If you are akin to using IRScrutinizer, you can generate any code you need from data on the hifi-remote/sony page.
[Link: hifi-remote.com]Try Sony Device 164 and these functions.
54
HD1 input, Component 1, LCD Video 3 (discrete)
55
HD2 input, Component 2, LCD Video 4 (discrete)
56
HD3 input (discrete)
Note that if you search the table on the site for video, there are discretes for Video1-Video9 which may or may not work for you.