Draw a text string or text from a specified file on top of a video, using the libfreetype library.
To enable compilation of this filter, you need to configure FFmpeg with --enable-libfreetype.
To enable default font fallback and the font option you need to configure FFmpeg with --enable-libfontconfig.
To enable the text_shaping option, you need to configure FFmpeg with --enable-libfribidi.
ffmpeg中用drawtext filter为视频添加文字。
如果想要使用drawtext，编译时需要加上--enable-libfreetype。
如果要选择多种字体，需要加上--enable-libfontconfig。
如果还需要字体变形，需要加上--enable-libfribidi。
drawtext 参数简介
-vf drawtext=fontcolor=white:fontsize=40:fontfile=msyh.ttf:text='Hello World':x=0:y=100
fontcolor 文字的颜色
可在https://ffmpeg.org/ffmpeg-utils.html#color-syntax中查询支持的颜色。fontsize 字体大小
The font size to be used for drawing text. The default value of fontsize is 16.
默认16
- fontfile 字体库文件
The font file to be used for drawing text.
The path must be included.
This parameter is mandatory(强制的) if the fontconfig support is disabled.
- text 要加的文字
The text string to be drawn. The text must be a sequence of UTF-8 encoded characters. This parameter is mandatory if no file is specified with the parameter textfile.
- textfile
A text file containing text to be drawn. The text must be a sequence of UTF-8 encoded characters.
This parameter is mandatory if no text string is specified with the parameter text.
If both text and textfile are specified, an error is thrown.
通过文件指定要添加的字体。
text and textfile不能同时存在。
- x=0:y=100 在什么坐标加文字
The expressions which specify the offsets where text will be drawn within the video frame. They are relative to the top/left border of the output image.
The default value of x and y is "0".
相对于左上角的坐标。
默认x=0， y=0
通过text添加文字
ffmpeg -i in.mp4 -vf drawtext=fontcolor=white:fontsize=40:fontfile=msyh.ttf:text='Hello World':x=0:y=100 -vframes 20 -y out.mp4
通过textfile添加文字
ffmpeg -i in.mp4 -vf drawtext=fontcolor=white:fontsize=40:fontfile=msyh.ttf:textfile='test.txt':x=0:y=20 -vframes 20 -y out.mp4
其中test.txt中的内容为:
Good Moring
Hello World
中华人民共和国
