Abstract:
Methods and systems configured for on-the-fly detection of available wireless bandwidth and for on-the-fly adapting quality of videos to the available wireless bandwidth are disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to video distribution. More particularly, the present invention relates to video distribution methods and systems for use in situations where the available wireless bandwidth for video distribution may fluctuate over time. 
         [0002]    Video distribution refers to the distribution of video content from a video source to an A/V (audio/video) device (for example, a plasma display or a LCD display). In an example prior art video distribution network, a plurality of video sources may be providing video content to a set-top box. The video sources may represent, for example, DVD players, high-definition (HD) players such as Blu-ray players, or other digital and/or analog video sources including, for example, cable/satellite feeds. The set-top box then provides the video signal from one or more of these video sources to a television set or a display device using some physical conduits such as HDMI (High Definition Media Interface) cables or co-axial cables. Since bandwidth tends to be abundant on the physical conduits, high quality video can readily be provided by the video sources (via the set-top boxes) and displayed on the A/V devices. 
         [0003]    The wireless interface presents a different challenge. A set-top box may provide the aforementioned video signal to a wireless access point for broadcast over the wireless medium using a suitable protocol such as, for example, any of the 802.11 protocols, LTE, WiMax, CDMA, etc. The wireless access point may represent a different device (such as a modem) or may be integrated with the set-top box. 
         [0004]    If the aforementioned A/V device has a suitable wireless interface, the video signal provided through the wireless medium can be received by the A/V device and displayed. However, it has been found that for some bandwidth-intensive video applications, such as high definition (HD) video streaming or playback, the wireless medium may from time to time provide insufficient bandwidth to satisfactorily carry the amount of data associated with these bandwidth-intensive video applications. This is because the available wireless bandwidth in a given home or enterprise environment is typically shared among many different wireless devices. At any given time, the amount of bandwidth available to a particular A/V device may fluctuate. 
         [0005]    In the case where the bandwidth allocated to the video application is insufficient, the video being displayed on the A/V device may need to be paused while waiting for additional video data to arrive through the wireless medium. In some cases, the video signal may be dropped altogether. For applications such as real time live video streaming, the pausing or cessation of the displayed video is clearly unacceptable. Even for video playback applications, the temporary pausing or cessation of the video playback represents an inconvenience to users. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:. 
           [0007]      FIG. 1  shows, in accordance with an embodiment of the invention, a video distribution system for uninterrupted display of a video on one or more displays even when the available wireless bandwidth fluctuates. 
           [0008]      FIG. 2  shows, in accordance with an embodiment of the invention, the steps for deciding which video quality would be selected for transmission to the video display device. 
           [0009]      FIG. 3  shows, in accordance with an embodiment of the invention, the steps for assessing the quality of the wireless channel. 
           [0010]      FIG. 4  shows, in accordance with an embodiment of the invention, a representation of three video streams containing the same video content but in different quality versions. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0011]    The present invention will now be described in detail with reference to a few embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. 
         [0012]    Various embodiments are described herein below, including methods and techniques. It should be kept in mind that the invention might also cover articles of manufacture that includes a computer readable medium on which computer-readable instructions for carrying out embodiments of the inventive technique are stored. The computer readable medium may include, for example, semiconductor, magnetic, opto-magnetic, optical, or other forms of computer readable medium for storing computer readable code. Further, the invention may also cover apparatuses for practicing embodiments of the invention. Such apparatus may include circuits, dedicated and/or programmable, to carry out tasks pertaining to embodiments of the invention. Examples of such apparatus include a general-purpose computer and/or a dedicated computing device when appropriately programmed and may include a combination of a computer/computing device and dedicated/programmable circuits adapted for the various tasks pertaining to embodiments of the invention. 
         [0013]      FIG. 1  shows, in accordance with an embodiment of the invention, a video distribution system for uninterrupted display of a video on one or more displays even when the available wireless bandwidth fluctuates. Portions of the video may be displayed with a higher quality version of the video when wireless bandwidth is abundant and a lower quality version of the same video when wireless bandwidth is limited. 
         [0014]    With reference to  FIG. 1 , there is shown a set-top box  102  coupled to receive video input from a plurality of video storage libraries  104 ,  106 , and  108 . Although set-top box  102  is shown to facilitate discussion, other devices such as gaming console or other media distribution devices may also be implemented. In the example of  FIG. 1 , video storage library  104  stores a high definition (HD) version of a given video content (such as a movie); video storage library  106  stores a standard quality (SD) version of the same content; and video storage library  108  stores a lower quality (LD) version of the same content. Other storage devices and/or other media formats may also be implemented if desired. 
         [0015]    These three versions have different bandwidth requirements for transmission, with the high definition version requiring the highest amount of bandwidth, the standard quality version requiring a lower amount of bandwidth, and the low quality version requiring the lowest amount of bandwidth for transmission. One skilled in the art will readily appreciate that these libraries may be implemented in one or more physical storage devices as needed. Further, although only three different versions are discussed, it should be recognized that any content may be encoded into any number of different quality versions, each with its own bandwidth requirement for transmission. 
         [0016]    Generally speaking, these different quality versions of the same movie may be encoded beforehand (non-real-time) and stored in video storage libraries  104 ,  106 , and  108 . Alternatively, encoding may take place on the fly (real-time) from a video source, such as from a high definition video player or from a video recorder, for example. In the example of  FIG. 1 , the video data from one or more of video storage libraries  104 ,  106 , and  108  are provided to set-top box  102  via co-axial cables although any other suitable transmission medium (such as twisted pairs, fiber optics, etc.) may also be employed. 
         [0017]    A video bandwidth adapter  110  is shown coupled between set-top box  102  and the video display devices, such as video display  112 , laptop computer  114 , desktop computer  116 , or smart phone  118 . Signal transmission between video bandwidth adapter  110  and set-top-box  102  may be accomplished via a physical medium in an embodiment. In one or more embodiments, signal transmission between video bandwidth adapter  110  and video display  112 , laptop computer  114 , desktop computer  116 , or smart phone  118  may be accomplished using the wireless medium via any one of the suitable protocols for wireless transmission of video data (such as 802.11N 4×4). 
         [0018]    Video bandwidth adapter  110  detects the available wireless bandwidth for video transmission, and depending on the available wireless bandwidth and the requirement of the video display device, selects the appropriate video signal from one of video storage libraries  104 ,  106 , or  108  for transmission to the video display device. For example, if video bandwidth adapter  110  ascertains that a large amount of wireless bandwidth is available, video bandwidth adapter  110  may select the high definition video signal from video storage library  104  to be delivered to video display  112 . At some other time, if video bandwidth adapter  110  ascertains that a low amount of wireless bandwidth is available, video bandwidth adapter  110  may select a lower quality video signal from, for example, video storage library  106  or  108  to be delivered to video display  112 . Video bandwidth adapter  110  may perform a similar function for videos transmitted for display on laptop computer  114 , desktop computer  116 , or smart phone  118 . 
         [0019]      FIG. 1  shows a display adapter  130 , representing an optional adapter for enabling legacy video displays to communicate with video bandwidth adapter  110 . Some legacy video displays and other video display devices may natively communicate using a different interface or protocol than that employed by video bandwidth adapter  110 . Display adapter  130  provides a communication bridge and some buffering functionality between such a legacy video display device and video bandwidth adapter  110 . It should be noted that if a video display device is compatible with video bandwidth adapter  110 , a display adapter is not required. 
         [0020]    In one or more embodiments, laptop computer  114 , desktop computer  116 , or smart phone  118  may be provisioned with software and/or software driver for communicating with video bandwidth adapter  110  via the wireless medium. In this manner, laptop computer  114 , desktop computer  116 , or smart phone  118  may display the video with the appropriate quality that may be transmitted as the available wireless bandwidth fluctuates. 
         [0021]      FIG. 2  shows, in an embodiment of the invention, the steps for deciding which video quality would be selected for transmission to the video display device. Generally speaking, the steps of  FIG. 2  are performed by logic circuitry in video bandwidth adapter  110  although such steps may also be delegated to another device if desired. Generally speaking, the video content may be conceptually or physically divided into a plurality of segments, with each pair of adjacent segments separated by a checkpoint. The video transmission may begin with a given segment using a default quality such as, for example a standard quality. However, any quality version may be set as the default quality if desired. In step  202 , the quality of the wireless channel is ascertained. If the quality of the wireless channel is unchanged, the method returns to step  202  to continue to monitor the quality of the wireless channel. Meanwhile, video transmission continues with the existing quality mode. 
         [0022]    However, if the quality of the wireless channel improves (step  204 ), the next segment would be transmitted in a better quality mode (e.g., standard quality to high definition quality) for display on the A/V device. Of course if the video transmission mode is already in the highest quality mode, the next segment will continue to be transmitted in the highest quality mode. Thereafter, the method returns to step  202  to continue to monitor the quality of the wireless channel. 
         [0023]    On the other hand, if the quality of the wireless channel degrades (step  206 ), the next segment would be transmitted in a lower quality mode (e.g., standard quality to lower quality). Of course if the video transmission mode is already in the lowest quality mode, the next segment will continue to be transmitted in the lowest quality mode if possible. Thereafter, the method returns to step  202  to continue to monitor the quality of the wireless channel. 
         [0024]      FIG. 3  shows, in accordance with an embodiment of the invention, the steps for assessing the quality of the wireless channel. In step  302 , the bit error rate (BER) in the last time period may be assessed through the over-the-air (OTA) interface. BER measurement through OTA is only one method of assessing wireless channel quality and other methods are possible, as can be appreciated by those skilled in the art. In this example, the last time period may be the last few milliseconds or during the last few video frames of a segment, for example. In step  304 , the congestion of the wireless channel is assessed based on, for example, the number of users and the channel activity. Channel activity may depend on the number and types of applications currently placing demand on wireless bandwidth, for example. Other parameters may also be employed to ascertain the congestion of the channel if desired. In step  306 , the wireless bandwidth available for video transmission is ascertained in view of the congestion determined in step  304 . This available wireless bandwidth may be compared to the available wireless bandwidth in the past to determine whether the wireless channel quality has stayed the same, has improved, or has degraded. 
         [0025]    In an embodiment, a relative figure of merit may be predefined and if parameters reflective of wireless channel congestion and bit error rate falls below this figure of merit for more than some predefined duration, the quality of the wireless channel may be deemed to have degraded to the point where standard video transmission is not possible and a lower quality video transmission mode is needed. For example, a KPI (Key Performance Indicator) may be predefined as a function of one or more of the video performance metrics (e.g., jitter, delay, channel quality, interference, etc.). Alternatively, if parameters reflective of wireless channel congestion and bit error rate exceeds this figure of merit for more than some predefined duration, the quality of the wireless channel may be deemed to have improved to the point where high definition video transmission is possible. 
         [0026]      FIG. 4  shows, in accordance with an embodiment of the invention, a representation of three video streams  402 ,  404 , and  406  containing the same video content but in different quality versions. Video streams  402 ,  404 , and  406  may represent files stored on one or more storage devices (e.g., hard drives or other non-volatile memory storage devices) or may be generated on-the-fly from a single video source (e.g., high definition video player or video recorder) as necessary. As can be seen, high definition video  402  requires more data to carry the high definition video than standard quality video  404 , which in turn requires more data to carry the video content than lower quality video  406 . 
         [0027]    Video streams  402 ,  404 , and  406  are divided into segments at the same location in the stream, e.g., between the same adjacent video frames in the same embodiment in all three video streams. Video segments  402   a,    402   b,  and  402   c  of high definition video stream  402  are delineated by breaks  412   a  and  412   b.  Video segments  404   a,    404   b,  and  404   c  of standard quality video stream  404  are delineated by breaks  414   a  and  414   b.  Video segments  406   a,    406   b,  and  406   c  of lower quality video stream  406  are delineated by breaks  416   a  and  416   b.  Depending on the available wireless bandwidth, the video stream may be displayed using a high definition segment  402   a,  to be followed by a standard definition segment  404   b,  to be followed by a low quality segment  404   c.  In this manner, although the video segment sequence (e.g., a-b-c) is still employed, the actual video displayed may comprise segments from different quality versions. 
         [0028]    As can be appreciated from the foregoing, embodiments of the invention allow the video stream to continue to be displayed even if the available wireless bandwidth falls below the threshold possible to display a higher quality video. In contrast to the prior art wherein such deficient wireless bandwidth situation would have caused a cessation of video display until video transmission catches up, embodiments of the invention allows the video display to continue albeit with a lower quality. With proper buffering and smoothing at the display device, it is possible to display the video using segments from different quality versions without the breaks visually perceptible to the human user. 
         [0029]    While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. For example, although a display  112  is shown in the example, the invention applies to any type of A/V device, whether stationary or mobile. As another example, although a video display is shown to facilitate discussion of the dynamic bandwidth adaptation aspects of the invention when video data is transmitted for displaying on the video display, the invention also applies to video sources (such as a video camera) that upload video to the network for real-time streaming or to storage device(s) or for processing for example. In such case, the video quality from the video source(s) may also be dynamically adapted to the available wireless bandwidth in an analogous manner to that discussed above. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the description be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.