I have definitely had 320x180 encoding working.
Specifically, this 62 megabyte video found on this page: http://www.bigbuckbunny.org/index.php/download/
With the title: "IPod 5G 320×180, 62 MB"
Maybe there are other factors or variables at play.
You might try sample_decode/sample_encode on the Big Buck Bunny video to convince your self that is not a
(I have gone through this process.)
Please let us know what you find out.
Thanks for verifying that it is supported.
When I read your post, I realized what was going on.
I need to use a custom SPS/PPS.
The SPS that I was using clashed with the input parameters.
Now the custom SPS's match the encoding parameters and all is well.