| United States Patent | 7,483,584 |
| Chen , et al. | January 27, 2009 |
Extended hybrid variable length coding of transform coefficients for video compression
Abstract
A method and an apparatus of image compression, and a memory to store a data structure for compression. The method includes, for an ordered series of quantized coefficients of a transform of an image block, forming from the series events that are a run of non-zero-valued coefficients in a first contiguous region defined by a breakpoint, a run of zero-valued coefficients in the first region, or a run of zero-valued coefficients that ends in a non-zero-amplitude coefficient in a second region defined by the breakpoint. A codeword is formed for each runlength of non-zero-valued and zero-valued coefficients in the first region using a first and a second coding method, respectively, and, and encoding the runs of zero-valued coefficient that end in a non-zero value in the second region according to a third coding method, including providing an exception codeword when the ending amplitude is not 1.
| Inventors: | Chen; Wen-hsiung (Sunnyvale, CA), Wu; Fang (Pleasanton, CA), Pelton; Gregory D. (Raleigh, NC), Toebes; John A. (Cary, NC) |
| Assignee: | Cisco Technology, Inc. (San Jose, CA) |
| Appl. No.: | 10/898,654 |
| Filed: | July 22, 2004 |