Streaming fails to initialise

[tomorch]

Hi. I've noticed that RA's built-in streaming functionality doesn't appear to be working with Swanstation. Having set the renderer to Software I attempt to Start Streaming via the Quick Menu and nothing happens. However checking the logs I can see the following:

[INFO] [Recording]: Custom timing given: FPS: 59.82, Sample rate: 44100.00
[INFO] [Recording]: Recording to udp://127.0.0.1:56401 @ 256x239. (FB size: 1024x512 pix_fmt: 0)
[ERROR] [Recording]: Failed to start recording.

My custom streaming configuration is as follows (which is working for all the other cores I use):

vcodec = libx264
acodec = libmp3lame
threads = 7
video_preset = fast
video_tune = animation
audio_global_quality = 80
sample_rate = 44100
format = flv