在 FFMPEG 中裁剪和转换时创建缩略图文件

Question

I'm currently using the following:

ffmpeg -y -i input.mov -i watermark.png -filter_complex "[0:v]crop=iw-0:ih-440,scale=480:640[bg];[bg][1:v]overlay=W-w-10:H-h-10" output.mp4

To resize, crop and watermark a video, all is working perfectly, however I'd like to grab a screenshot midway through. I've tried adding:

-qscale:v 2 thumbnail.jpg

After the input.mov, however it then ruins the rest of the script. Bit of a noob to FFMpeg.

EDIT:

The following:

ffmpeg -y -i input.mov -vframes 1 -q:v 2 thumbnail.jpg -i watermark.png -filter_complex "[0:v]crop=iw-0:ih-440,scale=480:640[bg];[bg][1:v]overlay=W-w-10:H-h-10" output.mp4

Creates the thumbnail and creates output.mp4, but not cropped or with the thumbnail. I'm assuming the thumbnail creation needs to go in that same sequence?

Answer 1

If the 10th frame is fine, then you can use

ffmpeg -y -i input.mov -i watermark.png -filter_complex "[0:v]crop=iw-0:ih-440,scale=480:640[bg];[bg][1:v]overlay=Ww-10:Hh-10,split=2[v][pic];[pic]trim=start_frame=10[pic]" -map "[v]" -map 0:a? output.mp4 -vframes 1 -map "[pic]" out.jpg

If you know the midway duration, eg 12.5s, then your trim arg can be trim=st=12.5

(If you're on a shell where [] are special characters, use single quotes for mapping)