[FFmpeg-user] Stop ffmpeg setting up all RTSP streams

[Spockter]

I am attempting to read video from a webcam that supports RTSP. FFmpeg fails 
to read the video and reports the error:

method SETUP failed: 503 Service Unavailable

The webcam supports 5 streams according to the RTSP DESCRIBE command response 
and when FFmpeg starts it attempts SETUP on each of the 5 streams. 
Unfortunately, the SETUP command fails on the 3rd stream with the above 503 
error. This is clearly a bug with the camera software, but it stops FFmpeg 
using any of the available streams.

I only need the first and second streams (video + audio). Ideally, I would 
like FFmpeg to only setup and use those streams thus avoiding the failure with 
the 3rd stream. Is there a way to control which streams it attempts SETUP on?

Alternatively, is there a way to force FFmpeg to ignore any streams that fail 
to be setup?

FYI, VLC is able to play the content from the webcam. I can see from a packet 
capture that it also attempts SETUP on all 5 streams and it too gets the 503 
error for stream 3 (as well as for streams 4 and 5). However, it ignores those 
errors and continues with the working streams 1 and 2.

Thanks for any help you can give.