OPUS, AAC, and ALAC: what they are, differences, and when to use them
Choosing the right format prevents playback issues and oversized files. In this guide you’ll see what OPUS, AAC, and ALAC bring to the table, how they actually work across iPhone, Android, car stereos, and TVs, and which bitrates perform best for voice notes, podcasts, and music.
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What are OPUS, AAC, and ALAC (simple explanation)
OPUS is an open codec that’s very efficient at low bitrates. It shines for voice notes, calls, and streaming; that’s why apps like WhatsApp and Telegram use it.
AAC (Advanced Audio Coding) is the modern standard for music and video audio. It’s widespread across iPhone/iTunes, YouTube, and streaming platforms.
ALAC (Apple Lossless) is lossless: it preserves the original quality and is ideal for archiving/editing, but it’s larger than AAC/OPUS.
Comparison table: quality, size, and typical use
| Format | Type | Main advantage | Limitation | Recommended use |
|---|---|---|---|---|
| OPUS | Lossy | Excellent at low bitrates (voice) | Spotty compatibility on older gear | Voice notes, interviews, app-based sharing |
| AAC (.m4a) | Lossy | High quality for music at 192–256 kbps | Less universal than MP3 on old car/TV units | Music, video audio, iPhone/iTunes |
| ALAC | Lossless | Identical quality to the original | Large size and partial compatibility | Master archive, editing, Hi-Fi library |
Recommended bitrate for voice, podcasts, and music
- Voice notes / interviews: 64–128 kbps (mono optional). For ultra-light files, 64 kbps.
- Podcast with gentle music: 128–160 kbps (CBR) or high VBR (q≈2 for MP3).
- Full music: 192–256 kbps. If your audience uses old devices, prioritize a universal format.
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Compatibility: iPhone, Android, car, and TV
- iPhone/iPad: Native M4A/AAC and ALAC. If it won’t play elsewhere, convert M4A to MP3.
- Android: AAC and OPUS are common; for older car/TV systems, MP3 is the safest choice.
- Older car stereos & TVs: often MP3-only. Use 128–192 kbps.
- Web/browser: OPUS works in most modern browsers; if unsure, also offer an MP3 version.
Quick conversions & real cases
“I have OPUS audios from WhatsApp”
Convert to a universal format for car/TV playback.
OPUS/OGG → compatible“I recorded on iPhone and it’s heavy”
M4A/AAC sounds good; convert for maximum compatibility if needed.
M4A/AAC → MP3“I want to extract audio from a video”
Grab the sound and save it as a lightweight file.
Video/YouTube → MP3Frequently asked questions
Which audio format is best for voice notes and long interviews?
For minimal size with good clarity, OPUS 64–96 kbps; for maximum compatibility, convert to MP3 64–128 kbps.
Does AAC sound better than MP3 in the car?
AAC can be more efficient, but many older car units only accept MP3. If in doubt, use MP3 128–192 kbps.
Is ALAC the same quality as WAV?
Yes—both are lossless; ALAC takes less space than WAV. For sharing, export a compressed copy.
How can I transcribe a long interview without wasting time?
Convert to a compatible file and use an audio-to-text transcription tool.
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