Abstract:
A method and apparatus control the use of transmission bandwidth by detecting a change in presentation of a video picture on a receiving telecommunication terminal; transmitting the detected change to a transmitting telecommunication terminal; and adjusting the transmission rate of the video picture in response to the detected change by the transmitting telecommunication terminal.

Description:
TECHNICAL FIELD 
     This invention relates to the communication of video information. 
     BACKGROUND 
     Video calls and video conferencing has become more common due to the improvement in technology. However, a large amount of bandwidth is still required to provide acceptable video resolution and motion. Within the prior art, it is known to limit and adjust the video resolution based on the bandwidth capabilities of the network which is transporting the video information. Within the prior art, when a video call is set up, a certain CODEC is used and is typically maintained for the duration of the call. The only changes that are typically made with respect to the CODEC and bit-rate of transmission are those to improve the network or terminal performance. The higher-quality imaging CODEC that is used translates into a high bit-rate of transmission. 
     SUMMARY 
     A method and apparatus control the use of transmission bandwidth by detecting a change in presentation of a video picture on a receiving telecommunication terminal; transmitting the detected change to a transmitting telecommunication terminal; and adjusting the transmission rate of the video picture in response to the detected change by the transmitting telecommunication terminal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  illustrates an embodiment; 
         FIGS. 2-4  illustrate examples of displays on a display of a terminal; and 
         FIGS. 5 and 6  illustrate, in flowchart form, operations performed by an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     During a video call, one embodiment is responsive to the area occupied by the video picture being reduced to a smaller size to reduce the transmission rate required to support the lower resolution of the smaller size. Similarly, the embodiment negotiates for increased transmission capacity if the video picture increases in size thus increasing the resolution of the video picture. 
     In another embodiment, a terminal that causes a portion of a video picture to be hidden behind an image being displayed by another application or from another source transmits a specification of the hidden section to the terminal or terminals that are transmitting the video picture to the receiving terminal. The transmitting terminal or terminals then eliminate the transmission of the area of the video picture that is being hidden by the display of the application. Note, that various things could be hiding the video picture other than the action of an application, including operations of the operating system, etc. 
     To understand the operation of the first embodiment, consider the following example. Terminal  121  and terminal  123  are engaged in a video call. Terminals  122  and  123  are similar in makeup to terminal  121 . The video picture of the video call is displayed for the user of terminal  121  on display  106 . This video picture is received from terminal  123 . Assume initially that video picture  201  of  FIG. 2  occupies the majority of display  106 . Since video picture  201  is a large area, terminals  121  and  123  have to utilize a high-quality imaging CODEC which results in a high bandwidth requirement being placed on transmission through wide area network (WAN)  124 . 
     Assume that the user of terminal  121 , using well known techniques, reduces the video picture  201  to the size illustrated in  FIG. 3 . Since video picture  201  is smaller in size, it requires less resolution than the video picture  201  of  FIG. 2 . Consequently, terminal  121  renegotiates the reduced bandwidth hence the CODEC required for the transmission of video information from terminal  123  to terminal  121 . 
     To understand the operations of the second embodiment, consider the following example. Initially, during the video call between terminal  121  and terminal  123 , video picture  201  is as illustrated in  FIG. 2  where video picture  201  occupies the entire screen of display  106  and is the only imaging object being displayed on display  106 . Then the user actuates an application that brings up application display  301  as illustrated in  FIG. 4 . Application display  301  overlays a portion of video picture  201 . Terminal  121  then transmits information to terminal  123  specifying the portion of video picture  201  that is overlaid by application display  301 . Terminal  123  then ceases to transmit the video information of the portion of video picture  201  that is overlaid by application display  301 . 
     Although the examples have explained the two embodiments as functioning separately, the two embodiments can also compliment each other and be in operation at the same time. Terminal  121  is illustrated in greater detail in  FIG. 1 . 
     Terminals  122  and  123  are similar in design. Processor  102  provides control of terminal  121  by executing programs and retrieving and storing data out of memory  101 . Operating system  112  supplies the overall control. Interface  117  interacts with interfaces  103 - 109 . Data is stored in data  113 . Call processing is controlled by call processing routine  116 . The selection and actuation of CODEC is controlled by CODEC routine  114 . Display control routine  111  controls the manipulation of images on display  106 . Video call control routine  108  controls the video aspects of a call. Audio generator routine  118  generates the necessary tones required for the operation of terminal  121 . Units  105 ,  106 , and  119  are interconnected to processor  102  via interfaces  107 ,  104 , and  109 , respectively. 
     Interface  103  contains the necessary hardware and software to interface and to communicate video calls via WAN  124 . 
       FIGS. 5 and 6  illustrate, in flowchart form, operations performed by an embodiment of a terminal. After being started in block  501 , decision block  502  determines if a video call is being established. If the answer is no, block  503  performs normal processing before transferring control back to decision block  502 . If the answer is yes in decision block  502 , block  504  establishes the visual call. 
     After execution of block  504 , decision block  506  determines if the size of the video picture has increased. If the answer is yes, block  507  increases the CODEC transmission rate either by choosing a new CODEC or increasing the transfer rate of the existing CODEC before transferring control to decision block  511 . 
     If the answer is no in decision block  506 , decision block  508  determines if the size of the video picture is decreasing. If the answer is yes, block  509  decreases the CODEC transmission rate by choosing a new CODEC or using an existing CODEC but lowering the transmission rate before transferring control to decision block  511 . 
     If the answer in decision block  508  is no, decision block  511  determines if the video picture is being overlapped. If the answer is yes, control is transferred to block  512  which signals the other terminal not to transmit the overlap portion before transferring control to decision block  601  of  FIG. 6 . 
     If the answer in decision block  511  is no, decision block  601  determines if the video picture is no longer being overlapped. If the answer is yes, block  602  signals the other terminal to transmit the formerly overlapped portion before transferring control to decision block  603 . 
     If the answer in decision block  601  is no, decision block  603  determines if a signal is being received from the endpoint of the call indicating that the video picture is being overlapped. This is the video picture that is being transmitted from the terminal executing the steps illustrated in  FIG. 6 . If the answer is yes, block  604  calculates the portion that is being overlapped and ceases to transmit that portion before transferring control to decision block  608 . 
     If the answer in decision block  603  is no, decision block  606  determines if a signal has been received from the endpoint indicating that the video picture is no longer being overlapped on the endpoint. This signal would be received from the terminal that is the endpoint of the video call. If the answer is yes in decision block  606 , block  607  starts to retransmit the formerly overlapped portion before transferring control to decision block  608 . 
     Decision block  608  determines if the video call has been terminated. If the answer is no, control is transferred back to decision block  506  of  FIG. 5 . If the answer is yes, block  609  performs normal processing before returning control back to decision block  502  of  FIG. 5 . 
     When the operations of the terminals, servers, or systems are implemented in software, it should be noted that the software can be stored on any computer-readable medium for use by or in connection with any computer related system or method. In the context of this document, a computer-readable medium is an electronic, magnetic, optical, or other physical device or means that can contain or store a computer program for use by or in connection with a computer related system or method. The software can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “computer-readable medium” can be any means that can store, communicate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. For example, the computer-readable medium can be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM) (electronic), a read-only memory (ROM) (electronic), an erasable programmable read-only memory (EPROM, EEPROM, or Flash memory) (electronic), and a portable compact disc read-only memory (CDROM) (optical). 
     In an alternative embodiment, where the terminals, servers, or systems is implemented in hardware, the stations, servers, or systems can be implemented with any or a combination of the following technologies, which are each well known in the art: a discrete logic circuit(s) having logic gates for implementing logic functions upon data signals, an application specific integrated circuit (ASIC) having appropriate combinational logic gates, a programmable gate array(s) (PGA), a field programmable gate array (FPGA), etc. 
     Of course, various changes and modifications to the illustrated embodiments described above would be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the following claims except in so far as limited by the prior art.