To study English from movies is consistent with the methodology of praxis. GNU/Linux provides us a bunch of tools to extract audio and subtitle from videos as well as play the music file with scrolling lyrics. Using this study mode, we can focus on the English pronunciation, vocabulary and wording adopted in the script.

Generate lyrics from subtitle

  1. Extract the audio from a video using ffmpeg, for example

     ffmpeg -i movie-file-name -vn -ar 44100 -ac 2 -b:a 192k -f mp3 movie-audio.mp3

    Here, -i specifies the input video file name, -vn disables the video, -ar specifies the audio sampling frequency in Hz, -ac specifies the number of audio channels, -b:a sets the audio bitrate in kbit/s and -f specifies the file format.

  2. Extract the embedded subtitle from mkv

    Install mkvtoolnix and mkvtoolnix-gui using apt-get. After opening a mkv file in mkvtoolnix-gui, select the English subtitle only and export it as a mks file. If the subtitle is an independent file, this step can be skipped.

    mkvtoolnix-gui

  3. Convert the subtitle file to lyrics using ffmpeg

     ffmpeg -i subtitle-file-name subtitle.lrc

Compile and install the tool for displaying lyrics

  1. Clone osdlyrics from GitHub

     git clone https://github.com/osdlyrics/osdlyrics.git
  2. Install the following dependencies using apt-get
    • intltool
    • libdbus-glib-1-dev and libdbus-glib-1-dev-bin
    • python3-future and python3-pycurl

  3. Enter the cloned directory, compile and install osdlyrics.

     ./autogen.sh
 ./configure PYTHON=/usr/bin/python3
 make -j4
 sudo make install

    However, after the installation, osdlyrics cannot be started reporting the following message, which indicates the error is caused by osdlyrics-daemon.

    Error: in function _start_daemon_cb: ol_main.c[769] Unable to start daemon: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ChildExited: Process org.osdlyrics.Daemon exited with status 1

    By manually running osdlyrics-daemon, we can see that the Python module osdlyrics cannot be found, even though it has been installed to /usr/local/lib/python3.7/site-packages. This is because the default path for searching packages by Python 3.7 should be /usr/local/lib/python3.7/dist-packages instead of ...site-packages. Hence, creating a symbolic link under this path which points to /usr/local/lib/python3.7/site-packages/osdlyrics solves the problem.

    Traceback (most recent call last): File “/usr/local/lib/osdlyrics/daemon/main.py”, line 27, in from osdlyrics import PACKAGE_VERSION ModuleNotFoundError: No module named 'osdlyrics'

  4. Run osdlyrics from the command line and select VLC as the associated music player. Even though my favorite music player Audacious is claimed to be supported, it actually does not work properly with osdlyrics at the moment. The command used by osdlyrics to start VLC is

     /usr/bin/vlc --started-from-file %U

Now the English movie audio can be played with a synchronously scrolling lyrics and a snapshot is given below. N.B. We can use VLC’s A-B mode to repeatedly listen to a fragment, which is very helpful for us to imitate the original pronunciation.

Scrolling lyrics

Scrolling lyrics