WO1999041734A1

WO1999041734A1 - Progressively-sectioned graphics (psg) file and software enabling selective download, upload and display

Info

Publication number: WO1999041734A1
Application number: PCT/US1999/003292
Authority: WO
Inventors: Dan Kikinis
Original assignee: Lextron Systems, Inc.
Priority date: 1998-02-17
Filing date: 1999-02-16
Publication date: 1999-08-19

Abstract

An image file system provides for storing image data in a file (23) in progressively enhanced sections, a first section (29) having reduced pixels resolution and minimal color specification, each subsequent section (31, 33, 35, 37,...) adding additional data for one or both of finer pixel resolution and more complete color, until a last image section provides final data addition for maximum resolution and color. A pointer in the header section (25) of the file points to section location. A sound bite in the sound section (27), which is optional, provides sound accompanying the image file. In this system, video stations of different complexity and capability can specify just those portions of a progressively sectioned file needed for the display, thereby avoiding the bandwidth requirement for downloading the entire file. In a preferred system, a YUV-style protocol is used, so a first section (29) can specify only colorless gray scale data for an image. In use for video frames the file system allows smooth video even in cases of severe bandwidth degradation, as the minimal first section will provide a decent gray-scale image.

Description

Progressively-Sectioned Graphics (PSG) File and Software Enabling Selective Download, Upload and Display

Field of the Invention

The present invention is in the field of computer graphics and pertains more particularly to methods and apparatus including software for storing, accessing, and displaying graphics data.

Background of the Invention

Computer graphics files are very well known in the art, and generally comprise data files having sequential data representing bit characteristics for display of bits in a bit map, which is how computer video displays present pictures of all sorts. Computer graphics files may be stored in memory, transmitted over computer networks, converted from one file format to another, and so on. A user having a PC, monitor, and appropriate software installed may display and edit graphics, and if equipped for video, may display individual graphics frame files in a rapid sequence forming a video display.

Uses for computer graphics files have grown apace with development of computer systems, hardware, and networks. Growth in computer products has also motivated new and better ways of storing and retrieving graphics information. For example, the development of a vast networked infrastructure of computers known as the Internet has occasioned much development of a wide variety of graphics file formats, along with various forms of compressing such - 2 - files so that they may be transmitted more quickly over network lines having limited bandwidth and may also be downloaded to a PC in a fashion requiring minimal memory for storage and more efficient video display.

A graphics file can take a wide variety of forms. Individual files may represent black and white, gray scale, or color graphics, or a combination. As a single example, one such graphic file format is known as a Joint Photographic Experts Group (JPEG) file. A JPEG file is commonly used for storage and transmission of graphics on the Internet and is widely used with color photographs and other renditions that are made available for download from a web page server. Another graphics file type commonly used on the Internet is a Graphics Interchange Format (GIF) file. A GIF file may represent a single graphic or a series of graphics sequenced with time so as to be presented in the form of animation or video. Again, color and gray scale representations are possible. These types of files are well known in the art. In a bitmap graphic data is stored as needed to display a specified number of pixels (picture elements) arranged typically in rows and columns on a computer video display, such as a CRT display monitor or a flat panel display.

The color management system most often used with computer graphics presentation is the Red Green Blue (RGB) system well known in the art. In the RGB system, three numbers are stored for each pixel in a bit map. One number for red, one for green, and one for blue. The numbers are used to determine the relative intensity of each color in forming a pixel. As these numbers are stored and used as computer data they are binary numbers.

The relative quality of a picture presented on a video display of a given size depends on a number of things, among them the bit map resolution, and the incremental resolution of the color values. For example, 16 specific intensity levels for a single color can be represented using a four-bit binary number. So one might choose to represent a color graphic in a file having bit map resolution - 3 - of 240 columns and 320 lines (76,840 pixels) using three four-bit numbers for each pixel. The result is a data portion for the file having 229,720 4-bit binary numbers. By representing the color increments with 8-bit binary numbers and storing (and displaying) more pixels for a higher bit-map resolution, one may present a higher quality picture.

RGB is not the only protocol for storing and presenting graphics. Another well known color management system commonly used with television broadcasts is known as the YUV system. The YUV system uses three values, which can be represented by binary numbers as does the RGB system, for representing color characteristics of a pixel. In the NUV system, however, one of the numbers (Y) is used for white-to-black gray scale, and the other two, (U and V), are used for color. Two numbers are adequate for color designation by use of what is known in the art as a color circle. Two numbers can be used to represent, by polar coordinates, an angle and a radius, thereby indicating a color and a saturation value, or the two numbers may represent coordinates in a cartesian system, locating a point that determines from center a vector providing a color and an intensity level. In digital display technology the actual association is made by look-up from a stored table or by formula conversion.

Many industry accepted formats are more or less standardized and well known in the art. Although actual content, format, and so on, may vary in different file types, virtually all conventional file types share a similar architecture. For example, a typical graphics file has a header, which is a section that describes important attributes of the bitmap data in the file. This information may include but is not limited to image resolution, compression type, color/black and white specifications, file size, etc. The header is followed by the image data section containing the bit map data set that defines the image. Νon-graphical data may also be included if there is text description of the image to be represented, or audio associated with the image, and so on. - 4 -

Even with the extensive development that has taken place and continues, there are still problems associated with state-of-the-art art file construction. For example, ability of individual computers to display color images varies widely. Some computers won't display color at all (monochrome display). Video display monitors vary in ability to display high-end graphics as well. Also sizes of viewable resolution can vary widely. Still, regardless of the computer's capabilities, it is necessary to download an entire file to display the associated image. The net result is that many, if not most users are downloading (or uploading, as the case may be) a lot more data than necessary when dealing with a conventional file. The user's computer than has to sort the data, convert, and the like, to get just the data needed to display.

Another less-than desirable characteristic of the current art is that efforts have been made to provide a user with a viewable image before all the data of a file is transmitted, so the viewer may, for example, make a decision as to whether or not to continue with the current image, or go on to another. Progressive compression is one of these methods, wherein the first image data received provides very large pixels, which are resolved as more data is downloaded into smaller and smaller pixels (also more of them) until the final image is resolved. The method simply doesn't provide much of an advantage, because the early image is of such poor quality.

A third problem relates to the capture and display of video/audio frame files. When transmitting sequential frames for a video data stream, if the data magnitude of each frame is too large for available bandwidth, which varies in such networks as the Internet, users may, and often do, experience loss of resolution, loss of audio quality (if present), and erratic video motion. These effects can be particularly frustrating during a video-phone calls taking place in real time. - 5 - What is clearly needed is a new type of graphics file and supporting software that would allow a user, regardless of platform capability, that is, even with a low-end station, to view a clear representation of a graphic image on a computer monitor without requiring a complete download of a high-end graphics file, and that would also allowing a user to specify how much of a file to take to be compatible with the user's hardware and software capabilities. Such a file as this would in some cases allow shorter download time, require less memory for user-end storage, and would require less bandwidth to transmit over a network.

Summary of the Invention

In a preferred embodiment of the present invention a computer graphics file is provided, comprising a header for providing information about file characteristics; and a plurality of image data sections in a sequential order from first to last. The header points to the location of subsequent image data sections, the first image data section provides a first and minimal bit-map usable by a computer for displaying an image associated with the file, and each subsequent image data section provides additional data for either higher resolution or more complete color specification for the image. Also in a preferred embodiment the image data is presented according to a YUV-style protocol, and the first image data section presents a series of values, one value per pixel to be displayed, defining a colorless gray scale image.

In some embodiments using the YUV-style protocol the series of values for the first section are stored as 4-bit binary numbers, and in some embodiments a section following the first section provides two additional values for each pixel, the two additional values specifying a color value for each pixel to be displayed. In typical embodiments of the invention the data of all the sections taken together - 6 - define a graphics image with either finer resolution or more complete color specification than any combination of the data of less than all of the sections.

In some cases a file according to an embodiment of the invention additionally comprises at least one section of audio data adapted to provide an audio bite to accompany an image to be displayed. These files are adapted to serve as frames in a video presentation, and the header comprises information for a next file as a next frame in the video presentation.

In an alternative embodiment a method for organizing a computer graphics file is provided, comprising steps of (a) defining the maximum pixel resolution of the image to be presented by the file; (b) defining the most complete color specification to be presented by the file; (c) preparing image pixel data representing the maximum pixel resolution and most complete color specification of the image to be presented by the file; and (d) dividing the image pixel data into a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the file, and a less complete color specification than the most complete color specification defined for the file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification. In a further step a header is provided with the file, the header providing information on characteristics of the file, including pointers to location of the image data file sections. In a preferred embodiment of the method the image data is organized as YUV-style data, and in step (d) only Y data is provided in the first section, providing thereby data in the first section providing a reduced pixel resolution, gray-scale image. In this case, in sections following the first section, U and V data is added providing color specification for the image associated with the file. There may also be a step for including an - 7 - audio data section with the image data sections, and a next file specification in the header to indicate a next file to be used as a frame in a video presentation.

In another embodiment a method for storing and transmitting a computer graphics file is provided, comprising steps of (a) dividing image pixel data for the file into a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the file, and a less complete color specification than the most complete color specification defined for the file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification; (b) adding a header to the file, the header providing information on file characteristics and pointers to file sections; (c) storing the file in a data storage system; (d) accepting a request for a file from an outside source, the request specifying sections to be accessed and transmitted; and (e) retrieving and transmitting from the stored file only those sections specified in the request.

In yet another embodiment computer graphics data retrieval and transmission system is provided, comprising a data storage apparatus; a retrieval system for accessing stored data; a transmission system for transmitting accessed data; at least one computer graphics file stored in the data storage apparatus as a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification; and control routines for managing activities of the retrieval and transmission system. The - 8 - control routines are adapted to receive requests for a to be transmitted, the requests specifying sections to be retrieved and transmitted, and to retrieve and transmit just the sections requested.

In still another embodiment a system for requesting, receiving and displaying computer graphics files is provided, comprising a video display system; a data storage system; a data link between the data storage system and the video display system; at least one computer graphics file stored in the data storage system as a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification; first control routines executing at the video display system; and second control routines executing at the data storage system. The first control routines are adapted to request a file by specifying sections of the file, the second control routines are adapted to retrieve and transmit on the data link the specified sections of the file requested, and the first control routines are further adapted to consolidate the data of the sections received and to display an image on the video display system from the consolidated data. The data storage system may be a server on the Internet, the video display system a PC connected to the Internet, and the data link is an Internet connection. The control routines at the PC may include an Internet browser application and a plug in for the browser providing capability to specify sections for sectioned files.

In still another embodiment of the invention, in an Internet system wherein graphics files are stored on an Internet server as progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first - 9 - section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification, a browser plug-in adapted to enable a user of a browser enhanced by the plug-in to specify sections of files to be accessed and transmitted to the user is provided. In still another embodiment wherein graphics files are stored on an Internet server as progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification, an Internet browser is provided adapted to enable a user to specify sections of files to be accessed and transmitted to the user. In yet another embodiment method for retrieving and transmitting a video presentation is provided, comprising steps of (a) storing video frames as individual progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first section to a last section for each frame file, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated frame file, and a less complete color specification than the most complete color specification defined for the associated frame file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to - 10 - complete the pixel resolution and complete color specification; (b) specifying in a header of each frame file information defining the next frame file in the video sequence; and (c) retrieving and transmitting at a pre-programmed frame rate individual frame files in the order defined by the header information. In the event that the period of the frame transmission rate is insufficient time to retrieve and transmit all sections of a file, the sections retrieved in the period is sufficient to provide a reduced resolution or reduced color image . In this method in step (a) audio data for audio equal in time to the frame period may be stored in a section of the file adjacent the first image data section. In embodiments of the invention as generally described above and described in enabling detail below, a system is provided wherein users of graphics data may specify just the data they need for a good presentation, rather than being forced to download complete files, then to sort the data to use that portion needed. The result is creation of virtual bandwidth, allowing quicker and more efficient operation in graphics retrieval and presentation.

Brief Description of the Drawing Figures

Fig. 1 A is a block diagram representing a typical RGB graphics file according to prior art.

Fig. IB is a block diagram representing a typical RGB graphics file that is progressively compressed according to prior art.

Fig. 2 is a block diagram representing a progressively-sectioned graphics (PSG) file according to an embodiment of the present invention.

Fig. 3 is a system diagram of a data-connected video display and storage system in an embodiment of the invention. 11 -

Description of the Preferred Embodiments

Fig. 1 A is a block diagram representing a typical RGB graphics file 11 according to prior art. File 11 comprises a header 13 and an RGB bitmap 15. Although compression techniques are normally used with color graphics files, compression is not required. File 11 may be compressed by any of several known techniques. Also, file 11 may be a black-and-white only file, a gray scale file, a color file, and so on. Header 13 typically comprises all necessary information required by a computer-software interface to manipulate RGB bitmap 15 for the purpose of download, storage and display. For example, file size may be recorded in the header as pre-knowledge for storage purposes. If, for instance, there is not enough memory to download one or more files, a user may be notified via screen pop-up. Resolution information pertaining to RGB bitmap 15 may be included in the header and affects the file size (i.e. more resolution, larger file). Color or gray scale information may be included in header 13 to enable proper display. Approximate download time may be included as well so a user may decide to abort if he or she feels that viewing a particular image is not worth the wait. There may information of other sorts as well.

Bitmap portion 15 of file 11 contains the bit map data necessary to form an image on a computer screen. Other data representing text, dimensioning, and the like, may also be present. In this prior art example, RGB bitmap 15 contains all of the data needed to display an image at the maximum quality level intended for viewing. All of file 11 must be completely downloaded before a complete and clear image can be viewed.

Fig. IB is a block diagram representing a typical RGB graphics file that is progressively compressed as known in the art. In this prior art example, an RGB - 12 - graphics file 17 comprises a header 19 and an RGB bitmap 21. RGB file 17 is essentially the same as RGB file 11 of Fig. IB except that RGB file 17 is compressed progressively. In progressive compression, typically a number of pixels are averaged in terms of color specification and assigned a lower resolution. As download and decompression begins, a full dimension image is soon displayed, however, due to the type of compression used, it may not be a discernible image. As download and decompression continues, the image gradually clears until it's full color and resolution is apparent.

Referring now to both prior art examples of Fig. 1 A and Fig. IB, the inventor uses these representations as basic examples of graphics file architecture as is known in the art. It will be apparent to one with skill in the art that graphics files 11 and 17 may take other known forms, such as all black and white, or gray scale, with various gray-scale resolution. It will also be apparent that there are many forms of compression known in the art that may be used to compress files 11 and 17. The inventor intends only to show that a common architecture is shared by graphics files although they may have many other varied characteristics.

Fig. 2 is a block diagram representing a progressively-sectioned graphics (PSG) file, according to an embodiment of the present invention, wherein the file is composed of a number of individual sections. PSG file 23 has a detailed header 25 and a series of following sections 27,

29, 31, 33, 35, and 37. Graphics file 23 is unique in that the first image section following the header comprises sufficient data to form a clear image of the complete file, and each further section provides additional data that adds to characteristics of the image, such as increased resolution and/or additional and more detailed color. Pointer information is provided in the header pointing to the beginning of each following section. Thus a new type of graphics file (23) is provided that is not available in current art. As described above, graphics file 23 - 13 - may be of the form of a single image file or may be used as a frame in a video presentation.

With each subsequent section, such as sections 29 and 31 , added data is provided to enhance the associated image at a better quality. A first section contains only basic data required to produce a reasonable gray-scale image, for example. A second section adds data for higher resolution and gray scale, for example. A third section first provides low resolution color. A next section may increase the number of colors displayed. This innovative sectioning technique allows a user who has a computer station not capable of using all of the file data to take only that portion of the file his/her computer can use, without the wasteful necessity of prior art files and techniques, wherein the user must take all of the file, and then discard the unnecessary data.

In a preferred embodiment of the present invention, the YUV-style image management system is used. This is a convenience, however, and not a limitation of the invention, as there are ways that the features of the invention may apply to RGB files as well. The use of the YUV-style color management system in a preferred embodiment is so that black and white and gray-scale imaging can be provided in early sections of a file without need for the large data requirements of color. In this way, a user may elect to view, for example, a basic gray-scale image by only downloading an early section, such as section 29. If a user wishes to see a low resolution color representation of the same image, he may download subsequent sections in order.

It is well known in the art that RGB and YUV-style or equivalent systems use three values (binary numbers) for each pixel in a bitmap image. For example, RGB assigns one value for red, one value for green and one value for blue to each pixel, and the three values determine the color of the pixel. The YUV-style system assigns a gray-scale value for white to black (Y), and two values (U & V) to each pixel to determine the gray scale and color of the pixel. Because the gray- - 14 - scale (Y) value in the YUV-style system is separate from the color values, it is particularly suited to objects of the invention.. A first section in a file according to an embodiment of the present invention can have only data for a gray scale image, which, as will be described in greater detail below, provides a unique advantage

In a sectioned YUV-style file in an embodiment of the invention, a 4-bit Y value for gray scale for each pixel, at a reduced resolution, is used in a first bit map section, providing 16 gray scale shades from white to black..

In the embodiment of the invention illustrated by Fig. 2 a sound bite 27 is provided immediately after header 25. This is optional, and provides either sound to accompany a still picture, or sound accompanying files used as video frames, in which case a next filename is typically included in header 25. PSG file 23 may represent a single image for viewing rather than a single frame of a video stream, as previously described, and may be displayed with or without sound. Referring again to Fig. 2, after header 25, sound bite 27 may be of any one of several different formats. Data may be provided for mono, stereo, etc. as is known in the art. Again, the sound bite is optional, and provides sound for a time, for example, equal to the period of a video frame frequency.

After the sound bite, in this exemplary embodiment, a first bit map section 29 provides a map of Y values only in a reduced resolution, in this example

320x240, providing data for a low-resolution 16 value gray-scale image. A next section 31 provides additional data to reach 640x480 resolution, but also complements Y-values to 8-bit Y value per pixel. Because only the additional data is necessary, the data size of section 31 is 87.5% of the data necessary for the image to be presented by the data up to this sectiion. The other 12.5% of the data is from section 29. The data provided in section 31 is just the data needed in addition to the data of section 29 for the new image. The original data need not be repeated. - 15 -

A next section 33 provides U and V values at 8 bits each per pixel for low resolution color. Again only data additional to that provided in previous sections is provided in section 33. A next section 35 provides additional data (8 bits per pixel) for 16 bit color. A final section 37 provides an additional 8 bits per pixel for 24-bit color, at which point a full resolution, 640x480, 24-bit true color image has been transmitted.

In an embodiment of the present invention wherein PSG file 23 represents one image to be viewed without sound, a user with a low-end system would not need all of the file. If for example, a user has a relatively low-resolution monochrome monitor, he will only need download sections 29, and 31. Section 29 provides the user with a 4-bit low resolution gray- scale image, and section 31 provides additional pixel data needed to upgrade the image that would be produced by section 29 alone to an 8-bit gray-scale image with 640x480 resolution. If the user, for example, has a relatively old color system, he may download header 25 and all sections up to and including section 33. A user with a high end system may download all of the file for maximum resolution and color. Even a user with a high end system may choose to use only parts of the file to improve transmission time and display efficiency. The additive nature of data within each subsequent file section keeps the used file size to a minimum for each user. Compression techniques, many of which are common in the art, may be applied individually to each section further reducing the amount of data to be transmitted and the memory required to store downloaded files. Some sections may however be uncompressed, or each section may use a different compression technique, most suitable for that set of data. An innovative software plug-in (not shown here) is provided and configured to a user's browser application for the purposes of understanding the sectioned nature of graphics file 23 and coordinating the download and execution - 16 - of graphics file 23 according to current settings available with the user's system and monitor. User configuration settings within the plug-in allow a user to physically set the desired quality of the image to be displayed rather than relying on a PC systems known settings. In this way, a user may determine how many sections such as section 29 will be downloaded regardless of monitor capability. For example, a video graphics array (VGA) monitor would not display the same resolution or color array as a super video graphics array (SVGA) monitor would. Therefore, a user having a VGA monitor would configure his plug-in not to download the high-end section containing SVGA related data enhancements, and so on.

Fig. 3 illustrates a simple system having a computer station 41 linked to the Internet by a data link 45, and a graphics database 43 stored and operable on an Internet server 42. . In one embodiment an executable browser application 47 runs on station 41, by which a user of the computer station connects to and browses the Internet. A skilled artisan will recognize that this diagram may illustrate other systems as well, such as a computer 41 as a node on a local area network (LAN) 45 with a file server 42 also connected to the LAN. There are other possibilities as well, encompassing all of the cases wherein a computer station may access and use graphics files over a network. Following the example of the Internet, file server 42 stores PSG files according to an embodiment of the present invention in database 43. Browser application 47 can be any browser known in the art, or new browsers that may become available. When a user at station 41 attempts to download a PSG file according to an embodiment of the present invention, if the user does not have a plug-in capable of interacting with these files, the server offers the user a download of a plug-in for interfacing with the PSG files. When a PSG plug-in 49 is installed for operation with browser 47 the user may configure his station for PSG file interaction, and download and use the PSG files at his station. - 17 -

Typically the unique PSG plug-in, in installation, will configure according to the characteristics of station 41. This may be automatic in some cases, and in some cases may be an interaction with the user via menu systems and entry fields as are known in the art. Once the plug-in is configured to the particular station 41 , interaction with PSG files will result in downloading only those sections of a file 23 (Fig. 2) that the station requires and can support. No extra, unusable data has to be transmitted or handled at the user's station, which results in an apparent bandwidth increase for the user.

A user's system and monitor may support 32-bit color at high resolution and may easily download and display all of a PSG file. A user, however, may configure his plug-in, at least temporarily, to only download up to 4-bit color at a lower than capable resolution. Thus, a user may select the quality of image to be viewed, as a tradeoff for download time, providing faster transmission and display. Download time is much shorter because high-end data is not downloaded.

As was previously described, there are substantial advantages provided by the new PSG file format when the files are used as frames for a video presentation. In such an embodiment header 25 will provide additional information relating to video sequencing such as a next file name, etc. In a video embodiment, after downloading header 25, a sound bite 27 is downloaded. Sound bite 27 may contain a choice of sound quality such as 4-bit, 8-bit, 12-bit, as well as different sample rates etc. A user may pre-configure his plug-in to play at 8-bit and so on. The process of downloading sequential sections is the same as in single-image viewing as described above with the exception of the time sequencing nature of a video application wherein each image is displayed only for a fraction of a second to be followed by the next file (frame) in the stream.

Just as described for single image use, a plug-in may be configured for video according to the hardware and software characteristics of the using station. - 18 -

Therefore, in downloading frames for a video display, the station need only take that portion of each frame file needed, enjoying thereby a distinct virtual bandwidth increase. Moreover, a user with high-end capabilities may configure intentionally for a lesser data mode of operation, guaranteeing bandwidth. The sectioning technique of the PSG files according to embodiments of the present invention provides a unique advantage not available in prior art systems. Referring again to Fig. 2, using derivative of the YUV-style system, a first section provides a gray scale image as previously described. A second section provides more resolution. Color data is added in later sections , and maximum color and resolution data are added in sections toward the end of the file.

In image transmission over wide area nets like the Internet, bandwidth is typically not guaranteed. Bandwidth typically varies by a considerable degree, causing frequent dropout and freeze in video transmissions. These serious problems are inherent in a prior art system that is RGB-based and requires the full data for each frame to be downloaded to get a complete frame image or some form of quality of service management.

In embodiments of the present invention, bandwidth degradation, even relatively serious failure, does not degrade the video presentation in as serious a manner as in the prior art (graceful degradation). For example, if bandwidth degrades, and there is, in the period of frame timing insufficient time to download an entire frame, the PSG system according to the present invention allows the portion of the file downloaded to be displayed, and, assuming at least the sound bite and the first bit map section is captured, the frame displayed will be at the very least a relatively good gray-scale image. High resolution color is the first to be lost, and low-resolution gray-scale data the last to be lost. So, even with relatively severe bandwidth degradation, the sound remains good, and a smooth, recognizable picture continues to be displayed. - 19 -

The advantages of the present invention for real-time video phone and/or conferencing applications will be readily apparent to the skilled artisan, having followed the teachings herein. Advantages in other applications will apparent as well. By providing a progressively sectioned graphics file construction and utilizing YUV-style data management, available bandwidth over a network may drop off significantly without seriously affecting video or audio performance. For example, with a minor drop in available bandwidth, only high-end data in a last section may be lost. This would perhaps cause a slight color and resolution loss barely noticeable to a user. If severe loss of bandwidth were experienced during transmission, perhaps all color and resolution data within the last three sections would be lost, leaving an 8-bit high resolution gray scale playback with audio still unaffected.

Placing sound bite 27 immediately after header 25 insures that audio quality is preserved under severe loss of bandwidth. If a user knows ahead of time that bandwidth is likely to be a problem over a certain network, he may configure his plug-in to play 4-bit audio, and download only sections 29 and 31 for gray-scale video. In an alternative embodiment, bandwidth detection methods may be employed and communicate line conditions to the plug-in for the purpose of automatic adjustment of quality in video calls and the like.

It will be apparent to one with skill in the art that a PSG file may be standardized and made convertible to other formats without departing from the spirit and scope of the present invention. For example, provisions could be provided to known applications to enable conversion of PSG files to other formats and conversion of other file types into PSG files. Software may be provided, for example, to operate with an existing database to dynamically convert requested files not in PSG format to PSG format prior to transmission, to interface with PSG-capable players and computer stations. - 20 -

It will also be apparent to those with skill in the art that PSG file 23 may have fewer or more sections than shown and described without departing from the spirit and scope of the present invention. For example, there may be several grayscale sections followed by several more color sections all following a chronological scheme of improved quality with regards to resolution and grayscale and color choice. The amount of sections within a PSG file will depend upon the desire and intent of the file's creator and the application intended for the file.

It will further be apparent to one with skill in the art that a PSG file according to embodiments of the present invention may be transmitted over a network such as the Internet, local area network (LAN) or other wide area networks (WAN) such as are known in the art. There are many other possibilities, including loading such files from any medium or over any data link. The invention is not limited to the examples described, and may operate with television presentations, video movies from CD and other media, and the like. The present invention is limited only by the scope of the claims that follow.

Claims

- 21 -What is claimed is:

1. A computer graphics file comprising: a header for providing information about file characteristics; and a plurality of image data sections in a sequential order from first to last; wherein the header points to the location of subsequent image data sections, the first image data section provides a first and minimal bit-map usable by a computer for displaying an image associated with the file, and each subsequent image data section provides additional data for either higher resolution or more complete color specification for the image.

2. The computer graphics file of claim 1 wherein the image data is presented according to a YUV-style protocol, and the first image data section presents a series of values, one value per pixel to be displayed, defining a colorless gray scale image.

3. The computer graphics file of claim 1 wherein the data in one or more image data sections s compressed data.

4. The computer graphics file of claim 2 wherein the series of values are stored as 4-bit binary numbers.

5. The computer graphics file of claim 2 wherein a section following the first section provides two additional values for each pixel, the two additional values specifying a color value for each pixel to be displayed.

6. The computer graphics file of claim 1 wherein the data of all the sections taken together define a graphics image with either finer resolution or more complete - 22 - color specification than any combination of the data of less than all of the sections.

7. The computer graphics file of claim 1 additionally comprising at least one section of audio data adapted to provide an audio bite to accompany an image to be displayed.

8. The computer graphics file of claim 7 wherein the graphics file is adapted to serve as a frame in a video presentation, and the header comprises information for a next file as a next frame in the video presentation.

9. A method for organizing a computer graphics file, comprising steps of:

(a) defining the maximum pixel resolution of the image to be presented by the file; (b) defining the most complete color specification to be presented by the file;

(c) preparing image pixel data representing the maximum pixel resolution and most complete color specification of the image to be presented by the file; and

(d) dividing the image pixel data into a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the file, and a less complete color specification than the most complete color specification defined for the file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification.

- 23 - 10. The method of claim 9 further comprising a step for providing a header with the file, the header providing information on characteristics of the file, including pointers to location of the image data file sections.

11. The method of claim 9 wherein the image data is organized as YUV-style data, and in step (d) only Y data is provided in the first section, providing thereby data in the first section providing a reduced pixel resolution, gray-scale image.

12. The method of claim 9 wherein instep (d), in sections following the first section, U and V data is added providing color specification for the image associated with the file.

13. The method of claim 9 further comprising a step for including an audio data section with the image data sections, and a next file specification in the header to indicate a next file to be used as a frame in a video presentation.

14. A method for storing and transmitting a computer graphics file, comprising steps of:

(a) dividing image pixel data for the file into a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the file, and a less complete color specification than the most complete color specification defined for the file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification;

(b) adding a header to the file, the header providing information on file characteristics and pointers to file sections; - 24 -

(c) storing the file in a data storage system;

(d) accepting a request for a file from an outside source, the request specifying sections to be accessed and transmitted; and

(e) retrieving and transmitting from the stored file only those sections specified in the request.

15. A computer graphics data retrieval and transmission system, comprising: a data storage apparatus; a retrieval system for accessing stored data; a transmission system for transmitting accessed data; at least one computer graphics file stored in the data storage apparatus as a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification; and control routines for managing activities of the retrieval and transmission system; wherein the control routines are adapted to receive requests for a to be transmitted, the requests specifying sections to be retrieved and transmitted, and to retrieve and transmit just the sections requested.

16. A system for requesting, receiving and displaying computer graphics files, comprising: a video display system; a data storage system; - 25 - a data link between the data storage system and the video display system; at least one computer graphics file stored in the data storage system as a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification; first control routines executing at the video display system; and second control routines executing at the data storage system; wherein the first control routines are adapted to request a file by specifying sections of the file, the second control routines are adapted to retrieve and transmit on the data link the specified sections of the file requested, and the first control routines are further adapted to consolidate the data of the sections received and to display an image on the video display system from the consolidated data.

17. The system of claim 16 wherein the data storage system comprises a server on the Internet, the video display system is a PC connected to the Internet, and the data link is an Internet connection.

18. The system of claim 17 wherein the control routines at the PC include an Internet browser application and a plug in for the browser providing capability to specify sections for sectioned files.

19. In an Internet system wherein graphics files are stored on an Internet server as progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first section to a last section, the first section - 26 - presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification, a browser plug-in adapted to enable a user of a browser enhanced by the plug-in to specify sections of files to be accessed and transmitted to the user.

20. In an Internet system wherein graphics files are stored on an Internet server as progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first section to a last section, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated file, and a less complete color specification than the most complete color specification defined for the associated file, with subsequent sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification, an Internet browser adapted to enable a user to specify sections of files to be accessed and transmitted to the user.

21. A method for retrieving and transmitting a video presentation, comprising steps of:

(a) storing video frames as individual progressively sectioned files, the sections comprising a plurality of sequential image data sections from a first section to a last section for each frame file, the first section presenting data for a number of pixels less than the maximum pixel resolution defined for the associated frame file, and a less complete color specification than the most complete color specification defined for the associated frame file, with subsequent - 27 - sections adding data to improve pixel resolution and/or color specification, with the last section adding the final data needed to complete the pixel resolution and complete color specification;

(b) specifying in a header of each frame file information defining the next frame file in the video sequence; and

(c) retrieving and transmitting at a pre-programmed frame rate individual frame files in the order defined by the header information; wherein, in the event that the period of the frame transmission rate is insufficient time to retrieve and transmit all sections of a file, the sections retrieved in the period is sufficient to provide a reduced resolution or reduced color image .

22. The method of claim 21 wherein, in step (a) audio data for audio equal in time to the frame period is stored in a section of the file adjacent the first image data section.