Apple Compressor 3 - Manual (Page 131)

13 Click Submit.
Using Distributed Processing with Compressor
You can increase speed and productivity by distributing processing across multiple
computers. The Apple Qmaster features of Compressor subdivide the work for speed,
route the work to the computers with the most available computing power, and direct
the processing across designated computers.
See the Distributed Processing Setup Guide, available in Compressor Help, for complete
instructions on setting up and managing an Apple Qmaster distributed processing network.
This section covers two specific topics that you should be aware of when you are using
the Apple Qmaster distributed processing system with Compressor.
Job Segmenting and Two-Pass or Multi-Pass Encoding
If you choose the two-pass or the multi-pass mode, and you have distributed processing
enabled, you may have to make a choice between speedier processing and ensuring the
highest possible quality.
The Apple Qmaster distributed processing system speeds up processing by distributing
work to multiple processing nodes (computers). One way it does this is by dividing up
the total number of frames in a job into smaller segments. Each of the processing
computers then works on a different segment. Since the nodes are working in parallel,
the job is finished sooner than it would have been on a single computer. But with two-pass
VBR and multi-pass encoding, each segment is treated individually so the bit-rate allocation
generated in the first pass for any one segment does not include information from the
segments processed on other computers.
First, evaluate the encoding difficulty (complexity) of your source media. Then, decide
whether or not to allow job segmenting (with the Allow Job Segmenting checkbox at
the top of the Encoder pane). If the distribution of simple and complex areas of the media
is similar throughout the whole source media file, then you can get the same quality
whether segmenting is turned on or not. In that case, it makes sense to allow segmenting
to speed up the processing time.
131 Chapter 8 Finalizing Jobs and Submitting Batches