如何使用ffmpeg在视频中心添加透明水印? [英] How to add transparent watermark in center of a video with ffmpeg?

问题描述

我目前正在使用这些命令:

左上角ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=10:10 [out]" outputvideo.flv右上角ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=main_w-overlay_w-10:10 [out]" outputvideo.flv左下角ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=10:main_h-overlay_h-10 [out]" outputvideo.flv右下角ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=(main_w-overlay_w-10)/2:(main_h-overlay_h-10)/2 [out]" outputvideo.flv

如何在视频中心放置水印?

解决方案

使用

ffmpeg -i input.mp4 -i logo.png -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2";-codec:a copy output.mp4

或使用缩短的叠加选项:

overlay=(W-w)/2:(H-h)/2

左上

这是一个简单的方法，因为如果您没有提供叠加选项，默认设置是将图像放置在左上角.

此示例添加了 5 个像素的填充，因此图像不会接触边缘:

overlay=5:5

右上角

使用 5 个像素的填充:

overlay=main_w-overlay_w-5:5

或使用缩短的选项:

overlay=W-w-5:5

右下

使用 5 个像素的填充:

overlay=main_w-overlay_w-5:main_h-overlay_h-5

或使用缩短的选项:

overlay=W-w-5:H-h-5

左下

使用 5 个像素的填充:

overlay=5:main_h-overlay_h

或使用缩短的选项:

overlay=5:H-h-5

透明度/不透明度/alpha

使用格式和colorchannelmixer 过滤器:

ffmpeg -i input.mp4 -i watermark.jpg -filter_complex "[1]format=rgba,colorchannelmixer=aa=0.5[logo];[0][logo]overlay=(Ww)/2:(Hh)/2:format=auto,format=yuv420p"-c:a 复制 output.mp4

提高质量

在叠加中使用format=auto选项过滤器可以使 PNG 水印看起来更好:

ffmpeg -i input.mp4 -i watermark.png -filter_complex "overlay=5:H-h-5:format=auto,format=yuv420p";-c:a 复制 output.mp4

注意添加了 format 过滤器(是的，与选项同名，但是一个独立的过滤器)将其重置为 MP4 输出所需的 YUV 4:2:0.如果您不输出 MP4，请删除 ,format=yuv420p.

与主视频相关的缩放水印

使用 scale2ref 过滤器:

使徽标占主视频大小 10% (1/10) 的示例:

ffmpeg -i input.mp4 -i watermark.png -filter_complex "[1][0]scale2ref=w=oh*mdar:h=ih*0.1[logo][video];[video][logo]overlay=5:Hh-5"-c:a 复制 output.mp4

I am currently using these commands:

Top left corner
ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=10:10 [out]" outputvideo.flv

Top right corner
ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=main_w-overlay_w-10:10 [out]" outputvideo.flv

Bottom left corner
ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=10:main_h-overlay_h-10 [out]" outputvideo.flv

Bottom right corner
ffmpeg –i inputvideo.avi -vf "movie=watermarklogo.png [watermark]; [in][watermark] overlay=(main_w-overlay_w-10)/2:(main_h-overlay_h-10)/2 [out]" outputvideo.flv

How to place watermark center of the video ?

解决方案

Examples to add a watermark / logo image on video using the overlay filter.

Centered

ffmpeg -i input.mp4 -i logo.png -filter_complex "overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2" -codec:a copy output.mp4

or with the shortened overlay options:

overlay=(W-w)/2:(H-h)/2

Top left

This is the easy one because the default, if you provide no options to overlay, is to place the image in the top left.

This example adds 5 pixels of padding so the image is not touching the edges:

overlay=5:5

Top right

With 5 pixels of padding:

overlay=main_w-overlay_w-5:5

or with the shortened options:

overlay=W-w-5:5

Bottom right

With 5 pixels of padding:

overlay=main_w-overlay_w-5:main_h-overlay_h-5

or with the shortened options:

overlay=W-w-5:H-h-5

Bottom left

With 5 pixels of padding:

overlay=5:main_h-overlay_h

or with the shortened options:

overlay=5:H-h-5

Transparency / opacity / alpha

Example to make watermark 50% transparent using the format and colorchannelmixer filters:

ffmpeg -i input.mp4 -i watermark.jpg -filter_complex "[1]format=rgba,colorchannelmixer=aa=0.5[logo];[0][logo]overlay=(W-w)/2:(H-h)/2:format=auto,format=yuv420p" -c:a copy output.mp4

Improved quality

Using the format=auto option in the overlay filter can make PNG watermarks look better:

ffmpeg -i input.mp4 -i watermark.png -filter_complex "overlay=5:H-h-5:format=auto,format=yuv420p" -c:a copy output.mp4

Note the addition of the format filter (yes, same name as the option, but a standalone filter) to reset it to YUV 4:2:0 which is needed for MP4 output. Remove ,format=yuv420p if you are not outputting MP4.

Scale watermark in relation to main video

Use the scale2ref filter:

Example to make logo 10% (1/10) the size of the main video:

ffmpeg -i input.mp4 -i watermark.png -filter_complex "[1][0]scale2ref=w=oh*mdar:h=ih*0.1[logo][video];[video][logo]overlay=5:H-h-5" -c:a copy output.mp4

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