How do I convert FLV to AAC?

Add your FLV file to the upload area above, then press Convert. The AAC file downloads straight to your device. You do not need an account, and there is no watermark.

Are my files uploaded to a server?

No. This conversion runs entirely inside your browser using WebAssembly, so the file never leaves your device — you can even disconnect from the internet after the page loads and it will still work.

Does converting to AAC reduce quality?

AAC uses lossy compression, so some data is discarded. At the default quality the difference is very hard to see or hear; raise the quality setting if you need to be certain, at the cost of a larger file.

How large a file can I convert?

Up to 512 MB per file for this conversion. Because the work happens in your browser, the practical limit is your device's memory — larger files work on a desktop with plenty of RAM and may fail on an older phone.

Can I convert several files at once?

Yes. Add as many as you like and press Convert All. Each file is processed independently, so one failure does not stop the rest, and you can download everything together as a ZIP.

Can I use this on my phone?

Yes. FileTools360 works in mobile browsers on iOS and Android, including choosing files straight from your camera roll. Very large videos may run out of memory on a phone — those are better converted on a laptop.

VideoAdjustable qualityRuns in your browser

FLV to AAC Converter

Turn FLV files into AAC in a couple of clicks. Obsolete Flash container. Convert to MP4 to keep it playable. The successor to MP3 — better quality per bit. The output is re-encoded, so quality depends on the settings you choose.

On your deviceNever uploadedGone when you close the tabHow this works

Drop your files here

FLV files (.flv) · up to 512 MB each

or paste files from your clipboard

Ready when you are

Drop a FLV file above and FileTools360 will turn it into AAC — right here on your device, without uploading anything.

⌘K to search converters

How to use it

1
Add your FLV files
Drag them onto the upload area, choose them from your device, or paste them from your clipboard. You can queue several at once.
2
Adjust the settings if you want to
The defaults suit most people. Open Advanced to control bitrate, sample rate and channels and start and end times.
3
Convert and download
Press Convert. Everything happens on your own device — nothing is uploaded. Download files one by one, or grab them all as a ZIP.

FLV and AAC explained

FLV was the container behind Flash video, which dominated online video until browsers removed Flash support entirely at the end of 2020. Nothing plays FLV natively today.

AAC is the successor to MP3 and is the default audio codec for MP4 video, Apple Music and YouTube. At the same bitrate it generally sounds noticeably better than MP3.

Where FLV files come from: Video downloaded or archived from the web before roughly 2015.
Where AAC is used: Streaming services, video soundtracks and Apple devices.

FLV vs AAC

The two formats solve different problems, which is why converting between them involves trade-offs rather than a straight upgrade.

FLV compared with AAC
Property	Source	Target
Compression	Container (depends on codec)	Lossy
Animation	Yes	—
Introduced	2002	1997
Browser support	Effectively dead — nothing plays it natively any more.	Excellent across modern devices.

FLV is stronger at: Historically small files for their era.
AAC is stronger at: Better quality per bit than MP3. The standard audio track for MP4 video. Excellent device support.

Why convert FLV to AAC?

This is not really a format swap — it is extraction. An FLV file carries a video track and an audio track side by side, and converting to AAC discards the picture and keeps the sound. People do it to turn a lecture, interview, podcast recording or music video into something they can listen to without the video, at a fraction of the file size.

FLV limitations that prompt the switch: Effectively dead — no browser or modern player supports it. Low quality ceiling by current standards.
What you give up: Still lossy. Patent licensing applies to encoders.

Does converting FLV to AAC reduce quality?

FLV stores your data exactly; AAC does not. Some detail is discarded permanently in exchange for a much smaller file, which is usually the right trade for sharing and publishing. Keep your FLV original if it is the only copy — the conversion cannot be undone.