As of version 3.2, FLV and other true video formats are no longer supported within the Timeline or Player control. Each video file to be edited must be preprocessed into an image sequence (literally a folder full of JPEGs) and accompanying MP3 soundtrack. This makes scrubbing and navigating through the mash much faster because only single frames are loaded at each random location. And since the soundtracks are distinct MP3s they are extracted directly to the sound buffer and only once the mash is actually played.
The Transcoder AMI can be utilized for this preprocessing step but it does not support rendering from image sequences so the original files are generally kept.
And video files are supported for playback by the new PlayerFLV control - the 'transcode' example uses this functionality to display the final H.264 rendering of the mash.
In terms of interface graphics, Movie Masher supports all the media file formats that can be imported by an SWF at runtime, including other SWFs. Assets can also be packaged together into SWFs and referenced by class name. This functionality is often used for collections of skin graphics, but it can also be used to create collections of sounds, images or other media.
Audio files can optionally have a waveform graphic that provides a visual
representation of the track in the timeline, making it easier to sync with other
tracks. If specified, this graphic should have a transparent or white background since it's
possible to overlap soundtracks in the timeline using transitions. The maximum width and height of the
image is 2880 pixels.
Supported image formats include JPEG, GIF, PNG and SWF.
JPEG images will usually provide better quality in smaller files, except for flat illustrations which might perform better in one of the palette or vector based formats. Transparency masks can be used in formats that support them, but these must be composited over other visuals - attempting to render transparent images in the main visual track will produce and error.
Since URLs to media files are specified in the configuration, most file organizational
structures are supported. The only requirement is for all the files that make up an image
sequence to be in the same directory. The example implementations that come with Movie Masher also
put soundracks and waveform graphics in there as well, to keep all the files that make up
a video in one place.
Learn more in media.