Interlaced video signal encoding and decoding method, by conversion of selected fields to progressive scan frames which function as reference frames for predictive encoding

A video decoding apparatus for executing decoding of successive code sequences which have been generated by encoding respective progressive scanning frames derived by doubling the scanning line density of one in every m fields of an original interlaced video signal (where m is an integer of 2 or greater), with the encoding process using intra-frame predictive encoding or unidirectional predictive encoding, and by encoding remaining fields of said video signal directly as interlaced scanning fields, with the encoding process using bidirectional predictive encoding based on preceding and succeeding ones of said progressive scanning frames, the video decoding apparatus comprising:

• first decoding means for decoding each of said code sequences corresponding to said progressive scanning frames by intra-frame decoding of said code sequence or by unidirectional predictive decoding of said code sequence using decoded ones of said progressive scanning frames,
• second decoding means for performing bidirectional predictive decoding of respective code sequences corresponding to each of said fields which have been encoded as interlaced scanning fields, using as reference frames decoded ones of said progressive scanning frames which precede and succeed the field corresponding to said code sequence along the time axis, and
• picture reconfiguration means for performing decimation of scanning lines of each of the progressive scanning frames which have been decoded by the first decoding means, to obtain a converted field having the same number of scanning lines as an interlaced scanning field, and for executing time-axis combination of respective ones of said converted fields with said fields which are derived by said second decoding means, in an appropriate sequence for reproducing said original interlaced video signal.

A video decoding apparatus for executing decoding of encoded progressive scanning frames derived by doubling the scanning line density of one in every m fields of an interlaced video signal (where m is an integer of 2 or greater), with the encoding process using intra-frame encoding or unidirectional predictive encoding, and by encoding remaining fields of said video signal directly as interlaced scanning fields, the video decoding apparatus comprising:

• decoding means for decoding each of said encoded progressive scanning frames by intra-frame decoding or by unidirectional predictive decoding using decoded ones of said progressive scanning frames, to thereby obtain a first series of reconstructed pictures,
• prediction error decoding means for decoding of prediction error values for each of said remaining fields which are encoded as interlaced scanning fields, interpolation means for performing over- sampling of said prediction error values in a vertical scanning direction of a field, to derive reconstructed prediction error values corresponding to ones of said progressive scanning frames, inter-picture prediction means for deriving prediction signal values for each of said fields which were encoded unchanged as interlaced scanning fields, using a preceding one and a succeeding one of said first series of reconstructed pictures as reference frames,
• adder means for adding to said prediction signal values said reconstructed prediction error values corresponding to progressive scanning lines, to thereby obtain a second series of reconstructed pictures, and picture reconfiguration means for inserting said second series of reconstructed pictures into said first series of reconstructed pictures to obtain a reconstructed video signal in which all pictures are expressed as progressive scanning frames.

An encoded video recording medium having recorded thereon code expressing interlaced video information which has been encoded by high-efficiency encoding of an interlaced video signal, said encoding being characterized in that,

• one in every m fields of said interlaced video signal (where m is an integer of 2 or greater) is converted to a progressive scanning frame having double the number of scanning lines while remaining fields are left unchanged as interlaced scanning fields,
• each of the progressive scanning frames is either independently internally encoded or is encoded by unidirectional prediction encoding using as reference frames progressive scanning frames which have already been encoded, to thereby obtain respective first code sequences corresponding to said progressive scanning frames,
• each of the remaining fields which are left unchanged as interlaced scanning fields is encoded by bidirectional prediction using preceding and succeeding ones of the encoded progressive scanning frames as reference frames, to thereby obtain respective second code sequences corresponding to said remaining fields, and
• said first and second code sequences are recorded to constitute said encoded video recorded medium.

A method of decoding successive code sequences which have been generated by a first encoding process applied to respective progressive scanning frames which have been derived by doubling the scanning line density of one in every m fields of an original interlaced video signal (where m is an integer of 2 or greater), with the first encoding process using intra-frame predictive encoding or unidirectional predictive encoding, and by encoding remaining fields of said video signal directly as interlaced scanning fields in a second encoding process, with the second encoding process using bidrectional predictive encoding based on preceding and succeeding ones of said progressive scanning frames, the method comprising:

• executing decoding each of respective code sequences corresponding to each of said progressive scanning frames by intra-frame decoding of said code sequence or by unidirectional predictive decoding of said code sequence using decoded ones of said progressive scanning frames, and
• executing predictive decoding of respective code sequences corresponding to each of said fields which have been encoded as interlaced scanning fields, using as reference frames decoded ones of said progressive scanning frames which precede and succeed the field corresponding to said code sequence along the time axis,
• performing decimation of scanning lines of each of the progressive scanning frames which have been decoded by the first decoding means, to obtain a converted field having the same number of scanning lines as an interlaced scanning field, and
• combining respective ones of said converted fields and said fields which are derived by said second decoding means, along the time axis, in an appropriate sequence for reproducing said original interlaced video signal.

A method of decoding successive code sequences which have been generated by encoding respective progressive scanning frames derived by doubling the scanning line density of one in every m fields of an original interlaced video signal (where m is an integer of 2 or greater), with the encoding process using intra-frame encoding or unidirectional predictive encoding, and by encoding remaining fields of said video signal directly as interlaced scanning fields,

• the decoding method comprising:
• decoding each of said progressive scanning frames by intra-frame decoding or by unidirectional predictive decoding using decoded ones of said progressive scanning frames, to thereby obtain a first series of reconstructed pictures, respective sets of prediction error values for each of said remaining fields which are encoded as interlaced scanning fields,
• performing over-sampling of said prediction error values in a vertical scanning direction of a field, to generate reconstructed prediction error values corresponding to scanning lines of a progressive scanning frame,
• deriving, for said each field which was encoded as an interlaced scanning field, prediction signal values based on selected ones of said first series of progressive scanning frames which precede and succeed said each field along the time axis, as reference frames,
• adding said prediction signal values to said reconstructed prediction error values, to thereby obtain a second series of reconstructed pictures, and inserting said second series of reconstructed pictures into said first series of reconstructed pictures to obtain a reconstructed video signal in which all pictures are expressed as progressive scanning frames.