Free online WEBM to FLAC converter

A video editor, music player, or archive system may require the audio from a WEBM file as FLAC. Converting it extracts the audio and encodes it as FLAC, but it cannot restore detail already removed by lossy compression.

What the WEBM format is

WEBM is an open container designed mainly for web video and audio. It commonly contains VP8, VP9, or AV1 video with Opus or Vorbis audio, although a WEBM file may contain audio only. Browsers, screen-recording tools, video-conferencing software, media downloaders, and streaming applications frequently create or provide WEBM files.

The .webm extension identifies the container, not one specific codec. Inspect the streams before converting with ffprobe input.webm or a media player’s codec information. A file without an audio stream cannot produce a meaningful FLAC file.

What the FLAC format is

FLAC is a lossless audio codec normally stored in a .flac file. Decoding FLAC reproduces exactly the audio samples stored in that file. It usually reduces uncompressed PCM or WAV size by about 30–60%, depending on the source.

FLAC supports metadata such as artist, album, title, and cover art and is widely supported by desktop music players, audio editors, media servers, and archival software. Unlike WEBM, a FLAC file is intended for audio and cannot retain a video stream.

Convert with FFmpeg

FFmpeg is the most direct desktop option because it can read the WEBM container, select its audio stream, and write FLAC without producing an intermediate video file. Install FFmpeg through your operating system’s package manager or from the official FFmpeg distribution, then open a terminal in the folder containing the source file.

For a file with one audio stream, run:

ffmpeg -i input.webm -vn -c:a flac output.flac

-vn excludes video, and -c:a flac selects the FLAC encoder. FFmpeg’s FLAC compression level changes encoding speed and file size, not decoded audio quality.

If the WEBM contains multiple audio streams, select the required one explicitly:

ffmpeg -i input.webm -map 0:a:0 -vn -c:a flac output.flac

0:a:0 means the first audio stream in the first input file. Replace it with 0:a:1 or another index after checking the stream list printed by FFmpeg.

To copy usable source metadata where possible, use:

ffmpeg -i input.webm -map 0:a:0 -map_metadata 0 -vn -c:a flac output.flac

For a folder of WEBM files on Linux or macOS:

for f in *.webm; do ffmpeg -i "$f" -vn -c:a flac "${f%.webm}.flac"; done

In Windows PowerShell:

Get-ChildItem *.webm | ForEach-Object { ffmpeg -i $_.FullName -vn -c:a flac (Join-Path $_.DirectoryName ($_.BaseName + '.flac')) }

Convert without installing software

You can convert the file for free on 101convert.com without installing software. Upload the WEBM file, select FLAC as the output format, start the conversion, and download the resulting file.

Quality and compatibility limits

WEBM audio is commonly encoded with lossy Opus or Vorbis. When that audio is converted to FLAC, FLAC preserves the decoded samples from the WEBM, but it cannot recover information discarded during the original lossy encoding. The resulting FLAC may therefore be larger than the source WEBM without sounding better.

FFmpeg normally preserves the input sample rate and channel count unless resampling or channel conversion is requested. Check the result with ffprobe output.flac and compare those properties with the input.

Some applications reject unusual metadata or embedded artwork. If compatibility fails, create a plain FLAC without source metadata:

ffmpeg -i input.webm -map 0:a:0 -map_metadata -1 -vn -c:a flac output.flac