Format and frame rate conversion for display of 24Hz source video

• US 6,549,240 B1
• Filed: 02/28/2000
• Issued: 04/15/2003
• Est. Priority Date: 09/26/1997
• Status: Expired due to Term

• Current Assignee: MediaTek, Inc.
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Reitmeier, Glenn A.
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US09/515,058
• Time in Patent Office: 1,142 Days
• Field of Search: 348/459, 348/448, 348/581, 348/445, 348/556, 348/558, 348/449, 348/441
• US Class Current: 348/459
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/223 using block-matching
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/127 Prioritisation of hardware or computational resources
• CPC Class Codes: H04N 19/134 characterised by the element, parameter or criterion affecting or controlling the adaptive coding
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/428 Recompression, e.g. by spatial or temporal decimation
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 21/4383 Accessing a communication channel
• CPC Class Codes: H04N 7/0105 using a storage device with different write and read speed
• CPC Class Codes: H04N 7/0112 one of the standards corresponding to a cinematograph film standard

Abstract

An apparatus for electronic format and frame rate conversion in a multiple format video processing system adapted to avoid display motion artifacts causes by 3:2 conversion of 24 Hz video source video by tripling the frame rate of the source video and responsively adjusting the format of the resultant video signal.

Claims

1. Apparatus for processing a digital video signal including video imagery associated with at least one of a plurality of transmitted display formats to produce an output video signal suitable for presentation on a display device, said display device having associated with it a single predetermined horizontal scanning frequency, said apparatus comprising:

a horizontal resizer, for adapting a horizontal format of said digital video signal in response to a first control signal;

a vertical resizer, for adapting a vertical format of said digital video signal in response to a second control signal;

a frame rate converter, for adapting by an integer multiple a frame rate of said digital video signal in response to a third control signal; and

a controller, for generating said first, second and third control signals in response to the transmitted display format of the video imagery included within said digital video signal;

wherein

said controller causing said horizontal resizer to adapt the horizontal format of said digital video signal to a size compatible with said predetermined horizontal scanning frequency of said display device;

said controller causing said vertical resizer to adapt the vertical format of said digital video signal to a size compatible with said adapted horizontal format of said digital video signal; and

said controller, in the case of an input video signal having a frame rate selected from the group of 24 and 25 Hz, causing said frame rate converter to multiply by n integer greater than 2 the frame rate of said digital video signal.

2. The apparatus of claim 1, further comprising:

a de-interlacer, for converting an interlaced digital video signal into a progressive scan digital video signal, said de-interlacer processing said digital video signal prior to said horizontal resizer, said vertical resizer and said frame rate converter.

3. The apparatus of claim 1, wherein said frame rate converter comprises a frame buffer for receiving said digital video signal according to a first addressing rate and providing a buffered digital video signal according to a second addressing rate, said second addressing rate being an integer multiple of said first addressing rate.

4. The apparatus of claim 3, wherein said second addressing rate is determined with respect to a display clock, said display clock providing a timing signal suitable for use in deriving horizontal and vertical deflection signals suitable for use by said display device.

5. The apparatus of claim 4, further comprising:

a raster generator, coupled to said display clock, for generating horizontal and vertical deflection signals suitable for use by said display device.

6. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line progressive scan display having a horizontal scanning frequency of approximately 65 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz, 1920 pixel by 1080 line transmitted display format, said controller causes said output video signal to approximate one of a 48 Hz, 1920 pixel by 1080 line transmitted display format video signal and a 72 Hz, 1920 pixel by 900 line transmitted display format video signal.

7. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line progressive scan display having a horizontal scanning frequency of approximately 65 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 16;

9 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1920 pixel by 900 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

8. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line progressive scan display having a horizontal scanning frequency of approximately 65 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 4;

3 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1408 pixel by 900 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

9. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line progressive scan display having a horizontal scanning frequency of approximately 63 kHz;

and wherein;

in the case of said digital video signal having a 25 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 864 line transmitted display format video signal having a frame rate of 75 HZ.

10. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line progressive scan display having a horizontal scanning frequency of approximately 63 kHz;

and wherein;

in the case of said digital video signal having a 50 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 576 line transmitted display format video signal having a frame rate of 100 HZ.

11. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line progressive scan display having a horizontal scanning frequency of approximately 45 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 16;

9 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1280 pixel by 600 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

12. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line progressive scan display having a horizontal scanning frequency of approximately 45 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 4;

3 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 960 pixel by 600 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

13. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line progressive scan display having a horizontal scanning frequency of approximately 47 kHz;

and wherein;

in the case of said digital video signal having a 25 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 384 line transmitted display format video signal having a frame rate of 75 HZ.

14. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line progressive scan display having a horizontal scanning frequency of approximately 47 kHz;

and wherein;

in the case of said digital video signal having a 50 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 564 line transmitted display format video signal having a frame rate of 100 HZ.

15. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line interlaced scan display having a horizontal scanning frequency of approximately 32 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 16;

9 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1920 pixel by 1280 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

16. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line interlaced scan display having a horizontal scanning frequency of approximately 32 kHz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 4;

3 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1408 pixel by 900 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

17. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line interlaced scan display having a horizontal scanning frequency of approximately 32 kHz;

and wherein;

in the case of said digital video signal having a 25 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 384 line transmitted display format video signal having a frame rate of 75 Hz.

18. The apparatus of claim 1, wherein said display device substantially comprises 1920 pixel by 1080 line interlaced scan display having a horizontal scanning frequency of approximately 32 kHz;

and wherein;

in the case of said digital video signal having a 50 Hz transmitted display format, said controller causes said output video signal to approximate a 720 pixel by 576 line transmitted display format video signal having a frame rate of 100 Hz.

19. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line interlaced scan display having a horizontal scanning frequency of approximately 23 Hz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 16;

9 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 1280 pixel by 600 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

20. The apparatus of claim 1, wherein said display device substantially comprises 1280 pixel by 720 line interlaced scan display having a horizontal scanning frequency of approximately 23 Hz;

and wherein;

in the case of said digital video signal having a 24 Hz and a 4;

3 aspect ratio transmitted display format, said controller causes said output video signal to approximate a 960 pixel by 600 line transmitted display format video signal having a frame rate of 48 Hz or 72 HZ.

21. The apparatus of claim 1, wherein said display device comprises one of a light valve, DMD or LCD display device.

22. A method for processing a digital video signal including video imagery associated with at least one of a plurality of transmitted display formats to produce an output video signal suitable for presentation on a display device, said display device having associated with it a single predetermined horizontal scanning frequency, said method comprising the steps of:

adapting a horizontal format of said digital video signal to a size compatible with said predetermined horizontal scanning frequency of said display device;

adapting a vertical format of said digital video signal to a size compatible with said adapted horizontal format of said digital video signal; and

multiplying a frame rate of said digital video signal by an integer multiple greater than 2 in response to said input video signal having a frame rate selected from the group consisting of 24 Hz and 25 hz.

23. The method of claim 22, further comprising the step of de-interlacing said input video signal in the case of said input video signal comprising an interlaced digital video signal.

24. The method of claim 22, wherein a frame rate converter is used to perform said step of multiplying, said frame rate converter comprising a frame buffer for receiving said digital video signal according to a first addressing rate and providing a buffered digital video signal according to a second addressing rate, said second addressing rate being an integer multiple of said first addressing rate.

25. The method of claim 24, wherein said second addressing rate is determined with respect to a display clock, said display clock providing a timing signal suitable for use in deriving horizontal and vertical deflection signals suitable for use by said display device.

26. The method of claim 25, further comprising the step of generating, using a raster generator coupled to said display clock, horizontal and vertical deflection signals suitable for use by said display device.

27. Method for use in a video processing system, said video processing system comprising a format converter and a frame rate converter, said format converter adapting at least one of a vertical format and a horizontal format of an input video signal in response to a format control signal, said frame rate converter adapting a frame rate of said input video signal in response to a frame rate control signal, said method comprising the steps of:

identifying a format and frame rate of said input video signal;

adapting said format of said Input video signal to a native display format having associated with it a predetermined horizontal scanning frequency; and

in the case of said frame rate of said input video signal being selected from the group consisting of 24 Hz and 25 Hz, multiplying said frame rate of said input video signal by an Integer greater than 2, wherein the spatial resolution of the input video signal is adapted to be compatible with the multiplied frame rate of the input video signal.