FLV to HEIC Converter

FLV to HEIC Converter

FLV is a video container; HEIC is a single-image format. Converting between them is therefore a frame-extraction job: you choose a moment (or a regular interval) in the Flash-era clip, and each sampled frame is written out as an HEIC photo. This page explains what each format actually is, what carries across the boundary, and which settings decide the result.

FLV Format at a Glance

HEIC Format at a Glance

How to Convert FLV to HEIC

1. Upload Your FLV File: Drag and drop the .flv onto the page or click "+ Add Files". Several clips can be queued and they share the settings you choose below.
2. Choose a Frame Selection mode: "Specific Frame" is preselected and grabs one still at the moment you type into "Time (seconds)". "Multiple Screenshots" instead walks the whole clip at the interval set under "Capture Rate", which starts at "1 second per frame".
3. Set Quality Preset and Image resolution: "Quality Preset" is preselected to "Very High (Recommended)"; drop it for smaller files, or switch to "Specific file size" to aim at a byte target. "Image resolution" starts on "Keep original" and can be changed to a preset, a percentage, or an explicit width and height.
4. Convert and Download: Click "Convert". Files upload over an encrypted connection, are processed on our servers and are deleted automatically after a few hours — no sign-up, no watermark.

How the Frame Is Produced

The extraction runs in two stages on our servers. The chosen frame is first decoded out of the FLV and written as a lossless PNG, and only then encoded to HEIC. That ordering matters: it means exactly one new generation of lossy compression is applied, on top of whatever the FLV's own codec already discarded, instead of the two you would get from a pipeline that stages through JPEG. "Time (seconds)" accepts decimals down to the millisecond — the field's own help text gives 2.100 as "2 seconds and 100 milliseconds" — so you can land on a precise moment rather than the nearest whole second.

In "Multiple Screenshots" mode the interval is literal: at the preselected "1 second per frame", a 90-second clip yields roughly 90 HEIC files, and at "10 seconds per frame" the same clip yields about 9. Several output files are offered as a single ZIP download.

Frequently Asked Questions

Does this play the FLV, or does it only save still images?

Still images only. HEIC is an image format, so the output is one photo per sampled frame with no motion and no audio. If you want the clip to remain watchable, convert the container instead with FLV to MP4.

What is the difference between HEIC and HEIF?

HEIF is the container standard — ISO/IEC 23008-12, Part 12 of MPEG-H, finalised in 2015 — and it can hold images compressed with different codecs. HEIC is the specific case where those images are HEVC/H.265-coded, which is the variant Apple ships on iOS and macOS. Every .heic file is an HEIF file; not every HEIF file is a .heic.

Will Windows or Chrome open the HEIC I get back?

Windows 11 from version 22H2 handles HEIC without extra software; Windows 10 from version 1803 needs the free HEIF Image Extensions from the Microsoft Store. Chrome and Firefox do not decode HEIC at all — Safari does. If the still has to work anywhere, extract it as FLV to JPG instead, or convert an existing file with HEIC to JPG.

Is the HEIC really smaller than the same frame as JPEG?

Usually, and often substantially — Apple's stated rationale for adopting HEIF was that it stores photos in about half the space of JPEG at comparable quality, because HEVC intra-frame coding is far more efficient than JPEG's DCT. The saving is largest on detailed photographic frames. On a small, soft, low-bitrate frame from an old FLV both formats end up small enough that the difference stops mattering.

Will the still be 8-bit or 10-bit?

8-bit, in practice. HEIC can store 10-bit and higher, but FLV files are essentially always 8-bit SDR, and the conversion carries forward the colour depth and gamut the source frame actually held. Nothing in the pipeline can invent wide-gamut or HDR data that the Flash-era encode never recorded.

Why does the extracted frame look soft or blocky?

That is the source, not the export. Old FLV clips were typically encoded at low bitrates with Sorenson Spark or On2 VP6 at 240p to 480p. HEIC reproduces the detail the frame contained; raising "Quality Preset" avoids adding fresh compression artefacts but cannot restore what the original codec threw away.

How many files will Multiple Screenshots produce?

Duration divided by the "Capture Rate" interval. The interval starts at "1 second per frame" and can be set anywhere from 0.1 seconds per frame — ten stills per second of video — up to 10 seconds per frame. A long clip at a short interval produces a very large number of images, so start sparse and re-run if you need more.

What happens to my FLV file after conversion?

It is uploaded over an encrypted connection, decoded on our servers, and both the upload and the generated HEIC files are deleted automatically after a few hours. No sign-up, no watermark, and files are never shared or made public.