Performance Overview

PFixer maintains constant communication with Lightroom. PFixer takes input from the user in the form of MIDI commands, keyboard shortcuts and Trackpad commands and sends them to Lightroom as needed. Conversely, PFixer must constantly track the state of Lightroom to operate properly and to provider updates to any MIDI controller hardware that might be present.

This is a two-way process:

PFixer --> Lightroom:

PFixer can send commands to Lightroom as fast as Lightroom can handle it. In fact, PFixer can send commands faster than Lightroom can handle it! It is important to maintain a good balance between performance and responsiveness.

Since a MIDI controller is capable of sending hundreds of updates per second, it could send so many updates that Lightroom would easily become bogged down simply trying to keep up. To solve this problem, PFixer queues up changes and sends them to Lightroom every 0.2 seconds by default but you can fine tune this setting in Preferences: a faster value (smaller number) means PFixer will send changes more often at the expense of a larger History in Lightroom. A slower value (larger number) will help with slower machines by sending updates to Lightroom less often. On a fast machine, a faster value will give the most pleasing experience.

Lightroom --> PFixer:

In the other direction, PFixer polls Lightroom approximately 10 times a second to determine if any changes have been made in Lightroom so that a MIDI controller can be kept up to date. For example, when you move to a new image in Lightroom, PFixer must make note of the change and let the MIDI controller know the new settings. PFixer has no control over Lightroom performance and has to wait for controls to become available inside of Lightroom before it can update the controller. The sliders are initially dim and then become available only when Lightroom is ready. This delay, though it may seems small, can have a devistating effect on perceived performance.

For this reason, it's important to concentrate on getting the best possible performance out of Lightroom on your machine.