发明名称 |
REDUCTION OF ERRORS DURING COMPUTATION OF INVERSE DISCRETE COSINE TRANSFORM |
摘要 |
Techniques are described to reduce rounding errors during computation of discrete cosine transform using fixed-point calculations. According to these techniques, a discrete cosine transform a matrix of scaled coefficients is calculated by multiplying coefficients in a matrix of coefficients by scale factors. Next, a midpoint bias value and a supplemental bias value are added to a DC coefficient of the matrix of scaled coefficients. Next, an inverse discrete cosine transform is applied to the resulting matrix of scaled coefficients. Values in the resulting matrix are then right-shifted in order to derive a matrix of pixel component values. As described herein, the addition of the supplemental bias value to the DC coefficient reduces rounding errors attributable to this right-shifting. As a result, a final version of a digital media file decompressed using these techniques may more closely resemble an original version of a digital media file. |
申请公布号 |
WO2008002881(A2) |
申请公布日期 |
2008.01.03 |
申请号 |
WO2007US72039 |
申请日期 |
2007.06.25 |
申请人 |
QUALCOMM INCORPORATED;GARUDADRI, HARINATH;REZNIK, YURIY |
发明人 |
GARUDADRI, HARINATH;REZNIK, YURIY |
分类号 |
G06F17/14 |
主分类号 |
G06F17/14 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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