FLV to OPUS Converter

Extract Opus Audio from FLV Online

FLV is the classic Flash Video container from the early YouTube era — Adobe ended Flash Player support on December 31, 2020, so these files are mostly archive material now: old lectures, screencasts, webcam captures, and stream rips. This tool lifts the soundtrack out of an FLV and re-encodes it to Opus, the open IETF codec (RFC 6716, published September 2012) behind Discord, WhatsApp, and WebRTC voice. The video is discarded — you get audio only — and because Opus stays clear at low and mid bitrates, salvaged dialogue or music lands in a compact, modern .opus file ready for a Discord or web pipeline.

How to Convert FLV to Opus

1. Upload Your FLV File: Drag and drop your .flv onto the page or click "+ Add Files". Several files queue and convert with the same settings.
2. Set the Quality Preset or Bitrate: Open Advanced Options and leave Quality Preset on Highest, or switch to Constant, Variable, or Custom Bitrate to name an exact kbps target — 24–48 kbps is plenty for voice, 96–128 kbps is transparent for music. Match or exceed the FLV's own audio bitrate; going higher won't recover detail the source never had.
3. Adjust Audio Channel, Sample Rate, or Trim (optional): Leave Audio Channel and Audio Sample Rate on Original, downmix to Mono to halve a voice file, or use Trim to keep just the segment you need.
4. Convert and Download: Click "Convert" and download your .opus file. No sign-up, no watermark.

Opus Bitrate Guide for Salvaged Flash Audio

Frequently Asked Questions

Does converting FLV to Opus keep the video?

No. Opus is an audio-only codec, so the Sorenson Spark, VP6, or H.264 video inside your FLV is dropped and only the soundtrack is saved as a .opus file. That is exactly what you want for rescuing a lecture, an interview, or music from a Flash-era archive. If you need to keep the picture, convert to a video format with FLV to MP4 instead.

Will I lose quality extracting Opus from an FLV file?

Yes, a little — this is a re-encode, not a copy. FLV audio is almost always already lossy (MP3, AAC, Nellymoser Asao for mic and webcam captures, Speex, or ADPCM), so this is a lossy-to-lossy generational step. Opus is vastly more efficient than the Nellymoser-era codecs Flash used, but it cannot undo loss that was baked in at record time — it can only avoid adding much more. Match or exceed the source bitrate and the extra loss stays inaudible to almost everyone.

What bitrate should I choose for salvaged Flash audio?

Match it to the content. Spoken-word FLV — lectures, screencasts, webcam recordings — sounds clean at 24–48 kbps in Mono, and the files stay tiny. Music or anything with wide dynamics is transparent by 96–128 kbps in Stereo. Opus reaches the same ceiling far lower than MP3, so there's no need for MP3-style 320 kbps; the codec ranges from 6 kbps up to 510 kbps, but for extracted audio you rarely need the top end. In our testing, a 60-second stereo Flash clip whose audio was 128 kbps MP3, re-encoded at 96 kbps Opus, came out near 0.7 MB with no audible loss.

Will my Opus file play everywhere?

Not quite. Opus plays natively in Chrome, Firefox, Edge, and Opera, on Android, in apps like VLC and Discord, and in Safari on recent Apple systems. The weak spots are older car stereos, legacy portable players, iTunes/Apple's Podcasts app, and Windows versions before 10 (which need a decoder such as LAV Filters). If you want maximum playback compatibility instead, convert FLV to MP3, which plays on effectively every device.

How are my files handled, and is there a size limit?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. The main practical limit is upload size and time: a long Flash capture can be large because it still carries full video, so it may take a while to upload even though the .opus you get back is small. To keep just a section, set a Trim start and duration, or run the result through the Audio Cutter afterward.