Apparatus for coding and decoding a digital video signal derived from a motion picture film source

A method of decoding a coded video signal to provide an interlaced output video signal with a field rate of 60 Hz, the coded video signal including frames derived by coding respective frames of a progressive video signal having a frame rate of 24 Hz, the progressive video signal being derived from an interlaced input video signal with a field rate of 60 Hz by eliminating duplicate fields, the frames of the coded video signal including a control signal having a state indicating the frames of the coded video signal resulting from coding lost-field frames of the progressive video signal, lost-field frames being frames of the progressive video signal wherefrom a duplicate field was eliminated, the method comprising steps of:

• extracting the control signal from the frames of the coded video signal;
• decoding the frames of the coded video signal to provide respective frames of a reconstructed progressive video signal;
• and
• in response to the control signal extracted from each one of the frames of the coded video signal, deriving three fields of the interlaced output video signal from the respective one of the frames of the reconstructed progressive video signal when the control signal indicates that the one of the frames of the coded video signal resulted from coding one of the lost-field frames, and deriving two fields of the interlaced output video signal from all others of the frames of the reconstructed progressive video signal.

Apparatus for generating a coded video signal by coding an input video signal with a field rate of 60 Hz derived from a motion picture film source using 2-3 pulldown, the apparatus comprising:

• detecting means for detecting duplicate fields in the input video signal;
• control signal generating means for generating a control signal having a state indicating each of the detected duplicated fields;
• eliminating means, operating in response to the state of the control signal, for eliminating the duplicate fields from the input video signal;
• generating means, operating on the input video signal following elimination of the duplicate fields by the eliminating means, for generating a progressive video signal composed of frames and having a frame rate of 24 Hz, the frames of the progressive video signal including lost-field frames generated from fields of the input video signal that were duplicates of the duplicate fields eliminated by the eliminating means;
• and
• coding means for coding the frames of the progressive video signal to produce respective frames of the coded video signal;
• and
• multiplexing means for including the control signal in each of the frames of the coded video signal, the state of the control signal indicating the frames of the coded video signal resulting from coding the lost-field frames of the progressive video signal.

Apparatus for decoding a coded video signal to provide an interlaced output video signal with a field rate of 60 Hz, the coded video signal including frames derived by coding respective frames of a progressive video signal having a frame rate of 24 Hz, the progressive video signal being derived from an interlaced input video signal with a field rate of 60 Hz by eliminating duplicate fields, the frames of the coded video signal including a control signal having a state indicating the frames of the coded video signal resulting from coding lost-field frames of the progressive video signal, the lost-field frames being frames of the progressive video signal wherefrom a duplicate field was eliminated, the apparatus comprising:

• decoding means for decoding the frames of the coded video signal to provide respective frames of a reconstructed progressive video signal;
• extracting means for extracting the control signal from the frames of the coded video signal;
• and
• field deriving means, operating in response to the control signal extracted from each one of the frames of the coded video signal, for deriving three fields of the interlaced output video signal from the respective one of the frames of the reconstructed progressive video signal when the state of the control signal indicates that the one of the frames of the coded video signal resulted from coding one of the lost-field frames, and deriving two fields of the interlaced output video signal from all others of the frames of the reconstructed progressive video signal.

System for deriving a recording signal for transfer to a medium, the recording signal being derived from an input video signal, and for deriving an output video signal from the recording signal reproduced from the medium, the recording signal having a constant bit rate substantially lower than the input video signal and the output video signal, the input video signal and the output video signal having a field rate of 60 Hz, the input video signal being derived from a motion picture film source using 2-3 pulldown, the system comprising:

• an encoding apparatus comprising:
• detecting means for detecting duplicate fields in the input video signal,
• control signal generating means for generating a control signal having a state indicating each of the detected duplicated fields,
• eliminating means, operating in response to the state of the control signal, for eliminating the duplicate fields from the input video signal,
• generating means, operating on the input video signal following elimination of the duplicate fields by the eliminating means, for generating a progressive video signal composed of frames and having a frame rate of 24 Hz,
• coding means for coding the frames of the progressive video signal to produce respective frames of the recording signal, and
• multiplexing means for including the control signal in each of the frames of the coded video signal, the state of the control signal indicating the frames of the coded video signal resulting from coding the lost-field frames of the progressive video signal;
• and
• a decoding apparatus comprising:
• decoding means for decoding the frames of the recording signal to provide respective frames of a reconstructed progressive video signal,
• extracting means for extracting the control signal from the frames of the recording signal, and
• field deriving means, operating in response to the control signal extracted from each one of the frames of the coded video signal, for deriving three fields of the interlaced output video signal from the respective one of the frames of the reconstructed progressive video signal when the state of the control signal indicates that the one of the frames of the coded video signal resulted from coding one of the lost-field frames, and for deriving two fields of the interlaced output video signal from all others of the frames of the reconstructed progressive video signal.

A method for generating, from an input video signal, a coded video signal for transfer to a medium at a constant bit rate, the input video signal having a field rate of 60 Hz and being derived from a motion picture film source using 2-3 pulldown, the method comprising steps of:

• providing:
• a hypothetical video buffer verifier having a size defined by vbv.sub.-- buffer.sub.-- size, and
• an output buffer;
• detecting duplicate fields in the input video signal;
• eliminating from the input video signal the duplicate fields detected in the detecting step;
• generating a progressive video signal from the fields of the input video signal that remain following the eliminating step, the progressive video signal comprising plural frames with a frame rate of 24 Hz;
• coding the progressive video signal to produce the coded video signal, the frames of the progressive video signal being coded with different numbers of bits;
• temporarily storing the coded video signal in the output buffer prior to transferring the coded video signal to the medium;
• and
• controlling the coding step using the hypothetical video buffer verifier with the size thereof reduced to vbv.sub.-- buffer.sub.-- size .times.4/5 to prevent input buffer overflow resulting from a duplication of fields that occurs when the coded video signal is decoded to provide a decoded video signal having a field rate of 60 Hz.

Apparatus for generating, from an input video signal, a coded video signal for transfer to a medium at a constant bit rate, the input video signal having a field rate of 60 Hz and being derived from a motion picture film source using 2-3 pulldown, the apparatus comprising:

• detecting means for detecting duplicate fields in the input video signal;
• eliminating means for eliminating from the input video signal the duplicate fields detected by the detecting means;
• generating means for generating a progressive video signal from the fields of the input video signal remaining following elimination of the duplicate fields by the eliminating means, the progressive video signal being composed of frames and having a frame rate of 24 Hz;
• coding means for coding the progressive video signal to produce the coded video signal, the frames of the progressive video signal being coded with different numbers of bits;
• output buffer means for temporarily storing the coded video signal prior to transfer of the coded video signal to the medium;
• and
• control means for controlling the coding means using the hypothetical video buffer verifier with the size thereof reduced to vbv.sub.-- buffer.sub.-- size .times.4/5 to prevent input buffer overflow resulting from a duplication of fields that occurs when the coded video signal is decoded to provide a decoded video signal having a field rate of 60 Hz.