The preferred file format for sound recordings is FLAC or uncompressed WAV. If you are not able to provide audio files in an uncompressed format, YouTube also accepts 320kbps MP3. YouTube will transcode the audio files into a variety of delivery formats; delivering compressed audio files may lead to degraded audio for the user.
All album images must be in PNG or JPEG format. To ensure good visual quality in the Art Tracks, the image must be square (height to width ratio of 1:1) with a maximum size of 4098x4098 pixels and a recommended minimum image size of 1400x1400 at 300 DPI.