PATENT DOCUMENT

Publication Number: US-8732269-B2
Application Number: US-201113313958-A
Country: US
Kind Code: B2

Title: Methods and apparatuses for transferring data

Abstract:
The present invention provides several methods and apparatuses for transmitting multimedia data using streaming media protocols such as real-time transfer protocols (RTP) and real-time streaming protocols (RTSP) in a computer network environment. In one exemplary embodiment, a request for RTP data and its associated extension is sent from the caching proxy server to the server. The request may be for one specific type of data or multiple unrelated types of data. The server responds to the request indicating its support for the requested RTP extension data. The caching proxy server determines whether to proceed or terminate the data transmission process based on the response provided by the server. If it is determined to proceed with the data transmission process, the caching proxy informs the server to send the requested and supported RTP data. The server sends the requested data in a variable and extendible header format.

Claims:
What is claimed is: 
     
       1. A method of frame thinning by a data processing device coupled to a network, comprising:
 receiving a message through the network, said message indicating a need to thin streaming media data being sent through the network; 
 assigning a plurality of frame types to the streaming media data, the frame types including at least one known frame type; 
 evaluating priority of streaming media data based on frame type; and 
 sending only selected streaming media data, 
 wherein the message is received at a caching proxy server that sends the selected streaming media data to a client device, the method further comprising performing the following at the caching proxy server: 
 prior to receiving the message, determining based on a data receiving rate or a data processing rate of the client device, that the client device requires frame thinning; 
 checking whether an originating server from which the streaming media data is sent to the caching proxy server supports all frame types required for frame thinning; and 
 responsive to receiving the message, and conditional upon determining that the originating server supports all frame types required for frame thinning, thinning the streaming media data to generate the selected streaming media data. 
 
     
     
       2. A method of  claim 1 , wherein said evaluating comprising:
 naming unsigned integers to the frame types; 
 assigning an integer value of “0” to an unknown frame type; 
 an integer value of “1” to a key frame type; 
 an integer value of “2” to a p-frame type; and 
 an integer value of “3” to a b-frame type. 
 
     
     
       3. A method of  claim 2 , wherein said key-frame being most important in priority than any other frames. 
     
     
       4. A method of  claim 2 , wherein said p-frame being less important in priority than key-frame, and more important in priority than b-frame. 
     
     
       5. A method of  claim 2 , wherein said b-frame being less important in priority than p-frame. 
     
     
       6. A method of  claim 2 , wherein said b-frame being less important in priority than key-frame. 
     
     
       7. A method of  claim 2 , wherein said unknown-frame being either more or less important in priority than key-frame, p-frame and b-frame. 
     
     
       8. A method of  claim 2 , wherein said key-frame being more important in priority than p-frames, b-frames, and any other frames. 
     
     
       9. A method of  claim 1 , further comprising:
 receiving a second message to further thin streaming media data; 
 processing message and eliminating more selected streaming media data and sending streaming media data of higher priority. 
 
     
     
       10. A method of  claim 9 , wherein said selected streaming media frame being eliminated being a b-frame, and sending streaming media data with higher priority than b-frame. 
     
     
       11. A method of  claim 9 , wherein said streaming media data being eliminated being a p-frames and b-frame, and sending frames with higher priority than both p-frames and b-frames. 
     
     
       12. A method as in  claim 1 , wherein the checking involves sending a request to the originating server for the streaming media data together with a request for the originating server to identify those frame types that are associated with the streaming media data and supported by the originating server. 
     
     
       13. A method as in  claim 2 , wherein the unsigned integer is sized to allow additional integer values to be assigned to other, unspecified frame types. 
     
     
       14. A non-transitory machine-readable medium that provides executable instructions, which when executed by a set of processors, cause said set of processors to perform frame thinning operations by a data processing device coupled to a network comprising:
 receiving a message through the network to thin frames in a streaming media data transmission from the data processing device; 
 assigning a plurality of frame types to the streaming media data, the frame types including at least one known frame type; 
 evaluating priority of frames based on frame type; and 
 sending only selected frames, 
 wherein the instructions cause the set of processors to send the selected frames to a client device, the instructions further causing the set of processors to perform the following:
 prior to receiving the message, determining based on a data receiving rate or a data processing rate of the client device, that the client device requires frame thinning; 
 checking whether an originating server from which the streaming media data is sent to the data processing device supports all frame types required for frame thinning; and 
 responsive to receiving the message, and conditional upon determining that the originating server supports all frame types required for frame thinning, thinning the streaming media data to generate the selected frames. 
 
 
     
     
       15. A machine-readable medium as in  claim 14 , wherein said frame priority being evaluated by naming unsigned integers to the frame types, said unsigned integers comprising:
 assigning an integer value of “0” to an unknown frame type; 
 an integer value of “1” to a key frame type; 
 an integer value of “2” to a p-frame type; and 
 an integer value of “3” to a b-frame type. 
 
     
     
       16. A machine-readable medium as in  claim 15 , wherein said key-frame being most important in priority than any other frames. 
     
     
       17. A machine-readable medium as in  claim 15 , wherein said p-frame being less important in priority than key-frame, and more important in priority than b-frame. 
     
     
       18. A machine-readable medium as in  claim 15 , wherein said b-frame being less important in priority than p-frame. 
     
     
       19. A machine-readable medium as in  claim 15 , wherein said b-frame being less important in priority than key-frame. 
     
     
       20. A machine-readable medium as in  claim 15 , wherein said unknown-frame being either more or less important in priority than key-frame, p-frame a b-frame. 
     
     
       21. A machine-readable medium as in  claim 15 , wherein said key-frame being more important in priority than p-frames, b-frames, and any other frames. 
     
     
       22. A machine-readable medium as in  claim 16 , further comprising:
 receiving a second request to further thin frames; 
 processing request and eliminating more selected frames and sending frames of higher priority. 
 
     
     
       23. A machine-readable medium as in  claim 22 , wherein said selected frame being eliminated being a p-frame, and sending frames with higher priority than p-frame. 
     
     
       24. A machine-readable medium as in  claim 22 , wherein said selected frame being eliminated being a p-frames and b-frame, and sending frames with higher priority than both p-frames and b-frames. 
     
     
       25. A machine-readable medium as in  claim 14 , wherein the checking involves sending a request to the originating server for the streaming media data together with a request for the originating server to identify those frame types that are associated with the streaming media data and supported by the originating server. 
     
     
       26. A machine-readable medium as in  claim 15 , wherein the unsigned integer is sized to allow additional integer values to be assigned to other, unspecified frame types. 
     
     
       27. A frame thinning data processing device coupled to a network comprising:
 means for receiving a message through the network to thin frames in a streaming media data transmission from said data processing device; 
 means for assigning a plurality of frame types to the streaming media data, the frame types including at least one known frame type; 
 means for evaluating priority of frames based on frame type; 
 means for sending only selected frames to a client device; 
 means for prior to receiving the message, determining based on a data receiving rate or a data processing rate of the client device, that the client device requires frame thinning; 
 means for checking whether an originating server from which the streaming media data is sent to the data processing device supports all frame types required for frame thinning; and 
 means for responsive to receiving the message, and conditional upon determining that the originating server supports all frame types required for frame thinning, thinning the streaming media data to generate the selected frames.

Description:
This application is a divisional of U.S. application Ser. No. 11/496,855 filed on Jul. 31, 2006 now U.S. Pat. No. 8,078,747, which is a continuation of U.S. application Ser. No. 09/603,108, filed on Jun. 22, 2000, now U.S. Pat. No. 7,191,242. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of multimedia data transmission. In particular, the present invention in one exemplary embodiment relates to multimedia data transmission of real-time transfer protocol (RTP) packets using real time streaming protocol (RTSP) in a computer network environment. 
     INTRODUCTION AND BACKGROUND OF THE INVENTION 
     Methods of transmitting data are commonly known and performed today on a routine basis to send various multimedia data such as text, graphics, audio, video, images etc. across computer networks situated in various parts of the world. Generally the transmission process requires both hardware and software for performing its function. Typically, the hardware includes various types of personal computers and hand held multimedia data sending or receiving devices. These devices run under the control of an operating system and utilize multimedia application software programs. As is known in the art, streaming media data is data which is transmitted to a receiving computer system and presented (usually after buffering temporarily at the receiving system) and then discarded (not stored) at the receiving system. 
     Currently, data is sent in form of packets from one multimedia device to another. A large amount of information is required to be sent in a real-tune manner in the data packets, which imposes a heavy load on the systems. Streaming media data, such as Real-Audio data in streaming media format specified by Real-Networks, is sent through the Internet is near real-time manner in many cases. 
     In one approach, the components involved in data transmission of streaming media are known to be a server (which may be referred to as originating server), a caching proxy server and a client. These components in various combinations communicate with each other for transmitting data packets in real-time. The communication link that currently exists between the components uses real-tune transfer protocols (RTP) and real-time streaming protocols (RTSP) to communicate and send packets to each other. For this approach to work, a caching proxy server needs to communicate with the system server, receive a stream of RTP data packets, and transfer the information contained within the RTP data packets to a client.  FIG. 1   a  shows an example of a prior method in which a caching proxy server receives streaming media data and provides this data to a client. In order to perform its function properly and efficiently, the caching proxy server needs several pieces of information from the server to be able to cache an RTP stream easily and reliably. 
     A problem with the current approach is that it is not able to provide some of the key required information such as data packet transmit time and video packet frame type information that a caching proxy needs to be efficient. 
     This information allows a caching proxy server to provide smooth packet delivery to its client by knowing the time an RTP data packet was intended to be sent, and type of video frame that is being sent without knowing the specific payload format. Another problem with the current approach is chat it is not able to provide multiple pieces of unrelated data in one delivery to the caching proxy server, furthermore, packets from the server may be “lost” and never reach the caching proxy server. In addition, there is normally no way to recreate a complete “pristine” copy at the caching proxy server. 
     Prior art servers communicate RTP information to the caching proxy server by sending information through a cache-control header. In one approach, a cache-control header contains normal header fields. In another approach, unrelated to cache control of RTP information, a single type of additional information has been added to the normal fields in a header extension format without specifying the type of additional information. In this approach only a single piece of RTP extension can be added to the normal field of the header and sent at anyone time. 
     A problem with using this limited, non-extensible approach is that a server is not able to attach multiple sets of unrelated data at a time to send to the caching proxy server. Another problem with this approach is that the header extension used in these methods are still not able to provide all the information a caching proxy server needs to cache a stream properly and to transmit the stream properly. Yet another problem with this approach is that there is no way to identify the particular extension independently of other possible extensions. 
     SUMMARY OF THE INVENTION 
     The present invention provides several methods and apparatuses for transmitting multimedia data using streaming media protocols such as real-time transfer protocols (RTP) and real-time streaming protocols (RTSP) in a computer network environment. In one exemplary embodiment, a request for RTP data is sent horn the caching proxy server to the server. The request may be for one specific type of data and its related extensions or multiple unrelated types of data and their related extensions. The server responds to the request indicating its support for the requested RTP data. The caching proxy server determines whether to proceed or terminate the data transmission process based on the response provided by the server. If it is determined to proceed with the data transmission process, the caching proxy informs the server to send the requested and supported RTP data. The server sends the requested data in a variable and extendible header format. 
     In another embodiment, the caching proxy server requests and receives packet transmit time data and/or packet frame type data from the server. The caching proxy server uses the frame type data to communicate with the client and supply frames based on client&#39;s capacity to handle loads at given times. Transmit time data is also used by the caching proxy to store packets locally and deliver these packets at appropriate times to the client for a smooth packet delivery. 
     Other features and advantages of the present invention will be apparent from the accompanying drawings, and from the detailed description, which follows below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not limited by the figures of the accompanying drawings in which like references indicate similar elements and in which; 
         FIG. 1   a  is a flowchart which shows a method in the prior art for transferring streaming media data to caching proxy server and then to a client. 
         FIG. 1   b  illustrates a network of computer systems in which media data may be exchanged and/or processed, according to one embodiment of the present invention. 
         FIG. 2  illustrates a block diagram of an exemplary digital processing system, which may be used in accordance with one embodiment of the present invention. 
         FIG. 3  illustrates one embodiment of a communication method between a server and a client using RTSP and RTP protocols. 
         FIG. 4  illustrates another embodiment of a communication method between a server, caching proxy server and a client. 
         FIG. 5  illustrates one embodiment of a RTSP, RTP negotiation process between a caching proxy and a server. 
         FIG. 6  illustrates one embodiment of a relationship between the server, caching proxy, and client during a transfer of a Transmit Time (TT) sub-extension to the caching proxy server and its use of TT information in transmitting streaming data to a client. 
         FIG. 7  illustrates one embodiment of process that takes place during transfer of a transmit time sub-extension between server and caching proxy server. 
         FIG. 8  illustrates one embodiment of process that takes place during transfer of a frame type sub-extension between server, and caching proxy server. 
         FIG. 9  is a flow diagram of one embodiment of an operation to provide various types of information to a caching proxy in an extensible header format. 
         FIG. 10  illustrates one embodiment of a relationship between the server, caching proxy, and client during a transfer of a Frame Type sub-extension. 
         FIG. 11  illustrates a block diagram of a machine readable medium which stores executable computer program instruction for execution by an exemplary caching proxy server, which may be used in accordance with one embodiment of the present invention. 
         FIG. 12  illustrates a block diagram of a machine readable medium which stores executable computer program instruction for execution by an exemplary originating server (server), which may be used in accordance with one embodiment of the present invention. 
         FIG. 13  illustrates a block diagram of a machine readable medium which stores executable computer program instruction for execution by an exemplary client, which may be used in accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     A method and system for providing multimedia data transmission using real-time transfer protocol (RTP) and real time streaming protocol (RTSP) are described. For purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. For example, various computer network system architectures and digital processing system architectures are provided for illustrative purposes rather than to be construed as limitations of the present invention. It will be evident, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form to facilitate explanation. 
       FIG. 1   b  is a diagram of a network of computer systems in which media data may be processed, according to one embodiment of the present invention. As shown in  FIG. 1   b , a number of client computer system, one or more of which may represent one implementation of a receiving system, are coupled together through an Internet  122 . It will be appreciated that the term “Internet” refers to a network of networks. Such networks may use a variety of protocols for exchange of information, such as TCP/IP, ATM, SNA, SDI, RTP, RTSP etc. The physical connections of the Internet and the protocols and communication procedures of the Internet are well known to those in the art. Access to the Internet  103  is typically provided by Internet service providers (ISPs), such as the ISP  124  and the ISP  126 , which may also be connected with caching proxy servers  130  and  132 . Users on client systems, such as the client computer systems  102 ,  104 ,  118 , and  120 , generally obtain access to the Internet through Internet service providers, such as ISPs  124  and  126 , which may also be connected through the internet with caching proxy servers  130  and  132 . Access to the Internet may facilitate transfer of information (e.g., email, text files, media files, etc.) between two or more digital processing systems, such as the client computer systems  102 ,  104 ,  118 , and  120  and/or a streaming media server system  128  which may be considered an originating server from which caching proxy servers receive streaming media data. For example, one or more of the client computer systems  102 ,  104 ,  118 , and  120  and/or the streaming media server  128  may provide media data (e.g., video and audio, or video, or audio) to another one or more of the client computer systems  102 ,  104 ,  118 , and  120  and/or the streaming media server  128 . Such may be provided in response to a request. As described herein, such media data may be transferred in the system  100  according tracks. Such tracks, in one embodiment of the invention, may be created according to a specific format of the streaming media data and/or a specific data communication (e.g., network) protocol(s). 
     The streaming media server  128  is typically comprised of at least one computer system to operate with one or more data communication protocols, such as the protocols of the World Wide Web, and as such, is typically coupled to the Internet  122 . Optionally, the streaming media server  128  may be part of an ISP which may provide access to the Internet and/or other network for client computer systems. The client computer systems  102 ,  104 ,  118 , and  120  may each, with appropriate web browsing software, access data, such as HTML documents (e.g., Web pages), which may be provided by the streaming media server  128 . Such data may provide media, such as QuickTime movies or QuickTime streaming media data, which may be presented by the client computer systems  102 ,  104 ,  118 , and  120 . 
     The ISP  124  provides Internet connectivity to the client computer system  102  via a modem interface  106 , which may be considered as part of the client computer system  102 . The client computer system may be a conventional computer system, such as a Macintosh computer, a “network” computer, a handheld portable computer, a Web TV system, or other types of digital processing systems (e.g., a cellular telephone having digital processing capabilities). Similarly, the ISP  126  provides Internet connectivity for the client computer systems  104 ,  118  and  120 , although as depicted in  FIG. 1   b , such connectivity may vary between various client computer systems, such as the client computer systems  102 ,  104 ,  118 , and  120 . For example, as shown in  FIG. 1   b , the client computer system  104  is coupled to the ISP  126  through a modem interface  108 , while the client computer systems  118  and  126  are part of a focal Area Network (FAN). The interfaces  106  and  108 , shown as modems  106  and  108 , respectively, in  FIG. 1   b , may be an analog modem, an ISDN modem, a cable modern, a satellite transmission interface (e.g., “Direct PC”), a wireless interface, or other interface for coupling a digital processing system, such as a client computer system, to another digital processing system. The client computer systems  118  and  120  are coupled to a FAN bus  112  through network interfaces  114  and  116 , respectively. The network interfaces  114  and  116  may be an Ethernet-type, Asynchronous Transfer Mode (ATM), or other type of network interface. The FAN bus is also coupled to a gateway digital processing system  110 , which may provide firewall and other Internet-related services for a LAN. The gateway digital processing system  110 , in turn, is coupled to the ISP  126  to provide Internet connectivity to the client computer systems  118  and  120 . The gateway digital processing system  110  may, for example, include a conventional server computer system. Similarly, the streaming media server  128  may, for example, include a conventional server computer system. 
     The system  100  may allow one or more of the client computer systems  102 ,  104 ,  118 , and  120  and/or the streaming media server  128  to provide media data (e.g., video and audio, or video, or audio) to another one or more of the client computer systems  102 ,  104 ,  118 , and  120  and/or the streaming media server  128 . Such data may be provided, for example, in response to a request by a receiving system, which may be, for example, one or more of the client computer systems  102 ,  104 ,  118 , and  120 . 
       FIG. 2  is a block diagram of an exemplary digital processing system which may be used in accordance with one embodiment of the present invention. For example, the digital processing system  250  shown in  FIG. 2  may be used as a client computer system, a streaming media server system, a conventional server system, etc. Furthermore, the digital processing system  250  may be used to perform one or more functions of an Internet service provider, such as the ISP  124  or  126 . The digital processing system  250  may be interfaced to external systems through a modem or network interface  268 . It will be appreciated that the modem or network interface  268  may be considered as part of the digital processing system  250 . The modem or network interface  168  may be an analog modem, an ISDN modem, a cable modem, a token ring interface, a satellite transmission interface, a wireless interface, or other interface(s) for providing a data communication link between two or more digital processing systems. 
     The digital processing system  250  includes a processor  252 , which may represent one or more processors and may include one or more conventional types of such processors, such as a Motorola PowerPC processor, an Intel Pentium (or x86) processor, etc. A memory  255  is coupled to the processor  252  by a bus  256 . The memory  255  may be a dynamic random access memory (DRAM) and/or may include static RAM (SRAM). The processor may also be coupled to other types of storage areas/memories (e.g., cache. Flash memory, disk, etc.), winch could be considered as part of the memory  255  or separate from the memory  255 . 
     The bus  256  further couples the processor  252  to a display controller  258 , a mass memory  262 , the modem or network interface  268 , and an input/output (I/O) controller  264 . The mass memory  262  may represent a magnetic, optical, magneto-optical, tape, and/or other type of machine-readable medium/device for storing information. For example, the mass memory  262  may represent a hard disk, a read-only or writable optical CD. etc. The display controller  258  controls in a conventional manner a display  260 , which may represent a cathode ray tube (CRT) display, a liquid crystal display (LCD), a plasma display, or other type of display device. The I/O controller  264  controls  170  device(s)  266 , which may include one or more keyboards, mouse/trackball or other pointing devices, magnetic and/or optical disk drives, printers, scanners, digital cameras, microphones, etc. 
     It will be appreciated that the digital processing system  250  represents only one example of a system, which may have many different configurations and architectures, and which may be employed with the present invention. For example, Macintosh and Intel systems often have multiple busses, such as a peripheral bus, a dedicated cache bus, etc. On the other hand, a network computer, which may be used as a digital processing device of the present invention, may not include, for example, a hard disk or other mass storage device, but may receive routines and/or data from a network connection, such as the modern or interface  268 , to be processed by the processor  252 . Similarly, a Web TV system, which is known in the art, may be considered to be a digital processing system of the present invention, but such a system may not include one or more I/O devices, such as those described above with reference to I/O device(s)  266 . Additionally, a portable communication and data processing system, which may employ a cellular telephone and/or paging capabilities, may be considered a digital processing system which may be used with the present invention. 
     In the system  250  shown in  FIG. 2 , the mass memory  262  (and/or the memory  254 ) may store media (e.g., video, audio, movies, etc.) which may be processed according the present invention (e.g. by way of tracks). Alternatively, media data may be received by the digital processing system  250 , for example, via the modem or network interface  268 , and stored and/or presented by the display  260  and/or I/O device(s)  266 . In one embodiment, packetized media data may be transmitted across a data communication network, such as a LAN and/or the Internet, in accordance with tracks. On the other hand, the processor  252  may execute one or more routines to use a file with one or more tracks, or alternatively, to create one or more tracks, to process media (e.g., a pre-packaged movie, audio file, video file, etc.) for presentation or packetization according to the tracks. Such routines may be stored in the mass memory  262 , the memory  264 , and/or another machine-readable medium accessible by the digital processing system  250 . In one embodiment, the digital processing system  250  may process media data having tracks embedded therein. Similarly, such embedded media data may be stored in the mass memory  262 , the memory  264 , and/or another machine-readable medium accessible by the digital processing system  250 . 
       FIG. 3  shows an example of components involved in data transmission scenario. An originating server  301  and a client  302  are shown as components involved in carrying out transmission of streaming media data using RTP and RTSP protocols as one embodiment of the present invention. The originating server  301  and the client  302  may communicate directly with each other or may communicate through an intermediary such as a caching proxy server. In one embodiment, the server  301  and the client  302  may be on separate local area networks (LAN). In another embodiment the server  301  and the client  302  may be connected through a wide area network. There may be either one or several clients  302  that are in communication with the server  301  directly or indirectly through an intermediary, such as the Internet. The server  301  and client  302  may interact with each other for sending various types of streaming media data in various formats. In one embodiment, the streaming media data may be sent in a downstream direction from server  301  to client  302 . In another embodiment the client  302  may send requests and other streaming media data information to server  301 . 
       FIG. 4  shows an example of one embodiment of a communication relationship between a client  302 , a caching proxy server (CP)  401  and the originating server  301 . There may be several types of connections between these components, but preferably the client  302  may be in communication with the caching proxy server  401  through an Internet connection, and the caching proxy server  401  may be in communication with the originating server  301  through an Internet connection 
     A caching proxy server  401  may be connected through the Internet with a single client  302  or several clients  302 . The caching proxy server  401  and its connected clients  302  may be on the same local area network or may be connected through a wide area network. In one embodiment it is preferable that the caching proxy server  401  and client  302  or clients  302  are connected through a local area network and in close proximity to each other. An exemplary embodiment of close proximity connection may be connection in the same company etc. where the connection may utilize a high bandwidth interface. The communicational link between the caching proxy server  401  and client  302  may be of a variety of types such as direct cable, fiber optic, radio frequency etc. These links may change and vary based on the need of a particular client  302  and advancements in technology. 
     A originating server  301  and a caching proxy server  401  may communicate using a communicational link such as direct cable, fiber optic, radio frequency etc. These links may change and vary based on a particular need and advancements in technology. The cashing proxy  401  may act as an intermediary between the originating server  301  and client  302  to transfer streaming media data and assist in smooth delivery of RTP packets from server  301  to client  302 . In so doing, a caching proxy server  401  may perform several of its own functions. In one embodiment the caching proxy  401  functions may be thinning frames, storing streaming media data locally, and transmitting streaming media data at offset times to client  302 . In another embodiment the caching proxy server&#39;s  401  functions may be negotiating with originating sever  301  for various RTP extension associated with various types of streaming media data, and receiving or responding to various client  302  requests etc. In one embodiment, one of the objectives of a caching proxy server  401  is to deliver a pristine and good quality copy of streaming media data to the client  302  and do so in an efficient and speedy manner. 
     Typically a client  302  may sent a request directly to the caching proxy server  401 . The caching proxy server  401  may then react to the client  302  request and either fetch the requested items from the system server or responds on its own. Its own response may be from a copy of streaming media data which has already been obtained from an originating server and which has been stored on a storage device controlled by the caching proxy server (e.g. a local hard disk of the caching proxy server). However the system may also be configured for the client  302  to send requests directly to the system server  301  and have the server  301  respond back directly to the client  302  or indirectly to the client  302  through a caching proxy server  401 . 
       FIG. 5  shows one exemplary method according to an embodiment of the present invention. In the operations of  FIG. 5 , an originating server (e.g. server  301 ) and a caching proxy server  401  communicate with each other to assist in smooth transmission of streaming media data. This communication aids smooth packet delivery in many ways including allowing the caching proxy server  401  to deliver to the client  302  good qualify streaming media data at a high speed. In addition, the communication also aids in assisting and managing client&#39;s load by ensuring that the client  302  gets a manageable amount of streaming media data and no frames are dropped in the process or only less important frames dropped in the process (through frame thinning). 
     Initially in operation  501 , the caching proxy server requests streaming media data from an originating server. The request may be made by asking the server  301  for “setup” in RTSP for audio or video streaming media data. The request may be for one type of streaming media data or several types of streaming media. The request may be for similar or unrelated types of streaming media data. The server  301  receives the request from the caching proxy server  401 , and the server  301  responds in the manner described with respect to operation  502  of  FIG. 5 . The “SETUP” request in RTSP in operation  501  may be initiated by the caching proxy server  401 , independently of a client system  302  requesting streaming media data or the request in operation  501  may be initiated by a client system  302  requesting the streaming media data from the caching proxy server  401  which in turn requests the requested streaming media data from the server  301  (if the caching proxy server  401  does not already have the requested streaming media data stored under its control, such as a local hard disk of the caching proxy server  401 ). The caching proxy server  401  may also log client&#39;s IP address for subsequent communication in the case where a client initiated the request. 
     The caching proxy server  401  and originating server  301  may establish a communication process in which the caching proxy server  401  and the originating server  301  may engage in a negotiation process  502  for communicating back and forth in order to aid a smooth streaming media data packet transmission. As shown in operation  501 , the caching proxy server  401  may communicate with the originating server  301  and request (e.g. by specifying names of RTP extensions) a set of RTP extensions associated with the streaming media data to be sent to the caching proxy server  401 . The set of extensions requested to the server  301  may be the same as the set of requests sent to the caching proxy server  401  from the client  302  (in those cases where the client specifies RTP extensions, such as security extensions, for its use). 
     The server  301  receives the request for RTP extensions from the caching proxy server  401 . The server  301  may then run its internal processes to determine whether the server  301  supports the requested RTP extensions. The outcome of this determination may be that the server  301  supports some but not all the requested RTP extensions, or that the server  301  supports none of the requested RTP extensions, or that the server  301  supports all of the requested RTP extensions. The server  301  may respond in operation  502  to the caching proxy server  401  by informing the caching proxy server  401  of the server&#39;s  301  supported RTP extensions. The server  301  may choose to respond  502  by indicating only the supported RTP extensions or may respond by indicating both the supported and unsupported RTP extensions, or the server  301  may not respond at all indicating no support for requested extensions. In one embodiment the response may be in an echo form or any several other forms. In one echo form of the invention, the server transmits the names of the requested RTP extensions and an associated code for each named extension. 
     The caching proxy server  401  receives a response from the server  301  indicating the supported RTP extensions or both the supported and unsupported RTP extensions. The caching proxy server  401  may check to see if a response has been sent for all the RTP extensions it had earlier requested. Caching proxy server  401  may have received none, one, some, or all responses to the requested RTP extensions. Caching proxy server  401  may evaluate further to check if any of the server  301  unsupported RTP extensions are required for streaming media data transmitting process. Required RTP extensions may be defined as RTP extensions that are necessary for carrying on a particular data transmission operation such as frame thinning etc at the caching proxy server  401 . As shown in  FIG. 5 , operations  501  and  502  relate to setup and negotiation for an audio track while operations  503  and  504  relate to similar setup and negotiation for a video/image track. 
     In one embodiment, the caching proxy server  401  may request multiple sets of RTP extensions at a time from the server  301 . If the RTP extensions requested are required and unsupported by the server  301 , then caching proxy server  401  may decide to terminate the negotiation process. It may also be the case that some of the extensions are supported and some are not. In such a situation, if the unsupported extensions are not required for the data transmission process then caching proxy server  401  may decide to proceed further and receive the supported extensions and the associated streaming media data. In another embodiment the caching proxy  402  may not receive a response for any of the RTP extensions requested. In such a case the caching proxy  402  may choose to terminate the negotiation process with the server  301 . 
     If the caching proxy server  402  decides not to terminate the negotiation process and to request the supported RTP extensions and streaming media data, it may send a request to the server  301  to send the streaming media data and the associated supported RIP extensions in operation  504 . In the example of  FIG. 5 , this request for the streaming media data and the associated RTP extensions occurs when the caching proxy server  401  sends a “PLAY” command in the RTSP protocol. 
     The server  301  in operation  505 , responds to the “PLAY” command by sending the streaming media data and by sending the requested and supported RTP extensions, which is associated with the streaming media data, to the caching proxy server  401  in a extended header format. This header may contain one, two or three similar or unrelated RTP extensions. 
     Upon receiving the streaming media data and receiving RTP extensions from the server  301 , the caching proxy  401  may store the streaming media data and the RTP extensions in a storing facility  601  (e.g. a storage device controlled by the caching proxy sever  401 , such as a local hard disk of the server  401 ) and terminate the transmission process with the server  301 . The caching proxy  401  may again reinitiate the negotiation process and repeat all the back and forth if another request for streaming media is submitted by the client  302 . This request may be similar or completely different from prior requests. Some of the extensions that may be requested by the cashing proxy sever  401  may be a transmit time sub-extension denoted by symbol “trti”, or frame type sub-extension denoted by symbol “ftry”, or packet position sub-extension denoted by symbol “papo”. Other extensions may also be requested (e.g. an extension which is used by the client  302  or server  401  to maintain a secure or encrypted or authenticated communication between client  302  and server  401 ). 
     For example, in one cycle of its operation a caching proxy server  401  may ask for three separate RTF sub-extensions one of which may be frame type sub-extension denoted by symbol “frty” (used in frame thinning by caching proxy server  401  as described below), the other may be transmit type sub-extension denoted by “trti” (used by the caching proxy server  401  as described below), and the last may be packet position sub-extension denoted by “papo” (which may be used to retrieve lost or missing packets). Let us also assume for the illustration of this example that “frty” sub-extension is required for the streaming media data transmission process. “Frty” may be denoted as a required sub-extension due to several reasons. One of the reasons may be that the client  302  cannot receive or process the data at a high data rate (and so frame thinning is required) and “frty” sub-extension will assist the data transmission process between a caching proxy server and the client  302  by allowing the caching proxy sever to perform frame thinning and therefore may be “necessary”. 
     The caching proxy  402  may receive the request and communicate with the server  301  by sending a single request to the server  301  asking for both sub-extensions. Let us assume further for the illustration of this example that the server  301  can only support one of the two RTF extensions. The server  301  may then send a response back to the caching proxy server indicating which sub-extension is supported. 
     If the supported sub-extension happens to be only “trti”, or “papo” or both but not “frty” then the caching proxy  402  will terminate the negotiation process between the caching proxy  402  and the server  301 . This is because “frty” was a required extension to the data transmission process and since it is not supported by the server  301 , the caching proxy  402  may not proceed further. If however, the supported sub-extension happens to be only “frty”, or frty and papo, or frty and trti, or frty, papo and trti, then the caching proxy server  401  may proceed further with the transmission process. The caching proxy server  401  in this instance may choose not to terminate the process since the required sub-extension thy is present in the response as supported by the server  301 . 
       FIG. 6  shows an example of a method for transmitting packet transmit time data which may be used with various embodiments of the present invention. The server  301  is connected with the caching proxy server  401  by way of a standard communication carrying devices such as fiber optic ware link, radio frequency communication, cable wire etc. A person having ordinary skill in the art will appreciate that any one-communication device is not essential for the data transfer operation in accordance with this invention and that these communications devices are interchangeable. It must be clear that it is important for the communication devices to allow communication in both directions i.e. from server  301  to caching proxy  402  or from caching proxy  402  to server  301 . 
     The communication between a caching proxy server  401  and the originating server  301  may be a direct communication relationship or there may also be other devices such as routers in the Internet acting as intermediaries to assist in streaming media data transfer. Typically, a caching proxy server  401  is located in closer proximity to the client  302  than the originating server  301 . This close proximity may be within a company, or on a designed local area network (LAN), or in the same geographic region, whereas typically caching proxy server and original system server  301  are further apart. 
     The caching proxy server  401  may have a storage facility  601  to store streaming media data  603  and/or the associated RTP extensions  602 . The storage facility  601  may be a local to the caching proxy server  401  or on an offsite from the caching proxy server  401  but in either case the storage is controlled by the caching proxy server  401 . The caching proxy server  401  may have a link established to store data received from the server  301  for a periods of time in the storage facility  601 , and then be able to retrieve the stored data at a later time for sending to client  302 . In the example of  FIG. 6 , the streaming media data  603  and its associated RTP extension (transmit time in this case) are stored together on a storage device  601 . Groups of streaming media data (e.g. a packet or a set of packets) are associated with a corresponding designation of a transmit tune so that each group has a transmit time which specifies when to transmit the particular group. It will be appreciated that the streaming media data and the associated RTP extension may be stored separately (but still be associated—e.g. packet No. xxx to be transmitted at time ABC, packet No. xxy is to be transmitted at time ABD, etc.) 
     In the example of  FIG. 6 , the streaming media data is received by the server  401  and the caching proxy server  401  receives the transmit time data from server  301  and stores it in the storing facility  601 . Transmit time data may be associated with each track of streaming media data. For example, in one instance the transmit time at  0  sec  602  may be associated with corresponding streaming media data  603 . In operation, in this exemplary embodiment, the streaming media data  0  will be sent to a client at transmit time  0 . 
       FIG. 7  shows one exemplary method for using transmit time as an RTP extension according to an embodiment of the present invention. In operation the method suggested in  FIG. 7  may utilize the system architecture as suggested in one of the embodiments of the present invention shown in  FIG. 6 . 
     In one example of the method of  FIG. 7 , a caching proxy server  401  receives a request from client  302  for streaming media data and then requests an RTP extension which specifics transmit nine information and requests the server  301  to send transmit time sub-extension RTP data  701  and associated streaming media data. Operation  701  shows the caching proxy server&#39;s request for streaming media data and transmit time which results from this request. The server receives the request in operation  702  as shown in  FIG. 7 . It may also be the case that a caching proxy server  401  already had received the requested streaming media data and its associated transmit time information from the server  301  and has stored the streaming media data and associated RTP extensions at a storing facility  601 . If such, then the caching proxy server  401  may start responding to clients  302  request without communicating with the originating server  301  thereby shipping to operations  707  and  708  of  FIG. 7 . 
     Assuming for illustration of this example that the original server  301  supports the transmit time information, server  301  will respond back to caching proxy server indicating its support of the requested sub-extension in operation  703 . If however the transmit time sub-extension is not supported by the original server  301 , the originating server  301  may or may not respond back to the caching proxy server  401  indicating its support for the requested sub-extension as shown in operation  709 . In the event of an unsupported sub-extension, the caching proxy  402  may terminate the negotiation process as shown in operation  710  with the server  301  and would typically inform the client  302  of the inability to provide streaming media data. In so doing, the caching proxy server  401  may first evaluate whether the missing transmit time information is required for running its processes. If the result of the determination is that transmit time information in this particular example is a required element, then the caching proxy server may decide whether to proceed or terminate the transmission process. 
     The server  301  in operation  704  sends the transmit time RTP data in an extended header format according to the RTP protocol to the caching proxy server. The header may consist of the normal header fields, the sub-extension character name and a sub-extension ID  704 . The sub-extension character name for a transmit time data may be a 4-character code denoted by “trti”. This code may uniquely identify and describe the content of the sub-extension as being transit time data. The sub-extension ID may identify the sub-extension in the RTP packet. 
     A transmit time sub-extension may consist of a single 64-bit unsigned integer representing the recommended transmission time of the RTP packet in milliseconds as shown in operation  704 . The transmit time may be offset from one another from the start of a media presentation. For example in one sub-cycle of operation, a session description protocol document for a uniform resource locator (URL) may include a range of 0-729.45 seconds. The client  302  may make a PLAY request  706  for the video, audio, text, graphics, and images etc. type data. 
     The caching proxy server  401  may receive the RTP data packet associated with streaming media data with the transmit time sub-extension as shown in more detail in  FIG. 6 . The caching proxy server  401  may then store the RTP transmit time data locally as shown in  FIG. 6 . The caching proxy server  401  may then strip off the header ID in operation  705  and send streaming media data associated with each track, in operation  707 , of transmit time individually at offset times to the client  302  allowing the client  302  to carry on PLAY operation  708 . An advantage of knowing and storing transit time at offsets locally at the caching proxy server, it may now be possible for the caching proxy saver  401  to selectively re-transmit data at different intervals to the client  302  or respond to clients request to send data corresponding to any particular time slot. 
       FIG. 8  shows one exemplary method for a stream thinning process by a caching proxy server according to an embodiment of the present invention. In operation a client  302  and caching proxy server  301  communicate with each other to assist in sending and receiving streaming media data and assisting in traffic flow control to the client  302 . In a method according to  FIG. 8 , a client  302  communicates with the caching proxy server  401  and indicates that it is overloaded or the caching proxy server  401  detects that the client is overloaded. As part of this communication, the caching proxy server  401  ensures that the client  302  does not get an amount of data that exceeds its data handling capacity. Caching proxy server also prevents at least selected frame being “dropped” or missing as a result of an overloaded client  302 . 
     A principle behind  FIG. 8  is that an overloaded client  302  may notify the caching proxy server that it has reached its capacity for receiving RTP data (e.g. streaming media data). The client  302  may have been overloaded due to several reasons including that a caching proxy server is sending RTP data very quickly and the client  302  is having difficulty receiving data at such a fast pace. The client  302  may inform the caching proxy server to stop sending streaming media data altogether, or to send data at a slower pace. The client  302  may also inform the caching proxy server to send only selected order of frames and not send any low order frames. The caching proxy server  401  will use the frame type data to determine which frames to transit to client  302 ; typically, higher priority frames are transmitted while lower priority frames are not transmitted. 
     A method of  FIG. 8  begins in operation  801  in which a caching proxy server  402  may communicate with the originating server  301  and request the server  301  for streaming media data and its associated frame type information. Tire frame type identities various types of data (e.g. frames) in streaming media data which allows “thinning” which may be defined as reducing frames, sending frames at a slower pace, or not sending certain frames at all. It will be appreciated that thinning apples to various types of data and that “frames” may be considered to be such various types of data. The server  301  may receive the request in operation  802  and may respond in operation  803  to the caching proxy server  401  indicating whether the server  301  supports the requested frame type streaming media data. If the server  301  supports this, the server&#39;s  301  response in operation  803  includes sending the associated RTP frame type sub-extension in a format described in block  804  along with an identifier code corresponding to the frame type extension requested by name in operation  801 . 
     If the server  301  does not support frame type sub-extension then file caching proxy server may terminate in operation  807  and  808  the communication with server  301 . The server  301  may indicate that it does not support the requested frame type streaming media data by either responding or not sending any response to the Caching Proxy server  401  which would also indicate no support of the requested RTP extension for the streaming media data. However, if the server  301  supports the frame type sub-extension, the caching proxy  402  may inform the server  301  to send the streaming media associated with the frame type information. In one embodiment, the server  301  may send the supported streaming media data sub-extensions without any further requests from the caching proxy server  401 . In another embodiment, the server  301  may wait for further a further request from the caching proxy server  401  to send the supported streaming media data sub-extensions. 
     The server  301  may then send the RTF sub-extension in an extended header format. The frame type sub-extension may consist of a single 16-bit unsigned integer value with several well-known values representing different frame types. The well known values may be “1” for a key frame, “2” for a p-frame, or “3” for a b-frame where key frame maybe of the highest order and most importance, b-frame of the lowest order and least importance, and b-frame somewhere between key frame and b-frame in terms of importance. There may also be other frames that may be added to this format. 
     The caching proxy server  401  may then store the streaming media data and its associated frame type sub-extension in its storing device  601  after receiving them from the originating server  301 . This is shown in operation  805  of  FIG. 8 . The caching proxy server  401  may then enter into a negotiating process with the client  302  in evaluating the client&#39;s capability at the time to handle streaming media data traffic  809 . Based upon the result of the negotiation process  809 , the caching proxy server  401  may thin frames (sending only selected, predetermined frames) and send streaming media data associated with selected frames  806  to the client  302 . 
     For example, in one cycle of operation a client  302  may inform the caching proxy server that it is overloaded. The client  302  may inform the caching proxy server  401  to stop sending frames altogether or to lower the bit rate if the transmission falls behind. In the case of lowering the bit rate and slowing down, the caching proxy server  401  may stop sending the lowest order frames of the streaming media data, the b-frame to the client  302 . The caching proxy server  401  and the client  302  may communicate further to evaluate if the client  302  is still overloaded. In one embodiment, if the client  302  is capable of handling die load alter thinning of the b-frame then the caching proxy server may send the client  302  key-frames and p-frames. However if the client  302  is stilt overloaded then the caching proxy server  401  may further reduce the data traffic to the client  302  and stop sending p-frames. The caching proxy server  401  may further evaluate client&#39;s  302  data handling capability and determine if any more frame thinning is necessary to reduce load on client  302 . In another embodiment the client  302  may directly specify to the caching proxy server  401 , which frames to send and which frames not to send until a subsequent request is sent to the caching proxy server  401  to change sending considerations. 
     After a client  302  retains its capability to cache frames, the caching proxy server  401  may again start sending the lower order frames to the client  302 . It may again send all the frames at a high speed or send the frames according to requests received by the client  302 . In the event that the client  302  gets overloaded again, the caching proxy-server  401  may repeat the thinning process until the client  302  is able to handle caching data again.  FIG. 10  shows an example of how a caching proxy server  401  receives streaming media data and its associated frame type (FT) RTP extension data from an originating server  301  and stores the streaming media data and associated frame type extension data on a storage device (e.g. a local hard disk of the caching proxy server  401 ) and then uses the frame type data to selectively thin frames of the streaming media data which is being transmitted to a client  302 . 
     Communication between a caching proxy server  401  and originating server  301  or caching proxy server  401  and client  302  is carried on using real-time transfer protocol (RTP) and real-time streaming protocol (RTSP) for sending/receiving streaming media data. An originating server  301  sends streaming media data packets in a streaming media format using RTP to a caching proxy server  401  whenever a transmission of streaming media data occurs. One of the embodiments of the present invention is to be able to modify the current existing RTP headers by being able to expand the header with sub-extensions and also be able to make the header format variable. Expansion of the header is useful because a caching proxy server  401  may need several pieces of information along with a RTP packet that will aid in providing a good quality streaming media data packet and smooth delivery to the client  302 . The extra in formation that may be needed can be provided by attaching it to the existing header by being able to expand the header field. It should also be clear that variability of the extended header is important because the extra pieces of information needed by the caching proxy  402  may vary each time. To accommodate for this variation, the extended header may have the capability to change and provide various types of information as needed by the caching proxy server  401 . 
     In accordance with one embodiment of the invention, in operation, an extended header consists of a normal header fields. A person having ordinary skill in the art is aware of the various header fields that are normally used in operation. The normal header fields are immediately followed by header extension fields. The extension field consists of several sub-extensions. There may be several header sub-extensions that are unrelated to each other and may vary per request of the caching proxy server  401 . The sub-extensions may have an extension type of “se”. The RTP extension length may be the total length of all the sub-extensions and may be defined in 32-bit words thereby being in full compliance with the RTP protocol. 
     The “se” sub-extension format may be such that a sub-extension ID immediately follows the normal RTP header field. The ID may identify the sub-extension within the RTP packet. This ID may be a one octet ID generated by the server  301  for each individual named RTP sub-extension. Each sub-extension may also have its unique name that is defined by a four-character name code. This name code uniquely identities and describes the type of data in each sub-extension. For example, the four character name code for a transmit time sub-extension may be “trti”, frame type sub-extension may be “frty” and packet position sub-extension maybe “papo”. This name code is associated with the one octet ID (generated by the server  301 ) so that the caching proxy server  401  can identify, form the octet ID the appropriate RTP extension data when it receives streaming media data. 
     In one embodiment of the present invention, the unique name may be “frty” associated with streaming media data for frame type information. The unique name “frty” may also have an unsigned integer associated with each different type of frame, in one embodiment the unsigned integer may be “1” for a key-frame, “2” for a p-frame, and “3” for a b-frame. A user may also add any additional frames in the future as need and technology advances and may use this header format without any need for much modifications. 
     In another embodiment of the present invention, the unique name may be “trti” associated with streaming media data for transmit time type information. 
     In another embodiment of the present invention, the unique name may be “papo” associated with streaming media data for packet position type information. 
       FIG. 9  shows an exemplary method of several aspects of the present invention. In a portion  901 , a caching proxy server  401  requests streaming media data from an originating server  301  and also requests by name one or more RTP extensions. This request is made using the RTSP protocol. In operation  903 , the server typically responds back (e.g. of a response would be an echo) a response to the caching proxy server  401  indicating its support for the requested RTP extensions. The server  301  also transmits to the caching proxy server  401  an identifier, such as a number code which corresponds to each name of die requested RTP extensions. Typically, the caching proxy server  401  will use the number code later in identifying received extended RTP data. The number code allows the caching proxy server  401  to identity the various types of RTP extension data in the streaming media which it receives as the server  301  may not use the name to designate the RTP extension type. In operation  905 , the caching proxy server  401  receives the server&#39;s  301  response and then in operation  907 , the CP server  401  determines whether the server  301  responded to all of the requested RTP extensions. 
     If the server  301  did not respond to all requested RTP extensions, then processing proceeds to operation  909 , followed by operation  911  in which it is determined whether any of the missing RTP extensions are critical to the caching proxy server&#39;s  401  processing. If they are not critical, then processing proceeds to operation  921 . If they are critical, then the caching proxy server  401  determines in operation  913  whether or not to terminate the operation/communication with the originating server  301 . As shown in operations  915  or  917 , the caching proxy server  401  may terminate operations/communications with the server  301  for this particular streaming media data which was requested or they proceed to receive the streaming media and whatever supported extensions can be provided. 
     In operation  921 , the CP server  401  requests the originating server  301  to send the requested streaming media data and its associated RTP extensions. In one embodiment, the CP server  401  transmits a “PLAY” request using RTSP, and this causes the server  301  to respond in operation  923  by transmitting the streaming media data and the associated RTP extensions. In operation  925 , the CP server  401  stores the streaming media data received from the server  301  and also stores the associated RTP extension data. In operation  927 , the CP server  401  may remove certain RTP extension data from the streaming media file, such as the transmit time or the frame type data. This is done in order to avoid sending the transmit time or the frame type information to the client  302  which receipts streaming media data. The RTP extension data, which is removed from the streaming media data, is stored separately but associated with the streaming media data. For example, transmit times for various packets are stored separately from the packets, but the association existing in the data received from the server  301  between the transmit time and the corresponding packets is maintained even when the transmit times are stored separately so that the caching proxy server  401  may determine the appropriate transmit time for each of the packets in the streaming media data. In operation  929 , the caching proxy server  401  evaluates a client&#39;s  302  request for streaming media data and responds accordingly. It will be appreciated that a client  302  will negotiate for streaming media data using the RTSP protocol and the CP server  401  will respond with the streaming media data by transmitting the data to the client  302 . In addition, the client  302  may request frame thinning. Further, the caching proxy server  401  may use the transmit times to determine when to transmit to various packets in the streaming media data to the client  302 . 
       FIG. 11  shows one type of exemplary machine readable media (e.g. RAM or hard disk or combination thereof) for storing executable computer program instructions for a caching proxy server  401  that may be used in accordance with the present invention. The caching proxy server  401  typically will have its own operating system (OS) software  1101 . This software  1101  may be the Macintosh OS. Or Windows NT or Unix, or other well known operating systems 
     The control software  1102  is for transmitting or receiving streaming media data using, for example RTP and RTSP protocols. The software  1102  is normally able to retrieve or send various types of streaming media data packets and direct commands for storing the received media in a storing facility  601 . Thus software  1102  performs the negotiation process with an originating server  301  and receives streaming media data, and its associated RTP extensions and causes the streaming media data and its associated RTP extensions to be stored on a storage device controlled by caching proxy server  401 .  FIG. 11  shows the storage of two streaming media data files  1103  and  1104 . 
     Streaming media data file  1103  may contain streaming media data  1  in streaming media format  1105 , transmit time associated with streaming media  1  ( 1106 ), and frame type associated with streaming media  1  ( 1107 ). In one embodiment, the operating system  1101  and control software  1102  may have the capability to separate streaming media data in packet  1  from other packets and store it separately in a storing facility  601  and to extract the RTP extensions (e.g. Transmit Time data or Frame Type data) from the stored streaming media packets and store these separately so that these packets do not include the RTP extensions. 
     The streaming media data file of  1104  may contain streaming media data  2  in streaming media format  1108 , transmit time associated with streaming media data  2  ( 1109 ), and frame type associated with streaming media  2  ( 1110 ). 
     The streaming media data  1105  and  1108  will usually not be in the same original format as the media data was at the originating server  301 . The streaming media data  1105  and  1108  may however be a full “pristine” copy of the original media data, because the “papo” extension may be used by the caching proxy server  401  to search for any missing packets in the streaming media data  1105  and  1108  and to request (again) these packets from the originating server. 
       FIG. 12  shows one type of exemplary machine readable media (e.g. RAM or hard disk or combination thereof) for storing executable computer program instructions for an originating server  301  that may be used in accordance with the present invention. The server  301  will typically have its own operating system  1201 . 
     The control software  1202  is for transmitting streaming media data to a caching proxy server  401  or to a client  302  using the RTP and RTSP protocols and the RTP extensions of the invention. Further, software  1202  receives requests from a client  302  or a caching proxy server  401  for streaming media and negotiates with a caching proxy server  401  for various types of streaming media data and associated RTP extensions, and responds to various requests by caching proxy servers  401  or clients  302 . 
     Software  1204  converts original media data  1203 , which is usually not in a packet format, to a streaming media data format (e.g. packet format) for transmitting to caching proxy sever  401  or client  302 . When converted, the converted streaming media data is a representation of the original media data  1203  that has a different format than the formal of the original media data  1203 . 
     The software  1206  creates RTP extension headers associated with various types of streaming media data. The system may assign various ID names and codes  1205  associated with various RTP extensions to various types of streaming media data before its sent to a caching proxy  401  or a client  301 . The software  1206 , in conjunction with software  1202 , performs the negotiation process with a caching proxy server  401  (or, in some cases where the client asks for an RTP extension, such as a security or encryption or authentication extension, the client) to transmit RTP extension data for an associated streaming media data and also performs the transmission process of transmitting streaming media data with its associated RTP extension. 
       FIG. 13  shows one type of exemplary machine readable media (e.g. RAM or hard disk or combination thereof) for storing executable computer program instructions for a client server  302  that may be used in accordance with the present invention. The client server  302  will typically have its own operating system  1301  such as a Macintosh OS, or Windows NT, or Unix, or other well-known operating systems. The client&#39;s media may also include Web Browser software  1303  such as Netscape&#39;s Navigator or Microsoft&#39;s Internet Explorer. 
     The streaming media data player software  1302  is for receiving and playing streaming media data transmitted to the client using the RTP protocol. The streaming media data player software  1302  may be Quicktime software from Apple computer or the Real Player from Real Networks. The streaming media data player software  1302  is typically able to send requests to a caching proxy server  401  or a server  301  for various different types of streaming media data and to receive and present (e.g. display images and produce sound) a representation of streaming media data. 
     In yet another embodiment the streaming media data player software  1302  may be able to communicate and negotiate with a caching proxy server  401  in order to regulate incoming data traffic to handle its load better (e.g. the software  1302  may ask a CP server  401  to perform frame thinning). 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from broader spirit and scope of the invention as set forth, in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather a restrictive sense.

Metadata:
Filing Date: 20111207
Publication Date: 20140520
Grant Date: 20140520
Priority Date: 20000622
Inventors: SERENYI DENIS
LECROY CHRIS
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L65/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/1108", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N21/23106", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N21/23106", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L65/65", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L67/535", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/765", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L9/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/612", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L67/568", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L65/765", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/1101", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L67/568", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L65/65", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L67/535", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/612", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N21/6437", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/104", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/329", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N21/6587", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/104", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/329", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N21/6587", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N21/6437", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L69/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L65/1108", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 24414129