I’ve finally found an answer.
There is such option as -sn which disables subtitles decoding from input stream. Also there are analogous options for audio and video decoding: -an and -vn respectively.
It also turned out that there is another way to achieve this. One may use the -map option to select which streams are to be decoded. So omitting the subtitles stream among the -map options does the job.
For example, if one has a movie file with 3 streams:
- Stream 0: video
- Stream 1: audio
- Stream 2: subtitles
the converting command for FFmpeg may look as follows:
ffmpeg -i <input file> -sn -vcodec <video codec> -acodec <audio codec> <output file>
or
ffmpeg -i <input file> -vcodec <video codec> -acodec <audio codec> -map 0:0 -map 0:1 <output file>
The former command line deselects the subtitles stream (probably all of them, if there are several) while the latter one selects only the necessary streams to decode.