📄 中华视频网 - 纵览最新视频编码标准h_264-avc.htm
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face=宋体>运动矢量可跨越图像边界：在以前的标准中，运动矢量限制在已编码参考图像的内部。图像边界外推法作为可选技术首次出现在</FONT></SPAN><SPAN
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face=宋体>中。</FONT></SPAN><SPAN
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face=宋体>多参考图像运动补偿：在</FONT></SPAN><SPAN lang=EN-US
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face=宋体>及以前的标准中，</FONT></SPAN><SPAN lang=EN-US
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face=宋体>帧只使用一帧，</FONT></SPAN><SPAN lang=EN-US
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face=宋体>帧只使用两帧图像进行预测。</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">H.264/AVC</SPAN><SPAN
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face=宋体>使用高级图像选择技术，可以用以前已编码过且保留在缓冲区的大量的图像进行预测，大大提高了编码效率。</FONT></SPAN><SPAN
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face=宋体>消除参考图像顺序和显示图像顺序的相关性：在以前的标准中，参考图像顺序依赖显示图像顺序，</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">H.264/AVC</SPAN><SPAN
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face=宋体>消除了该限制，可以任意选择。</FONT></SPAN><SPAN
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face=宋体>消除参考图像与图像表示方法的限制：在以前的标准中，</FONT></SPAN><SPAN
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face=宋体>帧图像不能作为预测图像，</FONT></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">H.264/AVC
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face=宋体>在很多情况可以利用</FONT></SPAN><SPAN lang=EN-US
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face=宋体>帧图像作为参考。</FONT></SPAN><SPAN
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face=宋体>加权预测：</FONT></SPAN><SPAN lang=EN-US
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H.264/AVC</SPAN><SPAN
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face=宋体>采用新技术，允许加权运动补偿预测和偏移一定量。在淡入淡出场景中该技术极大提高编码效率，该技术还可用于其他多种用途。</FONT></SPAN><SPAN
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face=宋体>改善</FONT></SPAN><SPAN lang=EN-US
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face=宋体>跳过</FONT></SPAN><SPAN lang=EN-US
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face=宋体>和</FONT></SPAN><SPAN lang=EN-US
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face=宋体>直接</FONT></SPAN><SPAN lang=EN-US
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face=宋体>运动推测：在以前的标准中，预测编码图像的</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; mso-ascii-font-family: Courier; mso-hansi-font-family: Courier"><FONT
face=宋体>跳过</FONT></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">”</SPAN><SPAN
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face=宋体>区不能有运动。当编码有全局运动的图像时，该限制非常有害。</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">H.264/AVC</SPAN><SPAN
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face=宋体>对</FONT></SPAN><SPAN lang=EN-US
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style="FONT-SIZE: 10.5pt; mso-ascii-font-family: Courier; mso-hansi-font-family: Courier"><FONT
face=宋体>跳过</FONT></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">”</SPAN><SPAN
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face=宋体>区的运动采用推测方法。对双预测的</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">B</SPAN><SPAN
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face=宋体>帧图像，采用高级运动预测方法，称为</FONT></SPAN><SPAN
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style="FONT-SIZE: 10.5pt; mso-ascii-font-family: Courier; mso-hansi-font-family: Courier"><FONT
face=宋体>直接</FONT></SPAN><SPAN lang=EN-US
style="FONT-SIZE: 10.5pt; FONT-FAMILY: Courier">”</SPAN><SPAN
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face=宋体>运动补偿，进一步改善编码效率。</FONT></SPAN><SPAN
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