Method of adaptively encoding and decoding motion image and apparatus therefor

• US 20030219160A1
• Filed: 12/23/2002
• Published: 11/27/2003
• Est. Priority Date: 05/22/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Chun, Kang-wook, Song, Byung-cheol
• Granted Patent: US 7,457,471 B2
• Time in Patent Office: Days
• US Class Current: 382/236
• 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 19/31 in the temporal domain
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence

Abstract

In a method of adaptively encoding input image data of a motion image in accordance with a temporal complexity of the motion image, and an apparatus therefore, the temporal complexity of the input image data is calculated. Next, an original frame rate of the input image data is converted into a converted frame rate based on the calculated temporal complexity. Thereafter, the input image data whose frame rate has been converted is encoded, and the encoding data of the encoded image data is controlled so that the encoded image data has information on the converted frame rate. Accordingly, the input image data is encoded at different frame rates in accordance with the temporal complexity of the input image data. Consequently, the encoded input image data is efficiently stored.

Claims

1. A method of adaptively encoding input image data of a motion image, the method comprising:

calculating a temporal complexity of the input image data;

converting an original frame rate of the input image data into a converted frame rate based on the calculated temporal complexity; and

encoding the input image data whose frame rate has been converted and adjusting encoding data of the encoded input image data so that the encoded input image data has information on the converted frame rate.

2. The method of claim 1, wherein the converting of the original frame rate comprises:

determining a frame rate value by comparing the calculated temporal complexity with a threshold value; and

converting the original frame rate of the input image data into the converted frame rate based on the determined frame rate value.

3. The method of claim 1, wherein the input image data is an encoded bitstream, and the calculating of the temporal complexity comprises:

decoding the encoded bitstream of the input image data; and

calculating the temporal complexity using motion vectors obtained during decoding the encoded bitstream.

4. The method of claim 1, wherein the encoding data is one of data of a picture coding extension in a data structure of the encoded input image data.

5. The method of claim 4, wherein the encoding data is one of the repeat_first_field (RFF) value and top_field_first (TFF) value of the picture coding extension.

6. The method of claim 5, wherein the encoding of the input image data comprises:

setting both the RFF and TFF values to be 0 if the calculated temporal complexity is equal to or greater than a first threshold value;

setting the RFF and TFF values to be 1 and 0, respectively, if the calculated temporal complexity is at or between a second threshold value and the first threshold value; and

setting both the RFF and TFF values to be 1 if the calculated temporal complexity is less than the second threshold value.

7. The method of claim 6, wherein the first threshold value is greater than the second threshold value.

8. The method of claim 1, wherein the input image data comprises macroblocks, and the calculating of the temporal complexity comprises:

calculating a motion activity per macroblock of the input image data.

9. The method of claim 8, wherein the macroblock has a motion vector, and the calculating of the motion activity comprises:

calculating a magnitude of the motion vector of the macroblock.

10. The method of claim 9, wherein, if the motion vector of the macroblock is (MV1,MV2), the motion activity is MV1²+MV2².

11. The method of claim 1, wherein the input image data comprises a number of sections, and the calculating of the temporal complexity and the determining of the frame rate comprise:

calculating the temporal complexity from a unit section having a predetermined number of the sections of the input image data.

12. The method of claim 11, wherein the unit section of the input image data is a group of pictures (GOP).

13. The method of claim 11, wherein the unit section of the input image data is a sequence.

14. An apparatus for adaptively encoding input image data of a motion image, comprising:

a temporal complexity calculation unit calculating a temporal complexity of the input image data;

a frame rate conversion unit converting an original frame rate of the input image data into a converted input image data based on the calculated temporal complexity; and

an encoder encoding the input image data whose frame rate has been converted and adjusting the encoded image data so that the encoded image data has information on the converted frame rate.

15. The apparatus of claim 14, wherein the frame rate conversion unit further comprises:

a frame rate determiner determining a frame rate value by comparing the calculated temporal complexity with a threshold value, the frame rate of the input image data converted into the converted frame rate based on the frame rate value determined by the frame rate determiner.

16. The apparatus of claim 14, wherein the input image data comprises an encoded data, and the temporal complexity calculation unit further comprises:

a decoder decoding the encoded data of the input image data using motion vectors of the encoded data, and the temporal complexity is calculated using the motion vectors obtained by the decoder.

17. The apparatus of claim 14, wherein the information comprises:

one of data of a picture coding extension in a data structure of the encoded input image data.

18. The apparatus of claim 17, wherein the data comprises:

one of an RFF value and a TFF value of the picture coding extension.

19. The apparatus of claim 18, wherein the frame rate conversion unit sets both the RFF and TFF values to be 0 if the calculated temporal complexity is equal to or greater than a first threshold value, sets the RFF and TFF values to be 1 and 0, respectively, if the calculated temporal complexity is at or between a second threshold value and the first threshold value, and sets both the RFF and TFF values to be 1 if the calculated temporal complexity is less than the second threshold value.

20. The apparatus of claim 19, wherein the first threshold value is greater than the second threshold value.

21. The apparatus of claim 20, wherein the input image data comprises a plurality of groups of pictures (GOPs), the temporal complexity calculation unit calculates the temporal complexity from a predetermined number of the GOPs, and the frame rate conversion unit converts the original frame rate into the converted frame data in response to the calculated temporal complexity of the predetermined number of the GOPs.

22. The apparatus of claim 20, wherein the input image data is not a progressive sequence, and the temporal complexity calculation unit converts the input image data into a sequence as the input image data.

23. The apparatus of claim 14, wherein the input image data comprises a plurality of macroblocks, and the temporal complexity is calculated based on motion activity per macroblock of the input image data.

24. The apparatus of claim 21, wherein the macroblock has a motion vector, and the motion activity is a magnitude of the motion vector of the macroblock.

25. The apparatus of claim 24, wherein, if the motion vector of the macroblock is (MV1,MV2), the motion activity is MV1²+MV2².

26. A recoding medium encoded with data readable by a computer to implement a method of encoding input image data of an input image having an original frame rate into an encoded input image data, the method comprising:

temporal complexity calculating data used to calculate a temporal complexity of the input image data;

frame rate converting data used to convert the original frame rate in response to the temporal complexity of the input image data; and

encoding data used to control the computer to encode the input image data at the converted frame rate other than the original frame data to generate encoded input image data.

27. The recording medium of claim 26, wherein the input image data comprises an encoded bitstream, and the computer used a motion vector of the encoded bitstream to decode the encoded bitstream into a decoded signal as the input image data to be used for calculating the temporal complexity, and the temporal complexity calculating data calculates the temporal complexity in response to a value of the motion vector.

28. The recording medium of claim 26, wherein the input image data comprises a plurality of macroblocks, and the temporal complexity calculating data enables the computer to calculate the temporal complexity from a predetermined number of macroblocks.

29. The recording medium of claim 26, wherein the input image data comprises a plurality of frames, and the temporal complexity calculating data enables the computer to calculate the temporal complexity from a predetermined number of frames.

30. The recording medium of claim 26, wherein the encoding data controls the computer to insert information on the converted frame rate into the encoded input image data.

31. The recording medium of claim 26, wherein the encoding data controls the computer to set one of data of a picture coding extension in a data structure of the encoded input image data as information on the converted frame rate.

32. The recording medium of claim 26, wherein the encoding data controls the computer to set one of an REF value and a TFF value of a picture coding extension of the encoded input image data as information on the converted frame rate.

33. A recoding medium encoded with data readable by a computer to implement a method of decoding encoded input image data of an input image into a decoded input image data, the method comprising:

converted frame rate control data used to control the computer to retrieve information on a converted frame rate of the encoded input image data from a syntax level of the encoded input image data; and

decoding data used to control the computer to decode the encoded input image data using the converted frame rate.

34. The recording medium of claim 33, wherein the converted frame rate control data controls the computer to retrieve information on the converted frame rate from a picture coding extension in a data structure of the encoded input image data to obtain the converted frame rate.

35. The recording medium of claim 33, wherein the converted frame rate control data controls the computer to retrieve information on the converted frame rate from one of an RFF value and a TFF value of a picture coding extension of the encoded input image data to obtain the converted frame rate.

36. The recording medium of claim 33, wherein the converted frame rate comprises a first frame rate and a second frame rate which are included in the encoded input image data, and the decoding data controls the computer to decode the encoded input image data using one of the first frame rate and the second frame rate read from the encoded input image data.

37. An apparatus for adaptively encoding and/or decoding an input image data of an input image, comprising:

a temporal complexity calculation unit calculating a temporal complexity of the input image data;

a frame rate conversion unit converting an original frame rate of the input image data into one of a first frame rate and a second frame rate based on the calculated temporal complexity;

an encoder encoding the input image data at one of the first frame rate and a second frame rate and inserting information on one of the first and second frame rates into the encoded input image data; and

a decoder retrieving one of the first frame rate and the second frame rate from the encoded input image data, decoding the encoded input image data at the first frame rate when the first frame rate is retrieved from the encoded input image data, and decoding the encoded input image data at the second frame rate when the converted frame rate retrieving unit retrieves the second frame rate from the encoded input image data.

38. An apparatus for adaptively decoding an encoded input image data of an input image, comprising:

a retrieving unit retrieving a first frame rate and a second frame rate from encoded input image data;

a decoder decoding the encoded input image data at the first frame rate when the retrieving unit retrieves the first frame rate from the encoded input image data, and decoding the encoded input image data at the second frame rate when the retrieving unit retrieves the second frame rate from the encoded input image data.

39. The apparatus of claim 38, wherein the encoded input image data comprises a picture coding extension in a data structure of the encoded input image data to represent one of the first frame rate and the second frame rate, and the retrieving unit retrieves one of the first frame rate and the second frame rate from the picture coding extension in a data structure of the encoded input image data.

40. The apparatus of claim 38, wherein the picture coding extension of the encoded input image data comprises one of an REF value and a TFF value to represent one of the first frame rate and the second frame rate, and the retrieving unit retrieves one of the first frame rate and the second frame rate from the one or a combination of the REF value and the TFF value of the picture coding extension in the data structure of the encoded input image data.

41. The apparatus of claim 38, wherein the encoded input image data comprises a plurality of macroblocks in a frame, and the temporal complexity represents a temporal complexity of a predetermined number of the macroblocks.

42. The apparatus of claim 38, wherein the encoded input image data comprises a plurality of macroblocks in a frame, and the temporal complexity represents a temporal complexity of each macroblock.

43. The apparatus of claim 38, wherein the encoded input image data comprises a plurality of fields or frames, and the temporal complexity represents a temporal complexity of a predetermined number of fields or frames.

44. The apparatus of claim 38, wherein the encoded input image data comprises a plurality of fields or frames, and the temporal complexity represents a temporal complexity of each field or frame.

45. A method of adaptively encoding and/or decoding an input image data of an input image, comprising:

calculating a temporal complexity of the input image data;

converting an original frame rate of the input image data into one of a first frame rate and a second frame rate based on the calculated temporal complexity;

encoding the input image data at one of the first frame rate and a second frame rate and inserting information on one of the first and second frame rates into the encoded input image data; and

retrieving one of the first frame rate and the second frame rate from the encoded input image data, decoding the encoded input image data at the first frame rate when the first frame rate is retrieved from the encoded input image data, and decoding the encoded input image data at the second frame rate when the converted frame rate retrieving unit retrieves the second frame rate from the encoded input image data.