The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)

The audience watches the Beethoven's Fidelio in separate boxes during the Film Festival at Vienna's Rathausplatz, Austria, on July 4, 2020. This year's Film Festival at Vienna's Rathausplatz opened on Saturday. (Xinhua/Guo Chen)