Audio Converter

About this tool

Voice recorders save WMA, WeChat saves AMR, meeting apps save M4A, music stores cache FLAC - and your player or editor refuses half of them. This tool reads the common audio formats (MP3, WAV, M4A/AAC, OGG, FLAC, AMR, WMA, AIFF, OPUS, MKA) and outputs the five that matter: MP3 for universal compatibility, WAV for uncompressed editing, M4A for the Apple ecosystem, OGG for the web, and FLAC for archival.

Two paths exist under the hood. When the source track already uses the target codec (say an MP3 file converted to MP3), the tool passes the original stream through untouched - bit-identical and finished in seconds. Otherwise it re-encodes at the bitrate you pick: 128k for everyday use, 192k as the balanced default, 320k when transparency matters. FLAC and WAV are lossless and carry no bitrate option.

As everywhere on DocWharf, the conversion is done by FFmpeg compiled to WebAssembly inside your browser: nothing is uploaded, nothing is stored, and private recordings stay private.

Features

• Reads MP3, WAV, M4A, AAC, OGG, FLAC, AMR, WMA, AIFF, OPUS and MKA audio
• Outputs MP3 / WAV / M4A / OGG / FLAC with selectable bitrate (128k / 192k / 320k)
• Lossless passthrough when the source codec already matches the target
• Turns niche formats like WeChat AMR voice or recorder WMA into universal MP3
• Fully local processing with live progress and a cancel button

How to use

1. Drop the audio file in - duration, codec and channels are read automatically
2. Pick the target format and bitrate (lossless formats skip the bitrate choice)
3. Click Convert - matching codecs are passed through without re-encoding
4. Preview the result and download

Frequently asked questions

MP3, M4A or FLAC - which should I pick?

MP3 for sharing, car stereos and older devices (universally playable); M4A (AAC) for the Apple ecosystem and better quality per bit; FLAC or WAV when archiving or planning further edits (lossless, no generation loss). OGG is mostly for web embedding where MP3 compatibility is not required.

What is the difference between lossless passthrough and re-encoding?

When the source codec matches the target (MP3 file to MP3, for example), the tool extracts the original stream and rewraps it - no math, bit-identical output. Different codecs must be re-encoded, and quality then depends on the bitrate: 320k MP3 is transparent for almost every listening scenario.

Can it convert WeChat AMR voice messages?

Yes. AMR is the narrowband codec behind WeChat voice notes, and the tool decodes it into MP3 or any other target. Note that AMR caps at 8 kHz sampling - conversion makes it playable everywhere but cannot restore clarity the source never had. The .aud/.silk containers WeChat uses internally are out of scope; export as AMR first.

Why did the converted file get bigger?

Converting a lossy format to a lossless one (MP3 to WAV/FLAC) grows the file a lot - lossless containers store the full waveform, and the size says nothing about improved quality. Likewise, upscaling bitrate does not bring back lost detail. When you need smaller files, use the Audio Compressor instead.

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