I had an application where I had to add 12 Axis cameras to an existing install, and I couldn't find documentation on the parameters for the substreams anywhere. I finally got it figured out, and I thought I'd post what worked for me. These settings worked for the P3245-LVE and the P3016. If anybody knows a better way or sees an error, please feel free to point me in a better direction. So, this is what I did:
First, set up the stream profiles in Stream|Stream Profiles. I added two streams, and named them 0 and 1, respectively. I only changed the resolution and frame rate, though there are other settings you can change.

Once I had streams to reference, I set them up in BI, referencing them via parameters.

The parameter settings refer to the stream by name, but it didn't work if I left it at that. I had to include the corresponding resolution, frame rate, etc. The profile links wound up looking like this in BI:
/axis-media/media.amp?Parameters=Name=0&resolution=1920x1080&fps=25&compression=30&videocodec=h265
/axis-media/media.amp?Parameters=Name=1&resolution=640x360&fps=6&compression=30&videocodec=h265
I don't know if this is the best way to do this, but it works. I am now getting my substream at the correct resolution, framerate, etc.:

Again, if anybody knows a better way, I'm all ears. Otherwise, I hope this keeps somebody else for searching in vain for documentation.
First, set up the stream profiles in Stream|Stream Profiles. I added two streams, and named them 0 and 1, respectively. I only changed the resolution and frame rate, though there are other settings you can change.

Once I had streams to reference, I set them up in BI, referencing them via parameters.

The parameter settings refer to the stream by name, but it didn't work if I left it at that. I had to include the corresponding resolution, frame rate, etc. The profile links wound up looking like this in BI:
/axis-media/media.amp?Parameters=Name=0&resolution=1920x1080&fps=25&compression=30&videocodec=h265
/axis-media/media.amp?Parameters=Name=1&resolution=640x360&fps=6&compression=30&videocodec=h265
I don't know if this is the best way to do this, but it works. I am now getting my substream at the correct resolution, framerate, etc.:

Again, if anybody knows a better way, I'm all ears. Otherwise, I hope this keeps somebody else for searching in vain for documentation.