发明名称 |
Preserving text quality in video encoding |
摘要 |
A video encoder receives a macro-block of an image frame, and determines whether the macro-block contains text. The video encoder computes a quantization parameter for quantizing the macro-block, with the quantization parameter computed to be smaller if the macro-block is determined to contain text. The video encoder encodes the macro-block using the quantization parameter. Text quality in the encoded macro-block is preserved. |
申请公布号 |
US9152875(B2) |
申请公布日期 |
2015.10.06 |
申请号 |
US201012777433 |
申请日期 |
2010.05.11 |
申请人 |
TEXAS INSTRUMENTS INCORPORATED |
发明人 |
Mathew Manu;Nagori Soyeb |
分类号 |
G06K9/32;H04N19/149;H04N19/61;H04N19/124;H04N19/14;H04N19/152 |
主分类号 |
G06K9/32 |
代理机构 |
|
代理人 |
Abyad Mirna;Cimino Frank D. |
主权项 |
1. A method of encoding image frames, each image frame containing a plurality of macro-blocks, each of the plurality of macro blocks formed of a plurality of pixels, the method comprising:
receiving a macro-block in an image frame; determining whether the macro-block contains text; computing a quantization parameter for quantizing the macro-block, wherein the quantization parameter is computed to be smaller than a predetermined value if the macro-block is determined to contain text, wherein the determining comprises calculating a gradient for each pixel in each of a plurality of sub-blocks in the macro-block, computing, corresponding to each of the plurality of sub-blocks, an edge pixel count value representing the number of pixels with gradients greater than a first threshold value, selecting the highest of the edge pixel count values determined by the computing, classifying the macro-block as containing text if the highest of the edge pixel count values selected by the selecting has a value between a second threshold value and a third threshold value; and encoding the macro-block using the quantization parameter. |
地址 |
Dallas TX US |