FLV to MP3 Converter - Extract Audio from FLV Free

This audio extraction tool converts FLV (Flash Video) files into universally compatible MP3 audio using FFmpeg WebAssembly running entirely within the browser. FLV is Adobe's legacy video container format that was the dominant streaming format during the early web video era (YouTube, Newgrounds, and countless Flash-based video players used it from 2005–2015). FLV files typically contain H.263 or VP6 video paired with MP3 or AAC audio tracks.

The converter loads the FFmpeg engine as a WebAssembly module, writes the uploaded FLV file to FFmpeg's virtual filesystem, then executes the demuxing and transcoding command with the -vn flag. This flag instructs FFmpeg to discard all video streams entirely, extracting only the audio track. The audio is then re-encoded using the LAME MP3 encoder at the user-selected bitrate (128, 192, 256, or 320 kbps). If the FLV already contains MP3 audio, this process involves decoding and re-encoding — a minor quality trade-off for consistent output formatting.

FFmpeg's progress events drive a real-time progress bar during processing. The HTML5 audio player provides instant preview of the extracted MP3. File size comparison highlights the dramatic reduction from video-plus-audio to audio-only. All processing runs browser-locally — FLV files are never uploaded to any server, ensuring complete privacy.