同時再生BGMプレイヤー is a free multimedia app developed by Yuki Kubota for iPhone. This app allows users to play background music (BGM) while their other content, such as YouTube videos or audiobooks, continues playing.

With 同時再生BGMプレイヤー, users can listen to music simultaneously with their audiobooks without interrupting the playback. This is especially useful when users want to enhance their audiobook experience or add some music to their sleep playlist.

The app also features a volume adjustment function, allowing users to fine-tune the volume with 100 different levels. By tapping the speaker icons on the top and playback screens, users can easily adjust the volume to their preference.

Additionally, 同時再生BGMプレイヤー includes a "Link Play" feature that synchronizes the BGM playback with the main content, such as YouTube or audiobooks. When the main content pauses, the BGM also stops, and when the main content resumes, the BGM playback starts again. This creates a seamless experience as if the BGM was originally part of the content.

The app comes with a variety of pre-installed music genres that are perfect for audiobooks, including jazz, Lo-Fi, peaceful sleep, and genre-specific options like fantasy and mystery. Users can also choose their own music from their iPhone's library to use as BGM by selecting it from the BGM selection screen.

Please note that the music played through this app cannot be controlled from the iPhone's control screen. If you have any additional features or genres you would like to see in the app, please leave a review with your suggestions.