Image processing method and apparatus for converting between data coded in different formats

• US 5,818,537 A
• Filed: 12/02/1996
• Issued: 10/06/1998
• Est. Priority Date: 12/28/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Enokida, Miyuki, Ohsawa, Hidefumi
• Primary Examiner(s): FLYNN, NATHAN J
• Application Number:
  US08/758,465
• Time in Patent Office: 673 Days
• Field of Search: 348/441, 348/442, 348/443, 348/444, 348/445, 348/446, 348/448, 348/450, 348/451, 348/452, 348/453, 348/454, 348/455, 348/456, 348/457, 348/458, 348/495
• US Class Current: 348/441
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/146 Data rate or code amount at the encoder output
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/48 using compressed domain processing techniques other than decoding, e.g. modification of transform coefficients, variable length coding [VLC] data or run-length data motion estimation in a transform domain H04N19/547; processing of decoded motion vectors H04N19/513
• CPC Class Codes: H04N 19/50 using predictive coding H04N19/61 takes precedence
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
• CPC Class Codes: H04N 21/234309 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo conversion of standards in analog television systems H04N7/01
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source
• CPC Class Codes: H04N 7/54 the signals being synchronous H04N21/23602, H04N21/23614, H04N21/2365, H04N21/2368, H04N21/4341, H04N21/4342, H04N21/4347, H04N21/4348 take precedence

Abstract

Image processing method and apparatus for converting between data encoded in different formats includes structure and steps for converting motion image data into first digital coded motion image data having a first encoding format and capable of being transmitted to a medium. The first digital coded motion image data is then converted into second digital coded motion image data without decoding entirely the first digital coded motion image data. The second digital coded motion image data has a second encoding format different from the first encoding format. Preferably, the second digital coded motion image data has a digital data amount which is less than that of the first digital coded motion image data.

Claims

1. Image processing apparatus comprising:

input means for inputting a first encoded motion image data stream having a first frame rate, said first encoded motion image data stream including (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data;

selection means for selecting a particular code of the first encoded motion image data stream;

decoding means for decoding the first encoded motion image data selected by said selection means;

coding means for encoding image data decoded by said decoding means to form a second encoded motion image data stream having a second frame rate different from the first frame rate; and

outputting means for outputting the second encoded motion image data coded by said coding means.

2. Image processing apparatus according to claim 1, wherein said decoding means extracts said intra frame code image data from the first encoded motion image data.

3. Image processing apparatus according to claim 1, wherein said second frame rate is lower than said first frame rate.

4. Image processing apparatus according to claim 1, wherein said input means for inputting inputs said first encoded motion image data from a first network.

5. Image processing apparatus according to claim 4, wherein said outputting means for outputting outputs said second encoded motion image data to a second network.

6. An image processing method comprising the steps of:

providing a first digital coded motion image data stream having a first encoding format and capable of being transmitted to a medium, the first digital coded motion image data stream including (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data;

selecting a particular code of the first digital coded motion image data;

decoding the first digital coded motion image data selected in said selecting step, said decoding step including the steps of extracting a predetermined code from said first digital coded motion image data and outputting said predetermined code; and

encoding the image data decoded by said decoding step to form a second digital coded motion image data stream, the second digital coded motion image data having a second encoding format different from the first encoding format.

7. An image processing of method according to claim 6, wherein said converting step includes the steps of extracting a particular code from said first coded image date and replacing it with a copy code.

8. An image processing method according to claim 7, wherein said first digital coded image data includes (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data.

9. An image processing method according to claim 8, wherein said particular code comprises a portion of said inter frame coded image data.

10. An image processing method according to claim 6, wherein said predetermined code comprises intra frame coded image data.

11. An image processing method according to claim 6, wherein said first digital coded motion image data is supplied by a video camera.

12. An image processing method according to claim 6, wherein said medium comprises a communication network.

13. An image processing method according to claim 6, wherein said medium comprises a recording medium.

14. An image processing method according to claim 6, wherein the second digital coded motion image data has a digital data amount which is lower than a digital data amount of the first digital coded image data.

15. Image processing apparatus comprising:

providing means for providing a first digital coded image data stream capable of being transmitted to a medium, the first digital coded image data stream including (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data;

selecting means for selecting a particular code of the first digital coded image data stream,

decoding means for decoding the first digital coded image data selected by said selecting means; and

coding means for encoding image data decoded by said decoding means to form second digital coded image data, the second digital coded image data having a digital data amount which is less than the digital data amount of the first digital coded image data.

16. Image processing apparatus according to claim 15, wherein said converting means includes means for replacing a particular code of said first digital coded image data with a copy code.

17. Image processing apparatus according to claim 15, wherein said particular code comprises a portion of said inter frame coded image data.

18. Image processing apparatus, according to claim 15, wherein said decoding means includes means for extracting a predetermined code included in said first digital coded image data, and for outputting the extracted code.

20. Image processing apparatus according to claim 15, wherein said digital coded motion image data is supplied by a video camera.

21. Image processing apparatus according to claim 15, wherein said medium comprises a communication network.

22. Image processing apparatus according to claim 15, wherein said medium comprises a recording medium.

23. An image processing method comprising the steps of:

providing a first digital coded motion image data stream capable of being transmitted to a medium, the first digital coded motion image data stream including (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data;

selecting a particular code of the first coded motion image data stream;

decoding the first digital coded motion image data selected by said selecting step, said decoding step including the steps of extracting a predetermined code from said first digital coded motion image data stream and outputting said predetermined code; and

encoding image data decoded by said decoding step to form a second digital coded motion image data stream, the second digital coded motion image data having a digital data amount which is less than a digital data amount of the first digital coded motion image data.

24. An image processing of method according to claim 23, wherein said converting step includes the steps of extracting a particular code from said first digital coded image date and replacing it with a copy code.

25. An image processing method according to claim 24, wherein said first digital coded image data includes (i) intra frame coded image data and (ii) inter frame coded image data which is different from the intra frame coded image data.

26. An image processing method according to claim 25, wherein said particular code comprises a portion of said inter frame coded image data.

27. An image processing method according to claim 23, wherein said predetermined code comprises intra frame coded image data.

28. An image processing method according to claim 23, wherein said digital coded motion image data is supplied by a video camera.

29. An image processing method according to claim 23, wherein said medium comprises a communication network.

30. An image processing method according to claim 23, wherein said medium comprises a recording medium.

31. Image processing apparatus comprising:

input means for inputting first encoded motion image data stream including intra frame coded image data and inter frame coded image data which is different from the intra frame coded image data, said first encoded motion image data stream having a first frame rate;

decoding means for decoding the first encoded motion image data;

selection means for selecting a decoding operation of said decoding means;

coding means for encoding image data decoded by said decoding means to form a second encoded motion image data stream having a second frame rate different from the first frame rate; and

outputting means for outputting the second encoded motion image data coded by said coding means.

19. Image processing apparatus according to claim 33, wherein said predetermined code comprises intra frame coded image data.

32. Apparatus according to claim 31, wherein said decoding means extracts said intra frame coded image data from the first encoded motion image data stream.

33. Apparatus according to claim 31, wherein said second frame rate is lower than said first frame rate.

34. Apparatus according to claim 31, wherein said input means inputs said first encoded motion image data stream from a first network.

35. Apparatus according to claim 31, wherein said outputting means outputs said second encoded motion image data stream to a second network.

36. An image processing method comprising the steps of:

an input step for inputting first encoded motion image data including intra frame coded image data and inter frame coded image data which is different from the intra frame coded image data, said first encoded motion image data stream having a first frame rate;

a decoding step for decoding the first encoded motion image data;

a selection step for selecting a decoding operation of said decoding step;

a coding step for encoding image data decoded by said decoding step to form a second encoded motion image data stream having a second frame rate which is different from the first frame rate; and

an outputting step for outputting the second encoded motion image data coded by said coding step.

37. A method according to claim 36, wherein said decoding step includes the step of extracting said intra frame code image data from the first encoded motion image data stream.

38. A method according to claim 36, wherein the second frame rate is lower than the first frame rate.

39. A method according to claim 36, wherein said input step inputs said first encoded motion image data stream from a first network.

40. A method according to claim 36, wherein said outputting step outputs said second encoded motion image data stream to a second network.