FLV Converter

For the most common job, use the dedicated FLV to MP4 converter.

Convert FLV to Any Video Format

FLV (Flash Video) is a container from the Adobe Flash era — originally built by Macromedia and released in September 2003 to stream video inside the Flash Player plugin that once powered YouTube, Hulu, and most of the early web. Adobe ended Flash Player support on December 31, 2020 and began blocking Flash content from running on January 12, 2021, so the players and browsers that used to open FLV no longer ship with the runtime it depended on. The result: a folder of old.flv captures, screen recordings, or downloaded clips that simply won't open on a modern Mac, iPhone, Android phone, or in any current browser. This converter re-encodes those files into formats today's devices speak natively — most often MP4 with H.264 video, which plays everywhere. Upload one file or a batch, pick a target format, and download. No sign-up, no watermark.

How to Convert FLV to MP4 (or Any Format)

1. Upload Your FLV File: Drag and drop your.flv file onto the page or click "Add Files" to browse. Batch conversion is supported — drop in several FLV files at once and each one processes in parallel.
2. Pick Video File Extension and Quality Preset: Choose your target container from the Video File Extension dropdown — MP4, MOV, AVI, WebM, MKV, GIF, or audio-only MP3, plus 30-plus others. The default Quality Preset is "Very High (Recommended)". For a smaller file, switch to Specific file size and enter a target in MB, or use Constant Quality (CRF) to tune by perceptual quality (18 = visually lossless, 23 = default, 28 = noticeably smaller).
3. Resize, Trim, or Set Codec (Optional): Under Video resolution, keep the original or pick a Preset Resolution (2160p, 1440p, 1080p, 720p, 480p, 360p, 240p), scale by percentage, or enter a custom Width × Height. Under Trim, choose Time Range and enter a start point and duration to cut dead footage. Advanced users can override the Video Codec (H.264, H.265, VP9, AV1, MPEG-4, XviD) and Audio Codec (AAC, MP3, Opus, FLAC, AC3, PCM).
4. Convert and Download: Click Convert. 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. Download each result individually or grab the whole batch as a single ZIP.

Why FLV Files Won't Play — and Which Format to Convert To

FLV was never a video codec; it is a container that wraps a codec. Over its life it carried Sorenson Spark (an H.263 variant), On2 VP6, and from Flash Player 9 (December 2007) onward, H.264 for video, plus MP3, AAC, ADPCM, Nellymoser, or Speex for audio. Playback failed not because the codec inside is exotic — much of it is ordinary H.264/AAC — but because mainstream players dropped FLV demuxing once Flash was retired and FLV stopped appearing on the web. The fix is to move the streams into a container modern software still parses.

Which target you choose depends on where the clip is going:

• FLV to MP4 (H.264/AAC) — the universal default. MP4 plays on Windows (since Windows 7), macOS, iOS, Android, every modern browser, smart TVs, Roku, Chromecast, and game consoles. If the FLV already holds H.264 video and AAC audio, the converter keeps that codec family by default and re-encodes at a visually lossless preset, so the result stays visually indistinguishable from the source; older Sorenson/VP6 FLVs are re-encoded to H.264 from a different codec. This is the right pick for nearly everyone.
• FLV to MOV — for Apple workflows. MOV is QuickTime's native container and imports cleanly into Final Cut Pro and iMovie. Use it when the destination is Mac editing rather than general sharing.
• FLV to AVI — for legacy Windows software and older non-linear editors that predate broad MP4 support. AVI is a 1992 Microsoft container with the widest backward compatibility on aging hardware.
• FLV to WebM — for embedding directly in a web page. WebM (VP9 or AV1) is royalty-free and plays in every modern desktop browser, producing smaller files than H.264 at the same quality for HTML5 <video> use.
• FLV to GIF — for a short, silent, looping animation that embeds anywhere, including Slack reactions, GitHub READMEs, and old forums. Because GIF is frame-by-frame with a limited palette, keep clips short; use the dedicated FLV to GIF tool to set framerate and palette size.
• FLV to MP3 — when you only want the audio. This discards the video track and exports the soundtrack as MP3 — useful for old lectures, podcasts, or music captured in Flash. See FLV to MP3.

FLV Container at a Glance

Output Format Comparison

A 480p Flash-era FLV holding Sorenson video and MP3 audio re-encodes to MP4/H.264 with no visible quality loss, and the MP4 opens natively on macOS, iOS, and in Chrome where the original FLV would not load at all.

Popular FLV Conversions

• FLV to MP4 — universal compatibility, the default choice
• FLV to MOV — Apple, QuickTime, and Final Cut
• FLV to AVI — legacy Windows and older editors
• FLV to MP3 — extract just the audio track
• FLV to GIF — short looping animation
• FLV to WebM — smaller files for web embeds

To shrink a converted clip without changing format, use Compress MP4. To cut footage before or after converting, the Video Cutter accepts FLV input directly. For other sources, the all-purpose Video Converter handles MOV, MKV, WebM, AVI, and 25-plus more.

Frequently Asked Questions

Why won't my FLV file play on my computer or phone?

FLV was designed for the Adobe Flash Player plugin, and Adobe ended Flash support on December 31, 2020, then blocked Flash content from running on January 12, 2021. Modern browsers removed the Flash runtime, and mainstream media players dropped FLV support once the format left the web. The file itself is usually fine — the software to open it is gone. VLC and ffmpeg still decode FLV, but the durable fix is to convert to MP4, which plays on every current device and browser without a plugin.

Does converting FLV to MP4 lose quality?

It depends on what is inside the FLV. The converter always re-encodes the video — there is no stream-copy pass. If the FLV already contains H.264 video and AAC audio (common for later Flash-era captures), the converter keeps that codec family by default and re-encodes at a visually lossless preset, so the output stays visually indistinguishable from the source. If it holds older Sorenson Spark or VP6 video, those streams are re-encoded to H.264 from a different codec, a larger generational step — setting Constant Quality (CRF) to 18-20 keeps the output visually indistinguishable from the source. The default "Very High" preset is tuned for visually-lossless results.

What video and audio codecs are inside an FLV file?

FLV is a container, not a codec. Its video track is typically Sorenson Spark (an H.263 variant), On2 VP6, or H.264 (supported from Flash Player 9 in December 2007). Its audio track is usually MP3, AAC, ADPCM, Nellymoser (used for microphone recordings), or Speex. You don't need to know which one your file uses — the converter detects the streams and re-encodes them to the codecs your chosen output format expects.

Which format should I convert FLV to?

MP4 with H.264 for almost every case — it plays everywhere and is the safest default. Choose MOV if you're editing on a Mac in Final Cut or iMovie, AVI for old Windows software, WebM for embedding in a web page, GIF for a short silent loop, or MP3 if you only want the audio. When in doubt, pick MP4.

Can I extract just the audio from an FLV file?

Yes. Select MP3 as the output format and the converter discards the video track, exporting only the soundtrack. This is useful for old Flash lectures, interviews, podcasts, or music. Use the dedicated FLV to MP3 tool for audio-specific options.

Can I batch convert a folder of FLV files at once?

Yes. Drop multiple.flv files into the uploader and each one converts independently to the format and settings you choose. There is no per-job file count limit. Download the results one by one or as a single ZIP. This is the fastest way to modernize an entire archive of old Flash recordings in one pass.

What's the file size limit, and are my files private?

Free uploads are limited to 400 MB per file and 5 jobs at a time; Basic raises the video cap to 1 GB and Pro to 4 GB. Files are processed on our servers and deleted automatically after a few hours. For very large source files, trim dead footage first.

What's the difference between FLV and F4V?

Both are Adobe Flash video formats, but they use different container structures. FLV is the original Flash Video container from 2003, whose native codec was Sorenson Spark (H.263). F4V is a newer format Adobe introduced around 2007, built on the ISO base media file format — the same foundation as MP4 — to carry H.264 video. If you have an .f4v file, converting it to MP4 keeps the same H.264 codec by default at a visually lossless preset, since the two share the same underlying structure. Both belong to the retired Flash era, so MP4 remains the durable target either way.