Implementation of mpcp mcu technology for the h.264 video standard

Abstract

A method for generating a video output signal that may receive a plurality of input video signals from a number of participants. The input video signals may have a plurality of input frames. The video output signal may comprise a plurality of output frames. A first of the output frames generally has at least a first slice having (a) a first coded portion carrying the image from a first of the participants and (b) a first unencoded portion for the image from a second of the participants. A second of the output frames generally has at least a second slice having (a) a second coded portion carrying the image from the second participant and (b) a second unencoded portion for the image from the first participant. The frames of the video output signal are generated as soon as one of the frames of the video input signal are received.

1 . A method for generating a video output signal, comprising the steps of:
 (A) receiving input video signals from a plurality of locations, each of said input video signals having a plurality of input frames, each of said input frames having a source slice carrying an image, each of said input frames being encoded using a reference frame at an encoding time; and   (B) generating said video output signal for transmission to said locations, said video output signal comprising a plurality of output frames, wherein (i) a first of said output frames has at least a first slice having (a) a first coded portion carrying said image from a first of said locations and (b) a first unencoded portion for said image from a second of said locations, (ii) a second of said output frames has at least a second slice having (a) a second coded portion carrying said image from said second location and (b) a second unencoded portion for said image from said first location and (iii) said output frames of said video output signal are generated as soon as one of said input frames of said input video signals is received.   
     
     
         2 . The method according to  claim 1 , wherein a third of said output frames has a third slice having (a) a third coded portion carrying said images from said first location and said second location and (b) a third unencoded portion for said image from a third of said locations. 
     
     
         3 . The method according to  claim 1 , further comprising the step of:
 prohibiting unrestricted motion vectors in said input video signals through a handshake process.   
     
     
         4 . The method according to  claim 1 , wherein said first unencoded portion indicates that a previously received coded portion from said second location should be repeated. 
     
     
         5 . The method according to  claim 1 , wherein output frames are generated without decoding said input frames. 
     
     
         6 . The method according to  claim 1 , further comprising the step of:
 changing a size of said image from said first location in said video output signal in response to said first location being an active speaker.   
     
     
         7 . The method according to  claim 1 , wherein said video output signal is compliant with at least one of an International Organization for Standardization/International Electrotechnical Commission 14496-10 standard and an International Telecommunication Union-Telecommunications Revised Recommendation H.264. 
     
     
         8 . A method for generating a video output signal, comprising the steps of:
 (A) receiving input video signals from a plurality of sources, each of said input video signals having a plurality of input frames, each of said input frames having a source slice carrying an image, each of said input frames being encoded using a subset of a plurality of reference frames at an encoding time; and   (B) generating said video output signal for transmission to a video on demand display, said video output signal comprising a plurality of output frames, wherein (i) a first of said output frames has at least a first slice having (a) a first coded portion carrying said image from a first of said sources and (b) a first unencoded portion for said image from a second of said sources, (ii) a second of said output frames has at least a second slice having (a) a second coded portion carrying said image from said second source and (b) a second unencoded portion for said image from said first source and (iii) said output frames of said video output signal are generated as soon as one of said input frames of said input video signals is received.   
     
     
         9 . The method according to  claim 8 , wherein a third of said output frames has a third slice having (a) a third coded portion carrying said images from said first source and said second source and (b) a third unencoded portion for said image from a third of said sources. 
     
     
         10 . The method according to  claim 9 , wherein said third unencoded portion comprises a non-rectangular shape. 
     
     
         11 . The method according to  claim 8 , wherein at least one of said images has a rectangular shape. 
     
     
         12 . The method according to  claim 8 , further comprising the step of:
 generating said reference frames from decoded versions of said output frames.   
     
     
         13 . The method according to  claim 11 , further comprising the step of:
 generating a reference picture list storing a plurality of reference picture numbers each pointing to a portion of one of said reference frames for use in encoding said input frames.   
     
     
         14 . A method for generating a video output signal, comprising the steps of:
 (A) receiving input video signals from a plurality of locations, each of said input video signals having a plurality of input frames, each of said input frames having a source slice carrying an image; and   (B) generating said video output signal for transmission to said locations, said video output signal comprising a plurality of output frames, wherein (i) a first of said output frames has (a) a first foreground slice carrying said image from a first of said locations and (b) a first background slice designated as unencoded, (ii) a second of said output frames has (a) a second foreground slice carrying said image from said second location and (b) a second background slice designated as unencoded and (iii) said output frames of said video output signal are generated as soon as one of said input frames of said input video signals received.   
     
     
         15 . The method according to  claim 14 , wherein said first foreground slice further carries said image from a third of said locations. 
     
     
         16 . The method according to  claim 14 , wherein said first output frame has a third foreground slice carrying said image from a third of said locations. 
     
     
         17 . The method according to  claim 14 , further comprising the step of:
 limiting each of said locations to one respective reference frame at a time through a handshake process.   
     
     
         18 . The method according to  claim 14 , further comprising the step of:
 limiting said locations to a maximum number of reference frames at a time through a handshake process.   
     
     
         19 . The method according to  claim 14 , further comprising the step of:
 prohibiting unrestricted motion vectors in said input video signals through a handshake process.