使用ffmpeg在纯背景颜色上叠加timelapse视频 [英] Overlay timelapse video on solid background colour using ffmpeg

问题描述

我有一个名为homescreen000001.png，homescreen000002.png等的主页屏幕截图，我正在尝试使用ffmpeg为这些图像创建一个延时视频.

I've got a load of screenshots of a homepage that are named homescreen000001.png, homescreen000002.png, etc and I'm trying to create a time-lapse video of these images using ffmpeg.

当我运行以下命令时，它已经可以正常工作了:

I've got it working in general when I run the following:

ffmpeg -f image2 \
       -i ~/Desktop/homescreen%06d.png \
       -r 0.5 \
       -s 1440x900 \ 
       -b:v 1M \
       -vcodec libx264 \ 
       -pix_fmt yuv420p \
       ~/Desktop/timelapse.mp4

但是，事实证明某些图像具有透明背景，因此背景在这些图像上显示为黑色.

However, it turns out that some of the images have transparent backgrounds so the background is showing up as black on those images.

我想要一个白色背景，所以我一直在尝试使用ffmpeg进行如下设置:

I'd like a white background so I've been trying to set that up using ffmpeg as follows:

ffmpeg -f image2 \
       -loop 1 \
       -i ~/Desktop/whitebg.png \
       -i ~/Desktop/homescreen%06d.png \
       -filter_complex overlay \ 
       -r 0.5 \
       -s 1440x900 \ 
       -b:v 1M \
       -vcodec libx264 \ 
       -pix_fmt yuv420p \
       ~/Desktop/timelapse.mp4

这里whitebg.png是2px x 2px png的白色背景，仅此而已.

Here whitebg.png is 2px x 2px png with a white background, and that's it.

此ffmpeg命令产生的视频非常小(文件大小)，只是一个白色背景.

This ffmpeg command produces a really tiny (in file size) video that's just a white background.

谁能解释我如何使用ffmpeg将图像作为延时视频覆盖在白色背景上?

Can anyone explain how I can overlay the images as a time-lapse video over a white background using ffmpeg?

推荐答案

您可以使用颜色过滤器作为背景:

ffmpeg -f lavfi -i color=c=white:s=1920x1080:r=24 -framerate 24 -i input_%04d.png -filter_complex "[0:v][1:v]overlay=shortest=1,format=yuv420p[out]" -map "[out]" output.mp4

另请参阅:

• 图像解复用器文档
• 重叠式过滤器文档
• 如何定位与ffmpeg重叠?

• image demuxer documentation
• overlay filter documentation
• How to position overlay with ffmpeg?

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