BUSAN: Kakao Talk, a popular mobile messaging app in South Korea, must have annoyed its share of moviegoers.

Asia's largest film festival is trying to ensure that message-addicted smartphone users don't look at the chat app during screenings.

The 20th Busan International Film Festival is showing a short clip before every movie with instructions not to check Kakao Talk messages because the glowing screen can disturb others.

The clip, which also lists other points of movie etiquette, was made by Kakao Friends, a festival sponsor that makes merchandising items with emoticon characters from Kakao Talk.

The new cinema etiquette is a glimpse into a future in which phone calls are eschewed in favor of sending messages and emoticons, especially among young people.

However, the festival message is only in Korean. In English, it simply asks audiences to turn off their phones.

In Asia, mobile messenger apps are so popular that they not only have taken over phone calls and text messages but are also widely used for other daily tasks such as taxi hailing and sending money. Many Korean smartphone users belong to multiple chat groups in Kakao Talk and are constantly exchanging messages with colleagues, friends and families.

The 10-day film festival runs until Saturday.