FLV vs OGV
A detailed comparison of Flash Video and OGV Video — file size, quality, compatibility, and which format to choose for your workflow.
Flash Video
Video FilesFLV was the dominant web video format during the Flash era. While Flash is now deprecated, many legacy video files still exist in FLV format and need conversion to modern formats.
About FLV filesOGV Video
Video FilesOGV (Ogg Video) is an open video format using Theora codec in an Ogg container.
About OGV filesStrengths Comparison
FLV Strengths
- Low overhead — the container is extremely compact.
- Designed for streaming — progressive download and seeking work well.
- Decoded natively by Flash Player on every OS for 20 years.
OGV Strengths
- Patent-free codec (Theora) and container (Ogg).
- Mandatory for Wikipedia uploads — preserves public-domain video.
- Good for small educational clips.
- Open-source reference implementations.
Limitations
FLV Limitations
- Flash Player is dead — no modern browser can play FLV without conversion.
- Legacy codecs (Sorenson, VP6) are poorly supported in modern tooling.
- Hardware video decoders never added FLV support.
- Metadata format is primitive compared to MP4 or MKV.
- Actively harmful to use today — every major security agency has warned against Flash since 2015.
OGV Limitations
- Compression lags H.264 by ~40% at equal quality.
- Hardware decoders never adopted Theora.
- WebM (VP9/AV1) is the modern open-codec choice.
- iOS and Safari never supported Theora natively.
Technical Specifications
| Specification | FLV | OGV |
|---|---|---|
| MIME type | video/x-flv | video/ogg |
| Extensions | .flv, .f4v | — |
| Video codecs | Sorenson Spark, VP6, H.264 (F4V) | — |
| Audio codecs | MP3, Nellymoser, AAC | — |
| Status | Deprecated since December 31, 2020 | — |
| Extension | — | .ogv |
| Container | — | Ogg |
| Video codec | — | Theora (typical); Dirac, VP8 (rare) |
| Audio codec | — | Vorbis, Opus, FLAC |
Typical File Sizes
FLV
- 10-min YouTube 2008-era video 40-80 MB
- 45-min TV show (FLV H.264) 200-500 MB
OGV
- Short educational clip (1 min, 480p) 8-15 MB
- Wikipedia demo video 5-50 MB
Ready to convert?
Convert between FLV and OGV online, free, and without installing anything. Encrypted upload, automatic deletion after 2 hours.
Frequently Asked Questions
FLV (Flash Video) is a video container format that bundles one or more video streams, audio tracks, and optional subtitles into a single file. The container format determines how metadata is organised and which codecs can live inside; the visual quality itself depends on the codec (H.264, H.265, VP9, AV1) rather than the FLV wrapper. It is part of the video files family.
OGV (OGV Video) is a video container format that bundles one or more video streams, audio tracks, and optional subtitles into a single file. The container format determines how metadata is organised and which codecs can live inside; the visual quality itself depends on the codec (H.264, H.265, VP9, AV1) rather than the OGV wrapper. It is part of the video files family.
VLC, MPV and PotPlayer play nearly every FLV file on desktop. Browser support varies: modern Chromium, Firefox and Safari play common containers via the HTML5 <video> tag, but niche FLV variants may fail. If a device refuses your FLV, convert to MP4 with our FLV to MP4 converter for universal playback.
VLC, MPV and PotPlayer play nearly every OGV file on desktop. Browser support varies: modern Chromium, Firefox and Safari play common containers via the HTML5 <video> tag, but niche OGV variants may fail. If a device refuses your OGV, convert to MP4 with our OGV to MP4 converter for universal playback.
Upload your FLV to KaijuConverter and pick MP4, MOV, MKV, WebM, or any other target. Our pipeline uses FFmpeg under the hood and stream-copies when codecs are compatible (no quality loss) or transcodes at high-quality defaults otherwise. Conversion runs server-side; both files delete within two hours.
Only when the target requires re-encoding. If the codecs inside FLV match what the target container supports, FFmpeg stream-copies the streams and the output is bit-identical to the source. Transcoding uses transparent quality defaults (CRF 20–23 H.264) and produces output indistinguishable from the original at normal viewing distance.