Multiple resolution, multi-stream video system using a single standard coder

• US 5,623,308 A
• Filed: 07/07/1995
• Issued: 04/22/1997
• Est. Priority Date: 07/07/1995
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Civanlar, Mehmet R., Gaglianello, Robert D.
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US08/499,700
• Time in Patent Office: 655 Days
• Field of Search: 348/390, 348/392, 348/424, 348/423
• US Class Current: 375/240.01
• 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 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 7/56 Synchronising systems therefor

Abstract

A video system is disclosed in which a single generic MPEG standard encoder (107) is used to simultaneously code and compress plural different resolution video signals from a single input video signal; and in which a single generic MPEG standard decoder (402) is used to simultaneously decode plural coded and compressed video signals of different resolutions and form a single composite video signal. The coder converts each frame of pixel data of the input video signal into plural frames having different resolutions, which are then combined into a common frame (106) for input to the generic MPEG encoder. The MPEG encoder produces a single coded and compressed output bitstream in slices of microblocks of pixel data, which output bitstream is demultiplexed (108) into separate resolution bitstreams using Slice Start Code identifiers associated with each slice and Macroblock Address Increments associated with the first macroblock in each slice, to properly route each slice to the appropriate output. The decoder processes (405) the slices within the coded and compressed bitstreams of different resolutions received from plural sources using the Slice Start Codes and Macroblock Address Increments of each slice to produce a single composite bitstream of successive slices. By merging the shoes from the plural sources into the composite bitstream in a predetermined manner, the generic MPEG decoder produces a digital output video signal that is a composite of the different resolution input video signals.

Claims

1. A video encoding system for simultaneously coding and compressing an input video signal in a frame format of pixel data having a predetermined resolution into a plurality of coded and compressed bitstreams representing the input video signal at different resolutions, the system comprising:

a single standard coder which converts to a coded and compressed output bitstream, pixel data from a frame of an input video signal having a predetermined resolution that is inputted to the coder in a raster scan order and processed by the coder in macroblocks of pixels, said output bitstream comprising a plurality slices which represent the coded and compressed pixel data in one or more macroblocks in a common row of macroblocks in the frame of the input video signal, each slice having an identifiable delineating slice start code (SSC) which identifies a row of the slice in the frame, and the first macroblock in each slice having an identifiable macroblock address increment (MAI) which identifies the position of that first macroblock in the slice relative to a fixed position in the frame and which can be retrieved from the coded and compressed pixel data in the slice in the output bitstream without decoding the slice;

means for converting a frame of pixel data of the input video signal of said predetermined resolution into a plurality of frames of pixel data having the different resolutions;

frame buffering means for commonly storing a frame of each of the plurality of frames of pixel data having different resolutions, wherein each of the plurality of frames of pixel data having the different resolutions are separated in said frame buffering means by a guard band;

means for supplying macroblocks of pixel data in a raster scanned order from said commonly stored frame in said frame buffering means to said single standard coder, said single standard coder outputting a single bitstream comprising a plurality of successive slices each of which contains the coded and compressed pixel data in at least one macroblock of pixel data in said commonly stored frame, the SSC of each slice being numbered according to the row of the associated pixel data of the slice in the commonly stored frame and the MAI of the first macroblock in each slice being numbered according to the relative position of the first macroblock in the slice in the commonly stored frame, wherein each slice is constrained to contain coded and compressed pixel data from no more than one of the frames of the different resolutions stored within said commonly stored frame; and

processing means for demultiplexing in accordance with their SSCs and MAIs the slices in the output bitstream of said single standard coder and forming separate bitstreams that are associated with each resolution, said processing means renumbering as is necessary the SSCs of the slices and the MAIs in the first macroblock of the slices in each resolution bitstream according to the resolution of each bitstream.

2. The video encoding system of claim 1 wherein said single standard coder is an MPEG standard encoder.

3. The video encoding system of claim 1 wherein said processing means deletes slices associated with the guard band in the commonly stored frame in forming the separate bitstreams associated with each resolution.

4. The video encoding system of claim 1 wherein said single standard encoder comprises means for predictively encoding macroblocks using motion estimation, and a predetermined pattern is stored in said guard band for limiting motion estimation to macroblocks within each of the different resolution frames commonly stored in the frame buffering means.

5. The video encoding system of claim 1 wherein said means for converting converts each frame of the input video signal into a 1/4, 1/8 and 1/64 resolution frame with respect to said predetermined resolution of the input video signal.

6. A video encoding system for simultaneously coding and compressing an input video signal in a frame format of pixel data having a predetermined resolution into a plurality of coded and compressed bitstreams representing the input video signal at different resolutions, the system comprising:

means for converting a frame of pixel data of the input video signal having said predetermined resolution into a plurality of frames of pixel data having the different resolutions;

a single standard coder which codes and compresses an input frame of pixel data supplied to an input of the coder in raster scan order, processes the inputted pixel data in macroblocks of pixels, and produces an output bitstream comprising successive slices of coded and compressed pixel data, each slice containing the coded and compressed pixel data in one or more macroblocks in a common row of macroblocks in the input frame, the number of macroblocks in each of the slices being programmable in the coder, each slice having an identifiable delineating slice start code (SSC) which identifies for all the macroblocks in the slice a relative row position in the input frame, and the first macroblock in each slice having an identifiable macroblock address increment (MAI) which identifies a relative frame position of that first macroblock in the input frame and which can be retrieved from the coded and compressed pixel data in the slice without decoding the slice;

means for combining into a common combined frame a frame of each of the plurality of frames of pixel data having the different resolutions, wherein the common combined frame includes a guard band area separating the frames of pixel data of each of the different resolutions;

means for supplying macroblocks of pixel data in a raster scanned order from said common combined frame as the input frame to said single standard coder, said single standard coder outputting a bitstream comprising successive slices each of which contains the coded and compressed pixel data in at least one macroblock of pixel data in said common combined frame, the SSC of each slice being numbered according to the row of the associated pixel data in the common combined frame and the MAI of the first macroblock in each slice being numbered according the relative position of the first macroblock in the slice in the common combined frame, the single standard coder being programmed so that each slice contains coded and compressed pixel data from no more than one of the frames having the different resolutions in said common combined frame; and

processing means for demultiplexing the slices in the output bitstream of the single standard coder and forming separate bitstreams that are associated with each resolution, said processing means renumbering as is necessary the SSCs of the slices and the MAIs in the first macroblock of the slices in each resolution bitstream according to the resolution of each bitstream.

7. The video encoding system of claim 6 wherein said single standard coder is an MPEG standard encoder.

8. The video encoding system of claim 6 wherein said processing means deletes slices associated with the guard band in the common frame in forming the separate bitstreams associated with each resolution.

9. The video encoding system of claim 6 wherein said single standard encoder comprises means for predictively encoding macroblocks using motion estimation, and a predetermined pattern is stored in said guard band for limiting motion estimation to macroblocks within each of the different resolution frames in said common combined frame.

10. The video encoding system of claim 6 wherein said means for converting converts each frame of the input video signal into a 1/4, 1/8 and 1/64 resolution frame with respect to said predetermined resolution of the input video signal.

11. A method for simultaneously coding and compressing an input video signal in a frame format of pixel data having a predetermined resolution into a plurality of coded and compressed bitstreams representing the input video signal at different resolutions using a single standard coder, the single standard coder coding and compressing an input frame of pixel data supplied to its input in raster scan order, processing the inputted pixel data in macroblocks of pixels, and producing an output bitstream comprising successive slices of coded and compressed pixel data, each slice containing the coded and compressed pixel data in one or more macroblocks in a common row of macroblocks in the input frame, the number of macroblocks in each of the slices being programmable in the coder, each slice having an identifiable delineating slice start code (SSC) which identifies for all the macroblocks in the slice a relative row position in the input frame, and the first macroblock in each slice having an identifiable macroblock address increment (MAI) which identifies a relative frame position of that first macroblock in the input frame and which can be retrieved from the coded and compressed pixel data in the slice without decoding the slice, the method comprising the steps of:

converting a frame of pixel data of the input video signal having said predetermined resolution into a plurality of frames of pixel data having different resolutions;

combining into a common combined frame a frame of each of the plurality of frames of pixel data having different resolutions, wherein the common combined frame includes a guard band area separating the frames of pixel data of each of the different resolutions;

supplying macroblocks of pixel data in a raster scanned order from said common combined frame as the input frame to the single standard coder, the single standard coder outputting a bitstream comprising successive slices each of which contains the coded and compressed pixel data in at least one macroblock of pixel data in said common combined frame, the SSC of each slice being numbered according to the row of the associated pixel data in the common combined frame and the MAI of the first macroblock in each slice being numbered according the relative position of the first macroblock in the slice in the common combined frame, the single standard coder being programmed so that each slice contains coded and compressed pixel data from no more than one of the frames having different resolutions in said common combined frame; and

demultiplexing the slices in the output bitstream of the single standard coder to form separate bitstreams that are associated with each resolution and renumbering as is necessary the SSCs of the slices and the MAIs in the first macroblock of the slices in each resolution bitstream according to the resolution of each bitstream.

12. The method of claim 11 wherein said single standard coder is an MPEG standard encoder.

13. The method of claim 11 wherein in said demultiplexing step slices associated with the guard band in the common frame are deleted in forming the separate bitstreams associated with each resolution.

14. The method of claim 11 wherein said single standard encoder predictively encodes macroblocks using motion estimation, and a predetermined pattern is stored in the guard band for limiting motion estimation to macroblocks within each of the different resolution frames in the common combined frame.

15. The method of claim 11 wherein said step of converting converts each frame of the input video signal into a 1/4, 1/8 and 1/64 resolution frame with respect to the predetermined resolution of the input video signal.

16. An encoding system for simultaneously coding and compressing an input image signal in a frame format of pixel data having a predetermined resolution into a plurality of coded and compressed bitstreams representing the image at different resolutions, the system comprising:

means for converting the input image signal into a plurality of image signals in different frame formats of pixel data having the different resolutions;

means for merging the plurality of image signals in the different frame formats of pixel data having the different resolutions to form a combined image signal in a single combined frame format of pixel data;

coding means for coding and compressing the combined image signal into an output bitstream having successive segments in which each successive segment is identifiably associated with a predetermined part of the combined image signal in the single combined frame format of pixel data without fully decoding the output bitstream, each segment of the output bitstream being identifiably associated with no more than one of the plurality of different resolution image signals that were combined to form the combined image signal; and

means for demultiplexing in a coded and compressed domain the output bitstream of said coding means into a plurality of separate bitstreams in accordance with the identifiable association of each segment in the output bitstream with a predetermined part of the combined image, each of the plurality of separate bitstreams being a coded and compressed bitstream that is associated with one of the different resolution image signals that were combined to form the combined image signal, wherein the plurality of separate bitstreams are independently decodable into the different resolution images.

17. In an encoding system of claim 16 in which the input image signal is a video signal having successive frames of pixel data and said coding means comprises means for estimating the frame-to-frame motion of groups of pixel data in successive frames, the combined frame format of pixel data formed by said means for combining including a guard band area for separating the plurality of different resolution image signals in the combined frame format of pixel data for purposes of limiting motion estimation to within each different resolution image within the combined frame format.

18. The encoding system of claim 17 wherein said coding means is an MPEG standard encoder.

19. The encoding system of claim 17 wherein said demultiplexing means in forming the plurality of separate bitstreams deletes segments of the output bitstream of said coding means associated with the guard band area in the combined frame format of pixel data.

20. The encoding system of claim 17 wherein the guard band area comprises a predetermined bit pattern in the combined frame format of pixel data.

21. A method for simultaneously coding and compressing an input image signal in a frame format of pixel data having a predetermined resolution into a plurality of coded and compressed bitstreams representing the image at different resolutions, the method comprising the steps of:

converting the input image signal into a plurality of image signals in different frame formats of pixel data having the different resolutions;

merging the plurality of image signals in the different frame formats of pixel data having the different resolutions to form a combined image signal in a single combined frame format of pixel data;

coding and compressing the combined image signal into an output bitstream having successive segments in which each successive segment is identifiably associated with a predetermined part of the combined image signal in the single combined frame format of pixel data without fully decoding the output bitstream, each segment of the output bitstream being identifiably associated with no more than one of the plurality of different resolution image signals that were combined to form the combined image signal; and

demultiplexing in a coded and compressed domain the output bitstream formed at the coding and compressing step into a plurality of separate bitstreams in accordance with the identifiable association of each segment in the output bitstream with a predetermined part of the combined image, each of the plurality of separate bitstreams being a coded and compressed bitstream that is associated with one of the different resolution image signals that were combined to form the combined image signal, wherein the plurality of separate bitstreams are independently decodable into the different resolution images.

22. In the method of claim 21 in which the input image signal is a video signal having successive frames of pixel data and the coding and compressing step comprises a step for estimating the frame-to-frame motion of groups of pixel data in successive frames, the combined frame format of pixel data formed at the merging step including a guard band area for separating the plurality of different resolution image signals in the combined frame format of pixel data for purposes of limiting motion estimation to within each different resolution image within the combined frame format.

23. The method of claim 22 wherein an MPEG standard encoder performs the coding and compressing step.

24. The method of claim 22 where in forming the plurality of separate bitstreams at the demultiplexing step segments of the output bitstream formed at the coding and compressing step that are associated with the guard band area in the combined frame format of pixel data are deleted.

25. The method of claim 22 wherein the guard band area comprises a predetermined bit pattern in the combined frame format of pixel data.