WAV: familiar and broadly accepted
WAVE is a RIFF-based wrapper that can contain different audio encodings, although linear PCM is common in music production. A WAV filename alone does not tell you the sample rate, bit depth or whether its contents are actually PCM.
Its main mastering advantage is predictable support across digital audio workstations, plugins and delivery systems. The trade-off is size: uncompressed PCM does not reduce redundant data.
FLAC: smaller without changing the samples
FLAC is a lossless audio codec. A correct encode-decode cycle reproduces the original PCM sample values, so the smaller file does not imply lower audio fidelity. This makes FLAC useful for archives and transfer when every system in the workflow supports it.
Support and metadata expectations still matter. If a mastering service explicitly requests WAV, sending FLAC can add an avoidable conversion or rejection even though the decoded audio is equivalent.
MP3: convenient, but already interpreted
MP3 uses perceptual coding to reduce the amount of stored information. A good high-bitrate encode can sound convincing, but it is not sample-identical to the source. Re-encoding or processing it cannot restore discarded information and may expose codec artifacts.
Use MP3 for quick approval and compatibility when appropriate. For mastering, return to the WAV, FLAC or original project export whenever one exists. If MP3 is the only legitimate source, disclose that limitation rather than upsampling it and calling it high resolution.
A sensible format decision
Choose the format the next stage accepts, then keep conversions to a minimum. Match the source sample rate unless a known delivery specification requires conversion, and use a high-quality sample-rate converter when it does.
Keep a lossless archive with unambiguous version names. Create MP3 or other delivery derivatives from that archive, not from another lossy copy. No format choice can improve a damaged source merely by increasing its stated bit depth or sample rate.
METHOD
How this guide was prepared
Format descriptions are based on the WAVE format profile maintained by the Library of Congress, the Xiph.Org FLAC specification and MPEG documentation for Layer III.
This is general educational information, not a guarantee of platform acceptance, pressing approval, authorship, or detector outcome. Requirements and services can change; check the receiving party before delivery.
PRIMARY SOURCES