Video formats get all the attention in a design workflow, and audio gets whatever the export dialog defaults to. That's backwards often enough to be worth fixing: a wrong audio format doesn't just sound slightly worse, it can fail outright — silently rejected by an upload form, or played back with sync drift after a codec mismatch.
Here's the format each stage of a project actually needs, and why.
The rule that settles most of this: lossless for masters, lossy for delivery
Audio formats split into two families, and almost every confusing decision collapses once you know which family you're choosing from.
Lossless (WAV, AIFF, FLAC) stores the audio data without discarding anything. Files are large — a few minutes of stereo audio easily runs 30-50MB — but nothing is lost, and it re-encodes cleanly every time you export from it again.
Lossy (MP3, AAC/M4A) discards audio data the format decides you won't notice, in exchange for a much smaller file. That's a genuine trade, not automatically a bad one — but it's a one-way trade. Every lossy-to-lossy re-export compounds the loss, the same way a JPEG saved from a JPEG degrades a little more each time.
The practical rule: keep your working master in a lossless format. Export lossy copies for delivery, as many times and in as many formats as you need, from that master — never from a previously-compressed copy.
The four formats you'll actually be asked for
WAV — the standard master format. Uncompressed, universally supported by every editing tool, and the correct choice for anything you might need to re-export later: a voiceover recording, a mixed soundtrack, a podcast master. Large files are the cost of a format you can always re-export from without further loss.
MP3 — the default delivery format when compatibility matters more than anything else. Every device and platform plays it. Use it for final delivery when you don't control the destination and need something that will simply work.
M4A — commonly confused with a codec, but it's actually a container — usually holding AAC-encoded audio, sometimes ALAC (lossless). This is the practical source of most "wrong format" confusion: two M4A files can be fundamentally different things depending on what's inside. If a platform specifically asks for M4A, check whether it wants the lossy (AAC) or lossless (ALAC) variant before you export — guessing wrong means re-doing the export, not a small quality hit.
AAC — generally a better-sounding lossy codec than MP3 at the same file size, and the format most streaming platforms and mobile ecosystems actually use internally (M4A is frequently just AAC in a different wrapper). Use it when the destination supports it and you want better quality per megabyte than MP3 delivers.
Where this actually goes wrong on a project
- Re-exporting from a lossy file because the master got lost. The most common and most avoidable failure. If your only surviving copy of a voiceover is the MP3 you delivered last month, every future export inherits that compression — there's no way back to the lossless version. Keep masters somewhere findable, not buried in a delivery folder that got cleaned up.
- Assuming M4A means "small file." It might be AAC (small) or ALAC (large, lossless). Open the file's properties or ask before you build a delivery pipeline around an assumption.
- Converting the same file lossy-to-lossy across tools. Recording app saves MP3 → edited in a tool that re-exports MP3 → uploaded to a platform that transcodes again on ingest. Three lossy passes on audio that started as one WAV recording. Each pass is a small, real quality loss that compounds.
- Sending the wrong sample rate or bit depth, not just the wrong format. A 48kHz/24-bit WAV dropped into a project expecting 44.1kHz/16-bit can cause sync or playback issues that have nothing to do with the file extension. Check the destination's actual spec, not just its format name.
When a quick, one-off browser conversion is the right tool
Not every audio task needs a full editing suite open. If you've got a single voice memo that needs to go from M4A to MP3 for a client who can't open the original, or a WAV export that needs to become something small enough to email, a free browser-based converter is genuinely the right scale of tool for that job — faster than opening a DAW for a thirty-second task, and you're not installing software for something you'll do twice a year.
That's specifically for files you already have the rights to and are moving between formats for your own use — a voice memo, your own recording, a file you're allowed to convert — not for pulling audio off someone else's platform, which is a different question entirely with its own rules. Tools like Free Video Convertor, for instance, publish exactly that scope on their own site: browser-based conversion of your own audio, video and image files, with a stated privacy position that files aren't stored on their servers, alongside an explicit note that the tool is meant for content you own or have permission to use.
The workflow that actually holds up: keep your project masters in your editing tool as WAV, and reach for a quick single-file browser converter only for the odd one-off delivery that doesn't justify opening the full project.
A simple decision path
- Recording or mixing something new? Work in WAV. Don't compress until you're ready to deliver.
- Delivering to an unknown destination? MP3. Universal compatibility beats marginal quality gains.
- Delivering to a platform that specifies AAC or M4A? Confirm whether it wants lossy or lossless before exporting.
- Re-exporting an old file for a new use? Find the original master first. If it's genuinely gone, export from the highest-quality copy you have and accept the loss — don't chain multiple lossy conversions trying to "fix" it.
- One-off file, no project open? A single-purpose browser converter is a reasonable choice, for your own files.
FAQ
Is AAC always better than MP3? At equivalent file sizes, generally yes — AAC tends to sound cleaner at lower bitrates. MP3's advantage is universal compatibility, which still matters when you don't control playback.
Can I convert MP3 back to WAV to "restore" quality? No. The format will report as WAV, but the lost data from the original MP3 compression is gone permanently. This is a common and understandable misconception — the file gets bigger, not better.
What sample rate should I export at? Match the destination's spec. 44.1kHz is standard for most web and streaming delivery; 48kHz is common for video-associated audio. Guessing rarely causes obvious problems, but mismatches can cause subtle sync issues down the line.
Do I need a DAW to convert one audio file? For a genuine one-off — a single personal recording, a quick format swap — no. A dedicated audio-conversion tool is faster and simpler than opening a full editing environment for a task that takes ten seconds.
Why does my M4A file sound worse than expected? Check whether it's the lossy (AAC) or lossless (ALAC) variant. If a lossy M4A was itself re-exported from an already-compressed source, that's two lossy passes stacked.
The short version
Lossless for anything you might touch again, lossy for anything you're handing off. Keep your masters somewhere you can find them in six months, and never re-export from a compressed copy just because it's the only file left. For the rare single file that needs a quick format swap and nothing more — your own voice memo, your own export, not someone else's — a free browser-based tool like Free Video Convertor beats opening your full editing suite.
