transfer of video (and other content) over a video distribution network, a video input/output (I/O) interface standard is employed. These standards typically employ protocols to control the transfer of the video. Among such standards are the DisplayPort (DP), Digital Video Interface (DVI), and High-Definition Multimedia Interface (HDMI) standards.

To ensure that video and other content, such as television programs, movies, and music, can only be viewed or listened to by paying customers or other authorized parties, various digital rights management (DRM) schemes have been developed to protect digital content as it is transmitted over the video distribution network. One such DRM scheme is the High-Bandwidth Digital Content Protection (HDCP). HDCP is a specified method developed by Digital Content Protection, L.L.C. (DCP) for protecting copyrighted digital content as it travels across connection interfaces and other protocols such as DisplayPort (DP), Digital Video Interface (DVI), High-Definition Multimedia Interface (HDMI). The HDMI specification defines an interface for carrying digital audio-visual content from a source to a sink or other display device.

The HDCP includes an authentication protocol through which a source verifies that a given sink is authorized to receive HDCP-protected content. The HDCP authentication protocol is an exchange of information between a source and a sink through which the sink affirms to the source that it is authorized to receive HDCP-protected content. Specifically, each HDCP-compliant source, HDCP-compliant sink or other HDCP-compliant device stores a set of secret keys, also known as Device Private Keys, that are unique to that device and from which that device may generate a unique key selection vector (KSV). During authentication, a pair of HDCP-compliant devices, such as an HDCP-compliant source and an HDCP-compliant sink, exchange their unique KSVs which are then used by one of the devices to verify that the other device stores such a set of secret keys.

The exchange of information also enables both the HDCP-compliant source and the HDCP-compliant sink to generate a shared secret value that cannot be determined by eavesdropping on that information exchange. By having the shared secret value embedded into the demonstration of authentication, the shared secret value can then be used as a symmetric key by which an HDCP-compliant source may encrypt HDCP-protected content intended for only an authorized sink or other device. Thus, a communication path is established between the HDCP-compliant source and the HDCP-compliant sink that only such authenticated devices may access.

A more involved authentication process is required when HDCP-protected content is to be transmitted from an HDCP-compliant source to one or more HDCP-compliant sinks through a repeater. To authenticate these sinks to an HDCP-compliant source, an HDCP-compliant repeater must pass along the KSVs of each sink to the HDCP-compliant source. The HDCP-compliant source then checks each of their KSVs against an HDCP Revocation List maintained by DCP, LLC (“HDCP blacklist”) to determine whether each sink is licensed to receive the HDCP-protected content. If each of these sinks is determined to be licensed to receive HDCP-protected content, the HDCP-compliant source may then transmit the HDCP-protected content to the repeater. The HDCP-compliant repeater must also establish and periodically manage authenticated links with each HDCP-compliant source and HDCP-compliant sink to which it is connected.

Though HDCP offers the benefit of encrypted content transmission, the required authentication protocol increases the switching delay in video distribution networks because every link in the transmission path, such as the repeaters or other network devices, must be authenticated. Moreover, whenever a new video distribution path is desired, the links forming the new path must likewise be authenticated. For example, when a user desires to switch from one video source to another, the new video source must carry out authentication with the repeater device, and because this authentication interrupts the delivery of video signals from the repeater to the sink, the repeater device must also re-authenticate with the sink. As a result of the various authentications carried out between each pair of devices in the transmission path, the time delay in response to switching from one source to another increases, which increases the time that delivery of video to the sink is disrupted. During such interruptions, a scrambled or “snowy” image of a blank screen may be displayed on the screen. The scrambled or “snowy” images resulting from such delays and interruptions may become bothersome to users.

Moreover, in a complex video distribution system with multiple layers, the length of such delays is amplified. Additionally, because the HDCP scheme operates under the surface, most users are not aware that these increased switching delays result from the copy protection schemes and often erroneously attribute the delays and disruptions to the individual components of the video distribution network.

To address the delay caused while switching video sources, a video protocol, the HDMI 2.1 specification, attempted to solve the problem by introducing quick media switching (QMS). Quick media switching relies on using a variable refresh rate (VRR) to eliminate the blackout period when an HDMI source device switches video modes. In theory, QMS allows the source to change frame rates continuously and seamlessly in the video delivered to a television or other video sink. As long as the resolution remains the same and only the frame rate changes, QMS will seamlessly switch between frame rates.

The QMS technology has the drawback that it requires the source to always output video at the same resolution and color space and can only handle changes in the frame rate. Further, the source must change frame rates in a specific manner with specified tolerances on the rate of change and with a continuity requirement, namely, the video signal delivered to the sink must be always present and never lost. In a real-world environments, however, users may switch between many diverse sources (such as a streaming box, a Blu-ray player, a gaming console, etc.) that have different resolutions, different color spaces, and/or different frame rates. If the resolution or color space changes when the user switches between sources, the QMS feature does not compensate for such changes.

Additionally, in scenarios where a repeater is used, such as when a switcher or multiplexer controls the switchover from one source to another source, the QMS feature likewise does not work because as the repeater changes between different inputs, the switching of inputs causes interruptions in, and temporary loss of, the video signal delivered to the TV. The temporary interruptions in the video signal causes the TV and the repeater to have to renegotiate the HDCP authentication, video timing, training, etc., between the repeater and the sink, extending the time that the end user must wait until content from the new source is viewed.

An additional cause of high switching delays in video distribution systems is the need for image processing within the video distribution network. As an example, scalers are often employed to convert a lower resolution video signal to a higher resolution video signal, known as “up-conversion” or “upscaling”, or to convert a higher resolution video signal to a lower resolution video signal, known as “down-conversion” or “downscaling”. Scalers are also often employed to change the refresh rate of distributed video. Such scalers are common components in video distribution networks, either as separate components or integrated within the network.

Such scalers, however, have the further drawback that they require a constant frame rate even when the content changes video frame rates, such as a change between television content (with its 60 Hz frame rate) and film content (with its 24 Hz frame rate). Whenever a video scaler receives a new video signal containing audiovisual data having a new resolution, a delay occurs until the scaler outputs the new video. That is, the video scaler must load the data and format it before outputting the scaled video. This process is known as achieving video lock. During a switching event, each scaler in the distribution path must achieve video lock in succession. Again, in a complex video distribution system with multiple layers, this delay is magnified. Thus, even when scalers are used, a transition from one video source to another having a different frame rate still results in a disruption in the video delivered to the television or other video sink.

In a known attempt to address this disruption in the video signal delivered to the sink, the output scaler may be configured to generate a repeating frame of the image data received from the former video source at the frame rate of that video source. The repeating frame of image content data is generated until the video lock is achieved. By repeating the same frame of video, the user is presented a cleaner and more aesthetically pleasing switchover in which a momentarily frozen screen is displayed. Upon achieving video lock with the incoming video after the switching discontinuity, the output scaler then “unfreezes” the video by ceasing output of the repeating frame and begins to output live scaled video. Such an implementation is described in U.S. Pat. No. 9,425,236, issued Sep. 27, 2016, to Velasco et al, the disclosure of which is incorporated herein by reference.

This freezing of the video screen, however, is sometimes noticeable by the end user. Moreover, when the video is “unfrozen” at the time video lock is achieved, the sudden transition from the frame rate of the former video signal to the frame rate of the new video signal is often noticeable and may be distracting to the viewer. For example, when the content changes video frame rates, such as the change from television content (with its 60 Hz frame rate) to film content (with its 24 Hz frame rate) described above, the scaler continues to output video at the 60 Hz frame rate and converts the 24 Hz frame rate video signal to a 60 Hz signal. This conversion generates motion artifacts, known as “skip and repeat”, which is often noticeable to the user.

Also, in addition to generating motion artifacts, the frame rate conversion introduces a 1 or 2 frame delay in the signal, known as latency, which may be noticeable to the user. This latency may be present even when the new signal inputted to the scaler has the same frame rate as the prior signal delivered to the scaler because the new input signal is not synchronized to the prior signal. For example, the timing at which the new signal contains the beginning of a frame may coincide with a timing when the prior signal is part way through a frame. As a result, a delay is introduced in the output of the scaler when the scaler switches from receiving the prior signal to receiving the new signal. Though it is possible to have the timing of the video signal of the new source synchronized to the timing of the video signal of the prior source using generator locking, also known as genlocking, the use of such genlocking is generally limited to professional environments.

It is therefore desirable to provide a video distribution network in which switching from one video source to another is carried out in a quicker and less disruptive manner. It is also desirable provide a video distribution network in which the switching from one video source to another is carried out cleanly and seamlessly without introducing any latency or motion artifacts into the signal delivered to the user. It is further desirable to provide a video distribution network in which the sink remains authenticated and video locked while such switching is carried out.

SUMMARY OF THE INVENTION

It is to be understood that both the general and detailed descriptions that follow are exemplary and explanatory only and are not restrictive.

DISCLOSURE OF INVENTION

In accordance with an aspect, a system for switching from delivering a first video signal to a sink device to delivering a second video signal to the sink device comprises: (a) a repeater device connected to the sink device, the sink device being previously authenticated, the repeater device being further configured to (1) receive the first video signal outputted by a first source device, the first source device being previously authenticated, and deliver the first video signal to the sink device, (2) receive a command to switch from receiving the first video signal to receiving the second video signal, the second video signal being outputted by a second source device, (3) terminate receiving the first video signal, (4) deliver a temporary video signal to the sink device so that the sink device remains authenticated while the second source device is being authenticated, the repeater device setting the frame rate of the temporary video signal to a minimum variable refresh rate (VRR) supported by the sink device, and (5) receive the second video signal upon completion of authentication of the second source device, and deliver the second video signal to the sink device.

According to a further aspect, in a repeater device, a method of switching from delivering a first video signal to a sink device to delivering a second video signal to the sink device comprises: (a) receiving the first video signal outputted by a first source device, the first source device being previously authenticated; (b) delivering the first video signal to the sink device, the sink device being previously authenticated; (c) receiving a command to switch from receiving the first video signal to receiving the second video signal, the second video signal being outputted by a second source device; (d) terminating the receiving of the first video signal; (e) delivering a temporary video signal to the sink device so that the sink device remains authenticated while the second source device is being authenticated, the frame rate of the temporary video signal being set to a minimum variable refresh rate (VRR) supported by the sink device; (f) receiving the second video signal from the second source device upon completion of authentication of the second source device; and (g) delivering the second video signal to the sink device.

According to another aspect, a video distribution network, comprises: (a) a first source device configured to output a first video signal; (b) a second source device configured to output a second video signal; (c) a sink device; and (d) a repeater device connected to the sink device, the sink device being previously authenticated, the repeater device being further configured to (1) receive the first video signal outputted by the first source device, the first source device being previously authenticated, and deliver the first video signal to the sink device, (2) receive a command to switch from receiving the first video signal to receiving the second video signal, (3) terminate receiving the first video signal, (4) deliver a temporary video signal to the sink device so that the sink device remains authenticated while the second source device is being authenticated, the repeater device setting the frame rate of the temporary video signal to a minimum variable refresh rate (VRR) supported by the sink device, and (5) receive the second video signal upon completion of authentication of the second source device, and deliver the second video signal to the sink device.

According to yet another aspect, a system for switching from delivering a first video signal to a sink device to delivering a second video signal to the sink device, comprises: (a) a repeater device connected to the sink device, the sink device being previously authenticated in accordance with a High-Bandwidth Digital Content Protection (HDCP) authentication protocol, the repeater device being further configured to (1) read Extended Display Identification Data (EDID) from the sink device to obtain the minimum variable refresh rate (VRR) supported by the sink device, (2) receive the first video signal outputted by a first source device, the first source device being previously authenticated in accordance with the HDCP authentication protocol, and deliver the first video signal to the sink device, the first video signal having a first frame rate, (3) receive a command to switch from receiving the first video signal to receiving the second video signal, the second video signal being outputted by a second source device, (4) terminate receiving the first video signal, (5) deliver a temporary video signal to the sink device so that the sink device remains authenticated while the second source device is being authenticated in accordance with the HDCP authentication protocol, the repeater device setting the frame rate of the temporary video signal to the minimum variable refresh rate (VRR) supported by the sink device, the temporary video signal including a repeating frame of video signal delivered at the minimum variable refresh rate (VRR) supported by the sink device, the repeating frame of video signal being one of (A) a last received frame of the first video signal, or (B) a blank frame of video signal, and (6) receive the second video signal upon completion of authentication of the second source device, and deliver the second video signal to the sink device, the second video signal having a second frame rate different than the first frame rate.

According to still another aspect, a system for switching from delivering a first video signal to a sink device to delivering a second video signal to the sink device, comprises: (a) a repeater device connected to the sink device, the sink device being previously authenticated in accordance with a High-Bandwidth Digital Content Protection (HDCP) authentication protocol, the repeater device being further configured to (1) read Extended Display Identification Data (EDID) from the sink device to obtain the minimum variable refresh rate (VRR) supported by the sink device, (2) receive the first video signal outputted by a first source device, the first source device being previously authenticated in accordance with the HDCP authentication protocol, and deliver the first video signal to the sink device, the first video signal having a first frame rate, (3) receive a command to switch from receiving the first video signal to receiving the second video signal, the second video signal being outputted by a second source device, the first video signal and the second video signal not being synchronized, (4) terminate receiving the first video signal, (5) deliver a temporary video signal to the sink device so that the sink device remains authenticated while the second source device is being authenticated in accordance with the HDCP authentication protocol, the repeater device setting the frame rate of the temporary video signal to the minimum variable refresh rate (VRR) supported by the sink device, the temporary video signal including a repeating frame of video signal delivered at the minimum variable refresh rate (VRR) supported by the sink device, the repeating frame of video signal being one of (A) a last received frame of the first video signal, or (B) a blank frame or black frame of video signal, (6) receive the second video signal upon completion of authentication of the second source device, (7) transition from a timing of the first video signal to a timing of the second video signal according to the variable refresh rate (VRR) upon the completion of the authentication of the second source device, and (8) deliver the second video signal to the sink device.

DETAILED DESCRIPTION OF THE INVENTION

The present embodiments provide a video distribution network in which switching from one video source to another video source is carried out with a smooth transition in the video that is delivered to a television or other video sink.

Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

List of Reference Numbers for the Major Elements in the Drawing

The following is a list of the major elements in the drawings in numerical order.100Known Switching System102HDMI Source104HDMI Sink106Video Signal200Video Distribution Network202Source1204Switcher206aSwitcher Input1206bSwitcher Input2206nSwitcher InputN208aMux Input In1208bMux Input In2208nMux Input InN210Mux212Mux Output Out1214Switcher Output216Sink222Source2300Reading Capabilities Steps302Device Disconnected Step304Connect Device Step306Read EDID Step308Save Step400Fast Switching Steps402System In Steady State404Initiate Source Switching Step406Prepare For Input Change Step408Display Supports VRR?410Blank Display Step412Change Input Step414Convert Frame Rate Step416Unblank Video Step418Switching Completed420Change to Minimum Supported VRR Step422Change Input Step424Adjust Output Resolution Step426Switching Completed Step500Video Distribution Network502Source1504Encoder1506Network508Decoder510Sink512Source2514Encoder2522Input Video Management524Coder-Decoder (Codec)526Frame Buffer528Memory530Scaler532Output Video Management700Fast Switching Steps702System In Steady State704Initiate Source Switching Step706Prepare For Input Change708Display Supports VRR?710Change to Minimum Supported VRR Step712Change Input Step714Adjust Output Step716Switching Completed800Video Distribution Network802Source1804Encoder1806Network808Decoder810Sink812Source2814Encoder2822Input Video Management824Coder-Decoder (Codec)826Scaler828Output Video Management1000Fast Switching Steps1002System In Steady State1004Initiate Source Switching Step1006Prepare For Input Change1008Display Supports VRR?1010Change to Minimum Supported VRR Step1012Change Input Step1014Adjust Output Resolution Step1016Switching Completed Step1100Video Distribution Network1102Source11104Encoder11106Network1108Decoder1110Sink1112Source21114Encoder21122Input Video Management1124Coder-Decoder (Codec)1126Output Video Management1300Fast Switching Steps1302System In Steady State1304Initiate Source Switching Step1306Prepare For Input Change1308Display Supports VRR?1310Change to Minimum Supported VRR Step1312Change Input Step1314Adjust Output Step1316Switching Completed

MODE(S) FOR CARRYING OUT THE INVENTION

The embodiments described herein are in the context of a video distribution network, but are not limited thereto, except as may be set forth expressly in the appended claims.

FIGS.1A-1Cshow a known switching operation carried out in accordance with the HDMI 2.1 specification.

Referring first toFIG.1A, the system in initially in a steady state in which a video signal106having a first pixel resolution and frame rate, such as a video signal having a 1920×1080 pixel resolution and 60 Hz frame rate, is transmitted from a source102to a sink104.

Then, asFIG.1Bshows, the frame rate of the video signal delivered by the source102is changed to another frame rate, such as to 23.976 Hz. Alternatively, another video source delivers a new video signal at the another frame rate. In theory, the QMS technology employed by the HDMI 2.1 specification provides for a transition of the video signal106to the new frame rate over an interval of several video frames. During this interval, no video signal is delivered to the sink104, resulting in a blank screen being displayed.

Then, asFIG.1Cshows, a video lock is achieved and a video signal106is now delivered at the new frame rate, e.g., 23.976 Hz, to the sink104.

The QMS technology, however, only works for changes in frame rates that occur while the same resolution and color space is maintained. The QMS technology is not capable of handling most real-world changes in frame rates where a repeater is used to switch from one source to another. Moreover, the QMS technology is not capable of handling switches between sources having different resolutions and/or different color spaces.

FIGS.2A-2Cshow a video distribution network200in accordance with an embodiment. The video distribution network200employs a switcher204as a repeater. The switcher202includes a multiplexer system (Mux)210as well as a plurality of switcher inputs, namely, Input1206a, Input2206b, . . . , InputN206n. Each of the plurality of switcher inputs receives a video signal from an associated source, when connected, and delivers the received video signal to a corresponding input on the Mux210. As an example, inFIGS.2A-2C, Input1206areceives a video signal from Source1202and delivers a video signal to Mux input In1208a, and Input2206breceives a video signal from Source2222and delivers a video signal to Mux input In2208b.

The Mux210, among other functions, connects one of the Mux inputs In1208a, In2208b, . . . , InN208nto a single output Out1212so that the video signal received from that Mux input is delivered to the output Out1212. The video signal received by the Mux output Out1212is then delivered to switcher Output214which, in turn, is delivered to Sink216.

FIG.2Ashows the video distribution network200in its initial steady state. A first video signal having, for example, a 1920×1080 resolution at a 60 Hz frame rate is outputted by Source1202and delivered to the switcher Input1206a. The 1920×1080, 60 Hz video signal is then delivered to the Mux210at Mux input In1208a. The Mux210provides a connection between the Mux input In1208aand the Mux output Out1212so that the 1920×1080, 60 Hz video signal is outputted from the Mux output Out1212to the switcher Output214. The 1920×1080, 60 Hz video signal is thereafter delivered to the Sink216.

A second video signal having, for example, a 1920×1080 resolution but at a 50 Hz frame rate is outputted by Source2222and delivered to the switcher Input2206band then to the Mux input In2208b. The Mux input In2208bis not connected to a Mux output so that the 1920×1080, 50 Hz video signal is not further delivered.

FIG.2Bshows the video distribution network200during a transition that follows a switching operation. Specifically, the Mux210has now disconnected the Mux output Out1212from the Mux input In1208aso that no video signal is being delivered to the Mux output Out1212. As a result, either no signal or an unstable signal is delivered from the Mux output Out1212to the switcher Output214. During this transition, the Mux210verifies that it is authorized to receive content from the Source2222and then affirms to the Source2222that it is authorized to receive the content. Then, private keys are exchanged between the Source2222and the Mux210. At the same time that these exchanges occur, and until the Mux210achieves authentication of the Source2222, either no signal or an unstable signal is delivered to the switcher Output214.

In accordance with an embodiment, during this interval, the switcher Output214delivers a temporary video signal to the Sink216. This temporary video signal has a frame rate that is the minimum VRR frame rate supported by the Sink216. Preferably, the temporary video signal contains the last frame that was received from the Source1202but now repeatedly delivered at the minimum VRR frame rate by the Output214to the Sink216. For example, when the minimum VRR frame rate supported by the Sink216is 48 Hz, the switcher Output214converts the last 60 Hz frame that it received from the Source202into a frame having a 48 Hz frame rate, and then repeatedly re-transmits this 48 Hz frame to the Sink216until authentication is attained.

Upon achieving successful authentication, the Output214discontinues delivering the 48 Hz frame rate video signal. AsFIG.2Cshows, the Mux210now connects the Mux input In2208bto the Mux output212so that now a 1920×1080, 50 Hz video signal is provided by the Source2222and delivered to the Sink216.

In this manner, switching from receiving a first video signal from Source1202to receiving a second video signal from Source2222, such as, for example, the transition from receiving and delivering a 1920×1080, 60 Hz video signal to receiving and delivering 1920×1080, 50 Hz video signal, is carried out seamlessly and with minimal noticeable disruption to the end user. Moreover, because the Mux210continued to transmit a temporary video signal to the Sink216during this transition, the sink remains HDCP authenticated, and a video lock may also be maintained between the Mux210and the Sink216, thereby reducing the time required to transition from Source1202to Source2220.

Additionally, during the transition to the new input signal, the, e.g., 48 Hz frame rate video signal contains an extended front porch interval due to its lower frame rate. When the extended front porch interval aligns with the new 50 Hz input signal, the system jumps the output sync to the new 50 Hz input signal frame rate, thereby allowing the TV to seamlessly process the new input signal without interruption.

ThoughFIGS.2A-2Cdepict switching from a first source providing a 1920×1080, 60 Hz video signal to a second source providing a 1920×1080, 50 Hz video signal, the resolution and frame rate shown are merely examples. Transitions between other resolutions and frame rates are within the scope of the embodiments. Moreover, thoughFIGS.2A-2Cdepict a sink supporting a minimum VRR frame rate of 48 Hz, the value is likewise merely an example, and other a minimum supported VRR frame rates are also within the scope of the embodiments.

For example, a first video signal having a 1920×1080 video resolution at a 60 Hz frame rate and an RGB color space, i.e., a 1920×1080, 60 Hz RGB video signal, may be provided by Source1202and initially delivered to the switcher204. A scaler located within the switcher204, such as within the Mux210or within the Output214, converts the 1920×1080, 60 Hz RGB video signal to a video signal having a 3840×2160 video resolution at a 60 Hz frame rate and an Y444 color space, that is, the scaler outputs a 3840×2160, 60 Hz Y444 VRR, and this video signal is delivered to the Sink216.

A second video signal having a 4096×2160 video resolution at a 50 Hz frame rate and a Y444 color space, i.e., a 4096×2160, 50 Hz Y444 video signal, may be provided by Source2220. When the Mux switches from receiving the first video signal from Source1202to receiving the second video signal from Source2220, no input is delivered to the scaler during the switching transition. Rather, the scaler outputs a temporary video signal in which the last 3840×2160, 60 Hz Y444 VRR video frame it had received is now repeatedly outputted at the minimum 48 Hz VRR frame rate supported by the Sink216.

Then, upon achieving successful authentication and video lock, the scaler discontinues outputting the 3840×2160, 48 Hz Y444 frame. The scaler now begins receiving the 4096×2160, 50 Hz Y444 video signal provided by Source2220, converts this video signal into a 3840×2160, 50 Hz Y444 VRR video signal, and delivers the new signal to the Sink216.

Also, thoughFIGS.2A-2Cdepict switching from a first source to a second source when the first video signal and the second video signal have different frame rates and/or different resolutions, the video distribution network200also provides advantages when the first video signal and the second video signal have the same frame rate. Typically, even when the first and second video signals have the same frame rate, the timing of the first video signal is not synchronized to the timing of the second video signal. That is, the first and second video signals are asynchronous. As a result, a latency may be introduced during the transition from the first video signal to the second video signal which may be noticeable to the user.

The video distribution network200ofFIGS.2A-2C, however, provides a transition that is carried out seamlessly and with minimal noticeable disruption to the end user even when the first and second video signals are asynchronous because a repeated frame is delivered in a temporary video signal having the minimum VRR frame rate supported by the Sink216.

FIGS.3and4A-4Cshow in greater detail the steps carried out by a repeater device, such as the video distribution network200shown inFIGS.2A-2C, according to an embodiment.

FIG.3is a flow chart300showing the steps carried out when a repeater device is first connected to a sink device. Initially, as shown at300, the repeater device is in a disconnected state, for example, when the switcher204is not connected to a sink or other display device.

Next, as shown at304, the repeater device is connected to the display or other sink device, such as by connecting the Output214of the switcher204to the Sink216. Then, as shown at306, the repeater device reads the extended display information data (EDID) stored in the display or other sink, such as the switcher204reading the EDID stored in the Sink216.

The EDID contains data that describes the capabilities of a sink or other display device and may be provided to a source device. The EDID may include some or all of a manufacturer name and serial number, a product type, a phosphor or filter type (as chromaticity data), timings supported by the display, a display size, luminance data and pixel mapping data. Additionally, the EDID includes a minimum variable refresh rate (minimum VRR) and a maximum variable refresh rate (maximum VRR) of the display. The VRR of the display refers to the manner by which a display adjusts its refresh rate to match the frame rate of the source device. The minimum VRR is the minimum frame rate at which the VRR feature is still working properly. Similarly, the maximum VRR is the maximum frame rate at which the VRR feature works properly.

After the repeater device reads the EDID stored in the sink or other display device, the repeater device saves the data to store the sink's display capabilities, as shown at308.

FIGS.4A-4Cis a flow chart400showing an example of the steps carried out by a repeater device while the repeater device switches from one source device to another according to an embodiment, such as when the switcher204ofFIGS.2A-2Cswitches from being first connected to Source1202to being connected to Source2220.

First, as shown at402inFIG.4A, the repeater device is in a steady state while it receives a video signal having a fixed resolution and frame rate from a first source device. The known repeater device then transmits the received video signal to a display or other sink device.

Then, as404shows, a switch from the first source device to another source device is initiated, such when a user desires to switch from receiving content contained in the first video signal to receiving content contained in the second video signal.

As406shows, the repeater device next prepares to switch from being connected to the output of one source device to a being connected to the output of another source device. Namely, the repeater device disconnects from the first source device. For example, the Mux210of the Switcher204severs the connection between the Mux Input In1208aand the Mux output Out1212.

Next, as408shows, the repeater device determines whether the sink or other display device supports a variable refresh rate (VRR), such as by the Switcher204determining whether the Sink216supports a VRR. If the sink or other display device does not support a VRR, then the repeater device proceeds in the manner shown inFIG.4Bwhile the repeater device is authenticated by the new source device and achieves a video lock. Alternatively, if the repeater device determines that the sink or other display device supports a variable refresh rate (VRR), then according to an embodiment, the repeater device proceeds in the manner shown inFIG.4Cwhile the repeater device is authenticated by the new source device and achieves a video lock.

Referring now toFIG.4B, if the sink or other display device does not support a variable refresh rate (VRR), then the repeater device delivers blank video frames to the display, as410shows. The repeater device delivers these blank video frames at the same resolution and frame rate as the video signal that was received from the prior source.

Then, as412shows, the multiplexer of the repeater device reconfigures its connections to be able to transfer the video signal received from the second source device to the display while continuing to deliver blank video frames.

Next, as414shows, the repeater device begins converting the frame rate of the video signal that is received from the new source device. The frame rate of the new video signal is converted to the frame rate supported by the display, that is, the same frame rate as that of the video signal previously delivered to the display.

Thereafter, as416shows, the repeater device stops delivering the blank video frames to the display, and the converted video signal received from the new source device is now delivered to the display.

As418shows, the transition from the video signal of the first source device to the video signal of the second source device is now completed.

Referring back to408inFIG.4A, if the repeater device determines that the sink or other display device supports a VRR, then the repeater device proceeds in the manner shown inFIG.4Caccording to an embodiment while the repeater device authenticates the new source device.

As shown at420, the repeater device produces a temporary output signal having a frame rate that is at the minimum VRR supported by the display. For example, the switcher204causes the Output214to output a temporary video signal having a frame rate that is at the minimum VRR frame rate supported by the Sink216. When this minimum VRR frame rate is 48 Hz, the Output214outputs a 48 Hz video signal.

The resolution of the temporary signal is the same as that of the first video signal. In the current example, the resolution of the temporary video signal produced by the Output214remains the same as that of the signal that was received from Source1202.

Then, as422shows, the multiplexer of the repeater device now carries out internal changes, such as to provide a connection between the new source device and the sink. For example, the Switcher204causes the Mux210to connect the Mux input In2208bto the Mux output Out1212. As a result, the second video signal provided by the Source2222, which was delivered to the Mux input In2208bvia the Switcher Input2206b, is now further delivered to Mux output Out1212and thereafter to the switcher Output214.

Next, as424shows, the new video signal stabilizes upon achieving successful authentication and video lock. If the resolution of the second video signal is supported by the sink device, the resolution of the second video signal is not changed by the repeater. For example, when a 1920×1080, 50 Hz video signal is provided by the Source2222, the switcher Output214delivers this 1920×1080, 50 Hz video signal to the Sink216.

Alternatively, if the second video signal provided by the Source2222does not have a resolution supported by the Sink216, a scaler (not shown) located within the Mux212converts the resolution of the new video signal to a resolution supported by the Sink216, and once video lock is attained, the switcher Output214may now deliver the newly scaled 50 Hz video signal to the Sink216.

Thereafter, as426shows, the switching from one video signal source to another has been completed.

In this manner, the repeater device switches from delivering a first video signal provided by a first source to delivering a second video signal provided by a second source. Because during the transition the repeater device temporarily transmits a minimum VRR frame rate video signal to the sink, the transition is made seamlessly and with minimal noticeable disruption to the user. Moreover, because of the transmission of the minimum VRR frame rate video signal during the transition, there is no interruption in the signals being delivered to the sink. The sink therefore remains HDCP authenticated, and a video lock is maintained between the repeater device and the sink, thereby reducing the time required to transition from one source to another source.

FIGS.5A-5Cshow an example of a video distribution network500in accordance with another embodiment in which the repeater functions are distributed among encoders and a decoder connected to each other over a data network. A first source, namely, Source1502, outputs a first video signal containing audiovisual data and having a first resolution and a first frame rate. The Source1502outputs the first video signal to a first encoder, namely, Encoder1504, which is capable of connecting to a data network506.

A second source, namely, Source2512, outputs a second video signal containing audiovisual data and having a second resolution and a second frame rate, which may be different than the first resolution and/or the first frame rate. The Source1502outputs the second video signal to a second encoder, namely, Encoder2514, which is similarly capable of connecting to the data network506.

A Decoder508is capable of connecting to the Source1502via the Encoder1504and the data network506or, alternatively, to the Source2512via the Encoder2514and the data network506. The Decoder508is also connected to a Sink510.

FIGS.5A-5Cfurther show an example of a transition in which the Decoder508switches from delivering the first video signal provided by the Source1502to delivering the second video signal provided by the Source2512.

FIG.5Ashows the video distribution network500in its initial steady state during which the Decoder508has previously authenticated the Source1502and the Sink510and is now subscribed to receive the first video signal from the Source1502via the Encoder1504and the data network506. The first video signal may have, for example, a 1920×1080 resolution at a 60 Hz frame rate. The 1920×1080, 60 Hz video signal is thereafter sent by the Decoder508to the Sink510.

The second video signal, which may have, for example, a 1280×720 resolution at a 50 Hz frame rate, is outputted by the Source2512and delivered to the Encoder2514. At this time, the 50 Hz video signal is not sent over the network506to the Decoder508.

FIG.5Bshows the video distribution network500during the transition following the switching operation. Specifically, the Decoder508receives a request, such as from an end user, to receiving the content provided by the Source2512and contained in the second video signal. The Decoder508terminates its data connection with the Encoder1504so that the 1920×1080, 60 Hz video signal is no longer received by the Decoder508.

In accordance with the embodiment, the Decoder508recognizes that it has entered a transitional state in which it no longer receives the 1920×1080, 60 Hz video signal from the Encoder1504but has not completed establishing a data connection with the Encoder2514to receive the 1280×720, 50 Hz video signal provided by the Source2512. During this transitional state, the Decoder508first verifies that it is authorized to receive content from the Source2512, affirms to the Source2512that it is authorized to receive the content, and then private keys are exchanged between the Encoder2514and the Decoder508. At the time these exchanges occur, and until the Decoder508attains authentication with the Source2512and achieves a video lock, either no signal or an unstable signal would ordinarily be delivered to the Sink510.

However, in accordance with the embodiment, the Decoder508delivers a temporary video signal during this interval to the Sink510. The temporary video signal is at the same resolution as the first video signal but is at the minimum VRR frame rate supported by the Sink510. Preferably, the temporary video signal contains the last frame previously delivered to the Sink510from the first video signal, but now repeatedly transmitted at the minimum VRR frame rate. For example, when the first video signal is at a resolution of 1920×1080 and at a 60 Hz frame rate, and the minimum VRR frame rate supported by the Sink510is 48 Hz, the Decoder508repeatedly transmits the last 1920×1080 frame from the first video signal, but at the 48 Hz minimum VRR frame rate. The Decoder508transmits this 1920×1080, 48 Hz temporary video signal to the Sink510.

Upon achieving successful authentication and video lock, the Decoder508discontinues delivering the temporary video signal to the Sink510. Namely, the Decoder508discontinues delivering the repeating frame of the 1920×1080, 48 Hz video signal.

Then, asFIG.5Cshows, the Decoder508now receives the second video signal from the Source2512via the Encoder2514and the network506, namely, the Decoder508now receives the 1280×720, 50 Hz video signal. The Decoder508converts the received 1280×720, 50 Hz video signal into a video signal having a resolution supported by the Sink510, such as into a 1920×1080, 50 Hz video signal. A scaler located within the Decoder508may be used to carry out this conversion. The Decoder508then delivers the scaled 1920×1080, 50 Hz video signal to the Sink510to be displayed.

In this manner, switching from a first video source to a second video source, such as the transition from receiving and displaying the 1920×1080, 60 Hz video signal provided by the Source1502to receiving the 1280×720, 50 Hz video signal provided by the Source2512and displaying the 1920×1080, 50 Hz video signal, is carried out seamlessly and with minimal disruption noticeable by the end user. Moreover, because the Decoder508continued to transmit a video signal to the Sink510during this transition, the Sink510remains HDCP authenticated and a video lock is maintained between the Decoder508and the Sink510, thereby reducing the time required to transition from displaying the content received from the Source1502to displaying the content received from the Source2512.

ThoughFIGS.5A-5Cdepict switching from a first source providing a 1920×1080, 60 Hz video signal to a second source providing a 1280×720 50 Hz video signal, these values are merely examples. Transitions between other resolutions and/or other frame rates are also within the scope of the embodiments. Moreover, thoughFIGS.5A-5Cdepict a sink supporting a minimum VRR frame rate of 48 Hz, the value is likewise merely an example, and other minimum supported VRR frame rates are also within the scope of the embodiments.

For example, a 1920×1080, 60 Hz RGB first video signal may be provided by the Source1502to the Encoder1504and delivered over the network506to the Decoder508. A scaler located within the Decoder508may convert the 1920×1080, 60 Hz RGB video signal to, for example, a 3840×2160, 60 Hz Y444 VRR video signal that is supported by the Sink510. The Decoder508then delivers the scaled 3840×2160, 60 Hz Y444 VRR video signal to the Sink510.

In this example, the second video signal may be a 4096×2160, 50 Hz Y444 video signal that is provided by the Source2512to the Encoder2514. When a transition from receiving the 1920×1080, 60 Hz RGB first video signal to receiving the 4096×2160, 50 Hz Y444 second video signal is initiated, the Decoder508first terminates the data connection to the Encoder1504over the network506to terminate receiving the 1920×1080, 60 Hz RGB first video signal. Then, the Decoder508initiates authentication of the Source2512.

While the authentication is being carried out, the Decoder508repeatedly outputs the last frame that was delivered to the sink but now at a 48 Hz frame rate, namely, the lowest frame rate supported by the Sink510. That is, the Decoder508repeatedly outputs the last frame of the 3840×2160, 60 Hz Y444 VRR video signal that was outputted by the scaler of the Decoder508to the Sink510, but now repeatedly outputs that frame at a 48 Hz frame rate.

Then, upon achieving successful authentication and video lock, the Decoder508discontinues repeatedly outputting the 3840×2160, 48 Hz Y444 frame. The scaler now begins receiving the 4096×2160, 50 Hz Y444 second video signal from Encoder2514, converts this video signal into a 3840×2160, 50 Hz Y444 VRR video signal. The Decoder508now delivers the newly converted signal to the Sink510.

Also, thoughFIGS.5A-5Cdepict switching from a first source to a second source when the first video signal and the second video signal have different frame rates and/or different resolutions, the video distribution network500also provides advantages when the first video signal and the second video signal have the same frame rate. Typically, even when the first and second video signals have the same frame rate, the timing of the first video signal is not synchronized to the timing of the second video signal. That is, the first and second video signals are asynchronous. As a result, a latency may be introduced during the transition from the first video signal to the second video signal which may be noticeable to the user.

The video distribution network500ofFIGS.5A-5C, however, provides a transition that is carried out seamlessly and with minimal noticeable disruption to the end user even when the first and second video signals are asynchronous because a repeated frame is delivered in a temporary video signal having the minimum VRR frame rate supported by the Sink510.

FIG.6is a diagram showing an example of some of the functions carried out by the Decoder508ofFIGS.5A-5Caccording to an embodiment. For example, Input Video Management522is carried out on the video signal received by the Decoder508, and then the video signal is decompressed, such as using a Coder-Decoder (Codec)524. As each frame of the video signal is decoded, that frame is held in a Frame Buffer526until a Scaler530converts the frame to another resolution. Output Video Management532may then be performed on the scaled video frame prior to delivery to the Sink510.

Alternatively, the frame held in the Frame Buffer526may be moved to a Memory528, and a frame previously stored in the Memory532may be delivered to the Frame Buffer526and then to the Scaler530.

FIG.7is a flow chart700showing an example of the steps carried out by a networked repeater device while the networked repeater device switches from a first video signal source to a second video signal source, such as when the Decoder508ofFIGS.5A-5Cswitches from the first video signal outputted by the Source1502to the Encoder1504to the second video signal outputted by the Source2512to the Encoder2514.

First, as shown at702, the networked repeater device is in a steady state while it receives a first video signal at a fixed resolution from a previously authenticated first source device. The networked repeater device then transmits the received first video signal to a previously authenticated display or other sink device. For example, the Decoder508is in a steady state while it receives the first video signal outputted by Source1502, which may be the 1920×1080, 60 Hz video signal, and transmits the received video signal to the Sink516.

Then, as704shows, a switch from receiving the first video signal provided by the first source device is carried out, such as when a user switches from viewing the content contained in the first video signal by requesting to viewing the content contained in the second video signal.

As706shows, the networked repeater device next prepares to connect to the output of the second source device. For example, the Decoder508may terminate the receiving and displaying of the 1920×1080, 60 Hz first video signal generated by the Source1502by terminating the data connection with the Encoder1504over the network506.

The networked repeater device then initiates establishing HDCP authentication with the new source device over the network. While the HDCP authentication is being established, the networked repeater device is neither able to deliver the first video signal received from the first source device nor deliver the second video signal received from the second source device. For example, the Decoder508may initiate HDCP authentication with the Source2512over the network506, and while HDCP authentication is being established, the Decoder508is neither able to transmit the 1920×1080, 60 Hz first video signal provided by the Source1502nor transmit the 1280×720, 50 Hz second video signal provided by the Source2512.

Next, as708shows, the networked repeater device determines whether the sink or other display device supports a variable refresh rate (VRR). For example, the Decoder508may determine whether the Sink510supports a VRR. If the sink does not support a VRR, then the networked repeater device delivers blank video frames to the sink or other display device until HDCP authentication and video lock are being established, in a manner analogous to the that shown inFIG.4B.

Alternatively, if a VRR is supported by the sink, the networked repeater device then outputs a temporary video signal having the minimum VRR frame rate supported by the sink or display, as710shows. The resolution of the temporary video signal is the same as that of the first video signal. Preferably, the temporary video signal is comprised of the last frame received from the first video signal by the networked repeater. This frame is transmitted repeatedly as the temporary video signal.

For example, the Frame Buffer526of the Decoder508stores the last frame received from the Source1502via the Encoder1504and the network506. The Decoder508then repeatedly outputs the frame stored in Frame Buffer526as a temporary video signal at the minimum VRR frame rate supported by the display of the Sink516. When the minimum VRR frame rate supported by the Sink516is 48 Hz, the Decoder508outputs a 48 Hz temporary video signal to the Sink516at the same 1920×1080 resolution.

Then, as712shows, the networked repeater device provides a data connection between the new source device and the sink to enable receiving the second video signal. For example, the Decoder508connects to the Source2512via the network506and the Encoder2514to enable receiving the 1280×720, 50 Hz second video signal.

Next, as714shows, the new video signal stabilizes upon the networked repeater device achieving successful authentication and video lock, and the networked repeater device now converts the resolution of the second video signal to the resolution supported by the sink device. For example, the Scaler530of the Decoder508converts the 1280×720, 50 Hz second video signal to the 1920×1080 resolution supported by the Sink510. The Output Video Management of the Decoder508now delivers the converted video signal to the Sink516.

Thereafter, as716shows, the switching from receiving a first video signal to receiving a second video signal has been completed.

FIGS.8A-8Cshow an example of a video distribution network800in accordance with another embodiment in which a decoder transmits a temporary video signal comprised of a repeating black frame or blank frame during a transition from a first video signal having a particular resolution and frame rate to a second video signal having a different resolution and/or frame rate. As inFIGS.5A-5C, the temporary repeating black frame or blank frame is delivered at the minimum VRR frame rate supported by the sink device. However, the video distribution network800employs a Decoder808that is simpler in function than the Decoder508shown inFIG.6.

A first source, namely, Source1802, outputs a first video signal containing audiovisual data and having a first resolution and a first frame rate. The Source1802outputs the first video signal to a first encoder, namely, Encoder1804, which is capable of connecting to a data network806.

A second source, namely, Source2812, outputs a second video signal containing audiovisual data and having a second resolution and a second frame rate, which may be different than the first resolution and/or the first frame rate. The Source1802outputs the second video signal to a second encoder, namely, Encoder2814, which is similarly capable of connecting to the data network806.

A Decoder808is capable of connecting to the Source1802via the Encoder1804and the data network806or, alternatively, to the Source2812via the Encoder2814and the data network806. The Decoder808is also connected to a Sink810.

FIGS.8A-8Cfurther show an example of a transition in which the Decoder808switches from receiving the first video signal generated by the Source1802to receiving the second video signal generated by the Source2812.

FIG.8Ashows the video distribution network800in its initial steady state during which the Decoder808has previously authenticated the Source1802and the Sink810and is now subscribed to receive the first video signal from the Source1802via the Encoder1804and the data network806. The first video signal may have, for example, a 1920×1080 resolution at a 60 Hz frame. The 1920×1080, 60 Hz video signal is thereafter sent by the Decoder808to the Sink810.

The second video signal, which may have, for example, a 1280×720 resolution at a 50 Hz frame rate, is outputted by the Source2812and delivered to the Encoder2814. At this time, the 1280×720, 50 Hz video signal is not sent over the network to the Decoder808.

FIG.8Bshows the video distribution network800during the transition following the switching operation. Specifically, the Decoder808receives a request, such as from an end user, to start receiving the content provided by the Source2812and contained in the second video signal. The Decoder808terminates its data connection with the Encoder1804so that the 1920×1080, 60 Hz video signal is no longer being received by the Decoder808.

In accordance with the embodiment, the Decoder808recognizes that it has entered a transitional state in which it no longer receives the 1920×1080, 60 Hz video signal from the Encoder1804but has not completed establishing a connection with the Encoder2814to receive the 1280×720, 50 Hz video signal provided by the Source2812. During this transitional state, the Decoder808first verifies that it is authorized to receive content from the Source2812, affirms to the Source2812that it is authorized to receive the content, and then private keys are exchanged between the Encoder2814and the Decoder808. At the time these exchanges occur, and until the Decoder808attains authentication with the Source2812and achieves a video lock, either no signal or an unstable signal would ordinarily be delivered to the Sink810.

However, in accordance with the embodiment, the Decoder808delivers a temporary video signal during this interval to the Sink810. The temporary video signal is at the same resolution as the first video signal but at the minimum VRR frame rate supported by the Sink810. Because the Decoder808is functionally simpler than the Decoder508ofFIGS.5A-5C and6, there is no frame buffer to store the last frame delivered to the Sink510from the first video signal. Rather, the temporary video signal is comprised of a black frame or a blank frame delivered repeatedly at the minimum supported VRR frame rate. For example, when the minimum VRR frame rate supported by the Sink810is 48 Hz, the Decoder808outputs a repeating black frame or blank frame having the same 1920×1080 resolution as the first video signal but at the 48 Hz minimum VRR frame rate. The Decoder808then this 1920×1080, 48 Hz temporary video signal to the Sink810.

Upon achieving successful authentication and video lock, the Decoder808discontinues delivering the temporary video signal to the Sink510. Namely, the Decoder508discontinues delivering the repeating 1920×1080, 48 Hz black frame or blank frame of the temporary video signal.

Then, asFIG.8Cshows, the Decoder808now receives the second video signal provided by the Source2812via the Encoder2814and the network806, namely, the Decoder808now receives the 1280×720, 50 Hz video signal. The Decoder808then converts the received 1280×720, 50 Hz video signal into a video signal having a resolution supported by the Sink510, such as into a 1920×1080, 50 Hz video signal. A scaler located within the Decoder808may be used to carry out this conversion. The Decoder808then delivers the scaled 1920×1080, 50 Hz video signal to the Sink810to be displayed.

In this manner, the switching from a first video source to a second video source, such as the transition from receiving and displaying the 1920×1080, 60 Hz video signal provided by the Source1802to receiving the 1280×720, 50 Hz video signal provided by the Source2812and displaying the 1920×1080, 50 Hz video signal, is carried out seamlessly and with minimal disruption noticeable by the end user. Moreover, because the Decoder808continued to transmit a video signal to the Sink810during this transition, the Sink810remains HDCP authenticated and a video lock is maintained between the Decoder808and the Sink810, thereby reducing the time required to transition from displaying the content received from the Source1802to displaying the content received from the Source2812.

ThoughFIGS.8A-8Cdepict switching from a first source providing a 1920×1080, 60 Hz video signal to a second source providing a 1280×720 50 Hz video signal, these values are merely examples. Transitions between other resolutions and/or other frame rates are also within the scope of the embodiments. Moreover, thoughFIGS.8A-8Cdepict a sink supporting a minimum VRR frame rate of 48 Hz, the value is likewise merely an example, and other minimum supported VRR frame rates are also within the scope of the embodiments.

FIG.9is a diagram showing an example of some of the functions carried out by the Decoder808ofFIGS.8A-8Caccording to an embodiment. For example, Input Video Management822is carried out on the received video signal. The video signal is then decompressed, such as using a Coder-Decoder (Codec)824. The decoded video signal is then converted to another resolution, such as by a Scaler826. Output Video Management828may then be performed on the scaled video frame prior to delivery to the Sink810.

The Decoder808ofFIGS.8A-8C and9is simpler in function than the Decoder508ofFIGS.5A-5C and6in that no frame buffer or memory is employed during the transition from the first video signal to the second video signal. Instead, the repeating black frame or blank frame is delivered rather than the repeating last frame as is used in the video distribution network500ofFIGS.5A-5C. Because a simpler Decoder808is employed, the cost of the video distribution network800is reduced.

FIG.10is a flow chart1000showing an example of the steps carried out by a networked repeater device while the networked repeater device switches from a first video signal source to a second video signal source, such as when the Decoder808ofFIGS.8A-8Cswitches from the first video signal outputted by the Source1802to the Encoder1804to the second video signal outputted by the Source2812to the Encoder2814.

First, as shown at1002, the networked repeater device is in a steady state while it receives a first video signal at a fixed resolution from a previously authenticated first source device. The networked repeater device then transmits the received first video signal to a previously authenticated display or other sink device. For example, the Decoder808is in a steady state while it receives the first video signal outputted by Source1802, which may be the 1920×1080, 60 Hz video signal, and transmits the received video signal to the Sink816.

Then, as1004shows, a switch from receiving the first video signal provided by the first source device is carried out, such as when a user switches from viewing the content contained in the first video signal by requesting to view the content contained in the second video signal.

As1006shows, the networked repeater device next prepares to connect to the output of the second source device. For example, the Decoder808may terminate the receiving and displaying of the 1920×1080, 60 Hz first video signal generated by the Source1802by terminating the data connection with the Encoder1804over the network806.

The networked repeater device then initiates establishing HDCP authentication with the new source device over the network. While the HDCP authentication is being established, the networked repeater device is neither able to deliver the first video signal received from the first source device nor deliver the second video signal received from the second source device. For example, the Decoder808may initiate HDCP authentication with the Source2812over the network806, and while the HDCP authentication and video lock are being established, the Decoder808is neither able to transmit the 1920×1080, 60 Hz first video signal provided by the Source1802nor transmit the 1280×720, 50 Hz second video signal provided by the Source2812.

Next, as1008shows, the networked repeater device determines whether the sink or other display device supports a variable refresh rate (VRR). For example, the Decoder808may determine whether the Sink810supports a VRR. If the sink does not support a VRR, then the networked repeater device delivers blank video frames to the sink or other display device until HDCP authentication and video lock are being established, in a manner analogous to that shown inFIG.4B.

Alternatively, if a VRR is supported by the sink, the networked repeater device then outputs a temporary video signal having the minimum VRR frame rate supported by the sink or display, as1010shows. The resolution of the temporary video signal is the same as that of the first video signal. Preferably, the temporary video signal is comprised of a black frame or blank frame which is transmitted repeatedly as the temporary video signal.

For example, the Decoder808outputs a temporary video signal comprised of the repeating black frame or blank frame at the minimum VRR frame rate supported by the display of the Sink816but at the same resolution as the first video signal. When the minimum VRR frame rate supported by the Sink816is 48 Hz, the Decoder808outputs a 48 Hz video signal to the Sink816at the 1920×1080 resolution.

Then, as1012shows, the networked repeater device provides a connection between the new source device and the sink to enable receiving the second video signal. For example, the Decoder808connects to the Source2812via the network806and the Encoder2814to enable receiving the 1280×720, 50 Hz second video signal.

Next, as1014shows, the new video signal stabilizes upon the networked repeater device achieving successful authentication and video lock, and the networked repeater device now converts the resolution of the second video signal to the resolution supported by the sink device. For example, the Scaler830of the Decoder808converts the 1280×720, 50 Hz second video signal to the 1920×1080 resolution supported by the Sink810. The Output Video Management of the Decoder808now delivers the converted video signal to the Sink816.

Thereafter, as1016shows, the switching from receiving a first video signal to receiving a second video signal has been completed.

FIGS.11A-11Cshow an example of a video distribution network1100in accordance with yet another embodiment in which a decoder transmits a temporary video signal comprised of a repeating black frame or blank frame during a transition from a first video signal having a particular resolution and frame rate to a second video signal having a different resolution and/or frame rate. As inFIGS.5A-5C and8A-8C, the temporary repeating black frame or blank frame is delivered at the minimum VRR frame rate supported by the sink device.

However, the video distribution network1100employs a Decoder1108that is simpler in function than the Decoder508shown inFIG.6in that no frame buffer or memory is employed. The Decoder1108is also functionally simpler than the Decoder508shown inFIG.6and the Decoder808shown inFIG.9in that scaling of the video signal is not carried out. Rather, the source devices of the video distribution network1100are set to output respective video signals at a resolution that is matched to the resolution of the sink device, thus eliminating the need for a scaling.

A first source, namely, Source11102, outputs a first video signal containing audiovisual data and having a first resolution and a first frame rate. The Source11102outputs the first video signal to a first encoder, namely, Encoder11104, which is capable of connecting to a data network1106.

A second source, namely, Source21112, outputs a second video signal containing audiovisual data and having a second resolution and a second frame rate, which may be different than the first resolution and/or the first frame rate. The Source11102outputs the second video signal to a second encoder, namely, Encoder21114, which is similarly capable of connecting to the data network1106.

A Decoder1108is capable of connecting to the Source11102via the Encoder11104and the data network1106or, alternatively, to the Source21112via the Encoder21114and the data network1106. The Decoder1108is also connected to a Sink1110.

FIGS.11A-11Cfurther show an example of a transition in which the Decoder1108switches from receiving the first video signal generated by the Source11102to receiving the second video signal generated by the Source21112.

FIG.11Ashows the video distribution network1100in its initial steady state during which the Decoder1108has previously authenticated the Source11102and the Sink1110and is now subscribed to receive the first video signal from the Source11102via the Encoder11104and the data network1106. The first video signal may have, for example, a 1920×1080 resolution at a 60 Hz frame. The 1920×1080, 60 Hz video signal is thereafter sent by the Decoder1108to the Sink1110.

The second video signal, also having the 1920×1080 resolution supported by the Sink1110but at a 50 Hz frame rate, is outputted by the Source21112and delivered to the Encoder21114. At this time, the 1920×1080, 50 Hz video signal is not sent over the network to the Decoder1108.

FIG.11Bshows the video distribution network1100during the transition following the switching operation. Specifically, the Decoder1108receives a request, such as from an end user, to start receiving the content provided by the Source21112and contained in the second video signal. The Decoder1108terminates its data connection with the Encoder11104so that the 1920×1080, 60 Hz video signal is no longer received by the Decoder1108.

In accordance with the embodiment, the Decoder1108recognizes that it has entered a transitional state in which it no longer receives the 1920×1080, 60 Hz video signal from the Encoder11104but has not completed establishing a connection with the Encoder21114to receive the 1920×1080, 50 Hz video signal provided by the Source21112. During this transitional state, the Decoder1108first verifies that it is authorized to receive content from the Source21112, affirms to the Source21112that it is authorized to receive the content, and then private keys are exchanged between the Encoder21114and the Decoder1108. At the time these exchanges occur, and until the Decoder1108attains authentication with the Source21112and achieves a video lock, either no signal or an unstable signal would ordinarily be delivered to the Sink1110.

However, in accordance with the embodiment, the Decoder1108delivers a temporary video signal during this interval to the Sink1110. The temporary video signal is at the same resolution as the first video signal but at the minimum VRR frame rate supported by the Sink1110. Because the Decoder1108is functionally simpler than the Decoder508ofFIGS.5A-5C and6and the Decoder808ofFIGS.8A-8C and9, there is no frame buffer to store the last frame delivered to the Sink from the first video signal. Rather, the temporary video signal is comprised of a black frame or a blank frame delivered repeatedly at the minimum supported VRR frame rate. For example, when the minimum VRR frame rate supported by the Sink1110is 48 Hz, the Decoder1108outputs a repeating black frame or blank frame having the same 1920×1080 resolution as the first video signal but at the 48 Hz minimum VRR frame rate. The Decoder1108then transmits this 1920×1080, 48 Hz temporary video signal to the Sink810.

Upon achieving successful authentication and video lock, the Decoder1108discontinues delivering the temporary video signal to the Sink1110. Namely, the Decoder1108discontinues delivering the 1920×1080, 48 Hz repeating black frame or blank frame of the temporary video signal.

Then, asFIG.11Cshows, the Decoder1108now receives the second video signal provided by the Source21112via the Encoder21114and the network1106, namely, the Decoder1108now receives the 1920×1080, 50 Hz video signal. The Decoder1108then delivers this 1920×1080, 50 Hz video signal to the Sink1110to be displayed.

In this manner, the switching from a first video signal provided by a first source to the second video signal provided by a second source, such as the transition from receiving and displaying the 1920×1080, 60 Hz video signal provided by the Source11102to receiving and then displaying the 1920×1080, 50 Hz video signal provided by the Source21112, is carried out seamlessly and with minimal disruption noticeable by the end user. Moreover, because the Decoder1108continued to transmit a video signal to the Sink1110during this transition, the Sink1110remains HDCP authenticated and a video lock is maintained between the Decoder1108and the Sink1110, thereby reducing the time required to transition from displaying the content received from the Source11102to displaying the content received from the Source21112.

ThoughFIGS.11A-11Cdepict switching from a first source providing a 1920×1080, 60 Hz video signal to a second source providing a 1920×1080, 50 Hz video signal, these values are merely examples. Transitions between other frame rates at other resolutions are also within the scope of the embodiments. Moreover, thoughFIGS.11A-11Cdepict a sink supporting a minimum VRR frame rate of 48 Hz, the value is likewise merely an example, and other minimum supported VRR frame rates are also within the scope of the embodiments.

FIG.12is a diagram showing an example of some of the functions carried out by the Decoder1108ofFIGS.11A-11Caccording to an embodiment. For example, Input Video Management1122is carried out on the received video signal. The video signal is then decompressed, such as using a Coder-Decoder (Codec)1124. Output Video Management828may then be performed on the decoded video signal prior to delivery to the Sink810.

The Decoder1108ofFIGS.11A-11C and12is simpler than the Decoder508ofFIGS.5A-5C and6in that no frame buffer or memory is needed because, during the transition from the first video signal to the second video signal, a repeating black frame or blank frame is delivered rather than the repeating last frame used inFIGS.5A-5C. Moreover, The Decoder1108ofFIGS.11A-11C and12is further simpler than the Decoder508ofFIGS.5A-5C and6and the Decoder808ofFIGS.8A-8C and9in that no scaling is carried out. Rather, the resolution of the video signals received by the Decoder1108is already matched to the resolution supported by the Sink1110. Because a simpler Decoder1108is employed, the cost of the video distribution network1100is further reduced.

FIG.13is a flow chart1300showing an example of the steps carried out by a networked repeater device while the networked repeater device switches from a from a first video signal source to a second video signal source, such as when the Decoder1108ofFIGS.11A-11Cswitches from receiving the first video signal outputted by the Source11102to the Encoder11104to receiving the second video signal stream outputted by the Source21112to the Encoder21114.

First, as shown at1302, the networked repeater device is in a steady state while it receives a first video signal at a fixed resolution from a previously authenticated first source device. The networked repeater device then transmits the received first video signal to a previously authenticated display or other sink device. For example, the Decoder1108is in a steady state while it receives the first video signal outputted by Source11102, which may be the 1920×1080, 60 Hz video signal, and transmits the received 1920×1080, 60 Hz video signal to the Sink1116.

Then, as1304shows, a switch from receiving the first video signal provided by the first source device is carried out, such as when a user switches from viewing the content contained in the first video signal by requesting to view the content contained in the second video signal.

As1306shows, the networked repeater device next prepares to connect to the output of the second source device. For example, the Decoder1108may terminate the receiving and displaying of the 1920×1080, 60 Hz first video signal generated by the Source11102by terminating the data connection with the Encoder11104over the network1106.

The networked repeater device then initiates establishing HDCP authentication with the new source device over the network. While the HDCP authentication is being established, the networked repeater device is neither able to deliver the first video signal received from the first source device nor deliver the second video signal received from the second source device. For example, the Decoder1108may initiate HDCP authentication with the Source21112over the network1106, and while the HDCP authentication is being established, the Decoder1108is neither able to transmit the 1920×1080, 60 Hz first video signal provided by the Source11102nor transmit the 1920×1080, 50 Hz second video signal provided by the Source21112.

Next, as1308shows, the networked repeater device determines whether the sink or other display device supports a variable refresh rate (VRR). For example, the Decoder1108may determine whether the Sink1110supports a VRR. If the sink does not support a VRR, then the networked repeater device delivers blank video frames to the sink or other display device until HDCP authentication and video lock are being established, in a manner analogous to that shown inFIG.4B.

Alternatively, if VRR is supported by the sink, the networked repeater device then outputs a temporary video signal having the minimum VRR frame rate supported by the sink or display, as1310shows. The resolution of the temporary video signal is the same as that of the first video signal. Preferably, the temporary video signal is comprised of a black frame or blank frame which is transmitted repeatedly as the temporary video signal.

For example, the Decoder1108outputs a temporary video signal comprised of the repeating black frame or blank frame at the minimum VRR frame rate supported by the display of the Sink1116but at the same resolution as the first video signal. When the minimum VRR frame rate supported by the Sink1116is 48 Hz, the Decoder1108outputs a 48 Hz video signal to the Sink1116at the prior 1920×1080 resolution.

Then, as1312shows, the networked repeater device provides a connection between the new source device and the sink to enable receiving the second video signal. For example, the Decoder1108connects to the Source21112via the network1106and the Encoder21114to enable receiving the 1920×1080, 50 Hz second video signal.

Next, as1314shows, the new video signal stabilizes upon the networked repeater device achieving successful authentication, and the networked repeater device now delivers the second video signal to the Sink1116.

Thereafter, as1316shows, the switching from receiving a first video signal to receiving a second video signal has been completed.

In this manner, the networked repeater device switches from delivering a video signal provided by a first source device to delivering a video signal provided by another source device. Because the networked repeater device transmits a minimum VRR frame rate video signal to the sink during the transition, the transition is made seamlessly and with minimal disruption noticeable to the end user. Moreover, because the continued transmission of the minimum VRR frame rate video signal during the transition, the sink remains HDCP authenticated to the networked repeater device and a video lock is maintained between the networked repeater device and the sink, thereby reducing the time required to transition from one source to another source.

INDUSTRIAL APPLICABILITY

To solve the aforementioned problems, the present embodiments provide a repeater environment in which, when a transition from a first source to a second source is carried out, a video signal is delivered to the sink at the same resolution but at the minimum VRR frame rate supported by the sink until the new video signal stabilizes.

It should be understood that this description is not intended to limit the embodiments. On the contrary, the embodiments are intended to cover alternatives, modifications, and equivalents, which are included in the spirit and scope of the embodiments as defined by the appended claims. Further, in the detailed description of the embodiments, numerous specific details are set forth to provide a comprehensive understanding of the claimed embodiments. However, one skilled in the art would understand that various embodiments may be practiced without such specific details.

Although the features and elements of aspects of the embodiments are described as being in particular combinations, each feature or element may be used alone, without the other features and elements of the embodiments, or in various combinations with or without other features and elements disclosed herein.

The above-described embodiments are intended to be illustrative in all respects, rather than restrictive, of the embodiments. Thus, the embodiments are capable of many variations in detailed implementation that may be derived from the description contained herein by a person skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the embodiments unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items.

In addition, the above disclosed methods are not meant to limit the aspects of the embodiments, or to suggest that the aspects of the embodiments should be implemented following the aforementioned methods. The purpose of the aforementioned methods is to facilitate the understanding of one or more aspects of the embodiments and to provide the reader with one or many possible implementations of the processed discussed herein. It should be understood by one of ordinary skill in the art that the steps of the aforementioned methods may be performed in a different order and that some steps may be eliminated or substituted.

ALTERNATE EMBODIMENTS

Alternate embodiments may be devised without departing from the spirit or the scope of the embodiments.