HEIF to FLV Converter

Convert HEIF to FLV: What This Tutorial Covers

This page is for the narrow case where something in a Flash-era pipeline still expects an .flv and all you have is a HEIF photo. Be clear about what happens: a HEIF is a single still image, so wrapping it in FLV produces a silent video that holds that one frame for a duration you choose — no motion, no audio. There is also a 12-year generational gap in play, since HEIF was finalised in 2015 and FLV arrived with Flash Player 7 in 2003. If you want the photo as a picture, use HEIF to JPG or HEIF to PNG. If you want a clip that plays on phones and modern browsers, HEIF to MP4 is a far better target. Choose FLV only when a legacy system specifically demands the extension.

How to Convert HEIF to FLV

1. Upload Your HEIF File: Drag and drop your .heif photo onto the page or click "+ Add Files". With several queued, Merge strategy offers "Merge images" for one combined clip or "Video per image" for a separate FLV per photo.
2. Set the Image Duration: The Image Duration dropdown runs from "1/60s (single frame at 60fps)" to "10 seconds per frame", defaulting to 5 seconds. This value alone sets how long the clip runs.
3. Choose a Video Codec and Quality Preset: Video Codec offers FLV (the default), H.264, Flash Video, and Flash Video (v2). Under File Compression, "Very High (Recommended)" is the default Quality Preset, with Constant Quality and Constraint Quality alongside it.
4. Convert and Download: Click "Convert" and save the .flv. Files are uploaded over an encrypted connection, converted on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

Walk-through: Picking a Codec and a Duration

The codec choice matters more than most people expect, because FLV outlived its original codec by several years.

• FLV (the default) writes an FLV1 stream — Sorenson Spark, a proprietary variant of H.263. This is the codec Flash Video shipped with and the one every FLV-era player understands. Pick it when compatibility with an old ingest system is the whole point.
• H.264 is also available here, and it is historically correct: Adobe added H.264 support in Flash Player 9 Update 3 on 3 December 2007. Choose it when the receiving system is late-Flash-era and you want a much better picture at the same size.
• Flash Video and Flash Video (v2) are the Flash Screen Video codecs, designed for screen recordings of largely static content rather than photographs. They are a poor fit for a camera image.
• Duration is the other lever. A splash or placeholder frame reads well at 3-5 seconds; a card that has to sit alongside other content works better at 8-10. If you merge several photos, each contributes a segment of that length, so five photos at 4 seconds gives a 20-second clip.
• Leave Video resolution on "Keep original" unless a target system demands a fixed frame size. Stretching one still to a larger Width x Height fills more pixels but adds no detail.

FLV Codec Options on This Page

What Still Opens an FLV

Frequently Asked Questions

Why is my converted FLV silent?

Because a HEIF is a single still photograph with no audio to encode, and for an image source this converter writes no audio track at all — there is no Audio Codec control on the page for that reason. The clip simply holds one frame for the Duration you set. To add music or narration, convert first and then add an audio track in a video editor, though for editing you are almost always better served by an MP4.

Which video codec does the FLV output use, and can I change it?

By default it writes FLV1, the Sorenson Spark codec — a proprietary variant of H.263 and the codec Flash Video shipped with from the beginning. You are not stuck with it: this page also offers H.264, plus the two Flash Screen Video codecs. H.264 in an FLV container is legitimate and was supported from Flash Player 9 Update 3 in December 2007, so if the receiving system is anything later than the mid-2000s it is usually the better pick. No audio codec is written either way, because the source is a photo.

Does anything still play FLV files?

Not in a browser. Adobe ended Flash Player support on 31 December 2020 and began blocking Flash content on 12 January 2021, and every major browser removed the plug-in. The FLV container is a different question — VLC, mpv, MPlayer, and anything built on FFmpeg open it happily, because they decode the video stream directly and never needed Flash. So an FLV is still openable on a desktop; it just cannot be embedded on a web page any more.

Will converting HEIF to FLV improve the quality or make it HD?

No, and this is a limit of the operation rather than a tool problem. The HEIF already holds a finished image, and putting it into a video frame cannot add detail. If you leave the codec on the FLV1 default, the picture will actually soften, because Sorenson Spark is far less efficient than the HEVC compression the HEIF used. Switching Video Codec to H.264 recovers a good deal of that. Choosing a larger resolution stretches the frame onto a bigger canvas but invents no pixels. For full fidelity, HEIF to PNG is lossless.

What if my .heif holds an image sequence rather than one photo?

Then the animation is kept. HEIF image sequences store their frames in a movie track inside the file, and that track is detected and used rather than being flattened to a single picture — so a sequence comes through as motion, not a frozen frame. Ordinary single-photo HEIFs, which is what a phone camera writes, take the still path and get the Image Duration treatment described above.

What is the difference between HEIF and HEIC, and does it change the output?

HEIF is the container standard, ISO/IEC 23008-12, finalised in March 2015. .heif is the generic structural brand that can wrap any codec, while .heic specifically signals HEVC Main or Main Still Picture image data — the variant Apple has written since iOS 11. Every HEIC is a HEIF, but not vice versa. For this conversion it makes no practical difference: the image is decoded and the same FLV is written either way. If your files end in .heic, use HEIC to FLV, which is set up for that extension.

Does my photo's full resolution make it into the video?

Not above 4096 pixels. Every image is normalised into a clean PNG and clamped so neither dimension exceeds 4096 before the video encode runs, because the frame-import stage is unreliable past that. A 48-megapixel capture therefore lands at 4096 on its long edge. That is still above 4K and irrelevant for playback, but it means an FLV is a poor container for preserving a high-megapixel original.

Why is there a white border around my picture?

That is the Background Color filling whatever part of the video frame the photo does not cover, and it is White by default for image sources. A portrait phone photo inside a landscape frame will always show it. Pick a different colour from the named options — Black is the conventional letterbox choice — or set a Fixed Resolution whose shape matches the photo so nothing needs filling.

How are my files handled and how long are they kept?

Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after the conversion. There is no sign-up, no watermark, and files are never shared or made public.