How to hardcode subtitles from stream with ffmpeg?

Question

I am trying to hardcode subtitles into a new video. The original video contains a subtitle stream, i.e, in total there vide, audio and subtitles (among other streams):

...
Stream #0:0(eng): Video: h264 (High 10), yuv420p10le(progressive), 1280x720, SAR 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 1k tbn, 4534142.86 tbc (default)
Stream #0:1(jpn): Audio: aac (HE-AAC), 48000 Hz, stereo, fltp
Metadata:
  title           : 2.0 AAC
Stream #0:2(eng): Subtitle: ass (default)
Metadata:
  title           : FFF
Stream #0:3: Attachment: ttf
Metadata:
  filename        : DFKanTeiRyu-XB.ttf
  mimetype        : application/x-truetype-font
...

I used the following command

ffmpeg -i input.mkv -c:v libx264  -c:a libmp3lame -c:s mov_text -map 0:0 -map 0:1 -map 0:2 output.mp4

which created an output file, but the subtitles were not hardcoded (and thus not shown/recognized by the stupid TV set).

How do I convert the video with the subtitles put into the video?

Answer 1

You can burn in subtitles directly from mkv using "subtitles" filter.

Just add -vf "subtitles='$PATH_TO_MKV':stream_index=$SUBTITLE_ID"

Example

ffmpeg -i input.mkv -c:v libx264 -vf "subtitles=input.mkv:stream_index=0" output.mkv

stream_index parameter is optional. It starts with zero, so stream_index=1 would select the 2nd subtitle stream in the container.

For more info, there's documentation for "subtitles" filter here http://ffmpeg.org/ffmpeg-filters.html#subtitles

And a general filtering guide at this link https://trac.ffmpeg.org/wiki/FilteringGuide

Answer 2

The way to do it is to extract the ass subtitles first:

ffmpeg -i input.mkv -c:s copy subtitle.ass

and then to 'burn' them into the video, as explained HERE:

ffmpeg -i video.avi -vf "ass=subtitle.ass" out.avi