I don't know for sure... but here are some thoughts. The difficulty in sending your laptop's audio over lan is that windows does not provide natively a 'channel' or something to listen on that a software developer could use to implement something. In essence, I believe a successful solution has to be either:
- a full-fledged virtual audio driver.
From what I understand, this seems like a complicated fare: Try making a fake driver that will support a plethora of inputs (mp3s, surround games and movies, various bitrates and sample rates, simultaneous applications), while also taking care of encoding, transmitting with low latency, receiving on the other end, that works well and is stable with various version of windows, all that with a damn low profit incentive given only a minority of people would be interested to buy it. Sounds like a bad business plan to me.
Have you tried pulseaudio on windows? Apparently it is cross-platform.
- a real sound card whose driver is designed to allow applications to record its output.
A few years ago, Creative Labs had a pretty good 'what you hear' channel that applications could record on. I remember playing audio over sound card hardware effect such as reverb
and recording it in realtime in my audio software using this "what you hear" channel. Technically, Shoutcast will be able to select this channel as the input and stream all your laptop sound. I don't have a Creative card anymore, so I don't know how well this works nowadays. Plus, I imagine you want to use your laptop's built-in audio, which likely would not have that feature, but an external Creative Audigy might!
- Audio Over IP / Audio Over Ethernet dedicated hardware.
More expensive and complicated than you current best bet: a physical audio cable to your main computer....
Plug the output of your laptop back into your laptop's linein with a mini <1 ft cable. Without a doubt, shoutcast can stream your sound card's line-in. The downside with this method is reduced audio quality with 2 superfluous DAC/ADC.