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Video formats

There are many video formats out on the web. Some formats are proprietary and require the respective company’s player; other formats are open and many players can play them. As Flowplayer runs a Flash video object to play the files, Flowplayer can handle virtually all formats which are supported by Flash.

Supported video formats

FormatVideo CodecAudio CodecFile SuffixDescription


FLV (Sorenson H.263)



The original Flash video container format. Also allows some other more exotic video codecs like On2 VP6 and Screen video.




.mp4 .mov .m4v

Supported since Flash version 9 update 3. The H.264 - aka MPEG-4 AVC or MPEG-4 Part 10 - video compression standard provides high quality at significantly lower bitrates compared to older codecs.





Similar to MP4, but Flash specific, or H.264/AAC in a FLV container. Useful for high-quality php-pseudostreaming, but rare otherwise.

For a complete description of Flash formats refer to this article.

If you also deploy your video to iOS with our ipad plugin please take note of the video encoding constraints on that platform. However, all videos which play on iOS will also play in Flash.

Be aware that otherwise valid MP4 files may carry video in a different encoding than H.264, like MPEG-4 Part 2. Playback of these files will fail.

H.264 files and metadata

H.264 encoded videos carry their metadata - duration, frame rate etc. - in the so called "moov atom".

By default encoding programs will insert the moov atom at the end of the video file which is suitable for playback of a local file in a desktop program. However, any kind of progressive download requires the metadata to be available right away for immediate playback. Otherwise the player has to wait for the entire video to be downloaded before playback starts.

Make sure to select an option in your transcoding program which puts the moov atom at the beginning of the file!

In case you already have a lot of MP4 videos with the moov atom at the end of the file, use a dedicated program such as QTIndexSwapper or MOOV Relocator to move it to the beginning.