Apparatus, systems and methods for providing multiple video data streams from a single source

• US 5,455,626 A
• Filed: 11/15/1993
• Issued: 10/03/1995
• Est. Priority Date: 11/15/1993
• Status: Expired due to Term

• Current Assignee: NVIDIA Corporation
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Xu, Frank, Nally, Robert M.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Murrell, Jeffrey S.
• Application Number:
  US08/152,182
• Time in Patent Office: 687 Days
• Field of Search: 348/715, 348/719, 348/720, 348/385, 348/387
• US Class Current: 348/385.1
• CPC Class Codes: H04N 5/9205 the additional signal being at least another television signal
• CPC Class Codes: H04N 7/0806 the signals being two or more video signals H04N7/0803, H04N7/081 take precedence

Abstract

A method is provided for generating a output composite video data stream. During a first phase of a set of processing phases, a frame of first video data is received and then downscaled to produce a first block of data. Also during the first phase, the first block is stored and then retrieved from a first memory space. The first block is next upscaled and then output as a first field of a composite video data stream. During a second phase of the set of processing phases, a frame of second video data is received and downscaled to produce a second block of data. Also during the second phase, the second block of data is stored and then retrieved from a second memory space. The second block is next upscaled during the second processing phase and then output as a second field of the composite video stream.

Claims

1. A method for generating an output composite video data stream comprising the steps of:

during a first phase of a set of processing phases;

receiving a frame of first vide data;

downscaling the frame of first video data to produce a first block of data;

storing the first block in a first memory space;

retrieving the first block of data from the first memory space;

upscaling the first block to produce an upscaled first block; and

outputting the upscaled first block as a first field of the composite video stream; and

during a second phase of the set of processing phases;

receiving a frame of second video data;

downscaling the frame of second video data to produce a second storage block of data;

storing the second block in a second memory space;

retrieving the second block from the second memory space;

upscaling the second block to produce on upscaled second block; and

outputting the upscaled second block as a second field of the composite video stream.

2. The method of claim 1 wherein the first phase of the set of phases is a one of first and third phases of a set of four processing phases.

3. The method of claim 1 wherein the second phase of the set of phases is a one of first, second, third, and fourth phases of a set of four processing phases.

4. The method of claim 1 wherein the frame of first video data has an x-dimension and a y-dimension, said step of downscaling the frame of first video data comprising a step of reducing both the x and y dimensions of the frame of first video data.

5. The method of claim 1 wherein the frame of second video data has an x-dimension and a y-dimension, said step of downscaling the frame of second video data comprising a step of reducing both the x and y dimensions of the frame of second video data.

6. The method of claim 1 wherein the frame of first video data has an x-dimension and a y-dimension, said step of upscaling the frame of first video data comprising a step of increasing the x-dimension of the frame of first video data.

7. The method of claim 1 wherein the frame of second video data has an x-dimension and a y-dimension, said step of upscaling the frame of second video data comprising a step of increasing the x-dimension of the frame of second video data.

8. A method of generating a composite video data stream comprising the steps of:

during a selected phase of a first set of processing phases;

receiving a frame of first video data;

downscaling the frame of first video data to produce a first block of video data;

storing the first block in a first object buffer;

during selected phase of a second set of processing phases;

receiving a frame of second video data;

downscaling the frame second video data to produce a second block of video data;

storing the second block in a second object buffer;

retrieving the first and second blocks from the first and second memory spaces; and

outputting each of the first and second blocks as a field of the composite video data stream.

9. The method of claim 8 wherein the selected phase of the first set of phases is a one of first and third phases of a set of four processing phases.

10. The method of claim 8 wherein the selected phase of the second set of phases is a one of first second third, and fourth phases of a set of four processing phases.

11. The method of claim 8 wherein the frame of first video data has an x-dimension and a y-dimension, said step of downscaling the frame of first video data comprising a step of reducing both the x and y dimensions of the frame of first video data.

12. The method of claim 8 wherein the frame of second video data has an x-dimension and a y-dimension, said step of downscaling the frame of second video data comprising a step of reducing both the x and y dimensions of the frame of second video data.

13. The method of claim 8 wherein the block of first video data has an x-dimension and a y-dimension, and said method further comprises a step of upscaling the block of first video data by increasing the x-dimension of the block of first video data prior to said step of outputting.

14. The method of claim 8 wherein the block of second video data has an x-dimension and a y-dimension, and said method further comprises a step of upscaling the block of second video data by increasing the x-dimension of the frame of second video data prior to said step of outputting.

15. A method for generating an output composite video data stream comprising the steps of:

receiving a first data stream composed of a sequence of frames of video data each having an x-dimension of a preselected number of pixels and a y-dimension of a preselected number of pixels;

receiving a second data stream composed of a sequence of frames of video data each having an x-dimension of a preselected number of pixels and a y-dimension of a preselected number of pixels;

downscaling the x and y dimensions of the frames of the first data stream to produce a sequence of first blocks of pixels;

writing the first blocks into a first object buffer associated with a first memory space during ones of first and third phases of four processing phases;

reading the first blocks of data out of a second object buffer associated with the first memory space during ones of the first and third phases;

upscaling the x-dimension of each first blocks;

outputting each first block as a first field of a composite video stream;

downscaling the x and y dimensions of the frames of the second data stream to produce a sequence of second blocks of pixels;

writing the second blocks of data into a third object buffer associated with a second memory space during ones of second and fourth phases of the four processing phases;

reading the second blocks out of a fourth object buffer the second memory space during ones of the second and fourth processing phases;

upscaling the x-dimension of each second block; and

outputting each second block as a second field of the composite video stream.

16. The method of claim 15 wherein the frames of the first video data stream have an x-dimension of 640 pixels and a y-dimension of 480 pixels.

17. The method of claim 15 wherein the frames of the second video data stream have a said y-dimension of 640 pixels and a said y-dimension of 480 pixels.

18. The method of claim 15 wherein said step of downscaling the x and y dimensions of the frames of the first data stream comprises a step of reducing the selected pixels in the x and y dimensions by a factor two.

19. The method of claim 15 wherein said step of downscaling the x and y dimensions of the frames of the second data stream comprises a step of reducing the selected pixels in the x and y dimensions by a factor of two.

20. The method of claim 15 wherein said step of upscaling the x-dimension of each of the first blocks comprises a step of doubling the pixels in the x-dimension of each of the first blocks.

21. The method of claim 15 wherein said step of upscaling the x-dimension of each of the second blocks comprises a step of doubling the pixels in the x-dimension of each of the second blocks.

22. The method of claim 15 wherein at least one of said first and second video data streams comprises an input composite video data stream including data derived from a plurality of video data sources.

23. The method of claim 15 wherein the input composite video data stream is composed of a plurality of fields, each of said fields being composed of video data derived from a plurality of video data sources.

24. The method of claim 15 wherein the first field comprises an even pixel field and the second field comprises an odd pixel field.

25. The method of claim 15 wherein at least one of said first and second video data streams comprises an input composite video data stream including data derived from a plurality of video data sources.

26. The method of claim 15 wherein the input composite video data stream is composed of a plurality of fields, each of said fields being composed of video data derived from a plurality of video data sources.

27. The method of claim 15 wherein the first field comprises an even pixel field and the second field comprises an odd pixel field.

28. A video processing system comprising:

a first video data source for generating a first stream of frames of video data;

a second video data source for generating a second stream of frames of video data;

a frame buffer; and

a processor coupled to said first and second video data sources and said frame buffer said processor operable to;

during a phase of a first set of phases;

receive a frame of said first video data;

downscale said frame of first video data to produce a first block of data;

store said first block in a first memory space in said frame buffer;

retrieve said first block of data from said first memory space;

upscale said first block to produce an upscaled first block;

output said upscaled first block as a first field of a composite video stream;

during a phase of a second set of phases;

receive a frame of said second video data from said second source;

downscale said frame of said second video data to produce a second block of data;

store said second block in a second memory space in said frame buffer;

retrieve said second block from said second memory space;

upscale said second block to produce an upscaled second block; and

output said upscaled second block as a second field of the composite video stream.

29. The system of claim 28 wherein said processor comprises a video processor.

30. The system of claim 28 wherein said frame buffer includes at least one video random access memory device.

31. The system of claim 28 wherein said phase of said first set of phases comprises a one of first and third phases of a set of four processing phases.

32. The system of claim 28 wherein said phase of said second set of phases is a one of first, second third, and fourth phases of a set of four processing phases.

33. The system of claim 28 wherein at least one of said first and second video data sources comprises a VCR.

34. The system of claim 28 wherein at least one of said first and second video data sources comprises a video camera.

35. The system of claim 28 wherein at least one of said first and second video data sources comprises a cable television cable.

36. A method of generating multiple video data streams from a single composite video data stream comprising the seeps of:

receiving a composite video stream composed of a sequence of fields of video data a first field in the sequence representing first video data and a second field in the sequence representing second video data;

during a first processing phase of a set of phases;

downscaling the first field to produce a first block of data;

storing the first block of data in a first memory space of a frame buffer using a random access port;

selectively retrieving and upscaling the first block of data; and

outputting to a first display space the upscaled first block of data from the first memory space using a serial port of the frame buffer; and

during a second processing phase of the set of phrases;

downscaling the second field to produce a second block of data;

storing the second block of data in a second memory space of the frame buffer using the random access port;

selectively retrieving and upscaling the second block of data; and

outputting to a second display space the upscaled second block of data from the serial port of the frame buffer.