Does converting FLAC to Opus lose quality?

Yes. Opus is a lossy format — the encoder permanently discards audio information that psychoacoustic models consider inaudible. At 96 kbps, most listeners cannot distinguish the result from the original FLAC for music content. At lower bitrates (24–48 kbps), the encoding is still excellent for voice and podcasts. Once converted, you cannot recover the lost data, so keep the original FLAC if archival quality matters.

What bitrate should I use for FLAC to Opus conversion?

For music, 96 kbps is transparent to most listeners and roughly equivalent to 192 kbps MP3. For voice and podcasts, 32–48 kbps produces clear audio. For low-bandwidth voice-over-IP scenarios, 16–24 kbps still sounds intelligible — a range where MP3 would break down entirely. Higher bitrates (128–192 kbps) are for audiophiles who want to maximize fidelity.

What is the FFmpeg command to convert FLAC to Opus?

The basic command is: ffmpeg -i input.flac -c:a libopus -b:a 96k output.opus. The -c:a libopus flag selects the Opus encoder, and -b:a sets the target bitrate. Add -vbr on for variable bitrate mode, which improves quality at the same average bitrate. You can also use -map_metadata 0 to copy tags from the FLAC file.

Is my FLAC file uploaded anywhere?

No. The metadata inspector uses the Web Audio API entirely in your browser. Your file is read into browser memory only and is never transmitted to any server. Refreshing the page clears all data.

What container should I use for Opus — .opus or .webm?

The .opus extension uses the Ogg container and is the most common choice for standalone audio files. The .webm container is preferred for web video tracks or when embedding Opus audio alongside a VP8/VP9 video stream. Both use the same Opus codec inside. For music and podcast conversion from FLAC, .opus is the standard choice.

Can I convert multiple FLAC files at once?

Yes, using a shell loop. On Linux/macOS: for f in *.flac; do ffmpeg -i "$f" -c:a libopus -b:a 96k "${f%.flac}.opus"; done. On Windows PowerShell: Get-ChildItem *.flac | ForEach-Object { ffmpeg -i $_.FullName -c:a libopus -b:a 96k ($_.BaseName + ".opus") }

FLAC to Opus Converter

Drop a FLAC file to inspect its metadata, choose an Opus bitrate, and get a ready-to-run FFmpeg command — nothing is uploaded.

Inspect FLAC Metadata

Drop a FLAC (or any audio) file to read its properties. Nothing is uploaded.

Drop FLAC file here or click to browse FLAC, WAV, OGG, MP3 accepted

FFmpeg Command Generator

Opus Bitrate

Variable Bitrate (-vbr on) — recommended for better quality

Copy metadata tags from source (-map_metadata 0)

ffmpeg -i input.flac -c:a libopus -b:a 96k -vbr on -map_metadata 0 output.opus

Install FFmpeg free at ffmpeg.org. Replace input.flac with your actual filename.

Batch convert (Linux / macOS)

for f in *.flac; do ffmpeg -i "$f" -c:a libopus -b:a 96k -vbr on -map_metadata 0 "${f%.flac}.opus"; done

Install FFmpeg

macOS brew install ffmpeg

Ubuntu sudo apt install ffmpeg

Windows winget install ffmpeg

Drop a FLAC file on the left to inspect its metadata

No file is uploaded — everything runs in your browser

Opus Bitrate Guide

6 – 24 kbps

Narrowband voice — basic speech intelligibility

24 – 48 kbps

Wideband voice — clear podcast / phone quality

48 – 64 kbps

Full-band voice — excellent spoken audio

64 – 96 kbps

Music — transparent to many listeners

96 – 128 kbps

Music — transparent quality (recommended)

128 – 192 kbps

Music — archival / near-lossless quality

FLAC vs. Opus — At a Glance

Property	FLAC	Opus
Codec type	Lossless	Lossy
Patent status	Royalty-free	Royalty-free (RFC 6716)
Typical file size	20 – 40 MB per track	2 – 8 MB per track
Bitrate range	400 – 1400 kbps	6 – 510 kbps
Audio quality	Bit-perfect	Transparent at 96+ kbps
Latency	N/A (non-streaming)	2.5 – 60 ms
Container	.flac	.opus / .webm / .ogg
Browser support	Limited	Chrome, Firefox, Edge, Safari 11+
Best for	Archival, DAW, mastering	Streaming, web, VoIP, mobile

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Summary

FLAC is a lossless audio format that preserves every bit of the original recording, but its large file sizes make it impractical for streaming, web apps, or portable devices. Opus is a modern, royalty-free codec that delivers better quality than MP3 at the same or lower bitrate, making it an excellent target for FLAC conversions where smaller files matter. This tool lets you drop a FLAC file to inspect its sample rate, duration, and channels, choose an Opus bitrate, then copy a ready-to-run FFmpeg command. Everything runs in your browser; no file is ever uploaded.

How it works

Drop a FLAC file onto the inspector panel (or click to browse).
The Web Audio API reads the file's sample rate, duration, and channel count locally.
Choose an Opus bitrate — 96 kbps for music, 32–48 kbps for voice/podcasts.
Optionally enable Variable Bitrate (VBR) for a better quality-to-size ratio.
Copy the generated FFmpeg command and run it in your terminal.
Verify the output Opus file in a player before deleting your original FLAC.

Use cases

Shrink a FLAC music library for web streaming with minimal quality loss.
Prepare audio for WebRTC or Discord bots, which natively use the Opus codec.
Reduce storage size of FLAC podcast archives for online distribution.
Convert FLAC game audio assets to Opus for smaller download bundles.
Archive spoken-word FLAC recordings at low Opus bitrates with excellent intelligibility.
Batch-convert an album by adapting the single-file command into a shell loop.
Check a FLAC file's sample rate and duration before encoding.
Generate a ready-to-paste FFmpeg command without memorizing its flags.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu