Abstract:
Motion Compensated Prediction (MCP) has been a key factor in most advanced video compression schemes. For further reduction in the residual signal energy in B-frames, bidirectional prediction where two motion-compensated signals are superimposed has also been utilized in most prior video coding standards such as MPEG-2 or MPEG-4/AVC. Syntax changes and appropriate motion vector prediction that allows efficient use of multi-parameter MCP is described. The prediction signal is constructed by linearly combining the motion-compensated signals from each parameter (or motion vector).

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims priority under 35 U.S.C. §119(e) of the U.S. Provisional Patent Application Ser. No. 61/365,306, filed Jul. 16, 2010 and entitled, “MULTI-PARAMETER MOTION FOR EFFICIENT PREDICTION IN VIDEO COMPRESSION.” The Provisional Patent Application Ser. No. 61/365,306, filed Jul. 16, 2010 and entitled, “MULTI-PARAMETER MOTION FOR EFFICIENT PREDICTION IN VIDEO COMPRESSION” is also hereby incorporated by reference in its entirety for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of image processing. More specifically, the present invention relates to inter coding of high definition videos. 
       BACKGROUND OF THE INVENTION 
       [0003]    Advances in video codecs, such as MPEG-4/AVC use motion compensated prediction for inter coding. A decoder expects a motion vector for a specific block size and location. The motion vector pinpoints a location in the reference image (the previously coded image) which constructs the prediction for the current block. If the location appointed by the motion vector is not on the image grid (e.g. a fractional-pel), interpolation of the sample values is performed. Various fixed and adaptive interpolation techniques have been proposed. The resolution of the motion vectors is able to be arbitrary (up to 1/12th pel has been proposed). 
         [0004]    However, interpolation is often fixed and cannot adapt to local statistics. For example, for interpolation of a value in the middle of four sample values, the average of the four is often used. Nevertheless, the actual value of the location is able to be close to one or two of locations if an edge is passing through the sampling locations. In this case, the average interpolation is not accurate. 
         [0005]    Multi-hypothesis prediction for motion-compensated prediction allows multiple motion vectors from different reference pictures for prediction of P-pictures. The prediction P of a block is constructed from N prediction blocks, each appointed by a motion vector mv i , iε[1, . . . , N], where P i  is the prediction resulting from motion compensation using motion vector mv i , and w i  is the weight associated with it: P=w 1 P 1 +w 2 P 2 + . . . +w N P N . For simplicity, it is assumed w i =1/N. 
         [0006]    Prior work only applies to P-pictures. 
       SUMMARY OF THE INVENTION 
       [0007]    Motion Compensated Prediction (MCP) has been a key factor in most advanced video compression schemes. For further reduction in the residual signal energy in B-frames, bidirectional prediction where two motion-compensated signals are superimposed has also been utilized in most prior video coding standards such as MPEG-2 or MPEG-4/AVC. Syntax changes and appropriate motion vector prediction that allows efficient use of multi-parameter MCP is described. The prediction signal is constructed by linearly combining the motion-compensated signals from each parameter (or motion vector). 
         [0008]    In one aspect, a method of encoding an image using multi-parameter motion prediction programmed in a controller in a device comprises predicting a first motion vector from a list of motion vector predictors, predicting remaining motion vectors recursively using differential prediction and generating a bitstream containing the first motion vector and the remaining motion vectors. Using differential prediction includes computing motion vector differences. The first motion vector is selected in an RD-optimized fashion. If the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. The remaining motion vectors include only remaining motion vector differences. The method further comprises ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. All motion vectors use a same reference frame whose index is signaled for each list. A number of available motion vectors for each prediction unit is transmitted in the bitstream. A maximum number of motion vectors allowed is pre-defined and fixed. The multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. The device is selected from the group consisting of a personal computer, a laptop computer, a computer workstation, a server, a mainframe computer, a handheld computer, a personal digital assistant, a cellular/mobile telephone, a smart appliance, a gaming console, a digital camera, a digital camcorder, a camera phone, an iPod®/iPhone, a video player, a DVD writer/player, a Blu-ray® writer/player, a television and a home entertainment system. 
         [0009]    In another aspect, an apparatus for encoding an image using multi-parameter motion prediction programmed in a controller in a device comprises a first prediction module for predicting a first motion vector from a list of motion vector predictors, a remaining prediction module for predicting remaining motion vectors recursively using differential prediction and a generating module for generating a bitstream containing the first motion vector and the remaining motion vectors. Using differential prediction includes computing motion vector differences. The first motion vector is selected in an RD-optimized fashion. If the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. The remaining motion vectors include only remaining motion vector differences. The apparatus of further comprises an ordering module for ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. All motion vectors use a same reference frame whose index is signaled for each list. A number of available motion vectors for each prediction unit is transmitted in the bitstream. A maximum number of motion vectors allowed is pre-defined and fixed. The multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. The device is selected from the group consisting of a personal computer, a laptop computer, a computer workstation, a server, a mainframe computer, a handheld computer, a personal digital assistant, a cellular/mobile telephone, a smart appliance, a gaming console, a digital camera, a digital camcorder, a camera phone, an iPod®/iPhone, a video player, a DVD writer/player, a Blu-ray® writer/player, a television and a home entertainment system. 
         [0010]    In another aspect, a device comprises a memory for storing an application, the application for predicting a first motion vector from a list of motion vector predictors, predicting remaining motion vectors recursively using differential prediction and generating a bitstream containing the first motion vector and the remaining motion vectors and a processing component coupled to the memory, the processing component configured for processing the application. Using differential prediction includes computing motion vector differences. The first motion vector is selected in an RD-optimized fashion. If the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. The remaining motion vectors include only remaining motion vector differences. The device further comprises ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. All motion vectors use a same reference frame whose index is signaled for each list. A number of available motion vectors for each prediction unit is transmitted in the bitstream. A maximum number of motion vectors allowed is pre-defined and fixed. The multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  illustrates a diagram of neighbors of a current block according to some embodiments. 
           [0012]      FIG. 2  illustrates a diagram for coding multi-parameter motion prediction signaling bits according to some embodiments. 
           [0013]      FIG. 3  illustrates a diagram of motion vector encoding for a bi-directional prediction unit according to some embodiments. 
           [0014]      FIG. 4  illustrates a flowchart of a method of encoding an image using multi-parameter motion prediction according to some embodiments. 
           [0015]      FIG. 5  illustrates a block diagram of an exemplary computing device configured to implement the multi-parameter motion prediction method according to some embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    The syntax described herein allows multiple motion parameters for B-pictures in addition to P-pictures. This increases the number of possible combinations of parameters significantly. Since permitting multiple motion parameters per block is able to dramatically increase the number of bits due to the signaling of the side information, proper encoding of the side information is inevitable to observe good coding gain. This includes reduction of the overhead, efficient prediction of the side information and design of the syntax and the context for effective context-adaptive arithmetic coding (e.g. context adaptive binary arithmetic coding). An extension to multi-view video coding is also beneficial. Multiple motion vectors are able to be from different views. A prediction is made from a linear combination of the motion compensated predictions (regardless of the views the prediction came from). To perform multi-parameter motion prediction, S is denoted as the list of the conventional motion vector predictors such as the motion vectors of the spatial and/or temporal neighbors. The first motion vector mv 1  is predicted using the conventional methods from the list S. The best motion vector predictor from the list is selected in an RD-optimized fashion. If the list S contains more than one motion vector, the index of the predictor is also coded into the bitstream along with the motion vector difference. The rest of the motion vectors mv i , iε[2, 3, . . . , N] are predicted either recursively (e.g. mv i , is differentially predicted from mv i-1 ) or from the same list S. Alternatively, the last encoded motion vector is able to be added to the list S, and the new list S is able to be used for prediction of the next motion vector. Assuming a recursive prediction of the motion vectors, the MV differences are computed as: 
         [0000]      mvd 1 =mv 1 −pmv, pmv ε  belongs to  S  
 
         [0000]      mvd i =mv i −mv i-1   , i  belongs to [2, 3 , . . . , N].  
 
         [0000]    The prediction of the block constructed by the decoder is independent of the order of the motion vectors (as long as all N motion vectors are decoded correctly); however, the encoder should find the “good” order for the motion vector coding such that the overhead from the side information is reduced as much as possible. 
         [0017]    Syntax Extensions 
         [0018]    Signaling of motion parameters is done at a Prediction Unit (PU) level (e.g. the smallest unit for which a prediction is constructed). Similar to H.264/AVC, for B-slices, it is signaled to the decoder whether the current PU is predicted from LIST_ 0  (backward) or LIST_ 1  (forward) or both (bi-directional). For P-slices, only prediction from LIST_ 0  is possible. Unlike the prior art, all motion vectors use the same reference frame whose index is signaled (per LIST). Then, for each LIST: the first motion vector difference dmv 1  is coded into the bitstream using conventional methods. If the list of predictors has more than one element, the index of the predictor is also coded, and a “1” at the end of the first motion vector difference indicates to the decoder that another motion vector difference will follow. On the other hand, a “0” indicates that the motion vector parsing of current LIST (for the current block) is done. 
         [0019]    The number of available motion vectors per PU is also transmitted in the bitstream and thus is efficiently coded. Truncated Unary binarization is used to represent the number of motion vectors N in binary. Thus, for the popular case that the maximum possible number of motion vectors is two, only 1 bit is transmitted, where a “0” signals to the decoder that only one motion vector is to follow and a “1” signals two motion vectors. Even in the case of two motion vectors, this signaling is different from prior art (e.g., H.264/AVC) since in H.264/AVC, two reference frame indices are also transmitted when two motion vectors are present (regardless of the LIST). 
         [0020]    Since PUs with multiple motion parameters often appear together in a picture, the number of MVs of neighboring blocks are used as a context in coding of the bit that signals whether to terminate MV parsing or not. The index of the three contexts defined is given by: 
         [0000]      χ=((NumberOfMVs( A )==1)?0:1)+((NumberOfMVs( B )==1)?0:1),
 
         [0000]    where A and B are neighbors to the left and top of the block to be coded as shown in  FIG. 1 . χ is the context index for coding of MPM signaling bits as shown in  FIG. 2 . 
         [0021]    For a block or PU, up to N motion vectors are allowed per list. N is a pre-defined fixed number which is hard-wired in to the decoder. The prediction signal is constructed by a linear combination of the motion compensated prediction from each motion vector. To simplify the encoder motion search and allow a better prediction of the motion vectors, all motion vectors of the same list from one reference frame are restricted. The proposed syntax changes and motion vector prediction for one list prediction case is described. In the case for B-pictures where two lists (forward and backward) are generally present, each list uses the described syntax separately from the other. 
         [0022]    Let pmv be the current motion vector predictor, e.g. the spatial or temporal motion vector predictor for the block to be coded. Furthermore, let S={mv 1 , mv 2 , . . . , mv M }, M≦N, be the set of all motion vectors selected for the current block (a non-skip block). In addition, let π(i)=j to be the position of the ith motion vector when written to the bit stream. In other words, it is a permutation of the set {1, 2, . . . , M} which determines the order in which motion vectors of the current block are written into the bit stream. Then, the motion vector differences are calculated according to 
         [0000]      δmv i =mv π(i) −mv (i-1)   , i= 1, 2 , . . . , M,   (1)
 
         [0000]    where π(0) and mv 0 =pmv. 
         [0023]    Once motion vector differences are computed, then they are encoded into the bit stream in the following way: first, the index of the reference frame that these motion vectors point to is binarized and coded in the bitstream. This follows by the first motion vector difference δmv 1 . Then, a one bit flag is added to signal to the decoder whether this motion vector difference was the last one or more motion vector differences will follow. In this case, a 1 is transmitted to signal the existence of another motion vector difference. Next, the second motion vector difference is binarized and coded into the bitstream. This process continues until δmv M  is coded. If M&lt;N, a 0 is transmitted next indicate the termination of the motion vector parsing process to the decoder. Otherwise, no extra bits are transmitted and the decoder terminates the parsing process due to prior knowledge of the maximum number of motion vectors. Since the motion vectors are differentially coded, the number of bits to transmit the entire set S also depends on the permutation π as well as the spatial/temporal predictor pmv. 
         [0024]    The coding of the last MV difference flags as shown in  FIG. 3  employs several new contexts of CABAC. The first flag which appears after the first MV difference employs three contexts based on the same flag in the spatial neighbors (top and left blocks) of the current block. The rest of the flags share one context. 
         [0025]    The multi-parameter motion technique is able to achieve up to 20% bit-rate reduction at the same quality when compared to the conventional single parameter motion methods such as the one used in H.264/AVC. 
       Example 
       [0026]    The algorithm has been implemented with N=2. Motion vectors of a block are jointly optimized. Since the order of the motion vectors also has an impact on the RD cost, the best order of the MVs is selected for improved performance. A maximum calibration unit size is 64 with a depth of 4. Internal bit-depth increase is 4. Additional tools are used in the example: arbitrary intra direction, DCT-based interpolation filter with 12 taps for luna and 6 taps for chroma and rate-distortion optimized quantization. Other tools are turned off unless specified. Five different Quantization Parameters for intra pictures (QPIs) (22, 26, 30, 34, 38) are considered to compute the average bit rate reduction for the low and high bit rate ranges. QPP (QP for P-Slices) is set to QPI+1. Approximately, two seconds of video is considered for all test sequences. The exact number of frames is reported in Table 1. The bit savings resulted from the new syntax changes for various resolutions and test sequences are listed in Table 2. 
         [0000]                                                        TABLE 1                   Sequences and frame numbers used in experiments.            Class   Sequence   Start Frame   Frames to be Encoded                    B1   Kimono   116   49           ParkScene   0   49       B2   Cactus   0   97           BasketballDrive   0   97           BQTerrace   0   129       C   BasketballDrill   0   97           BQMall   0   129           PartyScene   0   97           RaceHorses   0   65       D   BasketballPass   0   97           BQSquare   0   129           BlowingBubbles   0   97           RaceHorses   0   65       E   Vidyo1   0   129           Vidyo3   0   129           Vidyo4   0   129                    
Table 2 lists these bit rate reductions for various resolutions and test sequences.
 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Average bit rate reduction of various test sequences/resolutions. 
               
             
          
           
               
                 Sequence/Resolution 
                 BD rate Low % 
                 BD rate High % 
               
               
                   
               
             
          
           
               
                 E 
                 Vidyo1 
                 −8.26 
                 −14.57 
               
               
                   
                 Vidyo3 
                 −8.93 
                 −13.34 
               
               
                   
                 Vidyo4 
                 −8.59 
                 −15.30 
               
             
          
           
               
                 Class E Average 
                 −8.59 
                 −14.40 
               
             
          
           
               
                 Class D 
                 Basketball Pass 
                 −5.35 
                 −5.88 
               
               
                   
                 Blowing Bubbles 
                 −2.83 
                 −4.21 
               
               
                   
                 BQ Square 
                 −12.86 
                 −14.12 
               
               
                   
                 Race Horses 
                 −2.64 
                 −2.91 
               
             
          
           
               
                 Class D Average 
                 −5.92 
                 −6.78 
               
             
          
           
               
                 Class C 
                 Basketball Drill 
                 −6.20 
                 −6.86 
               
               
                   
                 BQ Mall 
                 −7.40 
                 −9.44 
               
               
                   
                 Party Scene 
                 −4.94 
                 −7.19 
               
               
                   
                 Race Horses 
                 −4.47 
                 −5.26 
               
             
          
           
               
                 Class C Average 
                 −5.75 
                 −7.19 
               
             
          
           
               
                 B 
                 Basketball Drive 
                 −8.56 
                 −10.62 
               
               
                   
                 BQ Terrace 
                 −34.36 
                 −25.15 
               
               
                   
                 Cactus 
                 −7.67 
                 −10.79 
               
               
                   
                 Kimono 
                 −4.18 
                 −5.83 
               
               
                   
                 Park Scene 
                 −5.18 
                 −5.78 
               
             
          
           
               
                 Class B Average 
                 −11.99 
                 −11.63 
               
               
                 AVERAGE 
                 −8.28 
                 −9.83 
               
               
                   
               
             
          
         
       
     
         [0027]    The method described herein shows significant coding gain with a marginal increase in decoder complexity. For example, for the case of N=2, the decoding complexity of P-slices is similar to B-slices. 
         [0028]      FIG. 4  illustrates a flowchart of a method of encoding an image using multi-parameter motion prediction according to some embodiments. In the step  400 , a first motion vector is predicted from a list of motion vector predictors. In the step  402 , remaining motion vectors are recursively predicted using differential prediction. In the step  404 , a bitstream containing the first motion vector and the remaining motion vectors is generated. In some embodiments, only the differences of the remaining motion vectors are included in the bitstream. In some embodiments, fewer or additional steps are included in the method. 
         [0029]      FIG. 5  illustrates a block diagram of an exemplary computing device  500  configured to implement the multi-parameter motion prediction method according to some embodiments. The computing device  500  is able to be used to acquire, store, compute, process, communicate and/or display information such as images and videos. For example, a computing device  500  is able to acquire and store a video. The multi-parameter motion prediction method is able to be used during or after acquiring the video, or when displaying the video on the device  500 . In general, a hardware structure suitable for implementing the computing device  500  includes a network interface  502 , a memory  504 , a processor  506 , I/O device(s)  508 , a bus  510  and a storage device  512 . The choice of processor is not critical as long as a suitable processor with sufficient speed is chosen. The memory  504  is able to be any conventional computer memory known in the art. The storage device  512  is able to include a hard drive, CDROM, CDRW, DVD, DVDRW, flash memory card or any other storage device. The computing device  500  is able to include one or more network interfaces  502 . An example of a network interface includes a network card connected to an Ethernet or other type of LAN. The I/O device(s)  508  are able to include one or more of the following: keyboard, mouse, monitor, display, printer, modem, touchscreen, button interface and other devices. In some embodiments, the hardware structure includes multiple processors and other hardware to perform parallel processing. Multi-parameter motion prediction application(s)  530  used to perform the multi-parameter motion prediction method are likely to be stored in the storage device  512  and memory  504  and processed as applications are typically processed. More or less components shown in  FIG. 5  are able to be included in the computing device  500 . In some embodiments, multi-parameter motion prediction hardware  520  is included. Although the computing device  500  in  FIG. 5  includes applications  530  and hardware  520  for implementing the multi-parameter motion prediction method, the multi-parameter motion prediction method is able to be implemented on a computing device in hardware, firmware, software or any combination thereof. For example, in some embodiments, the multi-parameter motion prediction applications  530  are programmed in a memory and executed using a processor. In another example, in some embodiments, the multi-parameter motion prediction hardware  520  is programmed hardware logic including gates specifically designed to implement the encoding method. 
         [0030]    In some embodiments, the multi-parameter motion prediction application(s)  530  include several applications and/or modules. Modules such as a first prediction module for predicting a first motion vector from a list of motion vector predictors, a remaining prediction module for predicting remaining motion vectors recursively using differential prediction and a generating module for generating a bitstream containing the first motion vector and the remaining motion vectors are able to perform the functions described herein. In some embodiments, modules include one or more sub-modules as well. In some embodiments, fewer or additional modules are able to be included. 
         [0031]    Examples of suitable computing devices include a personal computer, a laptop computer, a computer workstation, a server, a mainframe computer, a handheld computer, a personal digital assistant, a cellular/mobile telephone, a smart appliance, a gaming console, a digital camera, a digital camcorder, a camera phone, an iPod®/iPhone, a video player, a DVD writer/player, a Blu-ray® writer/player, a television, a home entertainment system or any other suitable computing device. 
         [0032]    To utilize the multi-parameter motion prediction method, a user acquires a video/image such as on a digital camcorder, and while or after the video is acquired, or when displaying the video, the multi-parameter motion prediction method is automatically used for inter coding each image of the video, so that the video is encoded efficiently while maintaining quality. The multi-parameter motion prediction method occurs automatically without user involvement. The video is also able to be decoded to be displayed using a similar method. 
         [0033]    In operation, multi-parameter motion prediction is used to encode and decode images such as frames of a video. The multi-parameter motion prediction method allows efficient use of multiple parameters when predicting motion. 
       Some Embodiments of Multi-Parameter Motion for Efficient Prediction in Video Compression 
       [0000]    
       
         1. A method of encoding an image using multi-parameter motion prediction programmed in a controller in a device comprising:
       a. predicting a first motion vector from a list of motion vector predictors;   b. predicting remaining motion vectors recursively using differential prediction; and   c. generating a bitstream containing the first motion vector and the remaining motion vectors.   
     
         2. The method of clause 1 wherein using differential prediction includes computing motion vector differences. 
         3. The method of clause 1 wherein the first motion vector is selected in an RD-optimized fashion. 
         4. The method of clause 1 wherein if the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. 
         5. The method of clause 1 wherein the remaining motion vectors include only remaining motion vector differences. 
         6. The method of clause 1 further comprising ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. 
         7. The method of clause 1 wherein all motion vectors use a same reference frame whose index is signaled for each list. 
         8. The method of clause 1 wherein a number of available motion vectors for each prediction unit is transmitted in the bitstream. 
         9. The method of clause 1 wherein a maximum number of motion vectors allowed is pre-defined and fixed. 
         10. The method of clause 1 wherein the multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. 
         11. The method of clause 1 wherein the device is selected from the group consisting of a personal computer, a laptop computer, a computer workstation, a server, a mainframe computer, a handheld computer, a personal digital assistant, a cellular/mobile telephone, a smart appliance, a gaming console, a digital camera, a digital camcorder, a camera phone, an iPod®/iPhone, a video player, a DVD writer/player, a Blu-ray® writer/player, a television and a home entertainment system. 
         12. An apparatus for encoding an image using multi-parameter motion prediction programmed in a controller in a device comprising:
       a. a first prediction module for predicting a first motion vector from a list of motion vector predictors;   b. a remaining prediction module for predicting remaining motion vectors recursively using differential prediction; and   c. a generating module for generating a bitstream containing the first motion vector and the remaining motion vectors.   
     
         13. The apparatus of clause 12 wherein using differential prediction includes computing motion vector differences. 
         14. The apparatus of clause 12 wherein the first motion vector is selected in an RD-optimized fashion. 
         15. The apparatus of clause 12 wherein if the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. 
         16. The apparatus of clause 12 wherein the remaining motion vectors include only remaining motion vector differences. 
         17. The apparatus of clause 12 further comprising an ordering module for ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. 
         18. The apparatus of clause 12 wherein all motion vectors use a same reference frame whose index is signaled for each list. 
         19. The apparatus of clause 12 wherein a number of available motion vectors for each prediction unit is transmitted in the bitstream. 
         20. The apparatus of clause 12 wherein a maximum number of motion vectors allowed is pre-defined and fixed. 
         21. The apparatus of clause 12 wherein the multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. 
         22. The apparatus of clause 12 wherein the device is selected from the group consisting of a personal computer, a laptop computer, a computer workstation, a server, a mainframe computer, a handheld computer, a personal digital assistant, a cellular/mobile telephone, a smart appliance, a gaming console, a digital camera, a digital camcorder, a camera phone, an iPod®/iPhone, a video player, a DVD writer/player, a Blu-ray® writer/player, a television and a home entertainment system. 
         23. A device comprising:
       a. a memory for storing an application, the application for:
           i. predicting a first motion vector from a list of motion vector predictors;   ii. predicting remaining motion vectors recursively using differential prediction; and   iii. generating a bitstream containing the first motion vector and the remaining motion vectors; and   
           b. a processing component coupled to the memory, the processing component configured for processing the application.   
     
         24. The device of clause 23 wherein using differential prediction includes computing motion vector differences. 
         25. The device of clause 23 wherein the first motion vector is selected in an RD-optimized fashion. 
         26. The device of clause 23 wherein if the list contains more than one motion vector, an index of the predictor is coded into the bitstream along with a motion vector difference. 
         27. The device of clause 23 wherein the remaining motion vectors include only remaining motion vector differences. 
         28. The device of clause 23 further comprising ordering the motion vectors in the bitstream in an order to reduce an overhead from side information. 
         29. The device of clause 23 wherein all motion vectors use a same reference frame whose index is signaled for each list. 
         30. The device of clause 23 wherein a number of available motion vectors for each prediction unit is transmitted in the bitstream. 
         31. The device of clause 23 wherein a maximum number of motion vectors allowed is pre-defined and fixed. 
         32. The device of clause 23 wherein the multi-parameter motion uses multiple motion vectors from one image to construct a motion-compensated prediction image. 
       
     
         [0077]    The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of principles of construction and operation of the invention. Such reference herein to specific embodiments and details thereof is not intended to limit the scope of the claims appended hereto. It will be readily apparent to one skilled in the art that other various modifications may be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention as defined by the claims.