发明公开
- 专利标题: CONTROL OF VIDEO ENCODING BY VARYING QUANTIZATION LEVELS
- 专利标题(中): 图像编码监测通过改变量化
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申请号: EP96912781.0申请日: 1996-04-19
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公开(公告)号: EP0781434A1公开(公告)日: 1997-07-02
- 发明人: AZADEGAN, Faramarz , YAMAKAGE, Tomoo , KOTO, Shin-ichiro , UNNO, Hiroaki , MIMURA, Hideki , KITAMURA, Tetsuya , COOKSON, Christopher, J. , THAGARD, Greg, B. , ROSEN, Andrew, Drusin
- 申请人: KABUSHIKI KAISHA TOSHIBA , TIME WARNER ENTERTAINMENT CO., L.P.
- 申请人地址: 72, Horikawa-cho, Saiwai-ku Kawasaki-shi, Kanagawa-ken 210 JP
- 专利权人: KABUSHIKI KAISHA TOSHIBA,TIME WARNER ENTERTAINMENT CO., L.P.
- 当前专利权人: KABUSHIKI KAISHA TOSHIBA,TIME WARNER ENTERTAINMENT CO., L.P.
- 当前专利权人地址: 72, Horikawa-cho, Saiwai-ku Kawasaki-shi, Kanagawa-ken 210 JP
- 代理机构: Dubois-Chabert, Guy, et al
- 优先权: US19950438014 19950508; US19950466766 19950606
- 国际公布: WO1996035998 19961114
- 主分类号: H04N5
- IPC分类号: H04N5 ; G06T9 ; G11B20 ; G11B27 ; H04N7 ; H04N9
摘要:
A method and system for re-encoding frames of a digital video stream without changing the previously calculated bit length of the stream. A set of macroblocks at a time are re-encoded (292), the number of resulting bits is calculated (306, 368) and the deviation from an estimated number of bits is calculated (372), either set-by-set or cumulatively. Based on the accuracy (372), of the estimate (422) and the remaining number of sets of macroblocks (424) to re-encode, a correction factor (710) for the quantization level of the next set of macroblocks is chosen from a lookup table. The correction factor is added to the quantization level of the next set of macroblocks (712) and the results stored as the new quantization level of the set (706). This sequential process is done for all sets of macroblocks in the digital stream which are to be recorded according to changed image qualities (706, 708, 710, 712, 714).
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