Currently we support the following file formats: .mp3, .m4a, mp4, .m4v, .mpg, pdf, .zip.

Recommended: In order to be better compatible with iTunes, iPad/tablets, and mobile, we highly recommend you use Mp3 or H.264 based mp4 and m4v.

The recommended stereo bit rate and sample rate for audio files. 

Stereo Bit Rate:  128 kbps
Sample Rate:  44.1 kHz 

You can also upload images in .jpg, .gif, and .png, for logos and banners.

The maximum allowed single file size is 3GB and the single image file size must be smaller than 1 MB.