I want to convert a gif file to a video with ffmpeg. I'm using:

```
ffmpeg -y -i /gif/583fd7661b46d.gif -strict -2 -an -b:v 32M /gif/mp4/583fd7661b46d.avi

```

The duration of my gif in photoshop is 27 seconds, but the duration of the video "583fd7661b46d.avi" generated is 15 seconds. How can I get the same duration of my gif in the video generated?