Advanced television system

• US 5,508,746 A
• Filed: 11/16/1994
• Issued: 04/16/1996
• Est. Priority Date: 06/24/1993
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Lim, Jae S.
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US08/340,771
• Time in Patent Office: 517 Days
• Field of Search: 348/426, 348/427, 348/429, 348/432, 348/433, 381/2
• US Class Current: 375/240.25
• CPC Class Codes: H04N 19/112 according to a given display mode, e.g. for interlaced or progressive display mode
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/187 the unit being a scalable video layer
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 7/015 High-definition television systems
• CPC Class Codes: H04N 7/04 Systems for the transmission of one television signal, i.e. both picture and sound, by a single carrier H04N7/084, H04N7/087 take precedence

Abstract

A method for incorporating future developments in video compression technology to migrate toward a better television system in a receiver-compatible manner. The invention uses enhancement data that can be combined with standard video data. Standard HDTV receivers will utilize standard video data, ignoring the enhancement data. More advanced HDTV receivers will combine the enhancement data with standard data. The television signal is transmitted in a format comprising a first set of bits that represents images at a first quality (e.g., first resolution) and that can be decoded to provide an output at the first resolution, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an output at a second resolution greater than the first resolution. The first set of bits is decoded according to a first decoding procedure to provide information representative of images at the first resolution. The second set of bits is decoded according to a second decoding procedure to provide the enhancement information. And at least some of the enhancement information and at least some of the information representative of images at the first resolution are used to provide the output at the second resolution.

Claims

1. A method of receiving and decoding a television signal representing an input video source, wherein the television signal has been encoded using a method comprising the steps of

encoding a first set of bits using a first transmission standard, the first set of bits representing images at a first quality and being capable of being decoded to provide an output at a first quality, and

encoding a second set of bits using a second transmission standard, the second set of bits representing enhancement information that can be decoded and used in the receiver with the first set of bits to provide an output at a second quality greater than the first quality,

wherein the second transmission standard comprises the steps of decoding the first set of bits to produce an estimate of the decoded images at a first quality, and comparing the estimate to the input video source and using the results of the comparison to produce the second set of bits,

the method of receiving and decoding comprising the steps of:

decoding the first set of bits according to a first decoding procedure to provide information representative of images at the first quality;

decoding the second set of bits according to a second decoding procedure to provide the enhancement information; and

combining the enhancement information with the information representative of the images at the first quality to provide output at the second quality.

2. The method of claim 1 wherein

said first and second quality comprise first and second resolutions.

3. The method of claim 1 wherein the second transmission standard further comprises the steps of processing the estimate with a prediction method to produce a predicted signal for the input video source and encoding information representative of the prediction method for use by the decoder.

4. The method of claim 3 wherein the comparison step comprises comparing the predicted signal to the input video source and using the difference in producing the second set of bits.

5. The method of claim 1 wherein

the step of decoding the second set of bits comprises the steps of

decoding a portion of the bits to provide information representative of a prediction method to be used to transform images from the first to the second quality, and

using the information to select the prediction method from among a plurality of prediction methods;

and

the step of using at least some of the enhancement information comprises the step of using the prediction method selected from the plurality of prediction methods to generate the output at the second quality.

6. The method of claim 5 wherein the television signal has been transmitted using a third set of bits that represents second enhancement information and that can be decoded and used in conjunction with the first and second sets of bits to provide an output at a third quality greater than the first and second qualities, wherein the method further comprises the steps of

decoding the third set of bits according to a third decoding procedure to provide the second enhancement information;

using at least some of the second enhancement information, and at least some of the first-mentioned enhancement information, and at least some of the information representative of images at the first quality to provide the output at the third quality.

7. The method of claim 5 wherein the step of using at least some of the enhancement information further comprises the steps of

decoding the enhancement information to provide an identification of a prediction method used in an encoder in a transmitter transmitting the television signal,

using the identification to select the prediction method used in the encoder from a plurality of prediction methods, and

using the prediction method selected from the plurality of prediction methods to process the information representative of images at the first quality to form predictions of images at the second quality.

8. The method of claim 7 wherein the predictions of images at the second quality are used as the output at the second quality.

9. The method of claim 7 wherein the steps of decoding the enhancement information further includes the steps of

decoding a residual computed at the transmitter that represents the difference between predictions of the input video source and the input video source itself;

and

combining the decoded residual and the predictions of the input video source to form the output at the second quality.

10. The method of claim 5 or 9 wherein the prediction method selected from the plurality of prediction methods uses spatial interpolation.

11. The method of claim 10 wherein the spatial interpolation is done by filtering.

12. The method of claim 5 or 9 wherein the prediction method selected from the plurality of prediction methods uses deinterlacing.

13. The method of claim 12 wherein the enhancement information includes information representative of a type of deinterlacing, the prediction method selected from the plurality of prediction methods using the type of deinterlacing.

14. The method of claim 5 or 9 wherein the prediction method selected from the plurality of prediction methods uses temporal interpolation.

15. The method of claim 14 wherein the temporal interpolation is done by filtering.

16. The system of claim 14 wherein the temporal interpolation is done by filtering.

17. A method of receiving and decoding an audio signal, the audio signal representing an input audio source, wherein the audio signal has been transmitted in a format comprising a first set of bits that represents audio at a first quality and that can be decoded to provide an output at the first quality, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an audio output at a second quality greater than the first quality, the method of receiving and decoding comprising the steps of:

decoding the first set of bits according to a first decoding procedure to provide information representative of audio at the first quality;

decoding the second set of bits according to a second decoding procedure to provide the enhancement information;

using at least some of the enhancement information and at least some of the information representative of audio at the first quality to provide the output at the second quality.

18. The method of claim 17 wherein the first and second quality comprise first and second accuracies.

19. The method of claim 17 wherein the audio signal is an audio portion of a television signal.

20. A system for receiving and decoding a television signal representing an input video source, wherein the television signal has been encoded by

encoding a first set of bits using a first transmission standard, the first set of bits representing images at a first quality and being capable of being decoded to provide an output at a first quality, and

encoding a second set of bits using a second transmission standard, the second set of bits representing enhancement information that can be decoded and used in the receiver with the first set of bits to provide an output at a second quality greater than the first quality,

wherein the second transmission standard comprises the steps of decoding the first set of bits to produce an estimate of the decoded images at a first quality, and comparing the estimate to the input video source and using the results of the comparison to produce the second set of bits,

the system for receiving and decoding comprising:

means for decoding the first set of bits according to a first decoding procedure to provide information representative of images at the first quality;

means for decoding the second set of bits according to a second decoding procedure to provide the enhancement information; and

means for combining the enhancement information with the information representative of the images at the first quality to provide output at the second quality.

21. The system of claim 20 wherein the second transmission standard further comprises processing the estimate with a prediction method to produce a predicted signal for the input video source and encoding information representative of the prediction method for use by the decoder.

22. The method of claim 21 wherein the comparison comprises comparing the predicted signal to the input video source and using the difference in producing the second set of bits.

23. The system of claim 20 wherein

said first and second quality comprise first and second resolutions.

24. The system of claim 23 wherein

the means for decoding the second set of bits comprises

means for decoding a portion of the bits to provide information representative of a prediction method to be used to transform images from the first to the second quality, and

means for using the information to select the prediction method from among a plurality of prediction methods;

and

the means for using at least some of the enhancement information comprises using the prediction method selected from the plurality of prediction methods to generate the output at the second quality.

25. The system of claim 24 wherein the television signal has been transmitted using a third set of bits that represents second enhancement information and that can be decoded and used in conjunction with the first and second sets of bits to provide an output at a third quality greater than the first and second qualities, wherein the system further comprises

means for decoding the third set of bits according to a third decoding procedure to provide the second enhancement information;

26. The system of claim 24 wherein the means for using at least some of the enhancement information further comprises

means for decoding the enhancement information to provide an identification of a prediction method used in an encoder in a transmitter transmitting the television signal,

means for using the identification to select the prediction method used in the encoder from a plurality of prediction methods, and

means for using the prediction method selected from the plurality of prediction methods to process the information representative of images at the first quality to form predictions of images at the second quality.

27. The system of claim 26 wherein the predictions of images at the second quality are used as the output at the second quality.

28. The system of claim 26 wherein the means for decoding the enhancement information further includes

means for decoding a residual computed at the transmitter that represents the difference between predictions of the input video source and the input video source itself;

and

means for combining the decoded residual and the predictions of the input video source to form the output at the second quality.

29. The system of claim 24 or 28 wherein the prediction method selected from the plurality of prediction methods uses temporal interpolation.

30. The system of claim 24 or 28 wherein the prediction method selected from the plurality of prediction methods uses spatial interpolation.

31. The system of claim 30 wherein the spatial interpolation is done by filtering.

32. The system of claim 24 or 28 wherein the prediction method selected from the plurality of prediction methods uses deinterlacing.

33. The system of claim 32 wherein the enhancement information includes information representative of a type of deinterlacing, the prediction method selected from the plurality of prediction methods using the type of deinterlacing.

means for using at least some of the second enhancement information, and at least some of the first-mentioned enhancement information, and at least some of the information representative of images at the first resolution to provide the output at the third quality.

34. A system of receiving and decoding an audio signal, the audio signal representing an input audio source, wherein the audio signal has been transmitted in a format comprising a first set of bits that represents audio at a first quality and that can be decoded to provide an output at the first quality, and a second set of bits that represents enhancement information and that can be decoded and used in conjunction with the first set of bits to provide an audio output at a second quality greater than the first quality, the system of receiving and decoding comprising:

means for decoding the first set of bits according to a first decoding procedure to provide information representative of audio at the first quality;

means for decoding the second set of bits according to a second decoding procedure to provide the enhancement information;

means for using at least some of the enhancement information and at least some of the information representative of audio at the first quality to provide the output at the second quality.

35. The system of claim 34 wherein the first and second quality comprise first and second accuracies.

36. The system of claim 34 wherein the audio signal is an audio portion of a television signal.

37. A method of encoding a television signal representing an input video source, comprising the steps of:

using a first transmission standard to encode the input video source to produce an encoded signal, the encoded signal being of a lower quality than the quality of the input video source;

using a second transmission standard to encode enhancement bits to permit the decoder to enhance the signal decoded from the encoded signal;

the second transmission standard comprising the steps of

decoding the encoded signal using a plurality of prediction methods to produce a plurality of estimates of the input video source, each estimate differing from the input video source by a residual;

selecting a prediction method from the plurality of prediction methods by one of the following steps;

selecting a prediction method based on the degree to which the estimate approaches the quality of the input video source;

selecting a prediction method based on the efficiency by which the residual can be encoded using the second transmission standard;

encoding information representative of the prediction method for use by the decoder.

38. The method of claim 37 wherein the prediction method comprises spatial interpolation.

39. The method of claim 37 wherein quality is measured in image resolution.

40. The method of claim 39 wherein as part of the encoding under the first transmission standard the input video source is subsampled or converted to a lower resolution scanning format, to thereby reduce its resolution to one of a set of standard resolutions of the first transmission standard.

41. The method of claim 40 wherein the input video source is converted from a progressively scanned format to an interlaced scanned format.

42. The method of claim 41 wherein the prediction method comprises deinterlacing to restore the image to the progressive scanning format of the input video source.

43. The method of claim 40 wherein the input video source is subsampled by one of spatial subsampling and temporal subsampling.

44. The method of claim 43 wherein the prediction method comprises interpolation corresponding to the subsampling performed as part of the first transmission standard.

45. The method of claim 44 wherein the subsampling is spatial subsampling and the prediction method comprises spatial interpolation.

46. The method of claim 44 wherein the subsampling is temporal subsampling and the prediction method comprises temporal interpolation.

47. A system for encoding a television signal representing an input video source, comprising:

means for using a first transmission standard to encode the input video source to produce an encoded signal, the encoded signal being of a lower quality than the quality of the input video source;

means for using a second transmission standard to encode enhancement bits to permit the decoder to enhance the signal decoded from the encoded signal;

the second transmission standard comprising the steps of

decoding the encoded signal using a plurality of prediction methods to produce a plurality of estimates of the input video source, each estimate differing from the input video source by a residual;

selecting a prediction method from the plurality of prediction methods by one of the following steps;

selecting a prediction method based on the degree to which the estimate approaches the quality of the input video source;

selecting a prediction method based on the efficiency by which the residual can be encoded using the second transmission standard;

encoding information representative of the prediction method for use by the decoder.

48. The system of claim 47 wherein the prediction method comprises spatial interpolation.

49. The system of claim 47 wherein quality is measured in image resolution.

50. The system of claim 49 wherein as part of the encoding under the first transmission standard the input video source is subsampled or converted to a lower resolution scanning format, to thereby reduce its resolution to one of a set of standard resolutions of the first transmission standard.

51. The system of claim 50 wherein the input video source is converted from a progressively scanned format to an interlaced scanned format.

52. The system of claim 51 wherein the prediction method comprises deinterlacing to restore the image to the progressive scanning format of the input video source.

53. The system of claim 50 wherein the input video source is subsampled by one of spatial subsampling and temporal subsampling.

54. The system of claim 53 wherein the prediction method comprises interpolation corresponding to the subsampling performed as part of the first transmission standard.

55. The system of claim 54 wherein the subsampling is spatial subsampling and the prediction method comprises spatial interpolation.

56. The system of claim 54 wherein the subsampling is temporal subsampling and the prediction method comprises temporal interpolation.