Selective prediction encoding and decoding methods and selective prediction encoding and decoding devices

• US 20060109911A1
• Filed: 10/24/2005
• Published: 05/25/2006
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Humax Company Limited
• Original Assignee: Humax Company Limited
• Inventors: Lee, Chung-Ku, Jang, Euee-S, Lee, Sun-Young, Won, Jong-Woo, Park, Sung-Won, Cho, Yong-Ho, Lee, Yung-Lyul
• Granted Patent: US 7,912,131 B2
• Time in Patent Office: Days
• US Class Current: 375/240.180
• CPC Class Codes: H04N 19/11 among a plurality of spatial predictive coding modes
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/15 by monitoring actual compressed data size at the memory before deciding storage at the transmission buffer
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

There are provided selective prediction encoding and decoding methods and selective prediction encoding and decoding devices. The selective prediction encoding device selects and performs one of an AC/DC prediction encoding method and an intra prediction encoding method which corresponds to the smaller of code amount from AC/DC prediction and an amount of AVC intra coding, records information indicating the selected encoding method in a header of a bit stream, and transmits the bit stream to the selective prediction decoding device. The selective prediction decoding device decodes the transmitted bit stream by the use of a decoding process corresponding to the information recorded in the header. Accordingly, it is possible to improve compression ratio and image quality by using the selective prediction encoding and decoding methods.

Claims

1. A selective prediction encoding method for identifying an encoding method for a macro block, comprising the steps of:

performing AC/DC prediction and (Advanced Video Coding (AVC) intra prediction for said macro block;

generating an AC/DC code amount from AC/DC prediction and an AVC code amount from AVC intra prediction for said macro block;

selecting between an AC/DC prediction encoding method and an AVC intra prediction encoding method for said macro block, the method which corresponds to the smaller of said AC/DC code amount and said AVC code amount;

performing the selected prediction encoding method to said macro block; and

,

recording an AC/DC flag indicating the AC/DC prediction encoding method in a flag field when the AC/DC prediction encoding method is selected and an AVC flag indicating the AVC intra prediction encoding method in the flag field when the AVC intra prediction encoding method is selected.

2. The selective prediction encoding method according to claim 1, further comprising the step of checking whether said macro block is a predetermined unit of process and performing the steps of claim 1, only when said macro block is one of said predetermined units of process.

3. The selective prediction encoding method according to claim 1, wherein the step of selecting further comprises selecting one of the AC/DC prediction encoding method and the AVC intra prediction encoding method in accordance with a predetermined criterion, when said AC/DC code amount and said AVC code amount are equal to each other.

4. The selective prediction encoding method according to claim 1, wherein the flag field is included in an MB-layer header of a bit stream.

5. A selective prediction encoding device for encoding a macro block, comprising:

an AC/DC prediction unit for performing an AC/DC prediction to a macro block and for generating an AC/DC code amount for said macro block from AC/DC prediction;

an Advanced Video Coding (AVC) intra prediction unit for performing AVC intra prediction to said macro block and for generating an AVC code amount of AVC intra coding; and

a control unit, said control unit controlling the AC/DC prediction unit and the AVC intra prediction unit, selecting one of an AC/DC prediction encoding method and an AVC intra prediction encoding method, which method corresponds to the smaller of said AC/DC code amount and said AVC code amount, and performing the selected encoding method.

6. The selective prediction encoding device according to claim 5, said control unit checking whether said macro block is a predetermined unit of process and controlling the AC/DC prediction unit and the AVC intra prediction unit to generate said AC/DC code amount and said AVC code amount only when said macro block is one of said predetermined units of process.

7. The selective prediction encoding device according to claim 5, wherein said control unit comprises:

a coding amount comparison section, said coding amount comparison section comparing the amount of AC/DC coding and the amount of AVC intra coding, selecting one of the AC/DC prediction encoding method and the AVC intra prediction encoding method which corresponds to the smaller of said AC/DC code amount and said AVC code amount, and performing the selected encoding method; and

a flag recording section, said flag recording section recording a flag indicating the AC/DC prediction encoding method in an AC/DC flag field when the AC/DC prediction encoding method is selected and recording an AVC flag indicating the AVC intra prediction encoding method in the flag field when the AVC intra prediction encoding method is selected.

8. The selective prediction encoding device according to claim 7, wherein the coding amount comparison section selects one encoding method from between the AC/DC prediction encoding method and AVC intra prediction encoding method in accordance with a predetermined criterion, when said AC/DC code amount and said AVC code amount are equal to each other.

9. An encoder comprising the selective prediction encoding device according to claim 5.

10. A decoder comprising the selective prediction encoding device according to claim 5.

15. An encoder comprising the selective prediction encoding device according to claim 6.

16. An encoder comprising the selective prediction encoding device according to claim 7.

17. An encoder comprising the selective prediction encoding device according to claim 8.

18. A decoder comprising the selective prediction encoding device according to claim 6.

19. A decoder comprising the selective prediction encoding device according to claim 7.

20. A decoder comprising the selective prediction encoding device according to claim 8.

11. A selective prediction decoding device comprising:

a flag value recognizing unit for recognizing a prediction flag value included in a header of a received bit stream;

an AC/DC decoding unit for decoding the bit stream by an AC/DC prediction decoding process;

an intra decoding unit for decoding the bit stream by an intra prediction decoding process; and

a control unit for controlling said AC/DC decoding unit and said intra decoding unit, whereby one of said AC/DC decoding unit and said intra decoding unit is activated in accordance with the prediction flag value recognized by said flag value recognizing unit.

12. The selective prediction decoding device according to claim 11, wherein the prediction flag value is recorded in a prediction flag field of an MB-layer header of the bit stream.

13. A selective prediction decoding method for identifying a decoding method for a macro block, comprising the steps of:

recognizing a prediction flag value identifying either an AC/DC coded macro block or an intra coded macro block, which flag value is included in a header of a received bit stream; and

decoding said received bit stream by one of an AC/DC prediction decoding process and an intra prediction decoding process in accordance with the recognized prediction flag value.

14. The selective prediction decoding method according to claim 13, wherein the prediction flag value is recorded in a prediction flag field of an MB-layer header of the bit stream.