What is .flv?
.flv (Flash Video) is a legacy video container format that was widely used to deliver streaming video over the web via Adobe Flash Player. It typically stores video encoded with codecs like Sorenson Spark, VP6, or H.264, along with audio (often MP3 or AAC) and basic metadata.
This quick guide explains when to use .flv files, how to open them on any device, and how to share them instantly with FileXhost.
When to use .flv files
- You need to work with older web video archives originally encoded for Flash Player.
- You are migrating legacy FLV content into modern formats like MP4 or WebM.
- You want to preserve historical video assets as-is while still making them downloadable.
- You manage a video library that still contains FLV files from older workflows.
How to open .flv files
Modern browsers no longer support Adobe Flash Player directly, so FLV files are usually opened with desktop media players or converted first. VLC Media Player, MPV, and some other players can open many FLV files natively. You can also use FFmpeg or dedicated converters to transcode FLV into MP4, WebM, or other modern containers. Upload FLV files to FileXhost to share them; recipients can download and play or convert them with compatible tools.
Algorithm details
FLV is a lightweight container format designed around streaming over RTMP and progressive download. It stores media in small tagged chunks that can be played as they arrive, allowing early web video sites to start playback before the full file downloaded. The format itself does not mandate a specific codec but historically bundled Sorenson Spark or On2 VP6 video, later adding support for H.264 and AAC as Flash evolved.
Browser & platform support
- Desktop: Current browsers do not play FLV directly because Adobe Flash Player is deprecated and disabled. FLV files must be converted or played with an external media player.
- Mobile: Native mobile platforms do not support FLV; files require conversion to formats like MP4 or WebM before playback.
- OS: Operating systems can open FLV through third-party media players and codec packs, not through built-in video apps in most cases.
Format comparison
| Feature | Details |
|---|---|
| Modern Relevance | FLV is effectively legacy; MP4 (H.264/H.265) and WebM (VP9/AV1) are the standard for web and app playback. |
| Streaming | Originally optimized for streaming with RTMP and Flash; modern streaming uses HLS/DASH with MP4 or fragmented formats. |
| Compatibility | Still supported by tools like VLC and FFmpeg but not by browsers without conversion. |
| Quality | Depends on the underlying codec; older Sorenson/VP6 encodes often look worse than modern H.264/VP9 encodes at the same bitrate. |
How to create flv files
- Legacy Authoring Tools: Older versions of Adobe Flash/Flash Media Encoder and third-party encoders exported FLV for web use.
- CLI: FFmpeg can still create FLV files from other video sources when needed for specialized workflows.
- Video Pipelines: Some historic content delivery pipelines produced FLV for Flash-based players.
- Screen Recorders: Older screen capture software sometimes output FLV by default.
How to convert flv files
- FileXhost: Upload FLV files for distribution; consumers can download and convert locally.
- Desktop: Use VLC or HandBrake to convert FLV to MP4, WebM, or MKV.
- CLI: Use FFmpeg to transcode FLV to modern containers and codecs.
- Online Tools: Web-based converters can accept FLV inputs and output MP4, WebM, or GIF.
Advantages & disadvantages
Advantages
- Simple, lightweight container format with good support in media tools
- Historically optimized for streaming with low startup latency
- Still readable by powerful players like VLC and FFmpeg
Disadvantages
- No direct support in modern browsers due to Flash deprecation
- Often uses outdated codecs with lower quality at a given bitrate
- Requires conversion for most playback scenarios today
Tools & software
Players
VLC Media Player, MPV, PotPlayer, KMPlayer
Converters
FFmpeg, HandBrake, Shutter Encoder, various online converters
Legacy Tools
Older Adobe Flash tools, historical Flash Media Server utilities
Frequently asked questions
Why won't my browser play FLV files anymore?
FLV playback depended on Adobe Flash Player, which has been deprecated and disabled in modern browsers for security and compatibility reasons. To view FLV content, download the file and open it in a media player or convert it to MP4 or WebM.
Should I keep using FLV for new projects?
No. For new projects, use modern containers like MP4 (H.264/H.265) or WebM (VP9/AV1). FLV should be treated as a legacy format that is only used when dealing with older archives.
How do I convert FLV to MP4?
Use tools like FFmpeg, HandBrake, or VLC. For example, with FFmpeg you can run a command that reads the FLV file and outputs an MP4 with H.264 video and AAC audio.
Is there any reason to keep FLV files?
Yes, if they are part of a historical archive or you need to preserve original encodes. However, for day-to-day playback and distribution, converting to modern formats is recommended.
Technical specs
- File type
- Video
- Extension
- .flv
- MIME type
- video/x-flv
- Compression
- Lossy
- Max file size on FileXhost
- Up to 25 MB per file on the free plan and up to 1 GB on Pro FileXhost accounts.
Share .flv files instantly
Upload your .flv file to FileXhost to get a clean, shareable URL in seconds. View the file in a modern browser, protect access with optional settings, and let others download it without any confusing ads or cluttered file pages.
Upload .flv file