Adobe Flash Video format. Once dominant for web streaming. Now largely deprecated in favor of MP4 and WebM.
Specifications
Extension.flv
MIME Typevideo/x-flv
StandardFlash Video
Quality★★★☆☆
Compatibility★★★☆☆
Compression★★★☆☆
Streaming Ready✅ Yes
Web Optimized✅ Yes
Mobile Optimized❌ No