Mood: The mood of this video appears to be lighthearted and playful, with a theme of music and creativity. The use of bright colors and bold fonts suggests a fun and energetic vibe. The title 'Happy Ending Song' implies a positive and uplifting tone, while the word 'Making' in the corner suggests that the video may be a behind-the-scenes look at the creation of the song.

Environment: The environment appears to be a music studio or a creative workspace, with a speaker and headphones visible in the background. The red and white striped wall with a cartoon drawing adds a playful touch to the setting. The yellow couch in the background suggests a relaxed and casual atmosphere.