Method of adaptively encoding and decoding motion image and apparatus therefor

• US 7,457,471 B2
• Filed: 12/23/2002
• Issued: 11/25/2008
• Est. Priority Date: 05/22/2002
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Chun, Kang-wook, Song, Byung-cheol
• Primary Examiner(s): Dang; Duy M
• Application Number:
  US10/326,271
• Publication Number:
  US 20030219160A1
• Time in Patent Office: 2,164 Days
• Field of Search: 382236-239, 382232-235, 375/240.02, 375/240.03, 375/240.12, 375/240.22, 375/240.29, 348/407.1, 348/620, 358/448, 358/539
• 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,

wherein the information on the converted frame rate is located in a unit of a sequence, a group of pictures, or a picture of the encoded input image data,

the encoding data of the encoded input image data comprises a picture coding extension in a data structure of the encoded input image data, and

the picture coding extension in a data structure of the encoded input image data comprises at least one of a repeat first field (RFF) value of the picture coding extension and a top field first (TFF) value of the picture coding extension.

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 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 REF 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.

5. The method of claim 4, wherein the first threshold value is greater than the second threshold value.

6. 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.

7. The method of claim 6, 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.

8. The method of claim 7, wherein, if the motion vector of the macroblock is (MV1,MV2), the motion activity is MV1²+MV2².

9. 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.

10. The method of claim 9, wherein the unit section of the input image data is a group of pictures (GOP).

11. The method of claim 9, wherein the unit section of the input image data is a sequence.

12. 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,

wherein the information on the converted frame rate is located in a unit of a sequence, a group of pictures, or a picture of the encoded input image data,

the information on the converted frame rate comprises data of a picture coding extension in a data structure of the encoded input image data, and

the picture coding extension in a data structure of the encoded input image data comprises at least at least one of an REF value of the picture coding extension and a TFF value of the picture coding extension.

13. The apparatus of claim 12, 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.

14. The apparatus of claim 12, 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.

15. The apparatus of claim 12, 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.

16. The apparatus of claim 15, wherein the first threshold value is greater than the second threshold value.

17. The apparatus of claim 16, 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.

18. The apparatus of claim 16, 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.

19. The apparatus of claim 18, wherein the macroblock has a motion vector, and the motion activity is a magnitude of the motion vector of the macroblock.

20. The apparatus of claim 19, wherein, if the motion vector of the macroblock is (MV1,MV2), the motion activity is MV1²+MV2².

21. The apparatus of claim 12, 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.