Sample peak is highest sample in file. True peak is highest after 4x oversampling reconstruction — what DAC actually outputs. Inter-sample peaks can be +0.5 to +3 dB higher.
Sample Peak -3.08 dBFS True Peak -3.08 dBTP — almost same, good master, no inter-sample clipping. If sample 0.0 dBFS, true can be +2 dBTP clipping on Spotify.
All platforms recommend -1.0 dBTP headroom to avoid clipping after MP3/AAC conversion. Apple requires -1.0. Our fix limits to -1.0 dBTP with lookahead.