Rate controlling method and apparatus for use in a transcoder
US7397855B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 14, 2004 |
| Grant date | Jul 8, 2008 |
| Priority date | — |
| Expiry date | Aug 16, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A rate controlling method for computing a reference quantization parameter is provided, for use in a transcoder having a variable length decoder, an inverse quantizer, a quantizer and a variable length encoder. The rate controlling method comprising: receiving an input quantization parameter and motion information for each of the macroblocks from the variable length decoder; analyzing the similarity of motion information between a current macroblock and its neighboring macroblocks to compute a scaling factor for the current macroblock when allocated within P- and B-pictures; computing a bit difference between a target outputting bit stream and a real outputting bit stream; estimating the fullness of a virtual buffer to encode the current macroblock in view of the scaling factor; and computing the reference parameter based on a target bit rate, the first quantization parameter and the bit difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.