Method, apparatus and record carrier for video signal recording and reading wherein signal blocks occurring during switching are repositioned and preserved

An apparatus for recording a video signal in tracks which are inclined relative to the longitudinal direction of a magnetic record carrier in the form of a tape by means of a plurality of write heads mounted on a rotatable head drum, the video signal comprising a sequence of lines, each with a first signal block containing a line synchronizing signal and a second signal block containing chrominance and luminance information of the video signal, the first signal blocks containing at least one additional signal in addition to the line synchronizing signal, wherein during recording, at least the additional signal in a specific first signal block is stored in a memory and is subsequently accommodated in one or more second signal blocks associated with one or more non-relevant lines in the video signal, said non-relevant lines corresponding to lines which occur outside of the display interval of the television picture signal, after which said one or more second signal blocks are recorded in a track on the record carrier, the apparatus comprising:

• an input terminal to which said video signal to be recorded is applied;
• first switching means, for cyclically changing over from recording with one of said plurality of write heads to another of said plurality of write heads, having an input, a plurality of outputs and a control input, said first switching means coupling the input to one of the outputs under the influence of a first control signal applied to the control input, each output of said first switching means being coupled to an associated write head;
• a memory, having an input, a control input and an output, for storing the at least one additional signal in said first signal block at the instant of changing over from recording with one write head to recording with another write head, under the influence of a second control signal applied to the control input of said memory, the input of said memory being coupled to the input terminal at least at the instant of said changing over of said write heads;
• second switching means having a first and a second input, an output, and a control input, the output of said memory being coupled to the first input of said second switching means and the output of said second switching means being coupled to the input of said first switching means, said second switching means coupling one of the first and second inputs to the output under the influence of a third control signal applied to the control input of said second switching means such that the first input is coupled to the output at the instant at which the one or more second signal blocks associated with the non-relevant lines in the video signal are recorded;
• and
• control means for generating said first, second and third control signals.

An apparatus for reproducing a video signal from a modified video signal recorded on a record carrier, in which the video signal comprises a sequence of lines with a first signal block containing a line synchronizing signal and a second signal block containing chrominance and luminance information of the video signal, the first signal blocks containing at least one additional signal in addition to the line synchronizing signal, said modified video signal having been formed by removing the at least one additional signal in a specific first signal block and inserting this removed at least one additional signal in one or more second signal blocks associated with one or more non-relevant lines in the video signal, said non-relevant lines corresponding to lines which occur outside of the display interval of a television picture signal, said apparatus for reproducing the video signal comprising:

• a plurality of read heads;
• first switching means for cyclically changing over from reading with one of said plurality of read heads to another of said plurality of read heads, said first switching means having two or more inputs respectively coupled to said read heads, an output and a control input, said first switching means coupling one of said inputs to the output under the influence of a first control signal applied to the control input;
• an output terminal for supplying the reproduced video signal;
• a memory for storing, under the influence of a second control signal applied to a control input of the memory, the at least one additional signal contained in the one or more second signal blocks in the modified video signal read from the track of the record carrier, said memory having an input coupled to the output of the first switching means at least at the instant at which the one or more second signal blocks in the non-relevant lines are read, and an output;
• delay means for delaying at least the first signal block in each line in the modified video signal read from the track, said delay means having an input coupled to the output of the first switching means, and an output;
• second switching means having a first and a second input coupled, respectively, to the outputs of said memory and said delay means, and an output, said second switching means coupling one of its first and second inputs to its output under control of a third control signal applied to a control signal input of said second switching means, whereby the first input of said second switching means is coupled to the output of said second switching means during the time of changing over of read heads, delayed by the time interval T, from reading with one of said read heads to another of said read heads;
• and
• control means for generating said first, second and third control signals.

An apparatus for recording a video signal in tracks which are inclined relative to the longitudinal direction of a magnetic record carrier in the form of a tape by means of a plurality of write heads mounted on a rotatable head drum, the video signal comprising a sequence of lines with a first signal block containing a line synchronizing signal and a second signal block containing chrominance and luminance information of the video signal, each of the first signal blocks containing at least one additional signal in addition to the line synchronizing signal, wherein during recording, at least the at least one additional signal in a specific first signal block is removed and subsequently inserted in one or more specific second signal blocks associated with one or more non-relevant lines in the video signal, said non-relevant lines corresponding to lines which occur outside of the display interval of the television picture signal, after which said signal blocks are recorded in a track on the record carrier, and wherein at least the at least one additional signal in a first signal block during which changing over from recording with one write head to recording with another write head is effected, is delayed by one or more line periods and is subsequently accommodated in a subsequent first signal block and recorded on the record carrier, while the at least one additional signal originally occurring in said subsequent first signal block prior to the insertion of the delayed at least one additional signal is subsequently accommodated in the specific second signal block and recorded on the record carrier, characterized in that the apparatus comprises:

• an input terminal for receiving the video signal to be recorded;
• a plurality of write heads;
• first switch means, for cyclically changing over from recording with one of said plurality of write heads to another of said plurality of write heads, having an input, two or more outputs, and a control input, said first switching means coupling the input to one of the outputs under the influence of a first control signal applied to the control input, the input terminal being coupled to the input of said first switching means and each output of said first switching means being coupled to an associated write head;
• a memory, having an input, an output, and a control signal input, for storing the at least one additional signal originally occurring in said subsequent first signal block under the influence of a second control signal applied to the control signal input of said memory, the input of said memory being coupled to said input terminal at least at the instant at which said subsequent first signal block is applied to the input terminal;
• second switching means having a first and a second input, an output, and a control signal input, the output of said memory being coupled to the first input of said second switching means and the output of said second switching means being coupled to the input of said first switching means, said second switching means coupled one of the first and second inputs to the output under the influence of a third control signal applied to a control signal input of said second switching means such that the first input is coupled to the output at the instant of recording of one or more second signal blocks associated with one or more non-relevant lines in the video signal;
• and
• control means for generating said first, second and third control signals.

An apparatus for reproducing a video signal from a modified video signal recorded in tracks which are inclined relative to the longitudinal direction of a magnetic record carrier in the form of a tape, in which the video signal comprises a sequence of lines with a first signal block containing a line synchronizing signal and a second signal block containing chrominance and luminance information of the video signal, the first signal blocks containing at least one additional signal in addition to the line synchronizing signal, said modified video signal having been formed by delaying for one or more line periods the at least one additional signal in a specific first signal block in the video signal which would have occurred during a changing over from recording with one write head to recording with another write head, inserting the delayed at least one additional signal into a subsequent first signal block, delaying the at least one additional signal originally occurring in said subsequent first signal block prior to the insertion of said delayed at least one additional signal, and then inserting the delayed subsequent first signal block at least one additional signal into one or more subsequent second signal blocks associated with one or more non-relevant video lines, characterized in that said apparatus comprises:

• a plurality of read heads;
• first switching means, for cyclically changing over said read heads, having a plurality of inputs respectively coupled to said read heads, an output and a control signal input, said switching means coupling one of said plurality of inputs to the output under the influence of a first control signal applied to the control signal input;
• an output terminal for supplying the video signal;
• memory means, having an input, an output and a control signal input, for storing, under control of a second control signal applied to the control signal input, the at least one additional signal occurring in the one or more subsequent second signal blocks in the non-relevant lines in the modified video signal read from the track, the input of said memory means being coupled to the output of the first switching means at least at the instant at which the second signal blocks are read;
• second switching means having a first and a second input, an output, and a control signal input, the output of said memory means being coupled to the first input of said second switching means, and the output of said second switching means being coupled to said output terminal, said second switching means coupling one of the first and second inputs to the output under the influence of a third control signal applied to the control signal input of the second switching means such that the first input is coupled to the output at the instant at which the relevant subsequent first signal block of the modified video signal is read from the track;
• and
• control means for generating said first, second and third control signals.

A method of reproducing a video signal from tracks which are inclined relative to the longitudinal direction of a magnetic record carrier in the form of a tape by means of a plurality of read heads mounted on a rotatable head drum, in which said read heads are cyclically changed over from one to another during the reading of the video signal, the video signal comprising a sequence of lines each having a first signal block containing a line synchronizing signal and a second block containing chrominance and luminance information of the video signal, the first signal blocks each containing at least one additional signal in addition to the line synchronizing signal, wherein during recording, for preserving at least the additional signal that would otherwise be lost during the time when write heads are cyclically changed over from one to another, the at least one additional signal occurring in a specific first signal block of the video signal have been stored and are inserted in one or more specific second signal blocks associated with one or more non-relevant lines in the video signal, thereby forming a modified video signal, said non-relevant lines corresponding to lines in the video signal which occur outside of the display interval of a television picture signal, and then said modified video signal is recorded on said magnetic record carrier, wherein said specific second signal blocks containing said at least one additional signal are recorded in a track on the record carrier, characterized in that said method of reproducing a video signal comprises the steps:

• removing said at least one additional signal occurring in said specific second signal blocks in said modified video signal corresponding to said non-relevant lines in said video signal;
• storing in a memory said removed at least one additional signal;
• and
• re-inserting said stored at least one additional signal into the specific first signal block, thereby reconstituting said video signal.