I am a simple display screen for an MPEG movie player. My step method advances the movie according to the current frame rate. If necessary, frames as skipped to maintain the desired frame rate. However, since even skipping frames takes time, it may not be possible to achieve fast frame rates with large frame sizes on slow machines.

	commands
	nextFrame previousFrame rewindMovie setFrameRate startPlaying stopPlaying

	drawing
	areasRemainingToFill: drawOn: drawScaledOn:

	file open/close
	closeFile mpegFileIsOpen openFileNamed: openMPEGFile

	initialization
	initialize

	other
	advanceFrame jpegMovieSize: measureMaxFrameRate

	stepping
	step stepTime

	accessing	top
	extent: Overridden to maintain movie aspect ratio.
	moviePosition Answer a number between 0.0 and 1.0 indicating the current position within the movie.
	moviePosition: Jump to the position the given fraction through the movie. The argument is a number between 0.0 and 1.0.
	repeat Answer the repeat flag.
	repeat: Set the repeat flag. If true, the movie will loop back to the beginning when it gets to the end.
	volume Answer the sound playback volume.
	volume: Set the sound playback volume to the given level, between 0.0 and 1.0.

	commands	top
	nextFrame Fetch the next frame into the frame buffer.
	previousFrame Go to the previous frame.
	rewindMovie Rewind to the beginning of the movie.
	setFrameRate Ask the user to specify the desired frame rate.
	startPlaying Start playing the movie at the current position.
	stopPlaying Stop playing the movie.

	drawing	top
	areasRemainingToFill: Drawing optimization. Since I completely fill my bounds with opaque pixels, this method tells Morphic that it isn't necessary to draw any morphs covered by me.
	drawOn: Draw the current frame image, if there is one. Otherwise, fill screen with gray.
	drawScaledOn: Draw the current frame image scaled to my bounds.

	file open/close	top
	closeFile Close my MPEG file, if any.
	mpegFileIsOpen Answer true if I have an open, valid MPEG file handle. If the handle is not valid, try to re-open the file.
	openFileNamed: Try to open the MPEG file with the given name. Answer true if successful.
	openMPEGFile Invoked by the 'Open' button. Prompt for a file name and try to open that file as an MPEG file.

	initialization	top
	initialize

	other	top
	advanceFrame Advance to the next frame if it is time to do so, skipping frames if necessary.
	jpegMovieSize: Convert all my frames to a JPEG and measure the total size.
	measureMaxFrameRate For testing. Play through the movie as fast as possible, updating the world each time, and report the frame rate.

	stepping	top
	step If I'm running and the mpegFile is open and has video, advance to the next frame. Stop if we we hit the end of the video.
	stepTime Run my step method as often as possible. Step does very little work if it is not time to advance to the next frame.