Audio output fidelity will be dependent upon both the source material and ultimately constrained by the capabilities of the output device.
- Apple AirPlay devices will always be in 16-bit 44.1kHz format, even when digitally connected to an AV Receiver. This is a limitation of AirPlay. However, it has been observed that the DACs in the wall-wart generation of AirPort Expresses aren't that good. You'll likely get better audio quality if you digitally connect the AirPort Express to an AV Receiver via a mini-Toslink to Toslink optical cable so that the AV Receiver's DAC is used instead.
- Sonos devices are limited to a maximum of 16-bit 48kHz, even when digitally connecting a "Sonos Connect" to a high quality DAC. This is a combination of a hardware limitation and a Sonos streaming protocol limitation.
- Google Cast devices are currently limited to 16-bit 44.1kHz. However some devices including, the new "Chromecast Audio" devices, have 24-bit 192kHz DACs. So hopefully this higher resolution will be supported by audio|acacia in the future.
- "This Browser" audio end-points are currently software constrained by audio|acacia to 16-bit 44.1kHz.
- Computer Soundcard audio end-points vary drastically in the quality of their DACs, generally with capabilities from 16-bit 44.1kHz to 32-bit 384kHz, so perceived audio fidelity will vary.
"I can't tell if I'm losing fidelity by using your software. Is there a way to monitor bitrate?"
Unfortunately there is not currently a way to monitor/view the output audio fidelity, but you can vote on such a feature request here. But I guess if you can't tell, that's a good thing right? :)