FFmpeg - 如何缩放视频然后应用水印？ [英] FFmpeg - How to scale a video then apply a watermark?

问题描述

我试图缩放视频，使其总是512宽，其中高度与原始视频成比例的变化。
一旦缩放，我想要对视频应用水印/叠加层，因此视频将缩放，但水印不会。

我能够实现每个这些分别使用以下过滤器：

比例

  -vfscale = 512：-1
  

水印

  -vfmovie = watermark.png [watermark]; [in] [watermark] overlay =（main_w- overlay_w）/ 2：（main_h-overlay_h）/ 2 [out]
  

自己。

然而，当尝试组合这两个时，我有点麻烦。

参数当然不起作用，因为它将覆盖另一个。

Ive尝试：

 code> -vfscale = 512：-1，movie = watermark.png [watermark]; [in] [watermark] overlay =（main_w-overlay_w）/ 2：（main_h-overlay_h）/ 2 [ 
  

我的想法是他的比例将首先被应用于水印，但是我所得到的只是一个错误

为电影过滤器指定的输入太多。 / p>

打开过滤器错误

然后更改，导致：

简单过滤器'scale = 512：-1;
movie = watermark.png
[水印];

打开过滤器时出错！

我想我需要做更多的一些过滤器，但是我努力

任何想法任何人？

非常感谢提前。

解决方案

感谢@DiJuMx和@LordNeckbeard，你们都让我更接近我的解决方案。我没有尝试过filter_complex选项，但它肯定看起来更简单。

我发现工作的解决方案是：

  -vfmovie = watermark.png [watermark]; [in] scale = 512：trunc（ow / a / 2）* 2 [scale]; [scale] [watermark] =（main_w-overlay_w）/ 2：（main_h-overlay_h）/ 2 [out]
  

Ive在尺度上替换了-1，因为在缩放时可能会导致视频高度不均匀的像素数量，从而导致编码错误。

Im trying to scale a video so that it is always 512 wide where the height changes in proportion to the original video. Once scaled, I then want to apply a watermark/overlay to the video, therefore the video will scale but the watermark wont.

I am able to achieve each of these separately using the following filters:

Scale

-vf "scale=512:-1"

Watermark

-vf "movie=watermark.png [watermark]; [in][watermark] overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 [out]"

They work successfully on their own.

However when trying to combine the two, Im having a bit of trouble.

Having both as parameters of course does not work as one will override the other.

Ive tried:

-vf "scale=512:-1,movie=watermark.png [watermark]; [in][watermark] overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 [out]"

my thinking was that the scale would be applied first then the watermark but all I get is an error

Too many inputs specified for the "movie" filter.

Error opening filters!

Then changing the , to a ; resulted in:

Simple filtergraph 'scale=512:-1; movie=watermark.png [watermark]; [in][watermark] overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 [out]' does not have exactly one input and output.

Error opening filters!

I presume I need to do something more with filterchains but Im struggling to figure it out.

Any ideas anyone?

Many thanks in advance.

解决方案

Thank you to both @DiJuMx and @LordNeckbeard, you both got me closer to my solution. Ive not tried the filter_complex option yet but it certainly looks simpler.

The solution I found to work is:

-vf "movie=watermark.png [watermark]; [in]scale=512:trunc(ow/a/2)*2 [scale]; [scale][watermark] overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 [out]"

Note that Ive replaced the -1 in the scale as that had the potential to cause an uneven number of pixels in the height of the video when scaling which would then cause encoding errors.

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