Time base converter which automatically adapts to varying video input rates
First Claim
1. A time base changer for a video converter for converting between a sequence of input video images at an input video rate and a sequence of output video images at an output video rate, said time base changer comprising:
- N video stores, where N is an integer greater than one, each for storing a video image;
means for enabling said video stores cyclically in turn and at said input video rate for storing successive input video images in successive said video stores;
multiplexer means connected to said video stores for outputting said video images stored therein;
control means successively providing multiplexer control signals at said output video rate to said multiplexer means for selecting adjacent pairs of the video stores such that a sequence of pairs of the video images are output from said video stores via said multiplexer means at said output video rate;
wherein said input video rate is a selectable one of a plurality of rates and wherein said enabling means comprises a counter clocked at said selected input video rate.
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Abstract
A time base changer for a video converter for converting between a sequence of input video images at an input video rate and a sequence of output video images at an output video rate is operable to convert from one of a number of input video rates to an output video rate. The time base changer includes N video stores 32 where N is a integer greater than one, each for storing a video image. The video stores are enabled cyclically and at the appropriate input video rate for storing successive input video images in successive video stores. Multiplexers 36 connected to the video stores can output pairs of video images from the video stores at the output video rate. The time base changer includes a counter 38 which can be clocked at the appropriate one of the input video rates. The counter is preferably a modulo-N counter. Control signals for controlling the multiplexer in the selection of the adjacent pairs of video stores preferably includes a samplers 44 for sampling the output of the counter 38 at the output video rate.
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Citations
18 Claims
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1. A time base changer for a video converter for converting between a sequence of input video images at an input video rate and a sequence of output video images at an output video rate, said time base changer comprising:
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N video stores, where N is an integer greater than one, each for storing a video image; means for enabling said video stores cyclically in turn and at said input video rate for storing successive input video images in successive said video stores; multiplexer means connected to said video stores for outputting said video images stored therein; control means successively providing multiplexer control signals at said output video rate to said multiplexer means for selecting adjacent pairs of the video stores such that a sequence of pairs of the video images are output from said video stores via said multiplexer means at said output video rate; wherein said input video rate is a selectable one of a plurality of rates and wherein said enabling means comprises a counter clocked at said selected input video rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification