Prediction method, apparatus, and medium for video encoder

• US 20050069211A1
• Filed: 05/28/2004
• Published: 03/31/2005
• Est. Priority Date: 09/30/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Nam-suk, Lee, Jae-hun
• Granted Patent: US 7,532,764 B2
• Time in Patent Office: Days
• US Class Current: 382/239
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A prediction method, apparatus, and medium including computer readable code, for calculating an average of intra-prediction costs or an average of inter-prediction costs of macroblocks of a received picture by encoding the received picture using an intra-prediction and/or inter-prediction in consideration of a type of the received picture, calculating a threshold value using the calculated average of intra-predication costs and/or inter-predication costs, and determining whether to perform intra-prediction on a subsequent picture based on the calculated threshold value. Accordingly, it is possible to considerably reduce the amount of computation that conventionally was required to encode a picture, without any deterioration in the encoding performance, by considerably reducing the number of macroblocks that need to undergo intra-prediction.

Claims

1. A prediction method, comprising:

calculating an average of intra-prediction costs or an average of inter-prediction costs of macroblocks of a received picture by encoding the received picture using intra-prediction and/or inter-prediction based on a type of the received picture;

calculating a threshold value based on the average of the intra-predication costs or the average of the inter-predication costs; and

determining whether to perform intra-prediction on a subsequent picture based on the calculated threshold value.

2. The prediction method of claim 1, wherein in the calculating of the average of intra-prediction costs or the average of the inter-prediction costs, if the received picture is an I picture, the received picture is encoded by performing the intra-prediction, and the average of intra-prediction costs of the macroblocks of the received picture is calculated.

3. The prediction method of claim 2, wherein in the calculating of the average of intra-predication costs or average of the inter-prediction costs, intra-prediction costs which are larger than a predetermined threshold value are excluded from the calculation of the average of the intra-prediction costs of the macroblocks of the received picture.

4. The prediction method of claim 1, wherein in the calculating of the average of intra-prediction costs or average of the inter-prediction costs, if the received picture is a P picture, the received picture is encoded by performing the inter-prediction and the intra-prediction, and the average of inter-prediction costs of the macroblocks of the received picture is calculated.

5. The prediction method of claim 4, wherein the calculating of the average of intra-prediction costs or average of the inter-predication costs further comprises:

receiving a given macroblock of a P picture and calculating an inter-prediction cost of the given macroblock by performing the inter-prediction;

calculating an intra-prediction cost of the given macroblock by performing the intra-prediction if the inter-prediction cost of the given macroblock is larger than a sum of the threshold value and a predetermined offset, selecting an inter-prediction mode if the intra-prediction cost of the given macroblock is larger than the inter-prediction cost of the given macroblock, and selecting an intra-prediction mode if the intra-prediction cost of the given macroblock is not larger than the inter-prediction cost of the given macroblock; and

calculating an average of inter-prediction costs of macroblocks of the P picture by performing a receiving of another given macroblock and calculating a respective inter-prediction cost, calculating a respective intra-prediction cost of the other given macroblock based on a size of the respective inter-predication costs, selecting of the inter-predication mode based on a size of the intra-predication cost, and selecting of the intra-prediction mode based on the size of the inter-predication cost of the other given macroblock, on each of the macroblocks of the P picture.

6. The prediction method of claim 5, wherein if the inter-prediction cost of the given macroblock is smaller than the sum of the threshold value and the predetermined offset, the inter-prediction mode is selected without performing the intra-prediction on the given macroblock of the P picture.

7. The prediction method of claim 1, wherein the calculating of the threshold value further comprises:

calculating a lower boundary for the average of the inter-prediction costs of the macroblocks of the received picture based on;

INTRA_LOW_TH=MAX(α

*avg_inter_cost, INTER_LOW_TH), where avg_inter_cost represents the average of the inter-prediction costs of the macroblocks of the received picture, and INTRA_LOW_TH represents the lower boundary for avg_inter_cost; and

calculating the threshold value based on;

INTER_TH=Max(avg_intra_cost, INTRA_LOW_TH) where INTER_TH represents the threshold value, and avg_intra_cost represents the average of the intra-prediction costs of the macroblocks of the received picture.

8. The prediction method of claim 1, wherein a number of macroblocks, for which an intra-predication mode is selected, account for less than 10% of a total number of macroblocks.

17. A medium comprising computer readable code controlling an operation of the prediction method of claim 1.

9. A prediction apparatus, comprising:

an encoding unit calculating an average of intra-prediction costs or an average of inter-prediction costs of macroblocks of a received picture by encoding the received picture using intra-prediction and/or inter-prediction in consideration of a type of the received picture;

a threshold value calculation unit calculating a threshold value using the calculated average of intra-predication costs or inter-prediction costs; and

a determination unit determining whether to perform intra-prediction on a subsequent picture based on the calculated threshold value obtained by the threshold value calculation unit.

10. The prediction apparatus of claim 9, wherein if the received picture is an I picture, the encoding unit encodes the received picture by performing the intra-prediction and calculates the average of intra-prediction costs of the macroblocks of the received picture.

11. The prediction apparatus of claim 9, wherein if the received picture is a P picture, the encoding unit encodes the received picture by performing the inter-prediction and the intra-prediction and calculates the average of inter-prediction costs of the macroblocks of the received picture.

12. The prediction apparatus of claim 9, wherein the encoding unit comprises:

an inter-prediction cost calculation unit, which receives a given macroblock of a P picture and calculates an inter-prediction cost of the given macroblock by performing the inter-prediction;

an intra-prediction cost calculation unit, which calculates an intra-prediction cost of the given macroblock by performing the intra-prediction if the inter-prediction cost of the given macroblock is larger than a sum of the threshold value and a predetermined offset;

a prediction mode determination unit, which selects an inter-prediction mode, if the intra-prediction cost of the given macroblock is larger than the inter-prediction cost of the given macroblock, and selects an intra-prediction mode, if the intra-prediction cost of the given macroblock is not larger than the inter-prediction cost of the given macroblock; and

an average calculation unit, which calculates an average of inter-prediction costs of all macroblocks of the P picture.

13. The prediction apparatus of claim 12, wherein the prediction mode determination unit selects the inter-prediction mode without performing the intra-prediction on the given macroblock of the P picture if the inter-prediction cost of the given macroblock is smaller than the sum of the threshold value and the predetermined offset.

14. The prediction apparatus of claim 9, wherein the determination unit calculates:

a lower boundary for the average of the inter-prediction costs of the macroblocks of the received picture based on;

INTRA_LOW_TH=MAX(α

*avg_inter_cost, INTER_LOW_TH), where avg_inter_cost represents the average of the inter-prediction costs of the macroblocks of the received picture, and INTRA_LOW_TH represents the lower boundary for avg_inter_cost; and

the threshold value based on;

INTER_TH=Max(avg_intra_cost, INTRA_LOW_TH), where INTER_TH represents the threshold value, and avg_intra_cost represents the average of the intra-prediction costs of the blocks of the received picture.

15. The prediction apparatus of claim 9, wherein a number of macroblocks, for which an intra-predication mode is selected, account for less than 10% of a total number of macroblocks.

18. A medium comprising computer readable code controlling the predication apparatus of claim 9 to perform the calculating of the average of intra-prediction costs or inter-prediction costs, calculating of the threshold value, and determining of whether to perform the intra-predication on a subsequent picture.

16. A medium comprising computer readable code to control:

calculating of an average of intra-prediction costs or an average of inter-prediction costs of macroblocks of a received picture by encoding the received picture using intra-prediction and/or inter-prediction in consideration of a type of the received picture;

calculating of a threshold value based on the calculated average; and

determining of whether to perform an intra-prediction on a subsequent picture based on the calculated threshold value.