You can burn text subtitles with one of two filters: `subtitles` or `ass`.

== `subtitles` filter ==
As of Nov 29, 2012 you can also simply use the [http://ffmpeg.org/ffmpeg.html#subtitles-1 subtitles filter]:

{{{
ffmpeg -i video.avi -vf subtitles=subtitle.srt out.avi
}}}

This filter requires `ffmpeg` to be compiled with `--enable-libass` (if you are building FFmpeg yourself, look for the `libass-dev` package on Debian-like distributions).

== `ass` filter ==
Using FFmpeg's [http://ffmpeg.org/ffmpeg.html#ass ass video filter] (see Wikipedia for [http://en.wikipedia.org/wiki/SubStation_Alpha#Advanced_SubStation_Alpha Advanced SubStation Alpha]), we can draw text of the subtitles into the movie, like this:
{{{
ffmpeg -i video.avi -vf "ass=subtitle.ass" out.avi
}}}

As with the `subtitles` filter, this filter requires `ffmpeg` to be compiled with `--enable-libass`.

If your subtitle is in `SubRip`, `MicroDVD` or any other supported text subtitles, you have to convert it to ASS before using the filter:
{{{
ffmpeg -i subtitle.srt subtitle.ass
}}}

For Windows users [http://ffmpeg.zeranoe.com/forum/viewtopic.php?f=10&t=318&start=20 this link] may be useful, as you have to setup font paths just right to get libass to work

== picture based subtitles ==

You can burn "picture based" subtitles into a movie as well (for instance, dvdsub is a type of picture based overlay subtitles), by using the overlay filter to overlay the images. Here is an example - an MKV with dvdsub subtitles in a separate stream:

{{{
ffmpeg -i input.mkv -filter_complex "[0:v][0:s]overlay[v]" -map [v] -map 0:a <output options> output.mkv
}}}

If you have multiple subtitle streams, you can select which one to use by replacing `[0:s]` with `[0:s:0]` to select the first subtitle stream or `[0:s:1]` to select the second subtitle stream, and so on. See also [http://ffmpeg.org/ffmpeg.html the official documentation]; search for "hardcode".