Embedding Subtitles in a Video File

The easiest way is with the MP4Box tool.

First install the GPAC

sudo apt-get install gpac

Then you can use the following command

MP4Box  -add  inputfile.srt  target.mp4

More about this command in this link.

Another Option to do so:

apt-get install mkvtoolnix

mkvmerge -o output.mkv video.mp4 subtitles.srt

or

mkvmerge -o output.mp4 video.mp4 subtitles.srt

In the case you need subtitle conversion:

ffmpeg -i file.srt file.vtt

or

ffmpeg -i file.vtt file.srt

More info in the ffmpeg manual ("man ffmpeg").

How to download only subtitles of videos using youtube-dl

Options:
--write-sub                      Write subtitle file
--write-auto-sub                 Write automatic subtitle file (YouTube only)
--all-subs                       Download all the available subtitles of the video
--list-subs                      List all available subtitles for the video
--sub-format FORMAT              Subtitle format, accepts formats preference, for example: "srt" or "ass/srt/best"
--sub-lang LANGS                 Languages of the subtitles to download (optional) separated by commas, use IETF language tags like 'en,pt'

So for example, to list all subs for a video:

youtube-dl --list-subs https://www.youtube.com/watch?v=Ye8mB6VsUHw

To download all subs, but not the video:

youtube-dl --all-subs --skip-download https://www.youtube.com/watch?v=Ye8mB6VsUHw

The other way, this really works but makes the file bigger:

mencoder movie.avi -sub movie.srt -o movie.hardsubs.avi -oac copy -ovc lavc -lavcopts vbitrate=1200

Source: Ubuntu Forums.


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