RAON audio field guide
Choose an audio format by what happens next
A format is not simply “high quality” or “small.” The useful question is what the file must do next: return to an editor, stay in an archive, play on an unfamiliar device, fit an upload limit, or reach students and collaborators without extra instructions.
Decision in one minute
- Still editing? Keep WAV or another lossless source.
- Sending to almost anyone? Export an MP3 copy.
- Archiving without WAV size? Use FLAC if your future software supports it.
- Received a phone recording? Keep the M4A original; convert only when the destination rejects it.
- Received OGG, AAC, or OPUS? Convert for compatibility, not because MP3 improves the sound.
Practical format comparison
| Format | Compression | Strongest use | Main caution |
|---|---|---|---|
| WAV | Usually uncompressed PCM | Recording, editing, exchange between production tools | Large; the extension does not guarantee every WAV uses the same codec |
| MP3 | Lossy | Sharing, uploads, broad playback compatibility | Repeated exports can add audible artifacts |
| M4A / AAC | Usually lossy AAC | Phone recordings, voice memos, modern mobile workflows | Older apps and some forms may reject it |
| FLAC | Lossless | Music archive and high-quality storage | Not accepted by every simple player or form |
| OGG | Container, often Vorbis or OPUS | Open media and web-oriented audio | The extension alone may not reveal the codec |
| AAC | Lossy codec | Mobile, streaming, and video-related audio | Standalone AAC support varies by browser and app |
| OPUS | Lossy codec | Speech, calls, streaming, efficient web audio | Some editing and upload workflows still expect MP3 or WAV |
Four workflows we use to make the decision
1. Rehearsal or lesson recording
Keep the recorder's original file first. If the original is WAV, that becomes the source for trimming and volume changes. Create a 128 kbps MP3 for spoken instruction or a 192 kbps MP3 for music-based practice. Send the MP3 and retain the original until the recipient confirms that the file opens and the useful section is present.
2. File rejected by an upload form
Read the error before converting. “Unsupported type” calls for a compatibility format such as MP3. “File too large” calls for trimming or a lower bitrate. Changing FLAC to a 320 kbps MP3 may fix the format but still miss a strict size limit. The error determines the tool.
3. Editing and later reuse
Use WAV when a simple uncompressed interchange file is needed. Use FLAC when lossless archiving matters and every future application is known to support it. Do not convert a low-bitrate MP3 to WAV expecting restored detail. The WAV becomes larger, but the audio information removed by MP3 compression does not return.
4. Phone memo sent to many devices
M4A is efficient and common on phones, so there is no reason to convert it when the target accepts it. Export MP3 when a school portal, older player, presentation system, or recipient cannot open the M4A. This creates a compatibility copy rather than a quality upgrade.
What RAON Tools does during conversion
- The browser reads the selected file. No conversion can start if the browser cannot decode the codec inside the file.
- Audio is decoded to samples. At this stage, the original compressed bitstream is no longer being copied directly.
- The selected operation is applied. Trimming and volume changes work on decoded audio; format conversion creates a new output.
- A new MP3 or WAV is encoded. MP3 output uses the selected bitrate. WAV output is larger because it is exported as uncompressed audio.
- The browser creates a local download. The result should be played and checked before the source is deleted.
Why the extension is not the whole story
A file extension is a clue, not a complete technical description. An M4A container may hold AAC or another codec. OGG can contain Vorbis or OPUS. WAV can contain PCM but may also contain codecs that a browser does not expect. A file can also be incomplete, protected, or renamed with the wrong extension. This is why one `.wav` file may work while another `.wav` file fails.
RAON Tools checks the selected extension before processing, but successful conversion still requires the browser decoder. When a file fails, test it in a trusted media player, verify its source, and try a current browser. For important recordings from specialist software, use that software's own export command to create a standard PCM WAV before browser conversion.
Source-first rule
A useful file workflow has two layers: a source and a delivery copy. The source preserves the best available material and remains available for later edits. The delivery copy is optimized for a recipient, form, device, or size limit. Confusing those roles is how people end up repeatedly converting MP3 files or deleting the only high-quality recording.
Use WAV to MP3 for a smaller delivery copy, M4A to MP3 for compatibility, or MP3 to WAV only when an editor requires WAV input.
한국어 핵심 정리
편집과 원본 보관에는 WAV나 FLAC, 공유와 업로드에는 MP3가 무난합니다. 휴대폰 녹음 M4A는 상대방이나 업로드 사이트가 지원한다면 그대로 사용하고, 열리지 않을 때만 MP3 호환용 복사본을 만드는 것이 좋습니다.
MP3를 WAV로 바꿔도 이미 손실된 음질이 복구되지는 않습니다. 파일 확장자가 같아도 내부 코덱이 다를 수 있어 브라우저 지원 여부가 달라질 수 있습니다. 중요한 원본은 유지하고, 변환 파일은 목적에 맞춘 전달용 파일로 구분하세요.