Apple Compressor (4.0) - Manual (Page 249)

Chapter 8 Use Apple Qmaster to set up a distributed processing system 249
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 choose 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. Because the nodes are working in parallel, the job is finished sooner than it would be
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. If your source media file
contains an uneven distribution of complex scenes (e.g. segments of mostly static material mixed
with segments of large amounts of action), job segmenting can result in uneven quality. Multi-pass
encoding can only be fully optimized if all the passes are performed on the same computer.
Note: The Allow Job Segmenting checkbox affects only the segmenting of individual jobs (source
files). If you submit batches with multiple jobs, the distributed processing system will continue to
speed up processing by distributing (unsegmented) jobs, even with job segmenting turned off.
For more information about variable bit rate (VBR) encoding, see MPEG-2 Encoder pane on
page 89. For more information about the Apple Qmaster distributed processing system, see
Distributed processing overview on page 215.
Example: Submit After Effects batches with the Generic Render command
The following template is a good starting point for using the Generic Render plug-in to render
After Effects projects:
[EXECUTABLE] ‑project [INPUT] ‑comp "Comp 1" ‑RStemplate "Multi‑Machine Settings"
‑OMtemplate "Multi‑Machine Sequence" ‑s [START FRAME] ‑e [END FRAME]‑output
[ITEM]/test[####].psd
Where:
[EXECUTABLE] = /Applications/Adobe\ After\ Effects\ 6.5/aerender
[INPUT] = /Volumes/Media/Projects/AEProjs/Wine_Country/QMproject.aep
[START FRAME] = 0
[END FRAME] = 544
[STEPS] = Not Used
[ITEM] = /Volumes/Media/Projects/AEProjs/Wine_Country/output
In the example above, “ Comp 1 ” is the name of the composition in your After Effects project and
“ test[####].psd ” is the output filename. Because you can’t select an output filename in the
template’s Item field before the output has been rendered, first select the output directory, and
then add the filename to the Item field.
Note: In the example, /Volumes/Media/Projects/ is the shared volume. If you create the project
on a computer that isn’t using the shared volume, copy the project to the shared volume, open
After Effects, and relink any missing media.