Formatting television pictures for side by side display

What is claimed is:

1. A video display system, comprising:

a first source of a first video signal representative of a first picture having a first display format ratio;

first signal processing means for speeding up said first video signal and cropping said first video signal by reducing said first display format ratio;

a second source of a second video signal representative of a second picture having .a second display format ratio;

video display means, having a disolay area with a third display format ratio greater than each of said first and second disolay format ratios, synchronized with said first and second video signals;

second signal processing means for speeding up said second video signal and cropping said first video signal by reducing said second display format ratio; and,

means for combining said first and second processed video signals for side-by-side display of said first and second pictures as modified by operation of said first and second signal processing means respectfully, said side-by-side pictures being of substantially comparable size.

2. The system of claim 1, wherein said first and second display format ratios are each approximately 4:3 and said third display format ratio is approximately 16:9, and said side-by-side pictures are each displayed in a display format ratio of approximately 8:9.

3. The system of claim 1, wherein said first and second pictures are controlled in picture size and image aspect ratio, as displayed, by said first and second signal processing means respectively.

4. The system of claim 1, wherein one of said signal processing means comprises means for compressing, storing and expanding a picture.

5. The system of claim 4, wherein said means for compressing, storing and expanding comprises:

means for sampling said picture;

a memory for storing said sampled picture; and,

means for enlarging said stored picture by interpolation to a size larger than as stored but smaller than as sampled.

6. The system of claim 1, wherein each of said video signals is speeded up by a factor of approximately 4/3 and reduced horizontally in display format ratio by a factor of approximately 1/3, each of said side-by-side pictures being displayed in a display format ratio of approximately 8:9 and substantially without image aspect ratio distortion.

7. The system of claim 1, comprising means for synchronizing said second video signal by delaying said second video signal by a fraction of a field period.

8. The system of claim 1, wherein said video display means has a display format ratio of width to height of M:N and said first video signal source has a display format ratio of A:B, said first signal processing means selectively speeding up said first video signal by a factor in a first range of approximately 1 to (M/N.div.A/B).

9. The system of claim 8, wherein said first signal processing means selectively reduces said first display format ratio horizontally by a factor in a second range of approximately 0 to [(M/N.div.A/B)-1].

10. The system of claim 1, wherein said video display means has a display format ratio of width to height of M:N and said first display format ratio is A:B, said first signal processing means selectively reducing said first disolay format ratio horizontally by a factor in a range of approximately 0 to [(M/N.div.A/B)-1].

11. The system of claim 1, wherein said video display means has a display format ratio of width to height of M:N and said second video signal source has a display format ratio of C:D, said second signal processing means selectively speeding up said second video signal by a factor in a first range of approximately 1 to (M/N.div.C/D).

12. The system of claim 11, wherein said second signal processing means selectively reduces said second display format ratio horizontally by a factor in a second range of approximately 0 to [(M/N.div.C/D)-1].

13. The system of claim 1, wherein said video display means has a display format ratio of width to height of M:N and said second display format ratio is C:D, said second signal processing means selectively reducing said second display format ratio horizontally by a factor in a range of approximately 0 to [(M/N.div.C/D)-1].

14. The system of claim 1, wherein:

said video display means has a display format ratio of width to height of M:N, said first display format ratio is A:B and said second display format ratio is C:D:

said first signal processing means selectively speeds up said first video signal by a factor in a first range of approximately 1 to (M/N.div.A/B) and selectively reduces said first disolay format ratio horizontally by a factor in a second range of approximately 0 to [(M/N.div.A/B)-1]; and,

said second signal processing means selectively speeds up said second video signal by a factor in a third range of approximately 1 to (M/N.div.C/D) and selectively reduces said second display format ratio horizontally by a factor in a fourth range of approximately 0 to [(M/N.div.C/D)-1].

15. The system of claim 14, wherein said first and third ranges are approximately 1 to 4/3 and said second and fourth ranges are approximately 0 to 1/3.

16. The system of claim 1, wherein said combining means generates multiplexed lines of video, each multiplexed line including a selectively speeded up and length-reduced video line from each of said video signal sources.

17. The system of claim 7, wherein said delaying means comprises a field memory.

18. A video display system, comprising:

a first source of a first video signal representative of a first picture having a first format display ratio;

first signal processing means for speeding up said first video signal by a factor of approximately 4/3 and cropping said first video signal by reducing said first display format ratio horizontally by a factor of approximately 1/3;

a second source of a second video signal representative of a second picture having a second display format ratio;

video display means synchronized with said first and second video signals and having display area with a third display format ratio of approximately 16:9;

second signal processing means for speeding up said second video signal by a factor of approximately 4/3 and cropping said first video signal by reducing said second display format ratio horizontally by a factor of approximately 1/3; and,

means for combining said first and second processed video signals for side-by-side display of said pictures, each of said side-by-side pictures being displayed in a display format ratio of approximately 8:9 and substantially without image aspect ratio distortion.

19. A video display system, comprising:

a first source of a first video signal representative of a first picture;

first signal processing means for speeding up said first video signal;

a second source of a second video signal representative of a second picture;

video display means having a wider display format ratio than each of said first and second video signals and synchronized with said first and second video signals;

second signal processing means for sampling said second picture and for speeding up said second video signal for synchronizing said second video signal with said first video signal and said video display means, including:

a memory for storing said sampled picture;

means for enlarging said stored picture by interpolation to a size larger than as stored but smaller than as sampled; and,

means for combining said first and second processed video signals for side-by-side display of said pictures, said pictures exhibiting substantially no image aspect ratio distortion.

20. A video system, comprising:

first and second video signal sources for first and second video signals representing first and second pictures respectively, said first and second pictures having first and second display format ratios respectively, each said display format ratio representing a numerical ratio of picture border width and picture border height;

video display means having a wide display format ratio and synchronized with

said first and second video signals;

signal processing means for modifying said first and second pictures by reducing said first and second display format ratios; and,

means for combining said first and second modified pictures for side-by-side display on said video display means. said side-by-side pictures being of substantially comparable size and exhibiting substantially no image aspect ratio distortion.

21. The system of claim 20, wherein said first and second modified pictures exhibit substantially no image aspect ratio distortion in said side-by-side display.

22. The system of claim 20, wherein each of said first and second format display ratios is reduced to approximately one-half as wide as said wide format display ratio of said video display means.

23. A video display system, comprising:

a first source of a first video signal representative of a first picture having a first display format ratio;

a first memory having write and read ports, said first video signal being written into said first memory at a slower rate than said first video signal is read from said first memory, at least one of said ports of said first memory being selectively disabled to reduce said first display format ratio;

a second source of a second video signal representative of a second picture having a second display format ratio;

a video display having a wider display format ratio than each of said first and second video signals and synchronized with said first and second video signals;

a second memory having write and read ports, said second video signal being written into said second memory at a slower rate than said second video signal is read from said second memory, at least one of said ports of said second memory being selectively disabled to reduce said second display format ratio; and,

a multiplexer coupled to said first and second memories, said first and second pictures as modified by propagation through said first and second memories being combined for a side-by-side display of said modified pictures, said side-by-side pictures being of substantially comparable size and exhibiting substantially no image aspect ratio distortion.

Description Submit all comments and votes

The invention relates to the field of televisions capable of displaying side by side pictures of substantially equal size from different sources, and in particular, to such televisions having a wide display format ratio screen.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is applicable to both direct view televisions and projection televisions.

2. Description of Related Art

The ratio of the width to the height of the borders of a picture or the borders of a display screen for a picture are referred to herein as the display format ratio, or alternatively, the format display ratio. The ratio of the width to the height of images forming a picture is referred to herein as the image aspect ratio. The result of a mismatch of display format ratios between a video source and a video display, or between a video source and a portion of a video display, which results in distorted images in a picture is referred to herein as image aspect ratio distortion.

Most televisions today have a display format ratio of 4:3. A wide display format ratio corresponds more closely to the display format ratio of movies, for example 16:9.

Televisions having a format display ratio of 4:3, often referred to as 4.times.3, are limited in the ways that single and multiple video signal sources can be displayed. Television signal transmissions of commercial broadcasters, except for experimental material, are broadcast with a 4.times.3 format display ratio. Many viewers find the 4.times.3 display format less pleasing than the wider format display ratio associated with the movies. Televisions with a wide format display ratio provide not only a more pleasing display, but are capable of displaying wide display format signal sources in a corresponding wide display format. Movies "look" like movies, not cropped or distorted versions thereof. The video source need not be cropped, either when converted from film to video, for example with a telecine device, or by processors in the television.

Televisions with a wide display format ratio are also suited to a wide variety of displays for both conventional and wide display format signals, as well as combinations thereof in multiple picture displays. However, the use of a wide display ratio screen entails numerous problems. Changing the display format ratios of multiple signal sources, developing consistent timing signals from asynchronous but simultaneously displayed sources, switching between multiple sources to generate multiple picture displays, and providing high resolution pictures from compressed data signals are general categories of such problems.

Televisions with a wide display format ratio can be implemented in television systems displaying video signals both at basic or standard horizontal scanning rates and multiples thereof, as well as by both interlaced and noninterlaced scanning. Standard NTSC video signals, for example, are displayed by interlacing the successive fields of each video frame, each field being generated by a raster scanning operation at a basic or standard horizontal scanning rate of approximately 15,734 Hz. The basic scanning rate for video signals is variously referred to as f.sub.H, 1f.sub.H, and 1H. The actual frequency of a 1f.sub.H signal will vary according to different video standards. In accordance with efforts to improve the picture quality of television apparatus, systems have been developed for displaying video signals progressively, in a noninterlaced fashion. Progressive scanning requires that each displayed frame must be scanned in the same time period allotted for scanning one of the two fields of the interlaced format. Flicker free AA-BB displays require that each field be scanned twice, consecutively. In each case, the horizontal scanning frequency must be twice that of the standard horizontal frequency. The scanning rate for such progressively scanned or flicker free displays is variously referred to as 2f.sub.H and 2H. A 2f.sub.H scanning frequency according to standards in the United States, for example, is approximately 31,468 Hz.

Television apparatus with conventional format display ratios can be equipped for displaying multiple pictures, for example from two video sources. The video sources may be the tuner in the television, a tuner in a video cassette recorder, a video camera, and others. In a mode often referred to as picture-in-picture (PIP), the tuner in the television provides a picture filling most of the screen, or display area, and an auxiliary video source provides a small inset picture generally within the boundaries of the larger picture. A PIP display mode in a wide screen television apparatus is shown in FIG. 1(c). In many instances, the inset picture can be positioned in a number of different locations. Another display mode is often referred to as channel scan, wherein a large number of small pictures, each from a different channel source, fill the screen in a freeze frame montage. There is no main picture, at least in terms of size. A channel scan display mode in a wide screen television apparatus is shown in FIG. 1(i). In wide screen television s apparatus, other display modes are possible. One is referred to as picture-outside-picture (POP). In this mode, several inset auxiliary pictures can share a common boundary with a main picture. A POP display mode in a wide screen television apparatus is shown in FIG. 1(f).

Horizontal scanning is accomplished in the same amount of time in a wide screen television apparatus as in a conventional television apparatus. However, the distance of the horizontal scan is greater in the wide screen television. This will stretch the picture horizontally, creating significant aspect ratio distortion of the images in the displayed picture. Accordingly, problems can be encountered when displaying a video signal having a conventional 4:3 display format ratio on a wide screen television apparatus, for example one having a 16:9 format display ratio. These particular format display ratios would result in a horizontal stretching or expansion by a factor of 4/3. This is a problem for displaying pictures having a 4:3 display format ratio as a main picture and as an auxiliary picture, such as a PIP or POP. This is also a problem for PIP and POP modes even if the main picture originates from a video source having a 16:9 format display ratio which matches the display means of the television apparatus.

Certain digital circuits, sometimes referred to generally as picture-in-picture processors, are available which can implement PIP and channel scan modes in a conventional television apparatus. One such picture-in-picture processor is designated as a CPIP chip and is available from Thomson Consumer Electronics, Inc. The CPIP chip is described more fully in a publication entitled The CTC 140 Picture in Picture (CPIP) Technical Training Manual, available from Thomson Consumer Electronics, Inc., Indianapolis, Ind. Such picture-in-picture processors are not suitable for implementing special display modes, such as PIP, POP and channel scan, in wide screen television apparatus. If an auxiliary picture developed by such a picture-in-picture processor from an auxiliary video source were displayed on a wide screen television apparatus without an external speedup circuit, the auxiliary picture, or pictures, would be geometrically distorted as described above. The auxiliary picture would exhibit a horizontal expansion by a factor of 4/3 due to the wider horizontal scanning of the wider picture tube, whether direct view or projection. If an external speedup circuit were used, the auxiliary picture would appear without aspect ratio distortion, but would not fill the screen or fill the portion of the screen otherwise allotted for the auxiliary display.

SUMMARY OF THE INVENTION

A wide screen television according to various inventive arrangements is capable of providing high resolution, single and multiple picture displays, from single and multiple sources having similar or different display format ratios, and with selectable display format ratios.

A display mode particularly suited for a wide screen television is side-by-side pictures of substantially the same size, from different video sources, for example two different channels. This mode is illustrated for a wide screen television in FIG. 1(d) for two 4:3 video sources. It will be appreciated that this mode can be considered a special case of the POP mode.

A wide screen television as taught herein can be provided with a signal processor for distorting a video signal, for example an auxiliary video signal, such that upon subsequent display the auxiliary picture will exhibit no image aspect ratio distortion. The distortion can be implementeel as an asymmetric compression. The compression factors will depend upon the relative display format ratios of the auxiliary video signal and the wide screen television apparatus. In order to display an auxiliary video signal having a 4:3 display format ratio on a television apparatus having a 16:9 format display ratio, the auxiliary picture will be horizontally compressed by a factor of 4:1 and vertically compressed by a factor of 3:1. In a television apparatus having a different display format ratio, for example 2:1, the horizontal compression factor would be 1.5 times greater than the vertical compression factor. The asymmetric compression produces geometrically distorted pictures which can then be stored in a video memory associated with a picture-in-picture processor. When the asymmetrically compressed auxiliary picture is read out of memory, in accordance with the normal operation the picture-in-picture processor, the resulting auxillary display exhibits no aspect ratio distortion and is proper size for its intended purpose, whether PIP, POP, channel scan or otherwise. The horizontal expansion realized by scanning in the wider television tube exactly cancels the extra compression, that is the asymmetric part, done prior to storage in the video memory.

A video display system according to an inventive arrangement comprises: a first source of a first video signal representative of a first picture having a first display format ratio; first signal processing means for speeding up the first video signal and reducing the first display format ratio; a second source of a second video signal representative of a second picture having a second display format ratio; video display means synchronized with the first and second video signals; second signal processing means for speeding up the second video signal and reducing the second display format ratio; and, means for combining the first and second processed video signals for side-by-side display of the first and second pictures as modified by operation of the first and second signal processing means respectfully, the side-by-side pictures being of substantially comparable size. The video display means will often have a third display format ratio greater than each of the first and second display format ratios.

In general terms, the video display means has a display format ratio of width to height of M:N, the first display format ratio is A:B and the second display format ratio is C:D; the first signal processing means selectively speeds up the first video signal by a factor in a first range of approximately 1 to (M/N.div.A/B) and selectively reduces the first display format ratio [video signal] horizontally by a factor in a second range of approximately 0 to [(M/N.div.A/B)-1]; and, the second signal processing means selectively speeds up the second video signal by a factor in a third range of approximately 1 to (M/N.div.C/D) and selectively reduces the second display format ratio horizontally by a factor in a fourth range of approximately 0 to [(M/N.div.C/D)-1].

If the first and second format display ratios are each approximately 4:3 and the third display format ratio is approximately 16:9, each of the the side-by-side pictures can be displayed in a format display ratio of approximately 8:9. If each of the video signals is speeded up by a factor of approximately 4/3 and the display format ratio of each is reduced horizontally by a factor of approximately 1/3, each of the side by side pictures is displayed substantially without image aspect ratio distortion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a)-1(i) are useful for explaining different display formats of a wide screen television.

FIG. 2 is a block diagram of a wide screen television in accordance with aspects of this invention and adapted for operation at 2f.sub.H horizontal scanning.

FIGS. 3 is a block diagram of the wide screen processor shown in FIG. 2.

FIG. 4 is a block diagram of a wide screen television in accordance with aspects of this invention and adapted for operation at 1f.sub.H horizontal scanning.

FIG. 5 is a block diagram of the wide screen processor shown in FIG. 4.

FIG. 6 is a block diagram showing further details of the wide screen processor common to FIGS. 3 and 5.

FIG. 7 is a block diagram of the picture-in-picture processor shown in FIG. 6.

FIG. 8 is a block diagram of the gate array shown in FIG. 6 and illustrating the main, auxiliary and output signal paths.

FIGS. 9 and 10 are timing diagrams useful for explaining the generation of the display format shown in FIG. 1(d), using fully cropped signals.

FIG. 11 is a block diagram showing the main signal path of FIG. 8 in more detail.

FIG. 12 is a block diagram showing the auxiliary signal path of FIG. 8 in more detail.

FIG. 13 is a block diagram of the the timing and control section of the picture-in-picture processor of FIG. 7.

FIG. 14 is a block diagram of a circuit for generating the internal 2f.sub.H signal in the 1f.sub.H to 2f.sub.H conversion.

FIG. 15 is a combination block and circuit diagram for the deflection circuit shown in FIG. 2.

FIG. 16 is a block diagram of the RGB interface shown in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The various parts of FIG. 1 illustrate some, but not all of the various combinations of single and multiple picture display formats which can be implemented according to different inventive arrangements. Those selected for illustration are intended to facilitate the description of particular circuits comprising wide screen televisions according to the inventive arrangements. For purposes of convenience in illustration and discussion herein, a conventional display format ratio of width to height for a video source or signal is generally deemed to be 4.times.3, whereas a wide screen display format ratio of width to height for a video source or signal is generally deemed to be 16.times.9. The inventive arrangements are not limited by these definitions.

FIG. 1(a) illustrates a television, direct view or projection, having a conventional format display ratio of 4.times.3. When a 16.times.9 format display ratio picture is transmitted, as a 4.times.3 format display ratio signal, black bars appear at the top and at the bottom. This is commonly referred to as letterbox format. In this instance, the viewed picture is rather small with respect to the entire available display area. Alternatively, the 16.times.9 format display ratio source is convened prior to transmission, so that it will fill the vertical extent of a viewing surface of 4.times.3 format display. However, much information will be cropped from the left and/or right sides. As a further alternative, the letterbox picture can be expanded vertically but not horizontally, whereby the resulting picture will evidence distortion by vertical elongation. None of the three alternatives is particularly appealing.

FIG. 1(b) shows a 16.times.9 screen. A 16.times.9 format display ratio video source would be fully displayed, without cropping and without distortion. A 16.times.9 format display ratio letterbox picture, which is itself in a 4.times.3 format display ratio signal, can be progressively scanned by line doubling or line addition, so as to provide a larger display with sufficient vertical resolution. A wide screen television in accordance with this invention can display such a 16.times.9 format display ratio signal whether the main source, the auxiliary source or an external RGB source.

FIG. 1(c) illustrates a 16.times.9 format display ratio main signal in which a 4.times.3 format display ratio inset picture is displayed. If both the main and auxiliary video signals are 16.times.9 format display ratio sources, the inset picture can also have a 16.times.9 format display ratio. The inset picture can be displayed in many different positions.

FIG. 1(d) illustrates a display format, wherein the main and auxiliary video signals are displayed with the same size picture. Each display area has an format display ratio of 8.times.9, which is of course different from both 16.times.9 and 4.times.3. In order to show a 4.times.3 format display ratio source in such a display area, without horizontal or vertical distortion, the signal must be cropped on the left and/or right sides. More of the picture can be shown, with less cropping, if some aspect ratio distortion by horizontal squeezing of the picture is tolerated. Horizontal squeezing results in vertical elongation of objects in the picture. The wide screen television according to this invention can provide any mix of cropping and aspect ratio distortion from maximum cropping with no aspect ratio distortion to no cropping with maximum aspect ratio distortion.

Data sampling limitations in the auxiliary video signal processing path complicate the generation of a high resolution picture which is as large in size as the display from the main video signal. Various methods can be developed for overcoming these complications.

FIG. 1(e) is a display format wherein a 4.times.3 format display ratio picture is displayed in the center of a 16.times.9 format display ratio screen. Dark bars are evident on the right and left sides.

FIG. 1(f) illustrates a display format wherein one large 4.times.3 format display ratio picture and three smaller 4.times.3 format display ratio pictures are displayed simultaneously. A smaller picture outside the perimeter of the large picture is sometimes referred to as a POP, that is a picture-outside-picture, rather than a PIP, a picture-in-picture. The terms PIP or picture-in-picture are used herein for both display formats. In those circumstances where the wide screen television is provided with two tuners, either both internal or one internal and one external, for example in a video cassette recorder, two of the displayed pictures can display movement in real time in accordance with the source. The remaining pictures can be displayed in freeze frame format. It will be appreciated that the addition of further tuners and additional auxiliary signal processing paths can provide for more than two moving pictures. It will also be appreciated that the large picture on the one hand, and the three small pictures on the other hand, can be switched in position, as shown in FIG. 1(g).

FIG. 1(h) illustrates an alternative wherein the 4.times.3 format display ratio picture is centered, and six smaller 4.times.3 format display ratio pictures are displayed in vertical columns on either side. As in the previously described format, a wide screen television provided with two tuners can provide two moving pictures. The remaining eleven pictures will be in freeze frame format.

FIG. 1(i) shows a display format having a grid of twelve 4.times.3 format display ratio pictures. Such a display format is particularly appropriate for a channel selection guide, wherein each picture is at least a freeze frame from a different channel. As before, the number of moving pictures will depend upon the number of available tuners and signal processing paths.

The various formats shown in FIG. 1 are illustrative, and not limiting, and can be implemented by wide screen televisions shown in the remaining drawings and described in detail below.

An overall block diagram for a wide screen television in accordance with inventive arrangements, and adapted to operate with 2f.sub.H horizontal scanning, is shown in FIG. 2 and generally designated 10. The television 10 generally comprises a video signals input section 20, a chassis or TV microprocessor 216, a wide screen processor 30, a 1f.sub.H to 2f.sub.H converter 40, a deflection circuit 50, an RGB interface 60, a YUV to RGB converter 240, kine drivers 242, direct view or projection tubes 244 and a power supply 70. The grouping of various circuits into different functional blocks is made for purposes of convenience in description, and is not intended as limiting the physical position of such circuits relative to one another.

The video signals input section 20 is adapted for receiving a plurality of composite video signals from different video sources. The video signals may be selectively switched for display as main and auxiliary video signals. An RF switch 204 has two antenna inputs ANT1 and ANT 2. These represent inputs for both off-air antenna reception and cable reception. The RF switch 204 controls which antenna input is supplied to a first tuner 206 and to a second tuner 208. The output of first tuner 206 is an input to a one-chip 202, which performs a number of functions related to tuning, horizontal and vertical deflection and video controls. The particular one-chip shown is industry designated type TA7730. The baseband video signal VIDEO OUT developed in the one-chip and resulting from the signal from first tuner 206 is an input to both video switch 200 and the TV1 input of wide screen processor 30. Other baseband video inputs to video switch 200 are designated AUX1 and AUX 2. These might be used for video cameras, laser disc players, video tape players, video games and the like. The output of the video switch 200, which is controlled by the chassis or TV microprocessor 216 is designated SWITCHED VIDEO. The SWITCHED VIDEO is another input to wide screen processor 30.

With further reference to FIG. 3, a switch SW1 wide screen processor selects between the TV1 and SWITCHED VIDEO signals as a SEL COMP OUT video signal which is an input to a Y/C decoder 210. The Y/C decoder 210 may be implemented as an adaptive line comb filter. Two further video sources S1 and S2 are also inputs to the Y/C decoder 210. Each of S1 and S2 represent different S-VHS sources, and each consists of separate luminarice and chrominance signals. A switch, which may be incorporated as part of the Y/C decoder, as in some adaptive line como filters, or which may be implemented as a separate switch, is responsive to the TV microprocessor 216 for selecting one pair of luminance and chrominance signals as outputs designated Y.sub.-- M and C.sub.-- IN respectively. The selected pair of luminance and chrominance signals is thereafter considered the main signal and is processed along a main signal path. Signal designations including .sub.-- M or .sub.-- MN refer to the main signal path. The chrominance signal C.sub.-- IN is redirected by the wide screen processor back to the one-chip, for developing color difference signals U.sub.-- M and V.sub.-- M. In this regard, U is an equivalent designation for (R-Y) and V is an equivalent designation for (B-Y). The Y.sub.-- M, U.sub.-- M, and V.sub.-- M signals are converted to digital form in the wide screen processor for further signal processing.

The second tuner 208, functionally defined as part of the wide screen processor 30, develops a baseband video signal TV2. A switch SW2 selects between the TV2 and SWITCHED VIDEO signals as an input to a Y/C decoder 220. The Y/C decoder 220 may be implemented as an adaptive line comb filter. Switches SW3 and SW4 select between the luminanee and chrominance outputs of Y/C decoder 220 and the luminance and chrominance signals of an external video source, designated Y.sub.-- EXT and C.sub.-- EXT respectively. The Y.sub.-- EXT and C.sub.-- EXT signals correspond to the S-VHS input S1. The Y/C decoder 220 and switches SW3 and SW4 may be combined, as in some adaptive line comb filters. The output of switches SW3 and SW4 is thereafter considered the auxiliary signal and is processed along an auxiliary signal path. The selected luminance output is designated Y.sub.-- A. Signal designations including .sub.-- A, .sub.-- AX and .sub.-- AUX refer to the auxiliary signal path. The selected chrominance is convened to color difference signals U.sub.-- A and V.sub.-- A. The Y.sub.-- A, U.sub.-- A and V.sub.-- A signals are converted to digital form for further signal processing. The arrangement of video signal source switching in the main and auxiliary signal paths maximizes flexibility in managing the source selection for the different parts of the different picture display formats.

A composite synchronizing signal COMP SYNC, corresponding to Y.sub.-- M is provided by the wide screen processor to a sync separator 212. The horizontal and vertical synchronizing components H and V respectively are inputs to a vertical countdown circuit 214. The vertical countdown circuit develops a VERTICAL RESET signal which is directed into the wide screen processor 30. The wide screen processor generates an internal vertical reset output signal INT VERT RST OUT directed to the RGB interface 60. A switch in the RGB interface 60 selects between the internal vertical reset output signal and the vertical synchronizing component of the external RGB source. The output of this switch is a selected vertical synchronizing component SEL.sub.-- VERT.sub.-- SYNC directed to the deflection circuit 50. Horizontal and vertical synchronizing signals of the auxiliary video signal are developed by sync separator 250 in the wide screen processor.

The 1f.sub.H to 2f.sub.H Converter 40 is responsible for convening interlaced video signals to progressively scanned noninterlaced signals, for example one wherein each horizontal line is displayed twice, or an additional set of horizontal lines is generated by interpolating adjacent horizontal lines of the same field. In some instances, the use of a previous line or the use of an interpolated line will depend upon the level of movement which is detected between adjacent fields or frames. The converter circuit 40 operates in conjunction with a video RAM 420. The video RAM may be used to store one or more fields of a frame, to enable the progressive display. The converted video data as Y.sub.-- 2f.sub.H, U.sub.-- 2f.sub.H and V.sub.-- 2f.sub.H signals is supplied to the RGB interface 60.

The RGB interface 60, shown in more detail in FIG. 16, enables selection of the converted video data or external RGB video data for display by the video signals input section. The external RGB signal is deemed to be a wide format display ratio signal adapted for 2f.sub.H scanning. The vertical synchronizing component of the main signal is supplied to the RGB interface by the wide screen processor as INT VERT RST OUT, enabling a selected vertical sync (f.sub.Vm or f.sub.Vext) to be available to the deflection circuit 50. Operation of the wide screen television enables user selection of an external RGB signal, by generating an internal/external control signal INT/EXT. However, the selection of an external RGB signal input, in the absence of such a signal, can result in vertical collapse of the raster, and damage to the cathode ray tube or projection tubes. Accordingly, the RGB interface circuit detects an external synchronizing signal, in order to override the selection of a non-existent external RGB input. The WSP microprocessor 340 also supplies color and tint controls for the external RGB signal.

The wide screen processor 30 comprises a picture in picture processor 320 for special signal processing of the auxiliary video signal. The term picture-in-picture is sometimes abbreviated as PIP or pix-in-pix. A gate array 300 combines the main and auxiliary video signal data in a wide variety of display formats, as shown by the examples of FIGS. 1(b) through 1(i). The picture-in-picture processor 320 and gate array 300 are under the control of a wide screen microprocessor (WSP .mu.P) 340. Microprocessor 340 is responsive to the TV microprocessor 216 over a serial bus. The serial bus includes four signal lines, for data, clock signals, enable signals and reset signals. The wide screen processor 30 also generates a composite vertical blanking/reset signal, as a three level sandcastle signal. Alternatively, the vertical blanking and reset signals can be generated as separate signals. A composite blanking signal is supplied by the video signal input section to the RGB interface.

The deflection circuit 50, shown in more detail in FIG. 15, receives a vertical reset signal from the wide screen processor, a selected 2f.sub.H horizontal synchronizing signal from the RGB interface 60 and additional control signals from the wide screen processor. These additional control signals relate to horizontal phasing, vertical size adjustment and east-west pin adjustment. The deflection circuit 50 supplies 2f.sub.H flyback pulses to the wide screen processor 30, the 1f.sub.H to 2f.sub.H converter 40 and the YUV to RGB converter 240.

Operating voltages for the entire wide screen television are generated by a power supply 70 which can be energized by an AC mains supply.

The wide screen processor 30 shown in more detail in FIG. 3. The principal components of the wide screen processor are a gate array 300, a picture-in-picture circuit 301, analog to digital and digital to analog converters, the second tuner 208, a wide screen processor microprocessor 340 and a wide screen output encoder 227. Further details of the wide screen processor, which are in common with both the 1f.