使用FFmpeg为视频添加文字时出错：无空格文字可正常添加

Hey there! This is such a common pitfall when working with FFmpeg's drawtext filter—let's get this sorted out quickly.

The Root Cause #

When you include spaces in your text without proper quoting or escaping, your shell (like bash, zsh, or Windows Command Prompt) treats the space as a parameter separator. That means FFmpeg sees something like Hello as the value for text=, and then World gets interpreted as an unexpected extra parameter for the filter, which triggers the error.

Solutions #

Here are the two most reliable ways to fix this:

1. Wrap the text value in single quotes (preferred for Linux/macOS)
   Enclose the entire text string inside single quotes within the drawtext filter's argument. This tells the shell to pass the whole string as a single value.
   Example correct command:

   ffmpeg -i input.mp4 -vf "drawtext=text='Hello World':fontsize=24:x=50:y=50" output.mp4
   

2. Escape spaces with a backslash
   If you prefer not to use quotes, you can add a backslash before each space to tell the shell to treat it as part of the string instead of a separator.
   Example:

   ffmpeg -i input.mp4 -vf "drawtext=text=Hello\ World:fontsize=24:x=50:y=50" output.mp4
   

3. Double quotes for Windows Command Prompt/PowerShell
   On Windows, single quotes might not work as expected—use double quotes instead for the text value (note the double double-quotes to escape inner quotes for the shell):

   ffmpeg -i input.mp4 -vf "drawtext=text=""Hello World"":fontsize=24:x=50:y=50" output.mp4
   

Script Variable Tip #

If you're using variables in a script (like a bash script), make sure you quote the variable when passing it to drawtext too. For example:

MY_TEXT="Hello Stack Overflow"
ffmpeg -i input.mp4 -vf "drawtext=text='$MY_TEXT':fontsize=24" output.mp4

This ensures that even if the variable has spaces, it's passed as a single, intact value to the filter.

内容的提问来源于stack exchange，提问作者robert tamunoemi