Where does D/A conversion take place?

Forum English (EN)
#1

Hi,

Does anyone know what data is actually sent to the DLNA remote device?
If I choose PCM quality in the settings, is the original file sent to the remote device and decoded there by the DAC or is the file being decoded by the local PC sound card, leading to a lower sound quality at the remote device?

Thanks,
Ben

#2

WASAPI loopback capture is used (see e.g. https://msdn.microsoft.com/de-de/library/windows/desktop/dd316551(v=vs.85).aspx). Basically every millisecond the sound output of the local sound-card gets captured, encoded and then sent to a network device.

#3

Thanks.
Is there any software that streams the digital file directly, without decoding and encoding it again on the PC?

#4

Having read Slash’s link on WASAPI it looks like the audio stream is captured before the sound card converts it to analogue audio. I hope this means if I play a lossless audio track, this is then captured, lossless, and sent all the way to my Dennon Reciever where lossless audio is converted to Analogue sound?!?

Perhaps someone could clarify?

Note that Windows Media player can send audio files to your receiver as long as the receiver is able to decode them. This usually means files without DRM, such as FLAC. Again, your reciver has to be FLAC compatible. The beauty of SWYH is that it captures from applications such as TIDAL - which does not support DLNA for some strange reason.

#5

again:
“Basically every millisecond the sound output of the local sound-card gets captured, encoded and then sent to a network device.”

SWYH records the current system sound via WASAPI as a tiny packet every millisecond (and uses a damn busy loop to do nothing in between, hence my thread “fix for 100% cpu usage”), encodes it and then adds it to the network stream. Whatever format / quality your sound-card outputs will be used to encode the sound stream. The source does not matter or rather the input will not be bit-wise the same as your input file (e.g. the sampling rate will be only 1KHz instead of around 44KHz+).
You can’t compare the normal dlna/upnp play to behavior windows media player uses, since they just send a copy of the file to the receiver. No encoding / decoding takes place.

SWYH and any other software (WASAPI is the only way left to record system sound btw) that captures the system sound can never have the same quality as the source file…