Apple Shake 4 - Manual (Page 168)

168 Chapter 5 Compatible File Formats and Image Resolutions
Shake is a hybrid renderer—it adapts its rendering from either scanlines or a group of
tiles. This means it never has to load the entire image, just a single piece of the image,
making a much smaller memory footprint than other compositors. Sometimes you
cannot load just a single line, for example, when using a Rotate node, in which case
Shake internally breaks the image down into small tiles to work with more
manageable bits.
QuickTime Files
Shake on Mac OS X supports the reading and writing of QuickTime files. QuickTime
support in Shake is limited, however. Embedded Flash and SMIL content is ignored, as
are all of QuickTime’s interactive features.
Audio tracks are also ignored by the FileIn node. If you read in a QuickTime file, you
must import its audio via the Audio Panel in a separate process. For more information
on using the Audio Panel, see Chapter 9, “
Using the Audio Panel ,” on page 277.
If you reference a QuickTime movie with more than one video track, Shake only reads
the first video track into your script; all others are ignored.
Note: You cannot read out (export) a QuickTime movie with a dynamically varying
frame size. The resulting file will be unusable.
Which Codec Is Best?
Compositing with Shake is best accomplished using source media files with little or no
compression. Ideally, you should then capture or create QuickTime movies for use with
Shake using codecs that apply the least amount of compression possible. QuickTime
includes the Uncompressed 8 and 10-bit 4:2:2 QuickTime codecs, as well as other codecs
for various formats of standard- and high-definition video. There are also a variety of
third-party codecs available that provide other bit depths and compression ratios.
Note: Always check with the developer regarding the compatibility of third-party
codecs with Shake.
Image Formats That Support tTmp Files
Shake creates temporary files (tmp files) when writing certain formats of images, or
when running out of memory. These temporary files are written like swap files, but are
used before memory-intensive activity occurs to avoid the slowdown of swapping.
Normally, Shake reads in only the portion of an image that it can fit into memory—
either a group of scan lines or a tile of the image. This means that any given image is
accessed not just once, but many times, with only the necessary portion of it being
read each time in order to save memory and processing time.
The ideal format to support this behavior is the native Shake .iff format (this format is
also licensed to Alias/Wavefront for their Maya software), but several other image
formats support this behavior as well.