FLAC vs OPUS
A detailed comparison of FLAC Audio and Opus Audio — file size, quality, compatibility, and which format to choose for your workflow.
FLAC Audio
Audio FilesFLAC is an open-source lossless audio codec that compresses audio to roughly 50-60% of its original size without any quality loss. It is the preferred format for audiophiles and music archival.
About FLAC filesOpus Audio
Audio FilesOpus is a versatile, open-source audio codec optimized for both speech and music at very low bitrates. It is the standard for WebRTC voice calls and excels at real-time communication.
About OPUS filesStrengths Comparison
FLAC Strengths
- Lossless — decoded audio is bit-exact identical to the source.
- 40-60% smaller than uncompressed WAV/AIFF.
- Free, patent-free, open-source reference implementation.
- Built-in error detection via MD5 checksums.
- Streaming-friendly — seek tables let you jump to any timestamp instantly.
OPUS Strengths
- Best-in-class quality across the entire bitrate range.
- Royalty-free and patent-free.
- Ultra-low latency — suitable for live voice and music.
- Handles speech and music equally well — no need to switch codecs.
- Mandatory codec in WebRTC, so supported in every browser by design.
Limitations
FLAC Limitations
- File sizes still large compared to lossy codecs (5-10× bigger than AAC for same audio).
- Not suitable for low-bandwidth scenarios like streaming on mobile data.
- Older MP3 players and car stereos may not decode FLAC.
- Slower to encode than lossy codecs.
OPUS Limitations
- Very low hardware decoder adoption — software-only on most phones.
- Older platforms (legacy Windows apps, old cars) may not play .opus files.
- Container semantics confusing — Opus lives inside Ogg, WebM, or MP4.
- Encoder tooling is less polished than AAC's commercial ecosystem.
Technical Specifications
| Specification | FLAC | OPUS |
|---|---|---|
| MIME type | audio/flac | audio/opus |
| Extension | .flac | — |
| Standard | Open-source reference implementation (Xiph.Org) | RFC 6716 (2012) |
| Max bit depth | 32 bits per sample | — |
| Max sample rate | 655 350 Hz | — |
| Max channels | 8 | — |
| Extensions | — | .opus, .ogg (container) |
| Sample rates | — | 8, 12, 16, 24, 48 kHz |
| Latency | — | 5-60 ms (configurable) |
Typical File Sizes
FLAC
- 3-min song (CD quality) 20-30 MB
- Full album (10 tracks, CD) 250-400 MB
- 3-min song (hi-res 24-bit/96 kHz) 80-120 MB
- Live concert recording (24-bit) 2-10 GB
OPUS
- Voice call (24 kbps) 180 KB/min
- Podcast (48 kbps) 21 MB/hour
- Music (128 kbps) ~1 MB/min
- High-fidelity music (160 kbps) ~1.2 MB/min
Ready to convert?
Convert between FLAC and OPUS online, free, and without installing anything. Encrypted upload, automatic deletion after 60 minutes.
Frequently Asked Questions
FLAC (Free Lossless Audio Codec) is an open-source audio format that compresses audio without any quality loss. Developed by the Xiph.Org Foundation, it typically reduces file sizes by 40-50% compared to WAV while preserving bit-perfect audio.
FLAC (Free sem perdas Audio codec) is an open-source audio formato that compresses audio sem any quality loss. Developed pelo Xiph.Org Foundation, it tipicamente reduces tamanho do arquivos by 40-50% comparado a WAV while preserving bit-perfect audio.
FLAC files play in VLC, foobar2000, Winamp, and most modern music players. Streaming services like Tidal and Amazon Music HD use FLAC. Android supports it natively, and Apple devices support it via third-party apps.
FLAC arquivos reproduzir in VLC, foobar2000, Winamp, e most moderno music players. Streaming services like Tidal e Amazon Music HD usar FLAC. Android suporta it natively, e Apple devices support it via third-party apps.
Both are lossless with similar compression ratios. Use FLAC for universal compatibility and open-source support. Use ALAC if you are fully invested in the Apple ecosystem since iTunes and Apple Music handle ALAC natively.
Both are sem perdas com similar compressão ratios. usar FLAC para universal compatibilidade e open-source support. usar ALAC if you are fully invested no Apple ecosystem since iTunes e Apple Music handle ALAC natively.