Reduced complexity video decoding by reducing the IDCT computation in B-frames

• US 20030021482A1
• Filed: 07/24/2001
• Published: 01/30/2003
• Est. Priority Date: 07/24/2001
• Status: Active Grant

• Current Assignee: Funai Electric Co., Ltd.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Chen, Yingwei, Zhong, Zhun, Lan, Tse-Hua
• Granted Patent: US 7,079,692 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 19/156 Availability of hardware or computational resources, e.g. encoding based on power-saving criteria
• 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 19/48 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 19/577 Motion compensation with bidirectional frame interpolation, i.e. using B-pictures
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

The present invention is directed to reduced B-frame decoding. According to the present invention, the number of transform coefficients in B-frames are reduced to produce reduced B-frames. Also, inverse scanning and inverse quantization is performed on the reduced B-frames. Further, an inverse transform is performed on the reduced B-frames. In one embodiment of the present invention, the reduced B-frames are produced by identifying blocks associated with the B-frames and selecting transform coefficients included in a predetermined area of the identified blocks.

Claims

1. A method for decoding video, comprising the steps of:

reducing a number of transform coefficients in B-frames to produce reduced B-frames;

inverse scanning the reduced B-frames;

performing inverse quantization on the reduced B-frames; and

performing an inverse transform on the reduced B-frames.

2. The method of claim 1, wherein the reduced B-frames are produced by:

identifying blocks associated with the B-frames; and

selecting transform coefficients included in a predetermined area of the blocks associated with the B-frames.

3. The method of claim 1, wherein the inverse scanning is inverse zig-zag scanning.

4. The method of claim 1, wherein the inverse transform is an inverse discrete cosine transform.

5. A memory medium including code for decoding video, the code comprising:

a code for reducing a number of transform coefficients in B-frames to produce reduced B-frames;

a code for inverse scanning the reduced B-frames;

a code for performing inverse quantization on the reduced B-frames; and

a code for performing an inverse transform on the reduced B-frames.

6. The memory medium of claim 5, wherein the code for producing the reduced B-frames includes:

a code for identifying blocks associated with the B-frames; and

a code for selecting transform coefficients included in a predetermined area of the blocks associated with the B-frames.

7. The memory medium of claim 5, wherein the inverse scanning is inverse zig-zag scanning.

8. The method of claim 5, wherein the inverse transform is an inverse discrete cosine transform.

9. An apparatus for decoding video, comprising:

means for reducing a number of transform coefficients in B-frames to produce reduced B-frames;

means for inverse scanning the reduced B-frames;

means for performing inverse quantization on the reduced B-frames; and

means for performing an inverse transform on the reduced B-frames.

10. The apparatus of claim 9, wherein the means for producing reduced B-frames includes:

means for identifying blocks associated with the B-frames; and

means for selecting transform coefficients included in a predetermined area of the blocks associated with the B-frames.

11. The apparatus of claim 9, wherein the inverse scanning is inverse zig-zag scanning.

12. The apparatus of claim 9, wherein the inverse transform is an inverse discrete cosine transform.

13. An apparatus for decoding video, comprising:

an inverse scan and quantization unit for reducing a number of transform coefficients in B-frames to produce reduced B-frames, inverse scanning the reduced B-frames and performing inverse quantization on the reduced B-frames; and

an inverse transform unit for performing an inverse transform on the reduced B-frames.

14. The apparatus of claim 13, wherein the reduced B-frames are produced by:

identifying blocks associated with the B-frames; and

selecting transform coefficients included in a predetermined area of the blocks associated with the B-frames.

15. The apparatus of claim 13, wherein the inverse scanning is inverse zig-zag scanning.

16. The apparatus of claim 13, wherein the inverse transform is an inverse discrete cosine transform.