According to w:User:Pietro Shakarian:

It fell into the public domain because it was not renewed after its 25-year copyright term. Films and other copyrighted materials in the United States are supposed to be renewed 25 years after their release. I know this because I've researched in Walter E. Hurst's "Film Superlist" - a guide to every single American film copyrighted and renewed. Pretty much all the films released in 1930 that I looked up were renewed in 1955. If a film or material is failed to be renewed, then it falls into the public domain. Such was the case with "Oceantics".

本作品在美國屬於公有領域，是因為該作品是在1929與1963年之間出版，沒有在該作品增加著作權聲明，且沒有進行著作權更新。除非此作品之作者已經過世一段時間，並達到公有領域所要求的條件，這類美國作品在其他不適用較短期限法則的國家或地區屬於有著作權狀態，如加拿大（作者過世後70年）、中國大陸（作者過世後50年，港澳除外）、德國（作者過世後70年）、墨西哥（作者過世後100年）、瑞士（作者過世後70年）與其他已簽署個別協議的國家。更多資訊請參考Commons:Hirtle chart。 العربية ∙ Deutsch ∙ English ∙ español ∙ français ∙ galego ∙ italiano ∙ 日本語 ∙ 한국어 ∙ македонски ∙ português ∙ português do Brasil ∙ русский ∙ sicilianu ∙ slovenščina ∙ українська ∙ 简体中文 ∙ 繁體中文 ∙ +/−