Video signal transmitting system

Abstract

Video signal transmitting system in which digital video signal are divided into groups of predetermined frames. Digital video signals of at least one frame are intraframe coded and then transmitted. Remaining digital video signals are interframe coded with reference to the intraframe coded digital video signals, and intraframe coded digital video signals of a subsequent group of frames and are then transmitted. A motion vector from a predetermined reference frame is detected. Video signals are interframe coded by the motion vector to transmit the video signals. A motion vector from a first frame which is a plurality of frames away from the reference frame is converted to a motion vector for a one frame interval between the reference frame and the first frame. The motion vector is optimized, and is then transmitted.

What is claimed is:  
     
       1. An apparatus for transmitting a digital video signal, comprising: 
       means for dividing the digital video signal into successive frame groups each having a plurality of frames, first means for processing said plurality of frames of each of said successive frame groups so that at least one of said plurality of frames is to be generated as an intra-frame signal, and  
       second means for processing a remaining of said plurality of frames based on said intra-frame signals of one of said each frame group and one successive frame group so that at least one of said remaining of said plurality of frames is to be generated as a first inter-frame signal.  
     
     
       2. The apparatus according to claim  1 , in which said apparatus further comprises, 
       third means for processing further remaining of said plurality of frames except for said intra-frame and first inter-frame based on said intra-frame of said one of said each frame group and said first inter-frame, or said intra-frame of said one successive frame group and said first inter-frame so that said further remaining of said plurality of frames are to be generated as second inter-frames signal.  
     
     
       3. The apparatus according to claim  2 , in which said apparatus further comprises, 
       means for adding an identification data to each of said first and second inter-frame signal so that a reference frame in a process of generating said first and second interframe signals can be identified.  
     
     
       4. An apparatus for transmitting a digital video signal provided as a plurality of successive frames separated by predetermined frame intervals, comprising: 
       means for producing a multi-frame interval motion vector from a first, predetermined reference frame of said plurality of successive frames to a second frame of said plurality of successive frames separated from said first, predetermined reference frame by a plurality of frame intervals;  
       means for interframe coding said second frame with the use of the motion vector;  
       means for converting said multi-frame interval motion vector to a one frame interval motion vector; and  
       means for transmitting said one frame interval motion vector.  
     
     
       5. The apparatus according to claim  4 , wherein said means for producing a multi-frame interval motion vector is operative to produce a plurality of multi-frame interval motion vectors, and wherein said means for converting said multi-frame interval motion vector to a one frame interval motion vector is operative to convert a plurality of multi-frame interval motion vectors to one frame interval motion vectors, said apparatus further comprising 
       means for run-length encoding said one frame interval motion vectors for transmission.  
     
     
       6. An apparatus for transmitting a digital video signal, comprising: 
       
         means for dividing the digital video signal into successive frame groups each having a plurality of frames;  
       
         first means for processing at least one of the frames in a frame group to generate an intra - frame signal,    
         second means for processing a second frame in said frame group as a function of said intra - frame signal to generate a first - type interframe signal;    
         third means for processing a third frame in said frame group which temporally follows said one frame and temporally precedes said second frame, said processing being a function of both said intra - frame signal and said first - type interframe signal to generate a second - type interframe signal; and    
         means for transmitting said intra - frame, first - type interframe and second - type interframe signals.    
     
     
       7. An encoding method for encoding digital video signals representing a plurality of successive pictures, comprising the steps of: 
       
         intracoding the digital video signals to produce an intracoded picture signal representing a first of said pictures;  
       
       
         reconstructing a picture which temporally precedes a second picture;  
       
       
         intercoding the digital video signals representing said second picture with the use of said temporally preceding picture to produce a first intercoded picture signal;  
       
       
         reconstructing pictures which temporally precede and follow a third picture; and  
       
       
         intercoding the digital video signals representing said third picture with the use of those reconstructed pictures which temporally precede and follow said third picture to produce a second interceded picture signal, wherein one of said reconstructed pictures which temporally precede and follow said third picture is reconstructed from the first interceded picture signal produced from intercoding said second picture.  
       
     
     
       8. The method of claim  7  further comprising the step of adding to each encoded picture signal a header including data identifying the respective encoded picture signal as an intracoded, first interceded or second intercoded picture signal, respectively.  
     
     
       9. The method of claim  7  wherein the reconstructed picture which temporally precedes said second picture is reconstructed from said intracoded picture signal.  
     
     
       10. The method of claim  7  wherein the reconstructed picture which temporally precedes said second picture is reconstructed from an intercoded picture signal.  
     
     
       11. The method of claim  7  wherein the reconstructed picture which temporally precedes said third picture is reconstructed from said intracoded picture signal and the reconstructed picture which temporally follows said third picture is reconstructed from said first intercoded picture signal.  
     
     
       12. The method of claim  7  wherein each of the reconstructed pictures which temporally follow and precede said third picture is reconstructed from an interceded picture signal.  
     
     
       13. The method of claim  7  wherein the reconstructed picture which temporally precedes said third picture is reconstructed from said first interceded picture signal and the reconstructed picture which temporally follows said third picture is reconstructed from an intracoded picture signal.  
     
     
       14. The method of claim  7  wherein each picture is represented by macro units; and wherein the step of intercoding the digital video signals representing said third picture includes the steps of selecting forward predictive coding, backward predictive coding or interpolative predictive coding for each macro unit of said third picture, encoding said digital video signals representing said third picture in accordance with the selected coding, and adding to each macro unit a header including data identifying said selected coding.  
     
     
       15. The method of claim  7  further comprising the steps of quantizing each of said intracoded, first interceded and second interceded picture signals with a quantizing step determined as a function of the encoded picture signals; and adding to each encoded picture signal header data identifying the quantizing step therefor.  
     
     
       16. A decoding method for decoding digital video signals representing successive pictures and received as an intracoded- type picture signal, a first - type interceded picture signal and a second - type interceded picture signal, comprising the steps of:    
         decoding said intracoded - type picture signal to produce a first decoded picture;    
         using a decoded picture which temporally precedes said second picture to decode said first - type interceded picture signal to produce a second decoded picture; and    
         using a decoded picture which temporally precedes said third picture and a decoded picture which temporally follows said third picture to decode said second - type intercoded picture signal to produce a third decoded picture, wherein one of the decoded pictures which temporally precede and follow said third picture is said second decoded picture.    
     
     
       17. The method of claim  16  wherein each received encoded picture signal includes header data identifying the respective encoded picture signal as an intracoded- type picture signal, a first - type intercoded picture signal or a second - type intercoded picture signal; and further comprising the step of separating said header data and selecting a decoding mode in accordance therewith.    
     
     
       18. The method of claim  16  wherein said decoded picture which temporally precedes said second picture is said first decoded picture.  
     
     
       19. The method of claim  16  wherein said decoded picture which temporally precedes said second picture is decoded from a first- type interceded picture signal.    
     
     
       20. The method of claim  16  wherein said decoded picture which temporally precedes said third picture is said first decoded picture and said decoded picture which temporally follows said third picture is said second decoded picture.  
     
     
       21. The method of claim  16  wherein each of the decoded pictures which temporally precede and follow said third picture are decoded from a first- type interceded picture signal.    
     
     
       22. The method of claim  16  wherein said decoded picture which temporally precedes said third picture is said second decoded picture and said decoded picture which temporally follows said third picture is said first decoded picture.  
     
     
       23. The method of claim  16  wherein each received encoded picture signal is formed of macro units containing header data identifying if the encoded picture signal was encoded in accordance with intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding; and each decoding step is performed in accordance with the header data of the respective encoded picture signal.  
     
     
       24. The method of claim  16  wherein each encoded picture signal is quantized with a respective quantizing step and each encoded picture signal includes header data identifying said respective quantizing step; and wherein each decoding step includes inverse quantizing the respective encoded picture signal in accordance with said identified quantizing step included in the header data thereof.  
     
     
       25. A method of encoding a picture which temporally follows a first picture and temporally precedes a second picture, each picture being represented by macro units of digital video signals, comprising the steps of: 
       
         selecting intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding for each macro unit of the picture to be encoded;  
       
       
         encoding each macro unit in accordance with the selected coding;  
       
       
         generating header data for each encoded macro unit, said header data identifying the coding selected therefor; and  
       
       
         transmitting the encoded macro units and header data.  
       
     
     
       26. The method of claim  25  wherein the step of encoding includes quantizing each macro unit with a quantizing step determined by the content of the encoded picture; and said step of generating header data includes generating data identifying said quantizing step.  
     
     
       27. A method of decoding a received encoded picture which temporally follows a first picture and temporally precedes a second picture, the encoded picture being formed of macro units that have been encoded by intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding and each macro unit having a header with header data that identifies the coding by which the macro unit was encoded, said method comprising the steps of: 
       
         separating said header data from the macro units of received encoded picture; and  
       
       
         decoding each macro unit by an inverse of one of said intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding as a function of said separated header data.  
       
     
     
       28. The method of claim  27  wherein each macro unit of the received encoded picture is quantized with a quantizing step and said header includes quantizing data that identifies said quantizing step; and wherein said step of decoding includes inverse quantizing said macro unit as a function of said quantizing data.  
     
     
       29. A method of encoding digital video signals representing a plurality of successive pictures supplied in a sequence, comprising the steps of: 
       
         reordering the sequence of said pictures;  
       
       
         selectively encoding the reordered pictures by intracoding or intercoding to produce coded picture data; and  
       
       
         generating temporal header data for the coded picture data of each picture to identify the sequence in which said successive pictures were supplied.  
       
     
     
       30. A method of decoding encoded picture data that had been selectively encoded by intracoding or interceding and that include temporal header data identifying an original sequence of successive pictures before such pictures were encoded, the encoded picture data being supplied in a sequence which differs from said original sequence, said method comprising the steps of: 
       
         separating said temporal header data from the supplied encoded picture data to detect said original sequence;  
       
       
         decoding the supplied encoded picture data by the inverse of intracoding or intercoding as a function of whether the encoded picture data had been encoded by intracoding or interceding, thereby producing decoded picture data; and  
       
       
         reordering the decoded picture data in response to said separated temporal header data to recover said original sequence of pictures.  
       
     
     
       31. A method of encoding motion vectors from one picture to another picture, comprising the steps of: 
       
         detecting a motion vector from one picture to another picture;  
       
       
         deriving a value of the detected motion vector;  
       
       
         dividing the derived motion vector value by a predetermined amount to produce a quotient value and a remainder value;  
       
       
         variable length coding said quotient value in accordance with a code table; and  
       
       
         encoding said remainder value.  
       
     
     
       32. The method of claim  31  wherein the step of encoding said remainder value comprises generating a plural bit signal representing said remainder value and generating a bit number signal representing the number of bits in said plural bit signal.  
     
     
       33. A method of decoding an encoded motion vector represented by a variable length encoded quotient value corresponding to an original motion vector value divided by a predetermined amount and an encoded remainder value, said method comprising the steps of separating said variable length encoded quotient value and said encoded remainder value; and using a variable length code table for decoding the encoded motion vector.  
     
     
       34. The method of claim  33  wherein said encoded remainder value is a plural bit signal and includes a bit number signal representing the number of bits in said plural bit signal.  
     
     
       35. A method of detecting motion vectors from a first picture to second and third pictures, respectively, wherein said third picture temporally follows said first picture and temporally precedes said second picture, said method comprising the steps of: 
       
         detecting a first motion vector from said first picture to said third picture;  
       
       
         determining a search area within which a second motion vector from said first picture to said second picture is to be detected, said search area being a function of said first motion vector and a number of pictures which separate said first and second pictures; and  
       
       
         detecting said second motion vector within said search area.  
       
     
     
       36. A record medium on which are recorded encoded digital video signals representing successive pictures, the recorded signals comprising an intracoded- type picture signal, a first - type interceded picture signal and a second - type interceded picture signal disposed in a sequence which differs from the temporal sequence of the successive pictures represented thereby.    
     
     
       37. The medium of claim  36  wherein each encoded picture signal includes a header identifying the respective encoded picture signal as an intracoded- type, a first - type intercoded or a second - type intercoded picture signal.    
     
     
       38. The medium of claim  36  wherein said second- type intercoded picture signal is encoded by one of forward, backward or interpolative predictive coding, and said second - type interceded picture signal includes header data identifying said one predictive coding.    
     
     
       39. The medium of claim  36  wherein the encoded picture signals are quantized with a quantizing step that differs from one type of encoded picture signal to another, and each encoded picture signal includes header data identifying the quantizing step with which that encoded picture signal was quantized.  
     
     
       40. The medium of claim  36  wherein each encoded picture signal includes header data to identify the location in said temporal sequence of successive pictures of the picture represented by said encoded picture signal.  
     
     
       41. Apparatus for encoding digital video signals representing a plurality of successive pictures, comprising: 
       
         means for intracoding the digital video signals to produce an intracoded picture signal representing a first of said pictures;  
       
       
         means for reconstructing a picture which temporally precedes a second picture;  
       
       
         means for interceding the digital video signals representing said second picture with the use of said temporally preceding picture to produce a first interceded picture signal;  
       
       
         means for reconstructing pictures which temporally precede and follow a third picture; and  
       
       
         means for interceding the digital video signals representing said third picture with the use of those reconstructed pictures which temporally precede and follow said third picture to produce a second interceded picture signal, wherein one of said reconstructed pictures which temporally precede and follow said third picture is reconstructed from the first interceded picture signal produced from intercoding said second picture.  
       
     
     
       42. The apparatus of claim  41  further comprising means for adding to each encoded picture signal a header including data identifying the respective encoded picture signal as an intracoded, first intercoded or second intercoded picture signal, respectively.  
     
     
       43. The apparatus of claim  41  wherein the reconstructed picture which temporally precedes said second picture is reconstructed from said intracoded picture signal.  
     
     
       44. The apparatus of claim  41  wherein the reconstructed picture which temporally precedes said second picture is reconstructed from an interceded picture signal.  
     
     
       45. The apparatus of claim  41  wherein the reconstructed picture which temporally precedes said third picture is reconstructed from said intracoded picture signal and the reconstructed picture which temporally follows said third picture is reconstructed from said first interceded picture signal.  
     
     
       46. The apparatus of claim  41  wherein each of the reconstructed pictures which temporally follow and precede said third picture is reconstructed from an intercoded picture signal.  
     
     
       47. The apparatus of claim  41  wherein the reconstructed picture which temporally precedes said third picture is reconstructed from said first interceded picture signal and the reconstructed picture which temporally follows said third picture is reconstructed from an intracoded picture signal.  
     
     
       48. The apparatus of claim  41  wherein each picture is represented by macro units; and wherein said means for interceding the digital video signals representing said third picture includes means for selecting forward predictive coding, backward predictive coding or interpolative predictive coding for each macro unit of said third picture, means for encoding said digital video signals representing said third picture in accordance with the selected coding, and means for adding to each macro unit a header including data identifying said selected coding.  
     
     
       49. The apparatus of claim  41  further comprising means for quantizing each of said intracoded, first interceded and second intercoded picture signals with a quantizing step determined as a function of the encoded picture signals; and means for adding to each encoded picture signal header data identifying the quantizing step therefor.  
     
     
       50. Apparatus for decoding digital video signals representing successive pictures and received as an intracoded- type picture signal, a first - type intercoded picture signal and a second - type interceded picture signal, comprising:    
         means for decoding said intracoded - type picture signal to produce a first decoded picture;    
         means operable with a decoded picture which temporally precedes said second picture for decoding said first - type interceded picture signal to produce a second decoded picture; and    
         means operable with a decoded picture which temporally precedes said third picture and with a decoded picture which temporally follows said third picture for decoding said second - type intercoded picture signal to produce a third decoded picture, wherein one of the decoded pictures which temporally precede and follow said third picture is said second decoded picture.    
     
     
       51. The apparatus of claim  50  wherein each received encoded picture signal includes header data identifying the respective encoded picture signal as an intracoded- type picture signal, a first - type intercoded picture signal or a second - type intercoded picture signal; and further comprising means for separating said header data and means for selecting a decoding mode in accordance with the separated header data.    
     
     
       52. The apparatus of claim  50  wherein said decoded picture which temporally precedes said second picture is said first decoded picture.  
     
     
       53. The apparatus of claim  50  wherein said decoded picture which temporally precedes said second picture is decoded from a first- type interceded picture signal.    
     
     
       54. The apparatus of claim  50  wherein said decoded picture which temporally precedes said third picture is said first decoded picture and said decoded picture which temporally follows said third picture is said second decoded picture.  
     
     
       55. The apparatus of claim  50  wherein each of the decoded pictures which temporally precede and follow said third picture are decoded from a first- type interceded picture signal.    
     
     
       56. The apparatus of claim  50  wherein said decoded picture which temporally precedes said third picture is said second decoded picture and said decoded picture which temporally follows said third picture is said first decoded picture.  
     
     
       57. The apparatus of claim  50  wherein each received encoded picture signal is formed of macro units containing header data identifying if the encoded picture signal was encoded in accordance with intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding; and each said means for decoding is operable in accordance with the header data of the respective encoded picture signal.  
     
     
       58. The apparatus of claim  50  wherein each encoded picture signal is quantized with a respective quantizing step and each encoded picture signal includes header data identifying said respective quantizing step; and wherein each said means for decoding includes means for inverse quantizing the respective encoded picture signal in accordance with said identified quantizing step included in the header data thereof.  
     
     
       59. Apparatus for encoding a picture which temporally follows a first picture and temporally precedes a second picture, each picture being represented by macro units of digital video signals, comprising: 
       
         means for selecting intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding for each macro unit of the picture to be encoded;  
       
       
         means for encoding each macro unit in accordance with the selected coding;  
       
       
         means for generating header data for each encoded macro unit, said header data identifying the coding selected therefor; and  
       
       
         means for transmitting the encoded macro units and header data.  
       
     
     
       60. The apparatus of claim  59  wherein the means for encoding includes means for quantizing each macro unit with a quantizing step determined by the content of the encoded picture; and said means for generating header data includes means for generating data identifying said quantizing step.  
     
     
       61. Apparatus for decoding a received encoded picture which temporally follows a first picture and temporally precedes a second picture, the encoded picture being formed of macro units that have been encoded by intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding and each macro unit having a header with header data that identifies the coding by which the macro unit was encoded, said apparatus comprising: 
       
         means for separating said header data from the macro units of the received encoded picture; and  
       
       
         means for decoding each macro unit by an inverse of one of said intracoding, forward predictive coding, backward predictive coding or interpolative predictive coding as a function of said separated header data.  
       
     
     
       62. The apparatus of claim  61  wherein each macro unit of the received encoded picture is quantized with a quantizing step and said header includes quantizing data that identifies said quantizing step; and wherein said means for decoding includes means for inverse quantizing said macro unit as a function of said quantizing data.  
     
     
       63. Apparatus for encoding digital video signals representing a plurality of successive pictures supplied in a sequence, comprising: 
       
         means for reordering the sequence of said pictures:  
       
       
         means for selectively encoding the reordered pictures by intracoding or intercoding to produce coded picture data; and  
       
       
         means for generating temporal header data for the coded picture data of each picture to identify the sequence in which said successive pictures were supplied.  
       
     
     
       64. Apparatus for decoding encoded picture data that had been selectively encoded by intracoding or intercoding and that include temporal header data identifying an original sequence of successive pictures before such pictures were encoded, the encoded picture data being supplied in a sequence which differs from said original sequence, said apparatus comprising: 
       
         means for separating said temporal header data from the supplied encoded picture data to detect said original sequence;  
       
       
         means for decoding the supplied encoded picture data by the inverse of intracoding or intercoding as a function of whether the encoded picture data had been encoded by intracoding or interceding, thereby to produce decoded picture data; and  
       
       
         means for reordering the decoded picture data in response to said separated temporal header data to recover said original sequence of pictures.  
       
     
     
       65. Apparatus for encoding motion vectors from one picture to another picture, comprising: 
       
         means for detecting a motion vector from one picture to another picture;  
       
       
         means for deriving a value of the detected motion vector;  
       
       
         means for dividing the derived motion vector value by a predetermined amount to produce a quotient value and a remainder value;  
       
       
         means for variable length coding said quotient value in accordance with a code table; and  
       
       
         means for encoding said remainder value.  
       
     
     
       66. The apparatus of claim  65  wherein the means for encoding said remainder value comprises means for generating a plural bit signal representing said remainder value and means for generating a bit number signal representing the number of bits in said plural bit signal.  
     
     
       67. Apparatus for decoding an encoded motion vector represented by a variable length encoded quotient value corresponding to an original motion vector value divided by a predetermined amount and an encoded remainder value, said apparatus comprising: means for separating said variable length encoded quotient value and said encoded remainder value; and means for using a variable length code table for decoding the encoded motion vector.  
     
     
       68. The apparatus of claim  67  wherein said encoded remainder value is a plural bit signal and includes a bit number signal representing the number of bits in said plural bit signal.  
     
     
       69. Apparatus for detecting motion vectors from a first picture to second and third pictures, respectively, wherein said third picture temporally follows said first picture and temporally precedes said second picture, said apparatus comprising: 
       
         means for detecting a first motion vector from said first picture to said third picture;  
       
       
         means for determining a search area within which a second motion vector from said first picture to said second picture is to be detected, said search area being a function of said first motion vector and a number of pictures which separate said first and second pictures; and  
       
       
         means for detecting said second motion vector within said search area.