FLV to MP4 | Fast & Free & Secure
Convert FLV to MP4 online in seconds. No signup. Secure processing; files auto-delete in ~2h. Works on mobile & desktop.
Smart Auto-Detection – ConvertSea
No need to select your file type — we've already detected it.
Just upload your file and choose the format you want to convert it to. Our system automatically recognizes the input format, so you can focus on getting the output you need.
What is FLV?
FLV (Flash Video) is a legacy multimedia container designed for delivery through Adobe Flash Player and RTMP streaming. A .flv file stores media as sequential “tags,” typically carrying H.263/Sorenson Spark or On2 VP6 video in older files and H.264/AVC in later ones, with MP3 or AAC audio. It also embeds timing metadata and cue points for web playback and simple interactivity. Because Flash reached end-of-life in 2020 and browsers removed the plug-in, FLV is now mainly used when converting archival content. Most modern players—VLC, mpv—and tools like FFmpeg can open and transcode FLV, but MP4 (H.264/AAC) or WebM (VP9/Opus) are preferred for size, compatibility, and HTML5 streaming. If you have FLV files, consider remuxing or re-encoding to MP4, and delivering via HLS or DASH.
What is MP4?
MP4 (MPEG-4 Part 14) is a flexible multimedia container built on the ISO Base Media File Format. A .mp4 bundles video, audio, subtitles, and metadata into track-based “boxes,” making it ideal for storage and streaming. Common video codecs include H.264/AVC and H.265/HEVC; audio is typically AAC, with ALAC or Dolby Digital (AC-3) sometimes used. MP4 can carry chapters, thumbnails, and subtitle tracks such as 3GPP Timed Text (tx3g), and it supports HDR signaling with HEVC (e.g., HDR10, HLG). Fragmented MP4 (fMP4) powers adaptive streaming like HLS and MPEG-DASH. Because virtually all browsers, phones, TVs, and social platforms play MP4—especially H.264/AAC—it’s the default choice for web video delivery. Editors and players (VLC, QuickTime, Premiere, Resolve) open MP4, and remuxing to MOV or MKV is often lossless when codecs match.
Upload Your File
Upload your file (drag & drop or click). Input type is auto-detected—no need to choose it.
Pick Format & Options
Pick the output format and (if available) adjust options like OCR, quality, bitrate, or resolution.
Convert & Download
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Convert Your Files Instantly – Fast, Secure & Free
Welcome to ConvertSea, the ultimate online tool to convert your files with speed, accuracy, and zero hassle. Whether you're changing image formats, converting videos, editing documents, or extracting audio, our platform delivers instant, high-quality results across hundreds of file types.
No downloads, no registration, and no watermarks — just upload your file, choose the format you need, and download your converted file in seconds.
From PDF to Word, MP3 to WAV, JPG to PNG, or MP4 to MOV, ConvertSea ensures that your content stays clean, secure, and exactly how you want it.