provide time period in ffmpeg drawtext filter

问题

I am trying to add text to video using ffmpeg and wants text to appear for a given period of time. I am trying to use DrawText filter but don't know how to provide time period for this filter. Can Anybody please help me.

Thanks

回答1:

The drawtext video filter has timeline editing support (see the output of ffmpeg -filters). This can evaluate an expression and allows you to provide the time(s) of when the filter should be enabled.

This example will enable the filter from 12 seconds to 3 minutes:

ffmpeg -i input.mp4 -vf "drawtext=enable='between(t,12,3*60)':fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'" -acodec copy output.mp4

The audio was stream copied in this example.

If you do not have timeline editing support then you will need to get a newer version. You can simply download a Linux build of ffmpeg or follow a step-by-step guide to compile ffmpeg.

Also see the FFmpeg and x264 Encoding Guide.

来源：https://stackoverflow.com/questions/21354421/provide-time-period-in-ffmpeg-drawtext-filter