convert mp4 to wav

concat wav files

sox short1.wav short2.wav short3.wav long.wav

Converting MP4 to gif

To convert the entire video to GIF, use the following command:

`ffmpeg -i small.mp4 small.gif`

To convert just a portion of a video clip to GIF, use the following command:

`ffmpeg -t 3 -ss 00:00:02 -i small.webm small-clip.gif`

The snippet above directs ffmpeg to create a GIF 3 seconds long starting at 2 seconds into the video. The default conversion doesn't appear to be high quality, so you can configure the bit rate via another parameter:

`ffmpeg -i small.mp4 -b 2048k small.gif`

Convert GIF to Video

The command is quite simple:

`ffmpeg -f gif -i animation.gif animation.mp4`

You can use this same command format to convert to other video formats:

ffmpeg -f gif -i animation.gif animation.mpeg
ffmpeg -f gif -i animation.gif animation.webm

ffmpeg and ImageMagick are awesome media utilities which you should take some time to check out if you have any questions about how to get something done!

optimize

gifsicle to scale down the image to a smaller size

I used ffmpeg -i foo.mp4 -r 5 -vf scale=270:-1 foo.gif , where -r 5 cuts it to 5 frames per second, and -vf scale=270:-1 scales the output to a width of 270 pixels and a height that matches the aspect ratio.

参考

1. https://superuser.com/questions/587511/concatenate-multiple-wav-files-using-single-command-without-extra-file