It is well worth understanding how the bus to output remapping works because once you understand how it is designed to work and work with it, it will save you countless visits to the I/O Setup window in the future. In this article, we lift the lid on Mapping Outputs To Busses In the Pro Tools I/O Setup Window.
These Are The Rules
When opening a session or project on a system that has a different I/O Setup, Pro Tools follows these rules to ensure the best possible remapping of the session’s or project’s I/O Setup to the new system…
Output busses are mapped to system Output paths by unique ID if possible.
Pro Tools always maps the Monitor Path of the session or project to the Monitor Path of the current system. It doesn’t matter if the name or format of the output assigned to the Monitor Path is different. It will still map.
Note that if Monitor subpaths exist in the session, Pro Tools uses the best matching format for the system monitor subpaths.
A session will remember if it has been on a system before. So if a mapping fails, and you fix it, those changes will stick and that session will open correctly from then on. This still works even if the session leaves your system and is opened on several other systems before returning.
However, this memory will only last as long as your output stays in the I/O Setup list. If you delete your outputs and recreate them from scratch, the session will lose its memory of them too.
TIP: Because of this we strongly recommend that you do not delete your I/O settings to fix problems when the session you receive from another studio doesn’t map.
It’s fine to rename an output, but if you delete and replace it, the memory will be lost.
This is because outputs contain hidden ID’s, and newly created outputs have new ID’s. But, if you save a copy of your I/O by exporting it as a .pio file, the original outputs can be restored.
TIP: This system memory is great for session templates. If you are regularly swapping sessions with the same people, you can swap the session once, fix any I/O mapping problems, and then save that session as a template. Now, every session generated with that template will have a memory of its future destination.
Output Busses that are mapped to system Output Paths by name and format if there is an exact match. If there is no match between output busses and system output paths, you can manually remap output busses and the good news is that Pro Tools then uses the manually re-mapped unique IDs the next time the session is opened on that system.
Note that the way Pro Tools is designed is not to send audio to the wrong output. This is why if the mapping doesn’t match it will leave it unmapped and mark it by showing the previously mapped bus in italics, along with “(path n/a)” rather than map it to the wrong output.
TIP: If you are swapping sessions regularly with people it makes a lot of sense to agree to a common naming policy for as many other outputs as possible to help Pro Tools map them correctly.
This is even more important when it comes to Dolby Atmos Objects. A common naming policy, or better still a common session template, is going to reduce the trips to the I/O Setup window to remap all the Dolby Atmos Objects.
After configuring the I/O Setup on any given system for a session or project, the settings are then retained with the session file or the project.
It Usually Just Works
Because the way Pro Tools works out the best fit for the Monitor Path to use when the path saved with the session isn’t available, often the only indication that all is well, other than you can hear what you expect to hear, without having to visit the I/O Setup window, is a “>” symbol indicated on the track output selector. To confirm this, the I/O Setup window will also inform you that it is downmixing by indicating a different output width in the Bus tab.
What’s more, when you take that session, that you have been monitoring in stereo and open it back up on your main system, its as if the session had never been via a stereo system, as you can see below, the session remembers the settings for the 7.1 system and automatically reconfigures the output mapping back to the larger channel count enabled system.
Different Playback Engines
This flexibility extends to Playback Engine. From version 12, Pro Tools saves a separate set of I/O Settings for each Playback Engine available on your system, which remembers the inputs, outputs and other hardware-based settings, like Monitor Path and Audition Path for each Playback Engine.
This means you can even change the hardware attached to your system and Pro Tools will automatically reconfigure the I/O settings for each interface configuration you have for that system. With busses retaining their mapping just as if it was a different system.
The I/O Setup Window And Dolby Atmos In Pro Tools
In the next article, The I/O Setup Window And Dolby Atmos In Pro Tools, with the introduction of Dolby Atmos into Pro Tools, Avid developed various features, which extends the fold-down option for going down from 7.1 to 5.1 to stereo and takes it one stage further for Dolby Atmos, handling objects, so that you can continue to work on Atmos Sessions in Pro Tools without needing a Dolby Atmos Renderer.