如何提取第一帧并恢复为ffmpeg的图像？ [英] How to extract the 1st frame and restore as an image with ffmpeg?

问题描述

任何人都知道这个伎俩？

如何安装ffmpeg？ yum install mpeg 只返回这个：

  ==== ==================================================符合：mpeg =============== ================================================== ===================== 
 libiec61883.i386：IEEE1394的流媒体库
 libiec61883.x86_64：IEEE1394的流媒体库
 qffmpeg-devel.i386：qffmpeg 
 qffmpeg-devel.x86_64的开发包：qffmpeg 
的开发包qffmpeg-libs.i386：qffmpeg 
的库库qffmpeg-libs.x86_64：库qffmpeg 
  

解决方案

它在联机帮助页上：

 
 *您可以从视频中提取图像，或从许多
图像创建视频：
 
从一个视频：
 
 ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-％03d.jpeg 
 
这将从每秒提取一个视频帧视频将
输出到名为foo-001.jpeg，foo-002.jpeg等的文件中。图像
将被重新缩放以适应新的WxH值。 
 
如果要仅提取有限数量的帧，可以使用
上述命令与-vframes或-t选项，或
组合 - ss从某个时间点开始提取。 
 

但当然你必须先安装它。我在Debian上，不要使用yum。

[更新为其他问题]

<$ p $对于* .avi中的avi，p>
i = 1
做
ffmpeg -i $ avi -vframes 1 -f image2 /tmp/$i.jpg; i = $（（i + 1））
done


测试和工作。 p>

[更新为另一个问题...]

  
 for flv in * .flv; do 
 ffmpeg -i $ flv -vframes 1 -f image2 $ {flv %%。flv} .jpg 
 done 
  

Anyone knows the trick?

And how to install ffmpeg ? yum install mpeg only returns this:

======================================================================================== Matched: mpeg ========================================================================================
libiec61883.i386 : Streaming library for IEEE1394
libiec61883.x86_64 : Streaming library for IEEE1394
qffmpeg-devel.i386 : Development package for qffmpeg
qffmpeg-devel.x86_64 : Development package for qffmpeg
qffmpeg-libs.i386 : Libraries for qffmpeg
qffmpeg-libs.x86_64 : Libraries for qffmpeg

解决方案

It's on the manpage:

* You can extract images from a video, or create a video from many
       images:

       For extracting images from a video:

               ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg

       This will extract one video frame per second from the video and will
       output them in files named foo-001.jpeg, foo-002.jpeg, etc. Images
       will be rescaled to fit the new WxH values.

       If you want to extract just a limited number of frames, you can use
       the above command in combination with the -vframes or -t option, or in
       combination with -ss to start extracting from a certain point in time.

But of course you have to install it first. I'm on Debian and don't use yum.

[update for the other question]

i=1
for avi in *.avi; do
 ffmpeg -i $avi -vframes 1 -f image2 /tmp/$i.jpg; i=$((i+1))
done

Tested and works.

[update for yet another question...]

for flv in *.flv; do
 ffmpeg -i $flv -vframes 1 -f image2 ${flv%%.flv}.jpg
done

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