Universal Studios also began their long line of "The Land Before Time" sequels that same year. By 1994 an average of six new direct-to-video films appeared each week. Erotic thrillers and R-rated action films were the two most successful genres. Family films became more important than such genres later in the 1990s, as retailers stocked more copies of blockbuster films instead of more titles. According to the "Los Angeles Times":  Some horror films that are unsuccessful in theaters, like "Witchcraft", begin successful direct-to-video series. Studios may also release sequels or spin-offs to a successful live action film straight to DVD, due to a lack of budget in comparison to the original. An example is the "Behind Enemy Lines" series of films. During the Golden Age of Porn in the 1970s, many pornographic films were released in theatres, some of which became some of the highest-grossing films in their release years, and in the pornography industry altogether. Toward the 1980s, porn began to shift to video release, because video allowed the producers to work on extremely low budgets and dispense with some film production elements, like scripts, and the increased privacy and convenience of the format change were preferred by the target market. During the late 1990s and onward, pornographers began releasing content through paysites on the Internet. Occasionally, a studio that makes a movie that was prepared as a direct-to-video film will release it theatrically at the last minute due to the success of another film with a similar subject matter or an ultimate studio decision. "" is an example of this. However, despite the movie's critically acclaimed success, its box-office performance was very poor, which has been attributed to its last minute decision to be released theatrically. The film had much better commercial success in its subsequent home video releases. Other times, a direct-to-video movie may get a limited theatrical screening in order to build excitement for the actual release of the video such as was done for 2010's "", and "Planet Hulk", 2016's ""  or 2013's "Sharknado". As DVDs gradually replaced VHS videocassettes, the term "direct-to-DVD" replaced "direct-to-video" in some instances. However, the word "video" does not necessarily refer to videocassettes. Many publications continue to use the term "direct-to-video" for DVDs or Blu-rays. Both disc-based release types may also be referred to as "direct-to-disc".