Method and apparatus for encoding a video signal

• US 6,351,492 B1
• Filed: 06/29/1998
• Issued: 02/26/2002
• Est. Priority Date: 03/14/1998
• Status: Expired due to Fees

• Current Assignee: ZTE Corporation
• Original Assignee: Daewoo Electronics Company Limited (Dayou Holdings Co.,Ltd.)
• Inventors: Kim, Jin-Hun
• Primary Examiner(s): BRITTON, HOWARD W
• Application Number:
  US09/106,081
• Time in Patent Office: 1,338 Days
• Field of Search: H04/N.730, 348/405.1, 375/240.02, 375/240.08, 375/240.24
• US Class Current: 375/240.08
• CPC Class Codes: H04N 19/20 using video object coding
• CPC Class Codes: H04N 19/649 the transform being applied to non rectangular image segments

Abstract

The encoding type of a target macroblock is determined based on the texture information thereof, and the shape information and the texture information on the target macroblock are re-formed in response to the encoding type. After the CBPY bit number of the target macroblock is determined based on the re-formed shape information, the CBPY bit number being the number of non-transparent subblock'"'"'s, the re-formed texture information of the target macroblock transformed and quantized into a set of quantized transformation coefficients for each non-transparent subblock based on the CBPY bit number. The CBPY information for the target macroblock is generated, wherein the CBPY information represents whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero component therein, and the encoding_type and the CBPY information for the target macroblock are multiplexed into a bit stream.

Claims

1. A method, for use in a video signal encoder, for coding texture information of a video signal which includes the texture information and shape information on each of macroblocks, each macroblock having M×

M pixels and being dividable into P number of equal-sized subblocks, M and P being positive integers, respectively, comprising the steps of;

(a) determining an encoding_type of a target macroblock based on the texture information thereof, wherein the encoding_type represents a more effective coding technique between a progressive and an interlaced coding techniques for encoding the texture information thereof;

(b) re-forming the shape information and the texture information on the target macroblock in response to the encoding_type to generate re-formed shape information and re-formed texture information thereof, respectively;

(c) detecting the re-formed shape information on a DCT-block basis to find a CBPY (coded block pattern type) bit number of the target macroblock, wherein the CBPY bit number is the number of bits for non-transparent subblocks, each non-transparent subblock having a subblock size and containing at least one object pixel;

(d) if the CBPY bit number is not zero, transforming the re-formed texture information of the target macroblock into a set of transformation coefficients for each non-transparent subblock based on the CBPY bit number and quantizing the set of transformation coefficients to thereby produce a set of quantized transformation coefficients;

(e) detecting the set of quantized transformation coefficients for said each non-transparent subblock to generate CBPY information for the target macroblock, wherein the CBPY information represents whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero component therein; and

(f) multiplexing the encoding_type and the CBPY information for the target macroblock to generate a bit stream.

2. The method of claim 1, wherein said bit stream is in sequence of the encoding_type and the CBPY information.

3. The method of claim 2, wherein the set of quantized transformation coefficients contains a DC component and a plurality of AC components and said CBPY information represents whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero AC component therein.

4. The method of claim 3, wherein the step (e) includes the steps of:

(e1) determining whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero AC component therein to thereby generate one bit CBPY for said each non-transparent subblock;

(e2) preparing a statistical coding table for the target macroblock corresponding to the CBPY bit number; and

(e3) encoding all CBPY'"'"'s for the target macroblock based on the statistical coding table to generate the CBPY information.

5. The method of claim 4, wherein the step (b) includes the steps of:

(b1) if the encoding_type of the target macroblock is determined as the progressive coding technique, preserving the shape information and the texture information; and

(b2) if the encoding_type of the target macroblock is determined as the interlaced coding technique, shuffling the shape information and the texture information to generate the interlaced shape information and the interlaced texture information, respectively.

6. The method of claim 5, wherein the step (a) includes the steps of:

(a1) calculating a frame and a field correlation coefficients, wherein the frame correlation coefficient is a sum of absolute first differences, each first differences being an error between a line pair including an even line and an adjacent odd line of the macroblock and the field correlation coefficient is a sum of absolute second differences and absolute third differences, each second difference and each third difference being errors between a consecutive even-line pair and between a consecutive odd-line pair, respectively, of the macroblock; and

(a2) deciding the encoding_type based on the frame and the field correlation coefficients.

7. The method of claim 6 further comprising, prior to the step (a), the steps of:

(x) producing encoded shape information by encoding the shape information on the target macroblock; and

(y) reconstructing the shape information on the target macroblock by decoding the encoded shape information.

8. An apparatus, for use in a video signal encoder, for coding texture information of a video signal which includes the texture information and shape information on each of macroblocks, each macroblock having M×

M pixels and being dividable into P number of equal-sized subblocks, M and P being positive integers, respectively, the apparatus comprising;

means for determining an encoding_type of a target macroblock based on the texture information thereof, wherein the encoding_type represents a more effective coding technique between a progressive and an interlaced coding techniques for encoding the texture information thereof;

means for re-forming the shape information and the texture information on the target macroblock in response to the encoding_type to generate re-formed shape information and re-formed texture information thereof, respectively;

means for detecting the re-formed shape information on a DCT-block basis to find a CBPY (coded block pattern type) bit number of the target macroblock, wherein the CBPY bit number is the number of bits for non-transparent subblocks, each non-transparent subblock having a subblock size and containing at least one object pixel;

means for transforming the re-formed texture information of the target macroblock into a set of transformation coefficients for each non-transparent subblock based on the CBPY bit number and quantizing the set of transformation coefficients to thereby produce a set of quantized transformation coefficients;

CBPY information generating means for detecting the set of quantized transformation coefficients for said each non-transparent subblock to generate CBPY information for the target macroblock, wherein the CBPY information represents whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero component therein; and

means for multiplexing the encoding_type and the CBPY information for the target macroblock to generate a bit stream.

9. The apparatus of claim 8, wherein said bit stream is in sequence of the encoding_type and the CBPY information.

10. The apparatus of claim 9, wherein the set of quantized transformation coefficients contains a DC component and a plurality of AC components and said CBPY information represents whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero AC component therein.

11. The apparatus of claim 10, wherein said CBPY information generating means includes:

means for determining whether or not the set of quantized transformation coefficients for said each non-transparent subblock contains at least one non-zero AC component therein to thereby generate one bit CBPY for said each non-transparent subblock;

means for preparing a statistical coding table for the target macroblock corresponding to the CBPY bit number; and

means for encoding all CBPY'"'"'s for the target macroblock based on the statistical coding table to generate the CBPY information.

12. The apparatus of claim 11, wherein said shape information re-forming means includes means for shuffling the shape information and the texture information to generate the interlaced shape information and the interlaced texture information, respectively.

13. The apparatus of claim 12, wherein said encoding_type determining means includes:

means for calculating a frame and a field correlation coefficients, wherein the frame correlation coefficient is a sum of absolute first differences, each first differences being an error between a line pair including an even line and an adjacent odd line of the macroblock and the field correlation coefficient is a sum of absolute second differences and absolute third differences, each second difference and each third difference being errors between a consecutive even-line pair and between a consecutive odd-line pair, respectively, of the macroblock; and

means for comparing the frame correlation coefficient with the field correlation coefficient to decide the encoding_type of the macroblock.

14. The apparatus of claim 13 further comprising:

means for producing encoded shape information by encoding the shape information on the target macroblock; and

means for reconstructing the shape information on the target macroblock by decoding the encoded shape information.