About using FLV video

The FLV file format contains encoded audio and video data for delivery by using Flash Player. For example, if you have a QuickTime or Windows Media video file, you use an encoder (such as Flash 8 Video Encoder, or Sorensen Squeeze) to convert that file to an FLV file.

Flash Player 7 supports FLV files that are encoded with the Sorenson Spark video codec. Flash Player 8 and later supports FLV files encoded with Sorenson Spark or On2 VP6 encoder in Flash. The On2 VP6 video codec supports an alpha channel. Different Flash Player versions support FLV in different ways. For more information, see the following table:

Codec	SWF file version (publish version)	Flash Player version required for playback
Sorenson Spark	6	6 and later
	7	7 and later
On2 VP6	6	8* and later
	7	8 and later
	8 and later	8 and later

Codec

SWF file version (publish version)

Flash Player version required for playback

Sorenson Spark

6 and later

7 and later

On2 VP6

8* and later

8 and later

*If your SWF file loads an FLV file, you can use the On2 VP6 video with having to republish your SWF file for Flash Player 8 and later, as long as users use Flash Player 8 and later to view your SWF file. Flash Player 8 and later supports publish and playback of On2 VP6 video.

For information on video fundamentals, such as streaming, progressive download, dimensions, encoding, importing, and bandwidth concerns, see Using Flash.

This section discusses using FLV video without components. You can also use the FLVPlayback component to play FLV files or use the VideoPlayback class to create a custom video player that loads FLV files dynamically (see www.adobe.com/devnet/flash or www.adobe.com/support/documentation/). For information on using FLV video with the FLVPlayback and Media components, review the FLVPlayback Component and Media components section in ActionScript 2.0 Components Language Reference.

As an alternative to importing video directly into the Flash authoring environment, you can use ActionScript to dynamically play external FLV files in Flash Player. You can play FLV files from an HTTP address or from a local file system. To play FLV files, use the NetConnection and NetStream classes and the attachVideo() method of the Video class. For more information, see NetConnection, NetStream, and attachVideo (Video.attachVideo method) in the ActionScript 2.0 Language Reference.

You can create FLV files by importing video into the Flash authoring tool and exporting it as an FLV file. If you have Flash, you can use the FLV Export plug-in to export FLV files from supported video-editing applications.

Using external FLV files provides certain capabilities that are not available when you use imported video:

Longer video clips can be used in your Flash documents without slowing down playback. External FLV files play using cached memory, which means that large files are stored in small pieces and accessed dynamically, requiring less memory than embedded video files.

An external FLV file can have a different frame rate than the Flash document in which it plays. For example, you can set the Flash document frame rate to 30 frames per second (fps) and the video frame rate to 21 fps. This setting gives you better control of the video than embedded video, to ensure smooth video playback. It also allows you to play FLV files at different frame rates without the need to alter existing Flash content.

With external FLV files, Flash document playback does not have to be interrupted while the video file is loading. Imported video files can sometimes interrupt document playback to perform certain functions, such as accessing a CD-ROM drive. FLV files can perform functions independently of the Flash document, which does not interrupt playback.

Captioning video content is easier with external FLV files because you can use event handlers to access metadata for the video.

TIP

To load FLV files from a web server, you might need to register the file extension and MIME type with your web server; check your web server documentation. The MIME type for FLV files is video/x-flv. For more information, see Configuring your server for FLV files.

For more information on FLV video, see the following topics:

Flash CS3

Comments

s.behninger said on Apr 16, 2008 at 1:31 AM :

FLV framerate being independent of the container movie's framerate is only half true.

We have discovered that (at least with streaming VP6 FLV, not tested with progressive download or H.263) the FLV's framerate must NOT exceed the container movie's framerate. In this case some FLV frames are simply left out, i.e. the FLV framerate is limited by the container movie's framerate.

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