Convert WMA to AC3 — Free Online Tool
Convert WMA (Windows Media Audio) files to AC3 (Dolby Digital) format using FFmpeg in your browser. This tool transcodes Microsoft's proprietary wmav2 codec into Dolby's ac3 codec — essential for authoring DVD/Blu-ray-compatible audio or preparing surround sound content from Windows Media sources.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
WMA files encode audio using Microsoft's wmav2 (or wmav1) codec, which is a proprietary lossy format designed for streaming and Windows ecosystem playback. AC3, also known as Dolby Digital, uses a completely different psychoacoustic compression model and is the native audio format for DVD and broadcast television. Because these two codecs are fundamentally incompatible, a full decode-and-re-encode is required: FFmpeg first decodes the WMA audio stream into uncompressed PCM internally, then re-encodes that raw audio using Dolby's ac3 encoder at your chosen bitrate (defaulting to 192k). There is no stream-copy shortcut here — every sample is fully processed. Because both formats are lossy, this conversion is a lossy-to-lossy transcode, which means some audio quality is lost in the two-generation compression cycle.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg media processing engine, which runs here as a WebAssembly binary (FFmpeg.wasm) entirely inside your browser — no server receives your file. |
-i input.wma
|
Specifies the input WMA file containing a Microsoft wmav2 (or wmav1) encoded audio stream that FFmpeg will decode into raw PCM for re-encoding. |
-c:a ac3
|
Instructs FFmpeg to encode the audio stream using the Dolby Digital (AC3) encoder, producing a bitstream compatible with DVD players, Blu-ray hardware, and broadcast systems. |
-b:a 192k
|
Sets the AC3 output bitrate to 192 kilobits per second, which is the standard baseline for Dolby Digital stereo and a common requirement for DVD and broadcast audio authoring. |
output.ac3
|
Defines the output filename with the .ac3 extension, which tells FFmpeg to write a raw Dolby Digital bitstream file — the native format expected by DVD authoring tools and broadcast muxers. |
Common Use Cases
- Preparing audio for DVD authoring tools that require AC3/Dolby Digital streams and cannot ingest WMA files directly
- Converting a WMA music or podcast library to AC3 for playback on a Blu-ray player or home theater receiver that supports Dolby Digital but not Windows Media Audio
- Replacing WMA audio tracks in video editing projects that target broadcast or cable TV delivery, where AC3 is a required deliverable format
- Migrating legacy Windows Media Player music rips (.wma) to AC3 for use in PowerDVD, media server software, or set-top boxes that mandate Dolby Digital
- Transcoding WMA radio or interview recordings to AC3 before muxing them into an MPEG transport stream for broadcast playout systems
- Testing Dolby Digital audio encoding pipelines using existing WMA source material without needing to re-record or source new audio
Frequently Asked Questions
Yes, some quality loss is unavoidable because both WMA and AC3 are lossy formats, meaning this is a lossy-to-lossy transcode. The WMA file has already discarded audio data during its original encoding, and re-encoding to AC3 introduces a second round of compression artifacts. The degree of audible degradation depends on the bitrate of the source WMA and the target AC3 bitrate — using the default 192k AC3 output for a 128k WMA source will not recover any lost quality. To minimize degradation, use the highest AC3 bitrate that fits your use case (up to 640k).
Yes, significantly so. WMA in its standard form is a stereo-only format — the wmav2 and wmav1 codecs used in typical .wma files do not carry multichannel audio. AC3 (Dolby Digital) was designed from the ground up for 5.1 surround sound and is the standard for DVD, Blu-ray, and broadcast audio. If your WMA source is stereo, the resulting AC3 file will also be stereo, but it will be in a container and codec that hardware decoders universally recognize for home theater playback.
Generally no. The AC3 format has very limited support for embedded metadata tags compared to WMA, which supports rich ID3-style tagging natively. FFmpeg will attempt to map common fields, but the .ac3 raw bitstream container is not designed to store album art, track numbers, or extended tags. If metadata preservation is important, consider wrapping the AC3 audio in an MKV or MP4 container instead, which support both AC3 audio and comprehensive metadata.
The two codecs use different compression algorithms with different efficiency profiles. AC3's psychoacoustic model is optimized for 192k as a standard broadcast-quality stereo bitrate, which is why 192k is the Dolby Digital baseline in most authoring workflows. WMA's wmav2 encoder achieves comparable perceived quality at 128k because Microsoft tuned it for lower-bitrate streaming scenarios. Using 192k AC3 for a 128k WMA source is appropriate and won't bloat the file excessively while ensuring the output meets Dolby Digital compatibility expectations.
Modify the value after the -b:a flag. For example, to encode at 320k, use: ffmpeg -i input.wma -c:a ac3 -b:a 320k output.ac3. AC3 supports bitrates from 96k up to 640k — higher bitrates reduce the impact of the lossy-to-lossy transcode. For DVD-compatible AC3, 192k or 256k are standard choices; for broadcast delivery or Blu-ray, 320k to 448k is more typical.
Yes, on the command line you can use a shell loop to process multiple files. On Linux or macOS: for f in *.wma; do ffmpeg -i "$f" -c:a ac3 -b:a 192k "${f%.wma}.ac3"; done. On Windows Command Prompt: for %f in (*.wma) do ffmpeg -i "%f" -c:a ac3 -b:a 192k "%~nf.ac3". The browser-based tool on this page processes one file at a time, so the command line approach is recommended for bulk conversions or files over 1GB.
Technical Notes
WMA files typically use the wmav2 codec (the default in this tool), though older files may use the original wmav1 codec — both are fully supported by FFmpeg's decoder. Since the .wma container does not support multichannel audio in its standard form, the AC3 output will match the channel layout of the source, most commonly stereo (2.0). The AC3 encoder in FFmpeg is Dolby-licensed and produces standard-compliant bitstreams valid for DVD authoring and broadcast use. One notable limitation: raw .ac3 files lack a proper container, so while they play in most media players, embedding them into DVD VOBs, MPEG-TS, or MKV/MP4 requires a separate muxing step. If your WMA source has DRM protection (a feature WMA supports), FFmpeg cannot decode the protected stream and the conversion will fail — you must use an unprotected WMA file. The default 192k bitrate is a safe choice for stereo AC3 compatible with nearly all Dolby Digital decoders, but you can raise this to 320k or higher if minimizing the quality impact of the lossy-to-lossy transcode is a priority.