AE视频输出文件大，按照下面的步骤进行转码就行了。
1、选择输出的流码尺寸，720P最好，不需要太大
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2、选择保存的视频格式，高清HD还是高清
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3、格式选择MP4，不要选其他
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4、安装并打开快剪辑软件
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5、打开软件之后，新建项目
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6、从本地导出你的AE视频
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7、直接点击保存导出
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8、在导出这个版块中设置尺寸、帧率、质量等
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9、设置之后，可以直接输出，这样占用内存就小了
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其实这个问题挺简单但是也挺复杂，首先说一下视频格式的问题吧。AE默认设置导出的是无损AVI文件，也就是未经任何压缩的文件，自然是非常大的了。标准720*576尺寸30不到就需要一个G甚至更多的空间，这么大的视频工作的时候自然是不便利的（如果需要网络传送的话），而且也会占用非常多的硬盘空间。
但是一般专业的影视后期工作者在AE输出的时候一般都会选择这个无损AVI，因为这个视频格式会完美的保留视频信息。所以我推荐在AE输出无损压缩，然后等需要的时候再到其他软件比如格式工厂里转码的方式来使视频变小。当然了，你也可以直接在AE里设置输出视频的格式和压缩方式。我给你画了一张图，标明了如何设置。
另外说一下，有空多学习一下视频格式或者镜头语言之类的基本功会对你的工作和学习帮助非常大，而现在很多老师只教软件，反而把这些基本功弃之不顾，完全是坑害学生。
