[FFmpeg-user] Burning DVD subtitles into video using overlay filter not working

[Paul B Mahol]

On 8/29/13, Thierry Lelegard <thierry at lelegard.fr> wrote:
> Hello all,
>
> Sorry, yet another "subtitles" + "not working" topic ;-)
>
> I have read the manual and a lot of posts about burning DVD subtitles into
> the video stream using the overlay filter. I cannot make it work on a small

What manual tells that for burning subtitles one should use overlay filter?

> file. To make it clear, I want to remove the subtitles as an independent
> stream and I want to burn/hardcode/encrust/whatever the subtitles into the
> video images.
>
> I have a small Matroska file (20 seconds) with one video stream, one audio
> stream and one DVD subtitle stream:
>
> Stream #0:0: Video: h264 (High), yuv420p, 1280x536 [SAR 1:1 DAR 160:67],
> 23.98 fps, 23.98 tbr, 1k tbn, 47.95 tbc (default)
> Stream #0:1: Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s
> (default)
> Stream #0:2: Subtitle: dvd_subtitle (default)
>
> The subtitles are correctly displayed when the file is played using vlc
> and mplayer. So, I assume that the subtitles data are correct.
>
> To make a test, I try to burn the subtitles into the video using the
> following
> command (full output at end of mail).
>
> ffmpeg -i f.mkv -filter_complex "[0:v][0:s]overlay" -codec:v mpeg2video
> -codec:a mp2 -ac 2 -y f.hardsubs.mpg

This can not work as overlay filter forks with video frames only.

>
> It seems the simplest possible command to do. Please don't comment on video
> quality, it is just a test to see if the subtitles are burnt into the
> video.
> The resulting video does not contain subtitles.
>
> I tried explicit x,y placement in the overlay and other options without more
> luck.
>
> Any idea? So many people report successful DVD subtitles processing using
> that type of command. What could be wrong?

Perhaps you should start reading documentation.