Audio normalization¶

HeapStream can normalize a video's audio loudness at upload time, so videos from different sources play at a consistent volume.

What audio normalization does¶

Normalization here means loudness normalization: adjusting a recording's gain so its average perceived loudness matches a fixed target. Loudness is measured in LUFS (Loudness Units relative to Full Scale) across the whole audio stream.

When to use it¶

Normalization helps most when your library mixes content from different sources or recording setups, say quiet dialogue in one video and loud music in the next. Like any audio processing it alters the original sound, so leave it off when your content is already consistently mastered.

Activating audio normalization¶

Normalization can only be enabled when uploading a video.

Target loudness¶

The target is -23 LUFS, per EBU R128. Normalization runs in two passes: one to measure the source's loudness, one to apply the gain.