[MacDV] Re: iMovie HD bugs

Matti Haveri matti.haveri at sjoki.uta.fi
Mon Apr 11 06:32:05 PDT 2005


[continued from the previous message]

3. Like iMovie 4, iMovie HD renders jaggy still images when exporting 
to iDVD or tape!

Here is an example illustrating the problem (205 KB. 100% part of a) 
an original still image imported to iMovie HD and b) after rendering 
in iMovie when exporting to iDVD):

<http://www.sjoki.uta.fi/~shmhav/iMovie_jaggy_still.jpg>

iMovie HD obviously deinterlaces still images just by duplicating the 
fields when it renders them for export to tape or iDVD. Now, this 
prevents flicker on a TV screen but the rendered still images are 
jaggy because vertical resolution is halved.

Workaround #1 is to turn ON the Ken Burns Effect before importing an 
image. (To eliminate any zoom, set the Start and End settings to the 
same setting. The easiest way to do that is to set the Start setting 
to what you want, then Option-click on the End side of the Start/End 
button). When the image(s) are imported, that causes iMovie HD to 
immediately use the Ken Burns Effect to render the still images into 
video clips. That eliminates its request later to render them when 
you send the project to tape or click the Create iDVD Project button. 
It's in THAT rendering that the jaggies are added. The images tend to 
flicker (see below).

Workaround #2 is to convert still images to good quality video with 
Photo To Movie or Still Life. These applications have more features 
than iMovie's built-in Ken Burns effect. Photo To Movie's High 
Quality setting renders still images into very good quality video 
that doesn't flicker.

Workaround #3 is to turn OFF the Ken Burns Effect before importing an 
image. Then remember to ignore iMovie HD's rendering prompt when you 
send the project to tape or click the Create iDVD Project button.

BTW, if iMovie's rendering prompt is ignored, then the images tend to 
be TOO sharp so they may flicker when viewed on an interlaced TV 
(interlace flicker). A good workaround is to slightly blur the stills 
in some 3rd party application, so that there are no 1-line horizontal 
lines that flicker on an interlaced TV screen. For example, 1 pixel 
90° (vertical) Motion Blur may be a good way to reduce still image 
flicker on a TV (the 1 pixel value applies to PAL/NTSC 576/480 
vertical resolutions and if the vertical resolution of the input 
still is larger you have to increase the filter's pixel value 
accordingly. For example: if the input still is 2048 x 1536, use 3 
pixel value in the filter because 1536/576=2.7).

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