WMA to Opus Converter

Drop a WMA file to inspect its metadata, choose a target Opus bitrate, and copy a ready-to-run FFmpeg command — nothing is uploaded.

Use the WMA to Opus Converter

Inspect WMA Metadata

Drop or select any audio file. It is decoded locally in your browser — no data is uploaded to any server.

FFmpeg Command Generator 

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

Install FFmpeg free at ffmpeg.org. Run this command in your terminal after replacing the file name.

Batch convert WMA files (Linux / macOS)

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

Batch convert WMA files (Windows PowerShell)

Get-ChildItem *.wma | ForEach-Object { ffmpeg -i $_.FullName -c:a libopus -b:a 96k -vbr on -map_metadata 0 ($_.BaseName + ".opus") }
Output File Size Estimator

Enter audio duration below, or inspect a file above to auto-fill.

hrs

min

sec

Formula: bitrate (kbps) × duration (s) / 8000

32 kbps

—

64 kbps

—

96 kbps

—

48 kbps

—

128 kbps

—

Duration: 3 min 30 sec (210 s)

Why No In-Browser Conversion?

Browsers expose the Web Audio API for decoding audio, but they do not include an Opus encoder, and WMA decoding is not universally supported. FFmpeg bundles a WMA decoder and libopus and handles the full pipeline:

  1. 1 FFmpeg opens the WMA container (ASF) and reads the compressed audio stream.
  2. 2 The WMA decoder decompresses the stream to raw PCM audio in memory.
  3. 3 libopus re-encodes the PCM data to Opus at the bitrate you specify.
  4. 4 FFmpeg wraps the Opus stream in an OGG container and writes the .opus file to disk.

Install FFmpeg at ffmpeg.org (free, open-source). On Linux: sudo apt install ffmpeg. On macOS: brew install ffmpeg.

Opus Bitrate Reference

Bitrate Quality Size / min Best For
24 kbps Acceptable ~0.18 MB Voice calls, minimal bandwidth
32 kbps Good ~0.24 MB Podcasts, audiobooks, speech
48 kbps Very Good ~0.36 MB Speech, transparent for voice
64 kbps Excellent ~0.48 MB Casual music listening
96 kbps Near-transparent ~0.72 MB General music, headphones
128 kbps Transparent ~0.96 MB Audiophile, archival Opus

WMA vs. Opus — At a Glance

WMA (Windows Media Audio)

  • Default codec for Windows Media Player and older Xbox
  • Supported by most Windows software and some car stereos
  • Proprietary Microsoft format, not royalty-free
  • Lower quality than Opus at equivalent bitrates
  • Not natively supported on macOS, iOS, or Linux without extra codecs

Opus (RFC 6716, libopus)

  • Outperforms WMA at all common bitrates
  • Royalty-free and open-source (Xiph.org / IETF)
  • Native support in all major browsers and WebRTC
  • Not supported by older car stereos or dedicated audio players
  • Apple devices have limited native Opus support outside browsers
Copied!

Summary

WMA (Windows Media Audio) is a proprietary Microsoft codec with decent compression but limited cross-platform support. Opus is a modern open-source codec standardized by the IETF (RFC 6716) that consistently outperforms WMA at equivalent bitrates, especially below 128 kbps, and is natively supported in all major browsers and WebRTC. Because browsers cannot encode Opus directly, converting WMA to Opus requires a local tool such as FFmpeg. This page lets you drop any WMA file to inspect its sample rate, duration, and channel count in the browser, choose an Opus bitrate, and copy a ready-to-run FFmpeg command. No file is ever uploaded.

How it works

  1. Drop a WMA file onto the inspector panel (or click to browse).
  2. The Web Audio API reads the file sample rate, duration, and channel count locally in your browser.
  3. Choose a target Opus bitrate in the command generator — 96 kbps is a solid general-purpose choice.
  4. Optionally enable VBR mode (-vbr on) for better quality at the same average bitrate.
  5. Copy the generated FFmpeg command and run it in your terminal.
  6. Verify the output Opus file in a media player before deleting the original WMA.

Use cases

  • Convert a legacy WMA music library to Opus for efficient cross-platform storage.
  • Reduce podcast or audiobook file sizes significantly with Opus at 32–64 kbps versus WMA at 128 kbps.
  • Prepare audio for WebRTC applications or web streaming where Opus is natively supported.
  • Replace proprietary WMA files with royalty-free Opus audio for open-content projects.
  • Batch-convert an entire WMA folder to Opus using a single shell loop.
  • Inspect an unknown WMA file to confirm its duration and sample rate before processing.
  • Generate ready-to-paste FFmpeg commands without memorizing Opus encoder flags.
  • Estimate output file size at different Opus bitrates before committing to a large batch.

Frequently Asked Questions

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