Extract Audio from WebM to AIFC — Free Online Tool
Extract audio from a WebM file and save it as AIFC, converting from Opus or Vorbis to uncompressed PCM (pcm_s16be) in Apple's extended AIFF container. This is the go-to workflow for pulling web-sourced audio into professional Mac and Pro Tools environments that expect high-fidelity, lossless audio files.
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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
WebM files typically carry audio encoded with Opus or Vorbis — both lossy, compressed codecs optimized for web streaming. AIFC, Apple's compressed/extended AIFF format, most commonly stores audio as uncompressed big-endian PCM. This conversion fully decodes the Opus or Vorbis audio stream from the WebM container, discards the video track entirely (-vn), and re-encodes the raw decoded audio into pcm_s16be (16-bit signed big-endian PCM) wrapped in the AIFC container. This is a lossy-to-lossless workflow in terms of the output format — the PCM output is uncompressed — but some quality loss from the original Opus/Vorbis encoding already exists and cannot be recovered. The video stream is not processed at all, making conversion fast.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the underlying engine that powers this browser tool via WebAssembly (FFmpeg.wasm) and can also be run directly on your desktop for files over 1GB. |
-i input.webm
|
Specifies the input WebM file. FFmpeg will detect its Matroska-based container and identify the audio stream (typically Opus or Vorbis) and any video stream for processing. |
-vn
|
Disables video output entirely, telling FFmpeg to ignore the VP9 video stream in the WebM file. Since AIFC is an audio-only format, this flag ensures no video processing overhead and produces a clean audio extraction. |
-c:a pcm_s16be
|
Decodes the Opus or Vorbis audio from the WebM and re-encodes it as 16-bit signed big-endian PCM — the standard uncompressed audio codec for the AIFC/AIFF format family, compatible with Pro Tools, Logic Pro, GarageBand, and virtually all Mac audio software. |
-b:a 128k
|
Specifies a target audio bitrate of 128kbps, but for pcm_s16be this flag has no practical effect — PCM is uncompressed and its bitrate is fixed by sample rate and bit depth, not a compression target. It is included for tooling consistency but can be omitted without changing the output. |
output.aifc
|
Sets the output filename with the .aifc extension, which tells FFmpeg to use the AIFC container muxer and wrap the big-endian PCM audio in Apple's extended AIFF format. |
Common Use Cases
- Importing audio from a WebM screen recording or video download into Pro Tools or Logic Pro, which expect AIFF/AIFC files for professional session work on macOS
- Archiving the audio track of a WebM video (e.g., a downloaded YouTube video or web conference recording) as a lossless PCM file for long-term storage without further compression artifacts
- Delivering extracted web audio to a post-production studio or broadcast facility that requires big-endian PCM in an Apple-compatible container per their asset specifications
- Preparing a music or voiceover track captured in WebM format for editing in GarageBand or Final Cut Pro, both of which have native support for AIFC files
- Extracting a clean audio stem from a WebM animation or web video to use as a sound effect or background track in an audio workstation that does not support Opus or Vorbis decoding
- Converting web-sourced audio for use on older Mac hardware or legacy audio software that predates widespread Opus support but handles AIFC natively
Frequently Asked Questions
No — the output AIFC file uses uncompressed pcm_s16be, which is a lossless format, but it cannot recover quality lost during the original Opus or Vorbis encoding in the WebM file. The PCM output is a perfect, uncompressed representation of what the decoder produces, meaning no additional quality is lost in this conversion step, but the audio fidelity is still bounded by the original lossy WebM encoding.
WebM audio (Opus or Vorbis) is highly compressed — Opus at 128kbps is typically 10–20x smaller than uncompressed audio of the same duration. The AIFC output uses pcm_s16be, which is raw uncompressed PCM at a fixed data rate of approximately 1.4 MB per minute per channel at CD quality (44.1kHz, 16-bit). A 10-minute WebM audio track that's a few MB could become 80–170 MB as AIFC PCM, which is expected and normal for lossless archival formats.
WebM files store metadata using Matroska-style tags, while AIFC uses a different chunk-based metadata structure. FFmpeg will attempt to map common tags (title, artist, album) to AIFC metadata chunks, but not all WebM metadata fields have direct AIFC equivalents and some may be silently dropped. If metadata fidelity is critical, verify the output file's tags in your audio software after conversion.
AIFC supports several PCM variants (16-bit, 24-bit, 32-bit, float) as well as compressed formats like A-law and μ-law. The default here is pcm_s16be — 16-bit signed big-endian PCM — because it is the most universally compatible AIFC variant, matching CD-quality audio and working across virtually all Mac software, DAWs, and broadcast tools. If your workflow requires 24-bit or 32-bit float precision, you can modify the -c:a flag in the FFmpeg command accordingly.
For PCM codecs like pcm_s16be, the -b:a bitrate flag has no meaningful effect since the bitrate is determined entirely by sample rate and bit depth — not a compression setting. To change bit depth, replace -c:a pcm_s16be with another codec such as pcm_s24be (24-bit) or pcm_f32be (32-bit float). For example: ffmpeg -i input.webm -vn -c:a pcm_s24be output.aifc will produce a higher bit-depth AIFC file suitable for professional audio mastering.
Yes — on the command line you can use a shell loop to process multiple files. On Linux or macOS: for f in *.webm; do ffmpeg -i "$f" -vn -c:a pcm_s16be "${f%.webm}.aifc"; done. On Windows (PowerShell): Get-ChildItem *.webm | ForEach-Object { ffmpeg -i $_.FullName -vn -c:a pcm_s16be ($_.BaseName + '.aifc') }. The browser-based tool on this page processes one file at a time, so the FFmpeg command is the recommended path for batch jobs or files over 1GB.
Technical Notes
The pcm_s16be codec writes 16-bit signed integers in big-endian byte order, which is the native endianness of the AIFC/AIFF format specification — originally designed for Motorola 68k and PowerPC Mac hardware. Modern Intel and Apple Silicon Macs handle big-endian PCM transparently in software, but it is worth noting for any low-level audio processing pipelines. Because WebM audio is always lossy (Opus or Vorbis), the decoded PCM output will contain the full dynamic range but not any frequency or spatial information that was discarded during the original WebM encode. If the source WebM uses Opus at a low bitrate (below 96kbps), audible compression artifacts will be present in the AIFC output. The -b:a 128k flag in the command is effectively inert for PCM output — PCM bitrate is a function of sample rate and bit depth only — so it does not need to be tuned. AIFC does not support multiple audio tracks, subtitles, chapters, or video, so any of these elements in the source WebM file are silently ignored. The AIFC container has a 4GB file size limit due to its 32-bit chunk size fields, which is relevant for very long recordings converted at high sample rates or bit depths.