Video window generator with scalable video

• US 5,402,513 A
• Filed: 06/27/1994
• Issued: 03/28/1995
• Est. Priority Date: 10/15/1991
• Status: Expired due to Term

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Pixel Semiconductor, Inc.
• Inventors: Schafer, John C.
• Primary Examiner(s): Boudreau, Leo H.
• Assistant Examiner(s): Johns, Andrew W.
• Application Number:
  US08/266,164
• Time in Patent Office: 274 Days
• Field of Search: 382/44, 382/47, 395/102, 395/139, 345/127, 345/131, 358/451
• US Class Current: 382/298
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: G09G 2340/125 wherein one of the images is motion video
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

A pixel processor is disclosed which is comprised of a video window generator (VWG) (10). VWG (10) utilizes a conversion section for receiving an input video signal in a YUV 422 video format and converting it to an RGB video format. The conversion section includes a chroma interpolator 56 for converting the YUV 422 video format to a YUV 444 video format, a color converter (58) for converting the YUV 444 video format to an RGB video format, and then to a gamma coding removal block (60) for removing gamma coding. After conversion, the RGB video format signal is then scaled down by a linear resampler block (62) to average information over a predetermined portion of the input display space for output to a predetermined portion of the output display space. The scaled video output is truncated by a quantization processor (64) and then input to a FIFO (66). A control unit (68) controls the operation of the system. The linear resampler circuit (68) is an interpolation filter for averaging the information of a number of pixels disposed about a point in the input display space that is to be mapped into a point in the output display space. The point in the output display space is comprised of a pixel. The interpolation filer operates on pixels disposing in an adjacent relationship within a row of pixels within an input array. If the point to be mapped into the output display space falls between two pixels, the weighted average is taken between the two adjacent pixels. Rows of pixels are selected in accordance with the nearest neighbor algorithm. The quantization processor (64) is operable to truncate a predetermined number of bits from each word in each of the color planes in the output data prior to outputting the data. The truncated data is then utilized as an error which is added to the value of the next pixel before truncation thereof.

Claims

1. A video scaling apparatus for scaling down video information originating in an input device end displaying the resulting scaled down video information in a designated window within a screen of an output video device, comprising:

a scaling input for receiving scaling information;

a video input for receiving real time input video information from the input video device;

means for designating a said window within said screen of said output video device;

an output for outputting scaled down video information into said designated window within said screen of said output video device in substantially real time; and

an averaging circuit coupled to said scaling input, said video input, and said output for averaging received said video information corresponding to a predetermined area within a screen of said input video device in accordance with a predetermined averaging algorithm and outputting the averaged video information through said output into a predetermined area of said designated window within said screen of said output video device, the ratio of said predetermined area of said screen of the input video device to said predetermined area of said window within the screen of said output video device being determined by the scaling information received on the scaling input.

2. The video scaling apparatus of claim 1 and further comprising a control circuit for receiving location parameters for determining the location of said predetermined area of said screen of said input video device that is to be scaled down for output to said window within said screen of said output video device.

3. The video scaling apparatus of claim 1 wherein said screen of said input video device is substantially the same size as said screen of said output video device wherein each of the input and output video screens are updated in frames and further comprising a buffering device for allowing the output averaged video information to be output at a different rate than the rate of the video information in the input video device.

4. The video scaling apparatus of claim 1 wherein the video information of said screen of said input video device is comprised of an array of pixels of a first predetermined array size and said window within said screen of said output video device is comprised of an array of pixels of a second predetermined array size.

5. The video scaling apparatus of claim 4 wherein said averaging circuit comprises an interpolation filter for generating the weighted average of at least two pixels disposed proximate to the point in the screen of the input video device that is to be mapped to a point in the screen of the output video device in accordance with the scaling information, the point in said screen of said output video device comprising a pixel in said screen having a value equal to the weighted average value generated by said interpolation filter.

6. The video scaling apparatus of claim 5 wherein said interpolation filter operates only on pixels in a horizontally adjacent relationship and said averaging circuit further comprises a nearest neighbor circuit for selecting rows of said video information within the rows of pixels in said screen of said input video device that are most proximate to said point in said screen of said output video device in accordance with a nearest neighbor algorithm.

7. A video scaling apparatus for scaling down video information originating in an input video device and displaying the resulting scaled down video information in a designated window within a screen of an output video device, comprising:

a scaling input for receiving scaling information;

a video input for receiving real time input video information in the form of an array of input pixels from the input video device;

means for designating a said window within said screen of said output video device;

an output for outputting scaled down video information into said designated window within said screen of said output video device in the form of an array of output pixels and in substantially real time; and

a processing circuit coupled to said scaling input, said video input, and said output for processing received said video information corresponding to a predetermined area within a screen of said input video device in accordance with a predetermined processing algorithm and outputting the processed video information through said output into a predetermined area of said designated window within said screen of said output video device such that ones of the output pixels are functions of at least two of the input pixels, the ratio of said predetermined area of said screen of said input video device to said predetermined area of said window within said screen of said output video device being determined by the scaling information received on the scaling input.

8. The video scaling apparatus of claim 7 and further comprising a control circuit for receiving location parameters for determining the location of said predetermined area of said screen of said input video device that is to be scaled for output to said window within said screen of said output video device.

9. The video scaling apparatus of claim 7 wherein said processing circuit comprises an interpolation filter for generating the weighted average of at least two pixels disposed proximate to the point in the screen of the input video device that is to be mapped to a point in the screen of the output video device in accordance with the scaling information, the point in said screen of said output video device comprising one of the output pixels, the output pixel having a value equal to the weighted average value of the two input pixels generated by said interpolation filter.

10. The video scaling apparatus of claim 9 wherein said interpolation filter operates only on input pixels in a horizontally adjacent relationship and said processing circuit further comprises a nearest neighbor circuit for selecting rows of said input pixels within the rows of pixels in the screen of said input video device that are most proximate to said point in the screen of said input video device that is to be mapped into said point in the screen of said output video device in accordance with a nearest neighbor algorithm.

11. An integrated single chip video processor, comprising:

a video input for receiving a real time video input signal in a first video format at a predetermined rate, said video input signal representing a screen of an input video device;

conversion circuitry for converting said video input signal to a second video format having a higher video bandwidth, said conversion circuitry outputting converted video;

a video scaling device for scaling down to a designated window within a screen of an output video device the converted video representing said screen of said input video device, said video scaling device including;

a scaling input for receiving scaling information;

an output for outputting scaled down video information into said window within said screen of said output video device in substantially real time; and

means for designating a said window within said screen of said output video device;

an averaging circuit coupled to said scaling input, said video input, and said output for averaging received said video information corresponding to a predetermined area within said screen of said input video device in accordance with a predetermined averaging algorithm and outputting the averaged video information through said output into a predetermined area of said designated window within said screen of said output video device, the ratio of said predetermined area of said screen of said input video device to said predetermined area of said window within said screen of said output video device determined by the scaling information received on said scaling input; and

an output buffer for receiving and buffering the video output of said scaling device at the input rate and operable to output the buffered video output of said scaling device at an output rate in substantially real time.

12. The pixel processor of claim 11, and further comprising quantizing circuitry for reducing the video information that is output by said video scaling device.

13. The video processor of claim 12, wherein said video input signal presents said screen of said input video device as an array of individual input pixels and said screen of said output video device is represented by an array of output pixels, each of said output pixels represented by a plurality of color planes, each color plane represented by a digital word, said quantizing device operable to quantize each of said digital words in each of said color planes by a predetermined number of digital bits associated with each of said color planes.

14. The video processor of claim 11, wherein said first video format is C_r C_b and said second video format is RGB, said conversion circuitry operable to convert said C_r C_b formatted video to RGB formatted video.

15. The video processor of claim 14, wherein said C_r C_b formatted video is a 444 ratio.

16. The video processor of claim 15, wherein said first video format is at a C_r C_b 422 ratio, said conversion circuitry operable to convert said C_r C_b 422 video format to a C_r C_b 444 video format prior to conversion to RGB video format.

17. The video processor of claim 16, and further comprising bypass circuitry for controlling said conversion circuitry to receive video information in either a YUV 422 video format, a YUV 444 video format or an RGB video format and to selectively convert said YUV 422 video format or said YUV 444 video format to an RGB video format.

18. The video processor of claim 11, and further comprising a control circuit for receiving location parameters for determining the location of said predetermined area of said screen of said input video device that is to be scaled for output to said window within said screen of said output video device.

19. The video processor of claim 11, wherein said screen of said input video device is substantially the same size as said screen of said output video device wherein said output rate is different than the input rate of the video information in said screen of said input video device.

20. The video processor of claim 11, wherein the video information of said screen of said input video device is comprised of an array of pixels of a first predetermined array size and said window within said screen of said output video device is comprised of an array of pixels of a second predetermined array size.

21. The video processor of claim 20, wherein said averaging circuit comprises an interpolation filter for generating the weighted average of at least two pixels disposed proximate to the point in said screen of said input video device that is to be mapped to a point in said screen of said output video device in accordance with the scaling information, the point in said screen of said output video device comprising a pixel in said screen having a value equal to the weighted average value generated by said interpolation filter.

22. The video processor of claim 21, wherein said interpolation filter operates only on pixels in a horizontally adjacent relationship in the rows of said first predetermined array and said averaging circuit further comprises a nearest neighbor circuit for selecting rows of said video information in the rows of pixels in said screen of said input video device that are most proximate to said point in said screen of said input video device that is to be mapped into said point in said screen of said output video device in accordance with a nearest neighbor algorithm.

23. The video processor of claim 11, wherein said output buffer is comprised of a first-in-first-out buffer that is loaded at the input rate and receives an output read clock for reading at an output frame rate different from the input rate.

24. A method for scaling down a video image in a screen of an input video device and mapping the scaled down video image to a designated window within a screen of an output video device, comprising the steps of:

receiving scaling information;

designating a said window within the screen of the output video device;

receiving on a video input, a real time video image from the screen of the input video device;

reducing a size of said received video image as a function of said received scaling information to facilitate said mapping of said received real time video image to the designated window within the screen of the output video device, wherein said reducing step includes the step of;

averaging a portion of the received video image associated with a predetermined area of the screen of the input video device in accordance with a predetermined averaging algorithm and outputting, in substantially real time, the averaged video image into a predetermined area of said window within the screen of the output video device, the ratio of the predetermined area of the screen of the input video device to the predetermined area of said window within the screen of the output video device determined by the scaling information.

25. The method of claim 24, and further comprising the step of receiving location parameters for determining the location of a predetermined area of the screen of the input video device that is scaled for output to said window within the screen of the output video device.

26. The method of claim 24, wherein the screen of the input is substantially the same size as the screen of the output video device and wherein each of the input and output screens are updated in frames, and further comprising, temporarily storing the output averaged video information and outputting the stored averaged video information at a different rate from the rate of the video information in the input video device.

27. The method of claim 24, wherein the video information of the screen of the input video device is comprised of an array of pixels of a first predetermined array size and said window within the screen of the output video device is comprised of an array of pixels of a second predetermined array size.

28. The method of claim 27, wherein the step of averaging comprises processing the video information through an interpolation filter and generating the weighted average of at least two pixels disposed proximate the point in the screen of the input video device that is to be mapped to a point in the screen of the output video device in accordance with the scaling information, the point in the screen of the output video device comprising a pixel in the screen having a value equal to the weighted average value generated by the step of processing through the interpolation filter.

29. The method of claim 28, wherein the step of processing the video information through the interpolation filter operates only on pixels in a horizontally adjacent relationship and the step of averaging further comprises selecting rows of the video information within the rows of pixels in the screen of the input video device in accordance with a nearest neighbor algorithm, such that rows of pixels that are most proximate to the point in the screen of the input video device that is to be mapped into the point in the screen of the output video device are selected.

30. A method for scaling down a video image in a screen of an input video device and mapping the scaled down video image to a window within a screen of an output video device, comprising the steps of:

receiving scaling information;

designating a said window within the screen of the output video device;

receiving on a video input, a real time video image from the screen of the input video device in the form of an array of input pixels;

reducing a size of said received video image as a function of said received scaling information to facilitate said mapping of said received real time video image to said window within the screen of the output video device, wherein said reducing step includes the step of;

processing a portion of the received video image associated with a predetermined area of the screen of the input video device in accordance with a predetermined processing algorithm and outputting, in substantially real time, the processed video image into a predetermined area of said window within the screen of the output video device in the form of an array of output pixels such that ones of the output pixels are functions of at least two of the input pixels, the ratio of the predetermined area of the screen of the input video device to the predetermined area of said window within the screen of the output video device determined by the scaling information;

31. The method of claim 30, and further comprising the step of receiving location parameters for determining the location of a predetermined area of the screen of the input video device that is scaled down for output to said window within the screen of the output video device.

32. The method of claim 30, wherein the step of processing comprises the step of processing the video information through an interpolation filter and generating the weighted average of at least two pixels disposed proximate the point in the screen of the input video device that is to be mapped to a point in the screen of the output video device in accordance with the scaling information, the point in the screen of the output video device comprising one of the output pixels, the output pixel having a value equal to the weighted average value generated by the step of processing the input pixels through the interpolation filter.

33. The method of claim 32, wherein the step of processing the video information through the interpolation filter operates only on input pixels in a horizontally adjacent relationship and the step of processing further comprises selecting rows of the video information within the rows of input pixels in accordance with a nearest neighbor algorithm, such that rows of input pixels that are most proximate to the point in the screen of the input video device that are to be mapped into the point in the screen of the output video device are selected.

34. A method for processing pixels that are disposed in a screen of an input video device in a predetermined array and which are transmitted at an input rate, comprising the steps of:

receiving on an input, a real time video input signal representing the pixels in the screen of the input video device at the input rate;

converting the video input signal into a second video format having a higher video bandwidth to provide converted video;

scaling down the converted video representing the screen of the input video device to a designated window within a screen of an output video device, the step of scaling down including the steps of;

designating a said window within the screen of the output video device;

averaging a portion of the converted video that represents a predetermined area of the screen of the input video device in accordance with a predetermined averaging algorithm and outputting the averaged video portion into a predetermined area of the designated window within the screen of the output video device, the ratio of the predetermined area of the screen of the input to the predetermined area of the window within the screen of the output video device determined by the scaling information, and

outputting the scaled down converted video; and

buffering the outputted scaled down converted video to temporarily store the scaled down converted video received at the input rate and outputting the temporarily stored scaled down converted video at a second rate in substantially real time.

35. The method of claim 34, further comprising the step of reducing the scaled down converted video prior to the step of buffering.

36. The method of claim 35, wherein each of the pixels in the screen of the output video device is represented by a plurality of color planes, each of the color planes represented by a digital word, wherein the step of reducing the scaled down converted video comprises the step of quantizing each of the digital words associated with each of the color planes by a predetermined number of digital bits.

37. The method of claim 34, wherein the first video format is a YUV format and the second video format is an RGB video format, the step of converting operable to convert the YUV format to the RGB format.

38. The method of claim 37, wherein the YUV format is at a 444 ratio.

39. The method of claim 38, wherein the first video rate is at a YUV 422 video format and, the step of converting operable to convert the YUV 422 video format ratio to a YUV 444 video format prior to conversion to the RGB video format.

40. The method of claim 39, and further comprising the step of bypassing the conversion of the YUV 422 video format to YUV 444 video format to allow reception of YUV 444 video format and bypassing the step of converting from YUV video format to RGB video format to allow reception of RGB formatted video.

41. The method of claim 34, and further comprising the step of receiving location parameters for determining the location of the predetermined area of the screen of the input video device that is to be scaled for output to the screen of the output video device.

42. The method of claim 41, wherein the screen of the input video device is substantially the same size as the screen of the output video device.

43. The method of claim 34, wherein the step of averaging comprises the steps of:

providing an interpolation filter; and

processing the converted video through the interpolation filter to generate the weighted average of at least two pixels disposed proximate to the point in the screen of the input video device that is to be mapped to a point in the screen of the output video device in accordance with the scaling information, the point in the screen of the output video device comprising a pixel in the screen having a value equal to the weighted average generated by the step of processing through the interpolation filter.

44. The method of claim 43, wherein the step of processing the converted video through the interpolation filter operates only on pixels in a horizontally adjacent relationship and the step of averaging comprises selecting rows of video information in accordance with a nearest neighbor algorithm, such that rows of pixels in the screen of the input video device that are proximate to the point in the screen of the input video device that is to be mapped into the point in the screen of the output video device are selected for mapping.

45. The method of claim 34, wherein the step of buffering the scaled down converted video comprises the step of processing the scaled down converted video through a first-in-first-out buffer having a write clock operable to write video at the input rate and a read clock received external to the first-in-first-out buffer that allows operation at an output rate.