Clipping and True Peak: Why a Track Distorts After Upload

A master can peak below 0 dBFS and still distort after it is encoded for streaming. The reason is inter-sample peaks: the reconstructed waveform between digital samples can exceed the highest stored sample value. Lossy codecs such as AAC and Ogg Vorbis can make this more noticeable, especially when the source is already heavily limited.

Sample peak and true peak are different

Sample peak measures the highest individual digital sample. True peak estimates the maximum level of the reconstructed waveform between samples, usually expressed in dBTP. A file showing −0.2 dBFS sample peak may have a higher true peak. That is why a sample-peak meter alone does not tell the whole story.

Clipping, limiting and codec overs

Clipping occurs when a signal exceeds the available digital or analogue headroom and its waveform is truncated or saturated. A limiter can control peaks, but pushing it too hard can create audible distortion, flatten transients and make the mix tiring. Encoding can introduce additional peak overs even when the source file does not clip.

A reliable mastering check

1. Use a meter that displays both sample peak and true peak.
2. Listen for harshness on vocals, cymbals, snare and dense high-frequency material.
3. Leave sensible headroom. A ceiling around −1 dBTP is a common conservative starting point for streaming, not a universal platform requirement.
4. Audition an encoded preview when possible, rather than judging only the WAV master.
5. If distortion is audible, revisit the mix or reduce limiting instead of simply lowering the final output after the damage has occurred.

What should you deliver?

Agree on the required bit depth, sample rate and file format with the distributor or client. Keep a high-resolution master and avoid repeated lossy conversions. The correct ceiling depends on the material, loudness target and delivery requirements; no single number guarantees a clean encode.

Takeaway: true-peak control is a way to reduce encoding surprises. It cannot replace good gain staging, a balanced mix and restrained limiting.

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