avconv：从图像上的子集制作视频

我正在尝试使用av​​conv在视频中制作一堆png，这些png的编号类似于 filename_< number> ，因此我通常只使用以下命令：

I am trying to make a bunch of png's into a video using avconv, the png's are numbered like filename_<number> so I usually just use the command:

avconv -r 10 -i filename_％d.png -b：v 1000k test.mp4

我现在想用文件 filename_8 - filename_50 $ c $的子集制作视频c>可以说，所以我已经将这些文件复制到新目录中并尝试了相同的命令，但是现在出现错误：

I now want to make a video from a subset of the files filename_8 - filename_50 lets say, so I've copied these files into a new directory and tried the same command but now I get the error:

filename_%d.png: No such file or directory

我认为这是因为编号没有不是从1开始？

I assume this is because the numbering doesn't start from 1?

如何实现？