Bit rate control through selective modification of DCT coefficients
US6912255B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2002 |
| Grant date | Jun 28, 2005 |
| Priority date | — |
| Expiry date | Dec 26, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An encoder including a DCT transformator for receiving an image or video frame and performing DCT transformation upon a pixel block in a macroblock of the frame, thereby providing a matrix of DCT coefficients, a zig-zag matrix-to-vector converter for receiving the matrix of DCT coefficients from the DCT transformator and creating a one-dimensional vector of DCT coefficients, an analyzer for receiving the one-dimensional vector of DCT coefficients and classifying the macroblock according to a level of detail and edginess, a rate controller for receiving the classification information from the analyzer and selecting DCT filtering parameters, a DCT filter for receiving the DCT filtering parameters selection from the rate controller and implementing the DCT filtering parameters upon the frame, thereby providing a filtered DCT coefficient vector, a quantizer for quantizing the filtered DCT coefficient vector, and a compressor for compressing the quantized results.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.