Audio formats and quality

TL;DR

• We accept WAV, FLAC, AIFF, ALAC (lossless) and MP3, M4A, AAC, OGG, Opus (lossy) as masters.
• Lossless uploads are kept bit-exact on storage and streamed as FLAC at the source sample rate + bit depth.
• Lossy uploads stream from the source file directly at the original bitrate. No re-encode.
• One exception we turn away at the door: .aif files that carry Ableton's own internal compression (Live's factory packs ship their loops this way). Nothing outside Ableton can read them, so we say so during the upload instead of storing a file that would never play; export or consolidate the sample from Ableton as a normal WAV or AIFF and it goes straight through.

What we keep

For every upload we store the master file exactly as you uploaded it. Nothing is re-encoded, normalized, or modified. The bytes that come off your disk are the bytes that sit in our storage. You can re-download the master from the track menu any time.

This matters because:

• Mastering engineers need bit-exact references.
• Producers may want to revert to the original after experimenting.
• The reference DAW project lives elsewhere, but the audio is canonical.

What gets streamed

A track plays in a few situations: your own listen page, a public share link, the embedded player on your profile. Streaming a 200 MB WAV would be slow + bandwidth-heavy + bad for mobile users, so we make a streamable version:

Master format	Streamed as	Sample rate kept	Bit depth kept
WAV / FLAC / AIFF / ALAC	FLAC	Yes (44.1k, 48k, 88.2k, 96k, 192k)	Yes (16/24/32-bit)
MP3 / M4A / AAC / OGG / Opus	source file, unchanged	n/a (already lossy)	n/a

So if you uploaded a 24-bit 96kHz WAV, the listener hears a 24-bit 96kHz FLAC. Nothing is folded down to a lossy MP3 on the way.

When to upload lossless vs lossy

Upload lossless if:

• The track is your final master and might end up on streaming services later (you'll want the same bytes for DSP delivery).
• A mastering engineer needs to work from it.
• You're using SoundAssist as your archive.

Upload lossy if:

• The track is a rough mix shared for feedback.
• The track is a DJ set / mix that was already lossy at the source (no point pretending otherwise).
• You're working with file-size limits and the listener doesn't need reference-quality.

Why not Opus?

We used to encode an Opus 510 stream alongside the lossless master. Opus at 510kbps is transparent to ~99% of listeners + a quarter the bandwidth of FLAC. Reasonable choice.

We switched to FLAC streaming in May 2026 because:

• Mastering engineers said "we want bit-exact reference, even for streaming."
• Sending the bytes out costs us nothing, so the bandwidth argument matters less.
• FLAC is more portable across DAWs + devices.

The Opus path still works for legacy tracks uploaded before the switch. Nothing breaks.