<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
How do I reverse a video with ffmpeg?<|im_end|>
<|im_start|>assistant
You can use the following command to reverse a video with ffmpeg:
```sh
ffmpeg -i my_video.mp4 -vf reverse my_video_reversed.mp4
```
Note that this command reverses only the video, not the audio. If you'd like to reverse both the video and the audio, use the following command:
```sh
ffmpeg -i my_video.mp4 -vf reverse -af areverse my_video_reversed.mp4
```<|im_end|>
<|im_start|>user
How do I also skip the first 30 seconds of the video?<|im_end|>
<|im_start|>assistant
To skip the first 30 seconds of the video and then reverse it, you can use the -ss option to set the start time for processing the input video. Here's the modified command:
```bash
ffmpeg -ss 30 -i input_video.mp4 -vf "reverse" -af "areverse" output_video_reversed.mp4
```

In this command, `-ss 30` tells ffmpeg to start processing the input video 30 seconds in, skipping the first 30 seconds. The rest of the command works the same as previously described, reversing both the video and audio streams and saving the result as a new file named output_video_reversed.mp4.<|im_end|>