MOV to FLV Converter

MOV to FLV Converter

.mov is Apple's QuickTime container, introduced in 1991 and still what iPhones, DSLRs and macOS screen recorders write today. .flv is Flash Video, the container Macromedia built for streaming inside Flash Player and Adobe retired in 2020. This page converts one to the other and, just as importantly, tells you what the format can and cannot do — because almost everyone who lands here is feeding a legacy system rather than making something they intend to share.

FLV Format at a Glance

Note that F4V — Adobe's own replacement — deliberately dropped Sorenson Spark, Screen video, VP6, ADPCM and Nellymoser. Adobe was signalling a decade ago that the classic FLV codec set was a dead end.

How to Convert MOV to FLV

1. Upload Your MOV File: Drag your .mov onto the page or click "+ Add Files". Several clips can be queued and converted in one batch with identical settings.
2. Set the Video Codec Deliberately: Open Advanced Options. Video Codec opens on FLV (Sorenson Spark). Unless a genuinely old Flash target requires Spark, switch it to H.264 — that is the codec most surviving FLV tooling actually expects, and it is what our own converter falls back to for .flv output when no codec is specified.
3. Choose the Audio Codec and Compression Mode: Audio Codec opens on AAC; switch to MP3 for anything that predates Flash Player 9. Under File Compression you get Quality Preset, Specific file size, Constant Bitrate, Constant Quality and Constraint Quality — plus Variable Bitrate when the codec is H.264.
4. Trim or Resize, Then Convert: Set Trim to Time Range for a start time and duration, or scale down with Preset Resolutions (height-only; width follows your source aspect). Click Convert and download the .flv. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

Codec Choices Inside the FLV Container

The single most useful thing to know here: the manual quality box is labelled CRF for every codec, but its meaning flips. On H.264 it is a real CRF on a 0–51 scale with about 18–23 being the useful band. On Sorenson Spark our encoder passes it to ffmpeg as -q:v, clamped to 1–31, where 1 is best quality — so an H.264 habit of typing 23 there produces a near-worst-case picture. Two rate-control contexts both apply to this page, so treat whatever number the box opens on as arbitrary rather than as a recommendation, and either set it consciously or stay on Quality Preset.

Why FLV Is a Legacy Target

Adobe stopped supporting Flash Player on 31 December 2020, began blocking Flash content from running on 12 January 2021, and now recommends that everyone uninstall the player outright — no security patches have shipped since. Browsers removed the plugin entirely. So an FLV you produce today will not play by double-clicking it on a normal machine; it plays in VLC, in ffmpeg-based tooling, and inside whatever specific legacy system asked you for it.

That is the only reason to make one: an old learning-management system, a broadcast ingest box, a Flash-based kiosk, or an archive whose catalogue expects .flv. For anything else — a website, a phone, a smart TV, an editing timeline — MOV to MP4 gives you the same H.264 video in a container everything made this century can open, usually at a smaller size. If you are moving in the other direction and rescuing an old archive, FLV to MP4 is the page you want.

Frequently Asked Questions

Does anything still play FLV files in 2026?

Not in a browser. Flash Player was end-of-lifed on 31 December 2020 and has been blocking content since 12 January 2021, and every mainstream browser dropped the plugin. FLV still opens fine in VLC, MPC-HC and anything built on ffmpeg, and legacy ingest systems that were designed around it still read it. What you cannot do is hand an FLV to a colleague and expect it to open.

Should I keep the preselected FLV codec or switch to H.264?

Switch to H.264 unless you have a concrete reason not to. Sorenson Spark is an H.263 derivative from 2002; it needs far more bits than H.264 for the same picture, and it only exists in the dropdown for pre-Flash-Player-9 targets. H.264 arrived in the Flash pipeline with Flash Player 9 in 2007, is what nearly all surviving FLV tooling expects, and is the codec our converter itself treats as the natural default for .flv output. Keep Spark only when you know the destination predates 2007.

Why do all the quality options vanish when I pick "Flash Video"?

Because Flash Video and Flash Video v2 are the Screen video codecs — lossless screencast encoders that ignore bitrate and quantiser settings entirely. Our option surface hides the whole File Compression group rather than showing controls that would do nothing. The trade is predictable: pristine text and UI edges, and very large files on camera footage, which is exactly the material those codecs were never designed for.

Which audio codec should I choose for an FLV?

AAC is preselected and is the right answer for anything from Flash Player 9 onward. MP3 is the safer pick for older Sorenson Spark workflows, because MP3 was in the FLV format from the beginning while AAC came later. ADPCM exists for very old Flash projects that expect it and is not a general-purpose choice — it is a simple fixed-rate scheme that spends far more bits than MP3 or AAC for a worse result.

Is FLV the same thing as F4V?

No, and the distinction matters if a system asked you for "Flash video". FLV is the original 2003 container. F4V arrived in 2007 and is built on the ISO base media file format — essentially MP4 with an Adobe extension — and it deliberately does not support Sorenson Spark, Screen video, VP6, ADPCM or Nellymoser. If your target accepts F4V, it accepts modern codecs, and you are better off producing an MP4.

Why is the FLV bigger or blurrier than the MOV I started with?

Sorenson Spark is roughly two codec generations behind the H.264 or HEVC inside a modern MOV, so it needs more bits to look the same — and if the quality settings ask for fewer bits, detail goes instead. Either switch the codec to H.264, which fixes both problems at once, or scale the picture down with Preset Resolutions so the encoder has less to describe. If you have already converted and just need it smaller, run the result through the video compressor.

Will HDR footage from a recent iPhone look right?

No. There is no HDR tone-mapping stage in the pipeline, so Dolby Vision and HLG clips get a plain colour conversion and typically look flat, grey or washed out — and FLV's codecs are 8-bit SDR regardless. Record or export an SDR version first, then convert that. The same caveat applies to interlaced camcorder footage: there is no deinterlacing step, so combing artefacts are re-encoded as they are.

Can I trim the clip instead of converting the whole thing?

Yes — set Trim to Time Range and give a start time and duration, in seconds or as HH:MM:SS.sss. That happens as part of this conversion, so the source is only encoded once. If you would rather cut the MOV first and decide on the format afterwards, use Video Cutter.

What happens to my file after the conversion?

It is uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours. Nothing is shared, published or made searchable, there is no sign-up, and no watermark is added to the output.