Video tape control time code reading
AssigneeSony Corporation
InventorKatsuichi Tachi
Life of this patent
Estimating the term…
Abstract
A video magnetic tape control time code reading method and apparatus employs a control time code comprising binary coded times and frame numbers which together form addresses of individual frames of a video signal recorded on a video magnetic tape which can be read, independently of the direction and speed of transport of the video tape, to ascertain whether the control time code corresponds to a recorded video signal having a frame frequency of 30 or 25 frames per second. Use is made of the fact that certain frame numbers occur in a 30 frame per second control time code which do not occur in a 25 frame per second control time code.
Claims15
A method for distinguishing between first and second control time codes recorded on a recording tape, said first and second control time codes including frame numbers sequentially repeating and having equal minimum values and said first control time code having a first maximum value which exceeds a second maximum value of said second control time code, said recording tape being transportable in a forward tape transport direction and in a reverse tape transport direction, said frame numbers sequentially increasing from said minimum to said maximum value during forward tape transport and sequentially decreasing from said maximum to said minimum value during reverse tape transport, comprising the steps of:
- detecting whether tape transport is in said forward or reverse tape transport direction;
- comparing a first frame number in a first frame with a next-occurring frame number;
- during forward tape transport, producing an output signal indicative of said first control time code in response to said first frame number being said second maximum value and said next-occurring frame number being other than said minimum values;
- and
- during reverse tape transport, producing an output signal indicative of said first control time code in response to said first frame number being said minimum values and said next-occurring frame number being other than said second maximum value.
A method for distinguishing between first and second different control time codes having at least frame codes which identify repeating sequences of contiguous frame numbers therein reproduced from a video magnetic tape containing video signals recorded thereon, comprising the steps of:
- sensing the presence and absence of predetermined frame numbers in the reproduced control time code;
- and
- detecting in dependence on the presence and absence of said predetermined frame numbers, whether said reproduced control time code is said first or said second control time code.
A method for distinguishing between at least first and second control time codes reproduced from a video tape which contains frames of video recorded thereon, said first control time code including at least first repeating sequences of frame codes identifying individual frames of said video, said first repeating sequences repetitively beginning with a first number and ending with a second number, said second control time code including at least second repeating sequences of frame codes identifying individual frames of said video, said second repeating sequences repetitively beginning with said first number and ending with a third number which is greater than said second number, comprising the steps of:
- sensing one of said first, second and third numbers;
- and
- sensing whether a next-occurring frame code after said sensing of said one of said first, second and third numbers includes a next frame number in one of said repeating sequences and producing in dependence thereon an output signal indicative of one of said first and second control time codes.
A video tape control time code reading apparatus for distinguishing one of at least first and second different control time codes having frame numbers corresponding respectively to frames of video signals having first and second different frame frequencies recorded on said video tape, the apparatus comprising:
- means for receiving said control time code;
- means for sensing the presence and absence of predetermined frame numbers within said control time code;
- and
- means operative in dependence on the presence and absence of said predetermined frame numbers, for distinguishing between said control time code being said first and said second time code.
Dependencies are inferred from the claim text.