FLV to AMR Converter

FLV to AMR: The One Question That Decides This Conversion

Is the audio in your FLV speech or music? That single question settles everything else on this page. AMR (Adaptive Multi-Rate) is a speech codec that 3GPP standardised in the late 1990s for GSM and UMTS mobile voice calls — it models the human vocal tract and deliberately discards everything outside the voice band. On a recorded lecture, interview, sermon, voice memo, or any spoken-word Flash-era clip, that produces a startlingly small file that still sounds like the speaker. On a song, it produces a muffled, warbly mess. This tool pulls the soundtrack out of the FLV, throws the picture away, and re-encodes the audio as AMR — so read the comparison below before you commit.

AMR Compared With the Other Ways to Save FLV Audio

When AMR Is the Right Answer — and When It Isn't

• Pick AMR Narrow Band when the endpoint is a telephony system, an IVR prompt, a feature phone, an MMS pipeline, or a voice archive where intelligibility matters and bytes do not.
• Pick AMR Wide Band when the endpoint explicitly supports wideband voice (G.722.2) and the source is still speech — you get a noticeably fuller voice for roughly twice the size.
• Pick MP3 instead for anything musical, anything stereo, or anything you simply want to play on a normal device: convert FLV to MP3.
• Remember the double hit. FLV audio is already lossy (usually MP3, or AAC in later files), so encoding it into a low-bitrate speech codec re-compresses an already-compressed stream. The quality floor is set by the FLV, and AMR lowers it further.

How to Convert FLV to AMR

1. Upload Your FLV File: Drag and drop or click "Add Files" to select your .flv files. Only the audio track is extracted — the video is discarded — and several files can be queued at once.
2. Choose AMR Narrow Band or AMR Wide Band: Open Advanced Options; those two entries are the whole Audio Codec list on this page. Make this choice first, because the bitrate and sample-rate lists below are codec-specific.
3. Set File Compression, Sample Rate and Channel (Optional): File Compression offers a Quality Preset dropdown (Highest down to Lowest) or Constant Bitrate, which lists the eight AMR-NB modes from 4.75 to 12.2 kbps or the nine AMR-WB modes from 6.60 to 23.85 kbps depending on the codec you picked. Audio Sample Rate offers only the rate the codec defines — 8000 HZ for Narrow Band, 16000 HZ for Wide Band — and Audio Channel offers only MONO. Trim takes a Start time and Duration if you want one slice of a long talk.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours. Download individually or as a ZIP. No sign-up, no watermark.

Walk-through: Choosing the Right AMR Mode

The bitrate mode is the one setting that really changes how the result sounds. AMR-NB defines eight fixed modes — 4.75, 5.15, 5.90, 6.70, 7.40, 7.95, 10.2 and 12.2 kbps — and every mode produces the same 8 kHz mono stream, just with more or fewer bits per second. AMR-WB defines nine modes from 6.60 to 23.85 kbps over a 16 kHz stream. Higher modes sound clearer; lower modes make smaller files.

• Clarity matters (a lecture or interview you will actually listen to): pick 12.2 kbps on Narrow Band — the GSM Enhanced Full Rate bitrate and the best AMR-NB can do — or 12.65 kbps and up on Wide Band.
• Only intelligibility matters (voicemail-style archive, MMS): drop to 5.90 or 4.75 kbps. Words stay understandable and the file shrinks to roughly 36 KB per minute at the lowest mode.
• The endpoint is a feature phone or telephony gateway: stay on Narrow Band. Those systems assume 8 kHz narrowband audio and will often reject a wideband file outright.
• You are unsure: Narrow Band at 12.2 kbps is the safest broadly compatible choice.

AMR Mode Reference

Common Errors and How to Fix Them

• "The audio sounds muffled or warbly" — the source was not pure speech. AMR filters out the frequencies music needs. Re-run the file through FLV to MP3 for full-spectrum output.
• "The file will not play on my phone or in my browser" — .amr is a telephony format rather than a consumer media format: no mainstream web browser plays it in an audio element, and support in stock phone apps is inconsistent. VLC, Audacity and ffmpeg-based tools open it reliably, and the file stays valid for MMS and telephony systems. For a clip that simply plays anywhere, use FLV to MP3.
• "No audio came out at all" — some FLV files are video-only (screen captures, silent animations) and have no audio track to extract. Open the FLV in VLC first to confirm it has sound.
• "The output is mono but my FLV was stereo" — expected. AMR is mono-only, and the Audio Channel dropdown on this page offers nothing but MONO. If you need stereo, AMR is the wrong format.
• "The bitrate list looks wrong for my codec" — the Constant Bitrate list is filtered by the codec you selected. Set Audio Codec first, then open the bitrate dropdown.

Frequently Asked Questions

Will music or a soundtrack in my FLV survive the AMR encode?

No. AMR is a speech-only codec built around an ACELP model of the human vocal tract, and it discards content outside the voice band — roughly 300-3400 Hz on Narrow Band. Music, sound effects and ambience come out muffled and warbly, and percussion turns to mush. There is also a double quality hit: FLV audio is already lossy MP3 or AAC, and AMR re-encodes it again at a tiny speech bitrate. If your FLV has any musical content worth keeping, use FLV to MP3 instead.

What is the difference between AMR Narrow Band and AMR Wide Band here?

Narrow Band samples at 8 kHz and runs 4.75-12.2 kbps across eight modes — the classic mobile-call codec. Wide Band samples at 16 kHz and runs 6.60-23.85 kbps across nine modes, capturing roughly 50-7000 Hz, which is the "HD voice" sound. Wide Band is clearly better on speech if the destination supports it; Narrow Band is what old handsets, MMS and telephony gateways expect. Both are mono.

What audio is actually inside an FLV file?

FLV files almost always carry MP3 audio, or AAC in later files, both of which are lossy. Adobe ended Flash Player support on December 31, 2020, so nothing creates new FLV content, but the container still decodes fine in modern tools — which is why extracting its audio still works. Because the source is already lossy, converting it to AMR stacks a second round of compression on top of the first.

Why is the AMR file so much smaller than the FLV?

Two reductions stack. First, the video track is discarded entirely, and in a typical FLV that is the large majority of the file. Second, the remaining audio is re-encoded from a full-spectrum stereo MP3 or AAC stream down to a mono speech stream of at most 23.85 kbps. The arithmetic is simple: one minute at 12.2 kbps is about 92 KB, and one minute at 4.75 kbps is about 36 KB, versus roughly 1 MB for the same minute as a 128 kbps MP3.

Is the AMR output always mono, and can I change the sample rate?

Mono always — we checked the option set on this page and the Audio Channel dropdown contains only MONO, with no Original or Stereo entry. The sample rate is fixed by the codec rather than by you: choosing Narrow Band leaves 8000 HZ as the only entry in Audio Sample Rate, and choosing Wide Band leaves 16000 HZ. The encoder downmixes and resamples the FLV's audio automatically to match.

Which AMR mode should I choose for a recorded talk?

For a lecture or interview you actually want to hear clearly, pick 12.2 kbps on Narrow Band, or 12.65 kbps and above on Wide Band. For a voicemail-style archive where you only need the words to be understandable and the file as small as possible, drop to 5.90 or 4.75 kbps. Every Narrow Band mode produces the same 8 kHz mono stream; the bitrate only trades clarity against size.

Can I extract just one section instead of the whole FLV?

Yes. Switch Trim from Unchanged to Time Range and enter a Start time and a Duration, either in plain seconds or as HH:MM:SS.sss. Only that window is decoded and encoded, which is much faster than processing a full-length recording and is the easiest way to test a bitrate mode before committing to the whole file.

How are my files handled after conversion?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared or made public. The practical limit on a long FLV is upload time rather than the encode, since AMR itself is extremely cheap to produce. To go the other direction and turn an existing AMR voice file into something widely playable, see AMR to MP3.